Jockey Journal Forum banner
1 - 20 of 32 Posts

·
Registered
Joined
·
90 Posts
Discussion Starter · #1 · (Edited)
I finally got around to installing the rockerboxes on my Triumph 650 engine. I had not tried to do this before because I was waiting to get the rebuilt engine in the frame before I installed them. I rebuilt this engine from boxes of parts and scrounging around for missing parts. Everything seemed to be going well until today. I have a build thread on the bike here.... http://www.jockeyjournal.com/forum/showthread.php?t=77597

This is my first rebuild of a Triumph.

Well, when I installed the intake rocker box I ran into problems. I adjusted the clearance so there was some play on the rocker arms....I figured it was loose if anything. I then slowly turned the engine through with a socket on the crankshaft. There seemed to be a slight interference as I turned it through on the right side around TDC just as the intake for that cylinder was beginning to open. I had a bad feeling about that so then I tried to come through while turning the crankshaft backwards. Shit...it stops dead while turning backwards. I'm pretty sure the piston is touching the valve. So does anyone have any input? I pulled the timing cover and redid the valve timing twice. Here is the way I have it timed.

I'm really hoping I don't have to pull the engine and split the cases again. BTW, the exhaust valves seem to be fine...at least they don't interfere with anything.

Would the direction the piston is in make any difference? When I put them in they looked symmetrical.

Thanks,

Ed
 

Attachments

·
Registered
Joined
·
588 Posts
Re: Triumph valve timing issue...HELP?

Im sure someone will correct me on this if i am wrong but i just went through this recently. First off. Back off the rockers for now. Get the right side piston to TDC. Then set your gears to this ....



Here are some other pics for reference. the rockers and valves won't be set until you torque the heads on anyway.



Make sure when you get the right side to TDC that you mark the crank gear. The original mark may not be visible because of the large nut. Just mark the tooth with a paint marker or something. Because of the diameter of the timing gears they will NOT remain synchronous after you kick it over. Don't expect the marks to line up after you rotate the motor.

This is how i set mine and the bike fired right up afterwards. hope this helps.
 

·
Registered
Joined
·
588 Posts
Re: Triumph valve timing issue...HELP?

AT a second glance of your picture .... your Intake cam is about a tooth off and should be on the short line. Also just to be sure ...... make sure you haven't lost a pushrod in the process of installing your rocker boxes. If the pushrod comes off the rocker during you tipping the rocker cover on, it will likely jam into the rocker cover and give you that "Locked" feeling. Just double check.
 

·
Registered
Joined
·
90 Posts
Discussion Starter · #4 · (Edited)
Re: Triumph valve timing issue...HELP?

AT a second glance of your picture .... your Intake cam is about a tooth off and should be on the short line. Also just to be sure ...... make sure you haven't lost a pushrod in the process of installing your rocker boxes. If the pushrod comes off the rocker during you tipping the rocker cover on, it will likely jam into the rocker cover and give you that "Locked" feeling. Just double check.
To me the timing in my picture looks right. The book says use the long line for T120 and TR6 and the short line for the 6T. Am I wrong? I will check the push rods again.

When I look again I notice that my intermediate wheel has slightly different markings than the book.....now I'm really confused

Ed
 

Attachments

·
Registered
Joined
·
588 Posts
Re: Triumph valve timing issue...HELP?

If you have a book for the 6T go off of that because my references are for a TR6 TR6R TR6C.

Basically you are saying that when you try to turn the motor over after aligning the gears, it is locking up right? Do you have the rocker box covers bolted down already ? When you remove the inspection /adjustment covers you should be able to see the rockers moving as you turn it over. It will have some resistance because of the valve springs but shouldn't lock all together.
 

·
Registered
Joined
·
90 Posts
Discussion Starter · #6 ·
Re: Triumph valve timing issue...HELP?

It's really weird. The left piston is fine...with the clearance normal. The right one however appears to hit the piston with the valve. I have the boxes snugged down and the inspection covers off. I can feel the arm move. If I back the valve clearance WAY off, I can turn it through. It seems to be starting down before TDC as the piston comes up (maybe to soon). I think I will pull the head and cylinders in the morning and see if the lifter blocks are installed correctly and to make sure I have the right ones.
 

·
Registered
Joined
·
90 Posts
Discussion Starter · #7 ·
Re: Triumph valve timing issue...HELP?

If you have a book for the 6T go off of that because my references are for a TR6 TR6R TR6C.

Basically you are saying that when you try to turn the motor over after aligning the gears, it is locking up right? Do you have the rocker box covers bolted down already ? When you remove the inspection /adjustment covers you should be able to see the rockers moving as you turn it over. It will have some resistance because of the valve springs but shouldn't lock all together.
It's a combination of tr6 and T120 parts so I should use those marks, right?
 

·
Registered
Joined
·
150 Posts
Re: Triumph valve timing issue...HELP?

Sounds like one of the pushrods have missed the ball end of the rocker.Try lifting and replacing the offending rocker box and as you nip them down the rockers should be free to slide axially compressing Thackeray washer
 

·
Registered
Joined
·
246 Posts
Re: Triumph valve timing issue...HELP?

If you install the gears on the cams and use the wrong keyways the marks don't jive anymore, and I think valves can hit pistons. If you use the keyway that lines up with the mark on the gear then you're good. I think You can tell by taking the nuts off and looking. Something to check.
 

