Ironhead Cam Performance Opinion

[chevelle]

I have done quite a bit of dyno experimentation using many different cams,carbs,exhaust on my stock 900 and my 4&5/8" stroked 900 as well as others but I will only touch on the above 2 bikes here.

(I have zero stock 1000 experience, but can only assume the same info applies to a stock 1000.)

Let me emphasize all this info is for stock 900's, bigger engines are a different story.

I have come to realize the guys at the factory knew their shiet,
and long before computer technology and digital dyno setups.

I used to think of the stock P cams as just that, stock P cams.
I think it has alot to do w/ the catalogs w/ lists of aftermarket cams, there must be a better, higher performance cam for my bike right? In some performance applications yes I agree.
But think back to days before govt mandates and emissions, what would be the reason for the engine designers, builders to use a sub par camshaft... and these were the days before the screaming chicken (HD performance brand)
I have not tested all the aftermarket cams of course but as of yet I have not found a bolt in cam that performs as well as the stock P in a stock engine.
I will clue you in if I do.....

To elaborate some on the "performance increases" guys feel once a different cam grind (or other performance change) is installed.
This is not meant to point fingers or call anyone a liar of course, just to mention a phenomenon I have felt myself as well.
I have bounced this off of a couple very experienced performance guys as well, they feel the same way.

I am begining to realize this situation; that is when guys install a so called hotrod cam
and the engine now runs with a "different" characteristic or rides with a "different" feeling.
This feeling immediately tells the rider... WoW this is a definite improvement.
But just because it feels different does not alway mean better performance.

Some times also when a cam or exhaust or whatever is changed, in effect they are often (not always) losing power in certain critical crusing rpm.
So your crusing around with less power, but when you twist the throttle to say pass a car, you feel that rush that the "on cam" power gives you.
Any guys that have ridden 2 stroke dirtbikes, know what the "on pipe" feeling is, and this situation of the hotrod cam feels much the same.
It's a total false sence of power that is induced from the flat spot you were crusing around in, even when your bike is tuned as best a DIY'er can.
I have a sneaking suspicion that most all performance cams give this false sence of power, in a 900 that is.

Dont get me wrong, I know there are many improvements that can be made and these are true genuine improvements even w/o a dyno graph, but on these 900's they were close to optimal from the factory.
If you do not have a a before dyno run or ET, and a after to compare them to then do yourself a favor and stick w/ the P cams, because I have the graphs and so far have found no extra power in swapping cams.

Exhaust has been by far the best opportunity I have found for increasing power and torque.

Just what I have learned so far on these dinosaurs if anyone cares.
How many of you think im CRAZY ?????


900 thread: http://xlforum.net/vbportal/forums/s....php?t=1222275

Stroker thread: http://xlforum.net/vbportal/forums/s....php?t=1265958

2:1 thread: http://xlforum.net/vbportal/forums/s....php?t=1367025

[shovithead]

No, you are not crazy. Even though I do not do dyno work, i do build a bike or two and a lot of 900's have been through my shop, not to mention my own personal collection. You can make them faster, but a increase in cid is necessary, short of a quarter horse here and there. Pipes, are a better hp booster than carbs or cams. Even a sprocket swap can get you closer to what you desire. Remember, these bikes were built to compete with the british twins that were kicking the K's ass. So they built them to run, and run good. When the big twin guys mess with me, i say, i can beat them to the beer store. They say they can go to California much more comfortable than me. I tell them, how often do you go toCalifornia? And, how many times do you go for beer? Sportsters are fast, in the HD world.

[Dragstews]

.
.
.
....Yep.......There's No Replacement for Displacement......

Aaaaaaa unless it's blown...!! "If it's not Blown, It's gotta Suck"

[Threadkiller]

I'm no Sporty lover, but I can pay my respects....."Sportsters! Blowing away Big-Twins since 1957"

[texas rattler]

77 was a great year for sportys, add some p cams and carb/pipes and youl have a honkin sporty.

[Jtw79]

So if you were to stroke it would you run P cams or? You have my attention with your dyno pulls to prove it.

