Valve Guide Wear?
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 1,085
Likes: 3
From: Ottawa Ontario, Canada
Valve Guide Wear?
I've replaced my valve seals already but was wondering about replacing my valve guides while I have the engine apart.
SDPC doesn't list an OEM replacement for the guides, so...
Where are the new valve guides coming from when heads get rebuilt? Are they the same as OEM guides? What's involved in pressing them out/in?
SDPC doesn't list an OEM replacement for the guides, so...
Where are the new valve guides coming from when heads get rebuilt? Are they the same as OEM guides? What's involved in pressing them out/in?
Racer
Joined: Feb 2004
Posts: 359
Likes: 7
From: St. Paul MN
In my research (sorry no real world experience), the stock valve guides are steel that wears much better than the various bronze alloy replacements that are installed during a rebuild.
The Service Manual discusses valve guide wear measurements before replacement or reaming them out to use new valves with oversize stems. Clearance more than 0.0037" must be repaired. Valves with stem diameters less than 0.313" should be replaced. It may be worth measuring to see if new guides are even needed.
Based on these two findings, I decided to buy low mileage non-rebuilt 243 heads instead of rebuilding cheaper higher mileage ones.
Hope this helps.
Todd
The Service Manual discusses valve guide wear measurements before replacement or reaming them out to use new valves with oversize stems. Clearance more than 0.0037" must be repaired. Valves with stem diameters less than 0.313" should be replaced. It may be worth measuring to see if new guides are even needed.
Based on these two findings, I decided to buy low mileage non-rebuilt 243 heads instead of rebuilding cheaper higher mileage ones.
Hope this helps.
Todd
Racer
Joined: Feb 2004
Posts: 359
Likes: 7
From: St. Paul MN
If you've still got the heads apart (and can get the seals off without destroying them), it may not hurt to try and measure the valve-to-guide clearance to see if new ones are even warranted. If you are running stock cam & heads I would expect them to run past 80k miles without needing attention (again from what I've read).
Todd
Todd
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 1,085
Likes: 3
From: Ottawa Ontario, Canada
Heads are completely apart right now and all the valve stems feel very good in the guides - very little freeplay. The surface of the valve stems looks good too, very little wear from what I can see. I will measure a few valve stems just for kicks but will likely just leave them as is.
Thanks for the information!
Thanks for the information!
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Burning Brakes
Joined: Jan 2008
Posts: 1,235
Likes: 51
In my research (sorry no real world experience), the stock valve guides are steel that wears much better than the various bronze alloy replacements that are installed during a rebuild.
The Service Manual discusses valve guide wear measurements before replacement or reaming them out to use new valves with oversize stems. Clearance more than 0.0037" must be repaired. Valves with stem diameters less than 0.313" should be replaced. It may be worth measuring to see if new guides are even needed.
Based on these two findings, I decided to buy low mileage non-rebuilt 243 heads instead of rebuilding cheaper higher mileage ones.
Hope this helps.
Todd
The Service Manual discusses valve guide wear measurements before replacement or reaming them out to use new valves with oversize stems. Clearance more than 0.0037" must be repaired. Valves with stem diameters less than 0.313" should be replaced. It may be worth measuring to see if new guides are even needed.
Based on these two findings, I decided to buy low mileage non-rebuilt 243 heads instead of rebuilding cheaper higher mileage ones.
Hope this helps.
Todd
Is the minimum of .313 also for the LS6?
Melting Slicks
Joined: Nov 2008
Posts: 2,938
Likes: 65
From: Rochester Hills MI
The guides are made from a very hard sintered metal alloy, much harder than the valve stem itself. Likely the only time you will ever need to replace one is due to a bent valve. If the tolerance is on the high side, it's more likely the valve stem is worn than the guide.
Burning Brakes
Joined: Jan 2008
Posts: 1,235
Likes: 51
What are my options in figuring out if i just need new valves or guides?
My valves are under spec from what ive read. I need to source some.
Should i buy just one new one and do the wiggle test to confirm the valves are the problem?
Should i get both intake and exhaust valves in stainless? I see manley makes them with stock height for around 150$ exhaust (8pcs) and 160$ intake (8pcs).
Thanks.
Last edited by Georgies; May 25, 2019 at 02:50 PM.
Burning Brakes
Joined: Jan 2008
Posts: 1,235
Likes: 51
SO FAR SO GOOD!!!!
My mistake was using the vernier!!
Last edited by Georgies; May 25, 2019 at 06:47 PM.
