Hi all. Needing a little help or maybe some moral support. I am in the process of getting a 340 street/cruiser ready for install while the body is getting overhauled. I found that the valve guides are worn out so I have a set of X heads that I had partially done back in 1991 and decided to finally use them. They have bronze guides installed and I have some Mopar Perf. 3/8 Teflon PC style valve seals that I installed but they seem to be extra tight on the valve stems that it’s very difficult to move the valve in the seals. Especially the exhaust valves but fit on the guide great. Tight enough that I think it would be too tight and possibly hold the valve open here or there or maybe wear the exhaust valve stem very quickly. I have a similar Fel-Pro set that doesn’t have the springs on the top part of the seal but they are too loose on the.503-.506 guides. I have some stock style but they also are too loose on the smaller guides. So I trying to decide what to do. Mancini’s website shows a set of regular rubber seals for .500 guides but look like stock seals. Has anyone used these on the smaller guides? Could I use the MP pc seals on the intakes and use the tall umbrellas on the exhaust? I also have a set of 5/16 stock seals that fit the guides really good but not sure if they are too small for the 3/8 valves and shouldn’t use them? I also pulled out the second head and found 2 of the exhaust valves are just a little different on the lower stems and only have single lock grooves which out of probably 100 keepers I don’t have any. All other 14 valves have 4 groove locks. Would anyone have any concerns about using the 2 odd ball ones by just getting some 7 degree single locks? I have tried to search for 2 matching ones P3690231 to no avail. Thanks for any input in advance
Needing some help with 340 valves and valve seals
- Thread starter Sedbld
- Start date
I would use the teflon seals - much better. Are you sure they are 3/8 and not 5/16? Did you lube the seal a little bit to test? (They should have break in fluid on the seals and in the guides when installing them) If the valve stem/seal is lubed up the stem usually moves pretty easily.
As far as the single vs. 4 groove valves: If the valves are identical in height, will seat the same, and put the retainer in the same place, then the engine won't know the difference. But check, check, check to be sure...
As far as the single vs. 4 groove valves: If the valves are identical in height, will seat the same, and put the retainer in the same place, then the engine won't know the difference. But check, check, check to be sure...
Yes I lubed everything before assembly with a slight mixture of assembly lube and engine oil as I have done for years. And they are 3/8 seals right out of the MP package but very hard to move.Especially the exhaust.
The 2 oddball valves measure identical to the other 6. Checked that first and all have the same stem height when installed with no spring at least with a straight edge bar. Couldn’t find any keepers to check the retainer height yet. Still digging around for those.
The 2 oddball valves measure identical to the other 6. Checked that first and all have the same stem height when installed with no spring at least with a straight edge bar. Couldn’t find any keepers to check the retainer height yet. Still digging around for those.
dvw
Well-Known Member
Not a fan of Teflon seals. Newer stuff out there that is better. These are the seals I use. They fit the .500" guide and 3/8" stem. Made from Viton material. They are very good. Been useing them for over 15 years in builds. COMP Cams 521-16 COMP Cams Valve Seals | Summit Racing
Doug
Doug
Thanks for the wakeup Doug.
I wasn't thinking right in my earlier post. We use the viton material for the valve seals, not Teflon. If I remember right, I think Teflon makes the stems too dry? Anyway, use the viton seals, much better than umbrella seals.
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