[Dragstews]

Stroke's like more duration ...........

[Jtw79]

That's what I would guess. Longer stroke= more volume to fill so you need to keep the valve open longer. So whose cam would have the specs to fit the bill?

[FeHd]

And makes it able to kick over.

[Dragstews]

Originally Posted by Jtw79

So whose cam would have the specs to fit the bill?

Aaaaa...Think there's a thread on here talking much about cams...

[Jtw79]

Okay you got me I need to search.

[Dragstews]

Originally Posted by Jtw79

Okay you got me I need to search.

I was going to ask Egor the name of it....But he's still out to lunch..

[Monte03]

Just what I have learned so far on these dinosaurs if anyone cares.
How many of you think im CRAZY ?????

Not Crazy at all Chevelle, you are a street rider that also has Dyno access, the info you are gathering is very interesting, looking forward to the Sifton 'H' cam reveiw..
I had changed my stock P Cams with Harley PB cams and you are correct, it changed the WoW factor (for a 55"er anyway) to further up the scale... an around Town stoplight to stoplite Sportster may be better served with the P .400 cams but dedicate funds on improving head flow with a good Porter..
Hey I remember buying a Lake Injector Carb when I was 21 thinking it's the new best hot setup.. we are all quick to search for the magic bullet only to find that there there are very few..
Monte

[chevelle]

Originally Posted by Monte03

Not Crazy at all Chevelle, you are a street rider that also has Dyno access, the info you are gathering is very interesting, looking forward to the Sifton 'H' cam reveiw..
Monte

I will let you know when I run the H's.
I'm hoping there will be some increase..... I'm not betting on it though.
Don't hold your breath.....

[Dragstews]

Originally Posted by chevelle

I will let you know when I run the H's.
I'm hoping there will be some increase..... I'm not betting on it though.
Don't hold your breath.....

If it wasn't a Huge undertaking to do a few dyno runs with the stock heads and then throw on a set that has the XLR valves and some port work...
Would love to see what the chart says on that....

This is pretty much what Branch did with his XR Hop-Up book...
Shoot....After pipes, carbs and cams. He even went to the trouble and time to add a windage tray in the sump for a few runs to see....

[chevelle]

Originally Posted by Dragstews

If it wasn't a Huge undertaking to do a few dyno runs with the stock heads and then throw on a set that has the XLR valves and some port work...
Would love to see what the chart says on that....

This is pretty much what Branch did with his XR Hop-Up book...
Shoot....After pipes, carbs and cams. He even went to the trouble and time to add a windage tray in the sump for a few runs to see....

I may do just that on my 4.625" stroker.
I have a set of Branch heads, and a set of stock to compare the two.
Although I believe even my stroker will be over ported w/ the 1.750" exh and 1.935" Int valves.
Again, this may be another lesson learned as far as bigger doesent always mean better.

[Dragstews]

.....Dyno Runs.....

Had the Buell at Daytona Bike Week a few years ago...

Alot of the portable Dyno's was in attendance....

Did a run at Carl's Speed shop...Showed great numbers on the chart....

Same night a few hours later went down to Gilly's Pub in New Symera and did another run....Shoot the number's was higher by 12 Horses .....

Pretty cool, I thought going 20 miles down the road and finding more Horse Power....



.....The Air was Heavy down there......

[chevelle]

Originally Posted by Jtw79

So if you were to stroke it would you run P cams or? You have my attention with your dyno pulls to prove it.

Im not so sure any cam will perform better than the P's on my small stroker either.

Check the stroker thread I posted.
You will see the P's are better than the PB+'s, that goes for both the stroker and the stocker.
I have yet to do alot of cam swaps on the stroker.
I ran some Andrews X cams and they did not perform well either (although I never posted runs), too much duration.

My stroker is also only 3' bore, I believe the larger bores of the 1000 may change things some.