·
Registered
Joined
·
90 Posts
Discussion Starter · #10 ·
Re: Triumph valve timing issue...HELP?

Sounds like one of the pushrods have missed the ball end of the rocker.Try lifting and replacing the offending rocker box and as you nip them down the rockers should be free to slide axially compressing Thackeray washer
I'll try taking it off again......I think I've had it off at least four times already..

Thanks
 

·
Registered
Joined
·
90 Posts
Discussion Starter · #11 ·
Re: Triumph valve timing issue...HELP?

Ok, I removed the rocker box again. both pushrods sit level and feel seated in the tappet block. I had another rockerbox sitting on the shelf so I tried that one. I very carefully seated the pushrod cups on the rocker arm as I lowered it on. I slowly turned the engine over and had the same problem. Just the right side. I will dig deeper tomorrow.
 

·
Registered
Joined
·
90 Posts
Discussion Starter · #12 ·
Re: Triumph valve timing issue...HELP?

If you install the gears on the cams and use the wrong keyways the marks don't jive anymore, and I think valves can hit pistons. If you use the keyway that lines up with the mark on the gear then you're good. I think You can tell by taking the nuts off and looking. Something to check.
I just saw your post. I will try that next.

Thanks
 

·
Registered
Joined
·
231 Posts
Re: Triumph valve timing issue...HELP?

are you sure the push rods are seating on both ends? They will have a suction feeling on the tappets as long as you have a drop of oil on there. Your gears look in line to me. what cams do you have in there?
 

·
Registered
Joined
·
561 Posts
Re: Triumph valve timing issue...HELP?

i'd go with checking your push rods are seated prperly.

only other comment re that 'locked up' feeling ;

when checking rocker/valve clearance and hand cranking the kickstart occaisionally I get a similar situation.

I figured mebe it is a crank quadrant prob', but then there are no other symptoms.

the other situation seems to be when the engine is at the top/bttm of the stroke and a second, harder push is required on the kick start toovercome the 'inertia'.

all the best.
 

·
Registered
Joined
·
588 Posts
Re: Triumph valve timing issue...HELP?

Maybe a stupid ass question but sometimes the problem is actually common sense so ...... are you sure your pushrods are all the same length? Also, it is VERY tricky to get a rocker on correctly on one of those motors unless you get the feel for it. My gut is telling me that it is something with those pushrods. Don't know why but thats what my gut is telling me. I use a little grease in the ends to form a little bit of a suction effect like was stated above. It really does help. Let us know what you find.
 

·
Registered
Joined
·
706 Posts
Re: Triumph valve timing issue...HELP?

On an engine this old which you built from parts I think you're making a mistake by timing the valves with the marks on the gears. They may be correct, but maybe not. Unless you disassembled a running engine and then put the gears back the same way, it's best to assume that the marks on the gears are wrong. Remember that the gears can be pressed onto the cams using different keyways!

The reason I say this is, if you just go ahead and slap it together by the marks and it isn't right, you can destroy the engine the first time it fires up. Better not to guess on something so important. Even if you don't wreck the engine, if the valve timing is not right on, the engine will never run well.

What to do? Degree the cams yourself. That is, see what the manual says, put a degree wheel on the crank, find TDC and check that the valves are opening and closing when the manual says they should.

If the valves still hit the pistons after you've properly degreed the cams, then you have to cut some material off the valve cutaways on the pistons. Or, grind the seats so that the valves sit a bit further up in the head (not too much though), or use a thicker head gasket (also not the best solution).

After the cams are degreed in and you're 'sure' that you've got everything dead nuts, assemble one side of the head using carburetor slide springs instead of valve springs, put the head on, tighten it up pretty good (no pushrods or pushrod tubes needed) and push the valve down by hand with the piston at and near TDC to check how much clearance there is between the piston and valves. If it's only .010~.020" that's not enough (sorry, I can't remember what the minimum valve to piston clearance should be).

I guess what I'm trying to say is that now is not the time to be in a rush to fire up the engine. If it takes another week or two to get the valve timing sorted it'll be well worth the wait.

I know this is a huge PITA, but it's stuff like this that makes the difference between Triumphs that 'run' and those that RUN!
 

·
Registered
Joined
·
706 Posts
Re: Triumph valve timing issue...HELP?

One intake and one ex. pushrod will be needed for the clearance test, sorry.
 

·
Registered
Joined
·
1,181 Posts
Re: Triumph valve timing issue...HELP?

Glider said:
If it's only .010~.020" that's not enough (sorry, I can't remember what the minimum valve to piston clearance should be).
.030" is absolute minimum. For safety, .050" is probably a safer number.

.030" can turn into .000" pretty fast when valves start to float, or piston bushes get worn out, or rods start to stretch, or big end starts to wear . . .

Degree'ing the cams yourself is great advice. Hell, no two manuals even show the same markings. Why trust them at all?

Jason
 

·
Registered
Joined
·
75 Posts
Re: Triumph valve timing issue...HELP?

You should be able to see through the spark plug hole and watch for contact. What cams do you have? Are your timing gears thick as the gear section like a 750 or are they recessed like 500/650's?
 
1 - 20 of 32 Posts
Top