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Old 11-10-2013, 05:16 AM   #1
Daddy Boy
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Default Thoughts about worn valve seats Triumph

I wanna know how to preserve our old heads from valve seat recession.
Reckon replacement is a big deal dollar and gettin a good job to boot?
There must be a heap of good heads n storage just because the seats are sunk!
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Old 11-11-2013, 03:13 AM   #2
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Default Re: Thoughts about worn valve seats Triumph

all i know is;
people go seriously re grinding in valves with out need every time the head comes off.

every other tank full put in full leaded fuel (if available ) or octane boost to protect seats.

i've had Triumph valve seats replaced, probably could have bought decent head slightly cheaper if'd i'd hunted around but as one of the best bits of advice from Tony the Torch goes 'you can always make more money but you can't make more time' ; and believe me this one has been a life line for me.
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Old 11-11-2013, 04:40 AM   #3
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Default Re: Thoughts about worn valve seats Triumph

I had a local guy here in New Zealand just upsize the valve to an 8mm car valve sealed up great and not sunken in at all. This was after I bought a set of black diamond (largest oversize) and discovered it was gunna be a rightoff!!
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Old 11-11-2013, 06:12 AM   #4
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Default Re: Thoughts about worn valve seats Triumph

Umm
so lets say you find a brand new head, you have fully rebuilt motor,you run a good oil.
And use unleaded fuel from your local gas station,you ride bike normally(whatever) you carbs and ignition are set up perfect
at what mileage do you see recession?
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Old 11-11-2013, 07:20 AM   #5
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Default Re: Thoughts about worn valve seats Triumph

I think you might be worried about something you needn't bother with. Richbob just described the bikes I own and the way I ride. After years and years of riding I have never had an issue with valve seat recession...ever.
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Old 11-11-2013, 08:17 AM   #6
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Default Re: Thoughts about worn valve seats Triumph

I think the greatest contributor to accelerated seat wear is people leaving guides in place long past their useful life. Too much stem-to-guide clearance allows sloppy closing which wears down the seat.

Jason
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Old 11-11-2013, 12:36 PM   #7
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Default Re: Thoughts about worn valve seats Triumph

just buy a larger diameter valve.

you reface the seat to fit the new valve and it sits right where it's supposed to sit.

there are replacement Triumph intake valves available up to 1.63" and it you need to go even bigger you can get Ford or Jaguar valves the are 5/16" stems and cut the length to fit.
I even but 1.75" Jaguar valves in a Triumph head once but it takes a lot of porting and welding work to make it breath right.

you can't really go by what the "Book" says....
after all the "Book" says you can't bore Triumphs out more that +.040"
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Old 11-11-2013, 01:03 PM   #8
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Default Re: Thoughts about worn valve seats Triumph

Quote:
Originally Posted by Goldy View Post
I think you might be worried about something you needn't bother with. Richbob just described the bikes I own and the way I ride. After years and years of riding I have never had an issue with valve seat recession...ever.
Yea,everything wears. I remember when the UK dropped leaded fuel(15+ years ago) was a panic for classic car and bike people
Lots of companies sprang up offering hardened valve seat conversions and a lots of fuel additives appeared on the market
At the time i was having a 67 air/oil cooled porsche motor rebuilt by porsche, i asked what about this problem porsche told me not a problem as air/oil cooled engines already have hardened valve seats(maybe just porsche but this motor is 1967)
so after that i ceased to worry about this problem(on everything,bikes and cars)???
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Old 11-12-2013, 03:21 AM   #9
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Default Re: Thoughts about worn valve seats Triumph

I see the involvement in re seat now. Look toward bigger.
Thank you all gentlemen.
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Old 11-12-2013, 06:01 PM   #10
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Default Re: Thoughts about worn valve seats Triumph

The biggest enemy of the Triumph valve seat is the AUTOMOTIVE machine shop.
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Old 11-13-2013, 12:51 AM   #11
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Default Re: Thoughts about worn valve seats Triumph

Bout time somebody started making good quality aftermarket heads.
I must show pics of this strip down and discuss this topic further.
The head is away getting an aluminium exhaust stub pressed in. Just like the other sideas the steel one started it's obvious demise.
Goin to a track day at Broadford in a month, so I'm just gonna clean the head up and ride.
Should be a good comparison to the modifications made for the next time.
Never been on a track before so I'm fairly exited.
Been reading Vizard so a few changes are in store.
Must get on a dyno and discover more about scavenge and test to see if this engine is getting it right.
To be cont....
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Old 11-13-2013, 06:17 PM   #12
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Default Re: Thoughts about worn valve seats Triumph

John Healy make a good point about Triumph seats from his experience. Guides are pounded in and the Triumph head lacks material for proper guide support.The metal is thicker on one side of the guide bore than the other.So the guide cocks to the thin side a little,then the valve seat needs excessive grinding to find a new seat....And Fouraceswes comment about auto machine shops is often valid,they can get rude replacing guides. Triumph factory used a puller to draw in the guides rather than hammer and drift. This is not to say a careful mechanic can't drive in guides on a heated head...but...
I have used over sized valves like Tony the Torch mentions ....The valves sitting up where they belong is the key to best performance.
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Old 11-13-2013, 10:49 PM   #13
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Default Re: Thoughts about worn valve seats Triumph

Hey Daddy Boy ,Check what David Vizard says regarding valve head size and port diameter,I'd be figuring that part of the equation rather than just using a bigger valve and finding the relationship is all wrong.
I dont know if he is still in business but Pete Smith of Epicycle Racing services replaced the seats in my 68 bonnie head and it was a top notch job,he knew exactly about the cast in seats used in those heads.
Cheers Rene
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Old 11-14-2013, 03:28 AM   #14
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Default Re: Thoughts about worn valve seats Triumph

Re cast in seats ,just had my head done and the reco'er had just done a full head rebuild on a daytona head.along with mine it was re heaet treated and he machined the seats out on the previous head and they were of the tapered type but my ones were a top hat shape which was good cause the inlet seats stayed in place during heat treatment
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Old 11-14-2013, 03:55 AM   #15
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Default Re: Thoughts about worn valve seats Triumph

I reckon I'll relieve the area around the worn seats for better flow for now just to see. The bigger valve job later or new seats shouldnt be hampered by relieving..
J.Healy also said the squish band is somethin to play with. Got some fluxless solder to test when head comes back.I did this test when I built the motor and squish was 0.060" JH reckons 0.032", but 50 is max so I wanna revise.
The bike runs grouse BTW, I'm just in search of more performance through knowledge from the brethren/breathmen, thats you. Cheers.
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