[Jtw79]

So after reading all your findings on XL forum with Dyno graphs I am reluctant to change my cams, but more interested in stroking the motor. Already built a 2-1 with Supertrapp discs in a megaphone pipe. Wish I lived near you so I could see what my motor is doing or not doing on the Dyno. Really like all the info you are posting, keep it up.

[Jtw79]

So Chevelle have you had a chance to bolt on the Branch heads to see what they will do? Thanks!

[J_F_Byrd]

Originally Posted by chevelle

I have done quite a bit of dyno experimentation using many different cams,carbs,exhaust on my stock 900 and my 4&5/8" stroked 900 as well as others but I will only touch on the above 2 bikes here.

(I have zero stock 1000 experience, but can only assume the same info applies to a stock 1000.)

Let me emphasize all this info is for stock 900's, bigger engines are a different story.

I have come to realize the guys at the factory knew their shiet,
and long before computer technology and digital dyno setups.

I used to think of the stock P cams as just that, stock P cams.
I think it has alot to do w/ the catalogs w/ lists of aftermarket cams, there must be a better, higher performance cam for my bike right? In some performance applications yes I agree.
But think back to days before govt mandates and emissions, what would be the reason for the engine designers, builders to use a sub par camshaft... and these were the days before the screaming chicken (HD performance brand)
I have not tested all the aftermarket cams of course but as of yet I have not found a bolt in cam that performs as well as the stock P in a stock engine.
I will clue you in if I do.....

To elaborate some on the "performance increases" guys feel once a different cam grind (or other performance change) is installed.
This is not meant to point fingers or call anyone a liar of course, just to mention a phenomenon I have felt myself as well.
I have bounced this off of a couple very experienced performance guys as well, they feel the same way.

I am begining to realize this situation; that is when guys install a so called hotrod cam
and the engine now runs with a "different" characteristic or rides with a "different" feeling.
This feeling immediately tells the rider... WoW this is a definite improvement.
But just because it feels different does not alway mean better performance.

Some times also when a cam or exhaust or whatever is changed, in effect they are often (not always) losing power in certain critical crusing rpm.
So your crusing around with less power, but when you twist the throttle to say pass a car, you feel that rush that the "on cam" power gives you.
Any guys that have ridden 2 stroke dirtbikes, know what the "on pipe" feeling is, and this situation of the hotrod cam feels much the same.
It's a total false sence of power that is induced from the flat spot you were crusing around in, even when your bike is tuned as best a DIY'er can.
I have a sneaking suspicion that most all performance cams give this false sence of power, in a 900 that is.

Dont get me wrong, I know there are many improvements that can be made and these are true genuine improvements even w/o a dyno graph, but on these 900's they were close to optimal from the factory.
If you do not have a a before dyno run or ET, and a after to compare them to then do yourself a favor and stick w/ the P cams, because I have the graphs and so far have found no extra power in swapping cams.

Exhaust has been by far the best opportunity I have found for increasing power and torque.

Just what I have learned so far on these dinosaurs if anyone cares.
How many of you think im CRAZY ?????


900 thread: http://xlforum.net/vbportal/forums/s....php?t=1222275

Stroker thread: http://xlforum.net/vbportal/forums/s....php?t=1265958

2:1 thread: http://xlforum.net/vbportal/forums/s....php?t=1367025

I have never understood why anyone would want a hot cam in any harley. To me, the entire point of an HD engine, is instant off-idle torque, in an engine that's main attribute, is that it's much happier at lower rpms. To trade one foot pound of that torque, for additional horsepower in a higher rpm range, isn't something I would ever want. I've ridden lots of dirt bikes, and built high winding small block chevys. If you want lots of high rpm horsepower, why would you ever want a harley in the first place. If you like down shifting, get a sport bike.

So no, you're not crazy. I couldn't agree more. If anyone ever issued cams for evo sportsters which created more low-end torque, even at the expense of power over 4.500 rpm, I'd be the first in line to order them. I'd much rather have more torque that's useful where I spend 99 percent of my time in the rpm range.

[chevelle]

Originally Posted by Jtw79

So Chevelle have you had a chance to bolt on the Branch heads to see what they will do? Thanks!

I set up my stock heads to run some Sifton H cams.
Its back together, but won't be able to run it until tomorrow.
I will let you know what the outcome is.
Cross your fingers.

Hopefully this post won't be deleted.
My last few threads/ posts have disapeared.

[kickstarts]

Originally Posted by J_F_Byrd

I have never understood why anyone would want a hot cam in any harley. To me, the entire point of an HD engine, is instant off-idle torque, in an engine that's main attribute, is that it's much happier at lower rpms. To trade one foot pound of that torque, for additional horsepower in a higher rpm range, isn't something I would ever want. I've ridden lots of dirt bikes, and built high winding small block chevys. If you want lots of high rpm horsepower, why would you ever want a harley in the first place. If you like down shifting, get a sport bike.

So no, you're not crazy. I couldn't agree more. If anyone ever issued cams for evo sportsters which created more low-end torque, even at the expense of power over 4.500 rpm, I'd be the first in line to order them. I'd much rather have more torque that's useful where I spend 99 percent of my time in the rpm range.

I agree.

High RPM performance cams and drag pipes are for the strip and Bonneville. I want all my power from idle to below 5,000 where I do all my riding. I'm willing to bet I've never spun one of my Sportsters over 5,000 RPM and if I have, it was only for 3 seconds and it was probably because I missed a shift. I want a cam, more precisely, that gives me the power and torque from idle to 3,500 and an exhaust system that helps the engine develop and apply that power all at the low to mid range. To me that means a muffler system. Every dyno graph I've seen with drag pipes has a huge hole somewhere in the off idle to 3,500 range.

With these big cams and drag pipes it just seems that your average street rider is spending money to lose power and torque and gas mileage.

[kickstarts]

I just looked through your links. Lots of great info, thanks for posting it.

The most interesting part I thought was the stroker exhaust tests. The 2 into 1 test you did was very impressive. I'd love to see the difference in your 2 into 1 setup and a set of drag pipes. After gaining so much with the 2/1 and the change in the power band, I'm gonna take a serious look at a 2/1 system.

[kickstarts]

Originally Posted by J_F_Byrd

I have never understood why anyone would want a hot cam in any harley. To me, the entire point of an HD engine, is instant off-idle torque, in an engine that's main attribute, is that it's much happier at lower rpms. To trade one foot pound of that torque, for additional horsepower in a higher rpm range, isn't something I would ever want. I've ridden lots of dirt bikes, and built high winding small block chevys. If you want lots of high rpm horsepower, why would you ever want a harley in the first place. If you like down shifting, get a sport bike.

So no, you're not crazy. I couldn't agree more. If anyone ever issued cams for evo sportsters which created more low-end torque, even at the expense of power over 4.500 rpm, I'd be the first in line to order them. I'd much rather have more torque that's useful where I spend 99 percent of my time in the rpm range.

Did you look at the dyno results for the exhaust testing he did here? Very interesting.

2:1 thread: http://xlforum.net/vbportal/forums/s....php?t=1367025

[chevelle]

Originally Posted by kickstarts

I just looked through your links. Lots of great info, thanks for posting it.

The most interesting part I thought was the stroker exhaust tests. The 2 into 1 test you did was very impressive. I'd love to see the difference in your 2 into 1 setup and a set of drag pipes. After gaining so much with the 2/1 and the change in the power band, I'm gonna take a serious look at a 2/1 system.

Glad you enjoyed the info, I will update as I can.
Im w/ you guys, if I can get additional power in the 2000-4000 range, thats what its all about for me.

The 1st 2:1 test I did was on my 4&5/8" stroker w/o muffler.
The 2nd 2:1 test was on my stock 900 w/ 22" supertrapp.
So it seems to work equally well on either bike.
I borrowed the supertrapp from another bike, once I get a dedicated muffler I am going to be doing more some more research and fine tune it.

[J_F_Byrd]

Originally Posted by kickstarts

Did you look at the dyno results for the exhaust testing he did here? Very interesting.

2:1 thread: http://xlforum.net/vbportal/forums/s....php?t=1367025

A big gain up to 5200 rpm. Looking at the way you merged the pipes, I would not have expected it. I wonder what your results would be with a 2 into 2 system of equal length, with good mufflers and a balance pipe a-la Evo.

[FeHd]

I dont have any dyno results, but when I put this homemade 2-1 with a baffled reverse cone on my 74, along with Andrews R5 cams it really came alive. My heads have big valves, 1.75 and 1.92, and a Branch port job. I look forward to seein how it runs with dual plugs and the roller rockers.

[mrmom9r]

Chevelle, could not agree more about P cams.

My story: year 1975, 1969 xlch, 77 cu. in ( 3 1//4 x 4 5/8) , branch heads. very light street bike. no slick, no wheelie bar.

Originally put together w/ Sifton minus -minus cams : et 12.19

sold by andrews on idea for more cam -v9 (i think) felt very fast ,big "hit" @ about 4,000 to 7,000 :et 13.05

go back to basics, stock P cams for a base line. et 11.49

Yes they do work. Learned my lesson about total gross HP vs. peak HP.

[Dr. Benway]

Given that Ironheads are such performers, (one guy on here somewhere claimed they could own a Hayabusa), better pushrod angle, etc. how come nobody like S&S is making repop Ironhead motors like they do with knuckles, pans, etc?

Or are they?

[kickstarts]

Originally Posted by Dr. Benway

Given that Ironheads are such performers, (one guy on here somewhere claimed they could own a Hayabusa), better pushrod angle, etc. how come nobody like S&S is making repop Ironhead motors like they do with knuckles, pans, etc?

Or are they?

I don't know if anyone is claiming that Ironheads are great performers, just that the original P cams do exactly what they were supposed to do originally and all the claims about the aftermarket cams fall flat or over cam your Ironhead to the point of being pointless on the street.

Someone made replacement Ironheads years ago but I haven't seen any since and I don't think there's a market for them. The Ironhead heads don't crack and they seem to last forever...plus it's just a girls bike anyway, a stepping stone to a real man's bike.

I also remember someone making late Ironhead aftermarket cases but not anymore.

[Dragstews]

Originally Posted by kickstarts

It's just a girls bike anyway, a stepping stone to a real man's bike.

........................................

[kickstarts]

Originally Posted by Dragstews

........................................

Nope, not this shit again. See my little "wink". Just being facetious. Thought I'd get it in first.

[FeHd]

Originally Posted by Dr. Benway

Given that Ironheads are such performers, (one guy on here somewhere claimed they could own a Hayabusa), better pushrod angle, etc. how come nobody like S&S is making repop Ironhead motors like they do with knuckles, pans, etc?

Or are they?

That guy was me, and if your going to reiterate negatively what I said, tell all of what I said, not just what you wanted to hear. What I said was in an impromptu from the light streetrace a good runnin ironhead ridden with skill will jump a Hayabusa from the hole dam near everytime. This is based on a couple of facts. One, I do it all the time. Two, Huyabusa's are a real bitch to launch hard due to the high center of G, short swingarm, and relatively inexperienced at launching riders. I noticed that you failed to mention that I also said one set up right with a good rider will leave a ironhead for dead from the hole and definitely in the Q. I also ride for a friend a 69 based ironhead dragbike that runs in the mid 9's, and it has beaten many more Huyabusa then it hasnt.

[Dr. Benway]

"one guy on here somewhere claimed they could own a Hayabusa"

How was that negative? Because I didn't include all the preconditions?
Sorry for the incomplete reporting, but it simply wasn't the main thrust of my question, which was about repop IH motors.

...and if Jesse doesn't know, they're not out there.

[Dragstews]

Originally Posted by Dr. Benway

.

...and if Jesse doesn't know, they're not out there.

Who.....Me...????

==========================================

Guys.... This talk is about cams.

What is best suited for your state of motor build....AND what YOU are after from it...

How are you going to be riding the bike, what rpm are to going to want the most to happen...
A Road Race cam wouldn't be right for a 1/4 drag bike. Or the other way around....

......Choice are many.......

[Monte03]

For what is is worth, their is a Set of Early Sifton .475 HH 'Magneto' Scorpion Cams on Ebay now, I had a set many years back in a 900cc with R Valves and 10:1 MC pistons, they were great all around cams....

[chevelle]

Update:

http://xlforum.net/vbportal/forums/s...1222275&page=6

[choptop37]

damn...you cant post the results fast enough...keep em coming!

[kickstarts]

Great thread, very interesting.

[Jtw79]

Chevelle, is that a -H hustler cam you tested? That's what I would call bolt in power. Now the hunt for one begins.

[kickstarts]

Originally Posted by Jtw79

Chevelle, is that a -H hustler cam you tested? That's what I would call bolt in power. Now the hunt for one begins.

He'll still have to recheck his results with his P cams against the changes he made before the latest dyno run. I'm also curious to see if there's an increase in the P results.

[kickstarts]

Originally Posted by chevelle

Update:

http://xlforum.net/vbportal/forums/s...1222275&page=6

You said you tried .008 lash on the cams. What do you mean by that? Tightened the pushrods? How do you measure this?

[Jtw79]

That is a good question Kickstarts. I can't think how Chevelle is measuring that either.

[kickstarts]

Originally Posted by Jtw79

That is a good question Kickstarts. I can't think how Chevelle is measuring that either.

It takes me 5 or 6 goes just to get them to spin at zero lash with my greasy dial indicating fingers...and would that .008 measurement be hot or cold...

[chevelle]

Originally Posted by kickstarts

It takes me 5 or 6 goes just to get them to spin at zero lash with my greasy dial indicating fingers...and would that .008 measurement be hot or cold...

Lashing is loosening, for lashing it doesn't matter hot or cold, your just marking the ball socket adjuster (where it was previously zero lash) and turning adjuster down (in this case 1/4 turn)
The tappet thread pitch is 32 TPI.
Works out to be about .031" every complete revolution, so 1/4 turn is about .008" , +/- of course.
You see?

[panhead_pete]

Originally Posted by chevelle

Lashing is loosening, for lashing it doesn't matter hot or cold, your just marking the ball socket adjuster (where it was previously zero lash) and turning adjuster down (in this case 1/4 turn)
The tappet thread pitch is 32 TPI.
Works out to be about .031" every complete revolution, so 1/4 turn is about .008" , +/- of course.
You see?

Cunning Plan Lord Blackadder.

[kickstarts]

Originally Posted by chevelle

Lashing is loosening, for lashing it doesn't matter hot or cold, your just marking the ball socket adjuster (where it was previously zero lash) and turning adjuster down (in this case 1/4 turn)
The tappet thread pitch is 32 TPI.
Works out to be about .031" every complete revolution, so 1/4 turn is about .008" , +/- of course.
You see?

I learn something new every day. Gotcha.

[FeHd]

How much duration do you think you lose in degrees with the .008 lash? These are intersesting figures, so much so I am thinking of putting the original P's back in my 74 just to run a comparision to the R5's I currently have. The PO had the big exhaust valve installed and a Branch porting, and I am running roller rockers, though the ratio is not changed, and grooved 10.1 Wiscoes with dual plug heads. The R5's have more lift then stock, but the same duration, I am quite curious now, the seat of the pants with them was quite noticeable, especially after 3500. Thanks for the research, very interesting reading.

[Monte03]

Originally Posted by Jtw79

Chevelle, is that a -H hustler cam you tested? That's what I would call bolt in power. Now the hunt for one begins.

I can safely add my BS as I sold the H Cams to Chevelle, No these H cams were years prior to the 'named' Cams by Sifton, even the spec paper is Typed Out like it was mid 60's..
What Chevelle is doing is bringing to light how the slightest change in the top end can have vast results, awesome stuff,
Who on these forums have not fell victim to a marketing add for THE BIGGEST AND BADDEST PART, these tests prove that HD did know what they were doing when they made the 1966 P cam standard, also how the best tuning is done by first on the Dyno and then Seat of the Pants road test, I can add that if a street bike and you on not happy on the road then 'WTF', I added PB cams to my 69 CH and was not too happy with moving the range up the RPM scale but the bike pulls and I got used to it.. all good stuff Chevelle!
Monte

[kickstarts]

Originally Posted by FeHd

How much duration do you think you lose in degrees with the .008 lash? These are intersesting figures, so much so I am thinking of putting the original P's back in my 74 just to run a comparision to the R5's I currently have. The PO had the big exhaust valve installed and a Branch porting, and I am running roller rockers, though the ratio is not changed, and grooved 10.1 Wiscoes with dual plug heads. The R5's have more lift then stock, but the same duration, I am quite curious now, the seat of the pants with them was quite noticeable, especially after 3500. Thanks for the research, very interesting reading.

If the .008 lash decreases the duration, the same lash would decrease the lift ultimately adding only .008 over the P cams, correct? You said the exhaust duration was basically the same as the P cams so that would equal out to being an exhaust came with a shorter duration and an increased lift of only .008 over the P exhaust cams.

The intake cams you described as having a longer, gentler opening ramp so with the gains from those cams you saw on the dyno it must be the difference in timing(if any compared to the P cams) and the duration that made the difference and not necessarily the lift because it was only .008 more after the lash adjustment?

Or am I talking out of my ass again...

[FeHd]

Originally Posted by kickstarts

If the .008 lash decreases the duration, the same lash would decrease the lift ultimately adding only .008 over the P cams, correct? You said the exhaust duration was basically the same as the P cams so that would equal out to being an exhaust came with a shorter duration and an increased lift of only .008 over the P exhaust cams.

The intake cams you described as having a longer, gentler opening ramp so with the gains from those cams you saw on the dyno it must be the difference in timing(if any compared to the P cams) and the duration that made the difference and not necessarily the lift because it was only .008 more after the lash adjustment?

Or am I talking out of my ass again...

Yes, the lift would also be .008 less. The R5's have a lift of .445 with a duration of 254 @ .053", and 306 @ .020", where the P has the same duration @ .053 and a little less with 294 @ .020. With .008 lash, the lift would be .437 on the R5.
I am curious to see if the .008 lash vs no lash makes the same difference as it did for Chevelle on my 61" engine.

[kickstarts]

Originally Posted by FeHd

Yes, the lift would also be .008 less. The R5's have a lift of .445 with a duration of 254 @ .053", and 306 @ .020", where the P has the same duration @ .053 and a little less with 294 @ .020. With .008 lash, the lift would be .437 on the R5.
I am curious to see if the .008 lash vs no lash makes the same difference as it did for Chevelle on my 61" engine.

So with increased lash on your R5's, you'd end up with .037 lift over the P cams and a shortened duration. If they act as Chevelle's dyno says, you would be expecting increased bottom end numbers, wouldn't you?

Is it the shorter duration and higher lift that creates low end numbers as compared to cams that come on in the higher RPM range?

[chevelle]

Glad to see I'm not the only one interested in this stuff.
DR DICK from the XLforum has clued me into a lot of this cam specific stuff.
Lashing the cams .008" is very minor.
Yes it makes the lobe slightly smaller overall, it eliminates any minor cam variences at very low lift.
I have noticed by graphing lobes that the first few thou is where the individual lobes in a set vary.
Lashing is the only thing we can do to see if engine responds differently.
You cannot make lobe larger obviously.
Most importantly, say your cams are opening just too soon, causing you to lose all your power, lashing even slightly may stop/help that.

[kickstarts]

Very interesting stuff. I like to hear people's opinions but it's even better when you can verify or disprove opinions on a dyno screen.

People love to talk about drag pipes(length, diameter, bends) but when you see the horror on the dyno screen, well, it's horrible.

Keep it coming whenever you get the chance!

[chevelle]

Originally Posted by FeHd

How much duration do you think you lose in degrees with the .008 lash? These are intersesting figures, so much so I am thinking of putting the original P's back in my 74 just to run a comparision to the R5's I currently have. The PO had the big exhaust valve installed and a Branch porting, and I am running roller rockers, though the ratio is not changed, and grooved 10.1 Wiscoes with dual plug heads. The R5's have more lift then stock, but the same duration, I am quite curious now, the seat of the pants with them was quite noticeable, especially after 3500. Thanks for the research, very interesting reading.

I'm going to be installing a set of R5's next, hopefully w/ in the next couple weeks.

[FeHd]

Originally Posted by chevelle

I'm going to be installing a set of R5's next, hopefully w/ in the next couple weeks.

Excellent, I look very forward to your findings. The good Dr is a plethora of info for sure, I do miss his readings. But I was banned for life by a mod there, so here I lurk now, lol.

[FeHd]

Originally Posted by kickstarts

So with increased lash on your R5's, you'd end up with .037 lift over the P cams and a shortened duration. If they act as Chevelle's dyno says, you would be expecting increased bottom end numbers, wouldn't you?

Is it the shorter duration and higher lift that creates low end numbers as compared to cams that come on in the higher RPM range?

I am expecting a bit of bottom end increase, along with some on top also. I want my cake and eat it too, lol. Increasing the lift without increasing the duration or overlap will generally give more power across the board, but it is limited. In order to do that the valve acceleration is increased, and the ramps are steeper, which is harder on the valvetrain. This and the fact the ironhead has such a large included angle on the valves is why I spent the dough for roller rockers. My guides are thanking me.

[FeHd]

Originally Posted by chevelle

Glad to see I'm not the only one interested in this stuff.
DR DICK from the XLforum has clued me into a lot of this cam specific stuff.
Lashing the cams .008" is very minor.
Yes it makes the lobe slightly smaller overall, it eliminates any minor cam variences at very low lift.
I have noticed by graphing lobes that the first few thou is where the individual lobes in a set vary.
Lashing is the only thing we can do to see if engine responds differently.
You cannot make lobe larger obviously.
Most importantly, say your cams are opening just too soon, causing you to lose all your power, lashing even slightly may stop/help that.

Oh no, I could read about this stuff all night. I'd much rather talk about this then rigid frames and springer forks. Here is some more good reading on the subject.
http://www.mechadyne-int.com/vva-ref...-emissions.pdf

[mrmom9r]

More than .008" of lift is being lost. The rocker ratio is 1.43 : 1 meaning
.008" x 1.43 = .011" of lift is lost.

Not that that means much. Just the facts, ma'am.

[chevelle]

Originally Posted by mrmom9r

More than .008" of lift is being lost. The rocker ratio is 1.43 : 1 meaning
.008" x 1.43 = .011" of lift is lost.

Not that that means much. Just the facts, ma'am.

Yes, .011" at the valve.
When I plot the lobes I dont use a ratio multiplier, just the cam alone.
Im more interested in the lobe mapping than what it does at the valve.

I believe I remember you saying you had plotted some cams back in the day, is that right mrmom9r?

[mrmom9r]

All of my stuff is plotted as lift at the valve vs. degrees of crank rotation to compute the area under the curve. Then converted to cfm to calculate gross total airflow per valve event.

the main thing you learn from all those hours is that the most is usually not the most effective.

My goal was to develop an understanding of total cfm per in./3 displacement, bad heads -big cam /good heads -less cam that sort of thing.

[chevelle]

There is an update, I did a few changes on the 900.
Click the link for the info.

http://xlforum.net/vbportal/forums/s....php?t=1222275

[chevelle]

Another update on the 900 dyno runs:

http://xlforum.net/vbportal/forums/s...1222275&page=7

[Dragstews]

English Doc.....English......

[Jtw79]

So Chevelle any new tests on the dyno coming soon? I need more. I saw a set of "early c grind Sifton cams" on ebay. Curious if any of the resident experts on here ever heard of them or tried them? Thanks.