I am having issues finding a valve seal that will fit my 062 vortec castings. I had originally planned on running comp's positive seals, but the tool I used to cut the guides to .530 had a defect and the seals are too loose to hold on to the guide. As a solution I bought fel pro ss72527 intake and ss72526 exhaust umbrella type seals. The exhaust seals have plenty of clearance, but the intake won't clear the guides. I guess my question is can I buy another set of exhaust seals and use them on the intake side? Or does anybody have any solution? I would hate to have to cut the guides more, but that may be my only option as most umbrella seals I see online look to big to fit inside my z28 style springs. Here are some pictures to help give a visual. The second picture is the positive seal that is too loose and the third is the frl pro that doesn't have enough clearance. Sent from my XT1635-01 using The H.A.M.B. mobile app
full disclosure: i am no master engine builder...but i have rebuilt a few SBC's (327/350) and i don't recall ever having different seals for intake and exhaust (same thing on the few motorcycle engines i have done) I would say that the valve stem (top side) doesn't care if it is intake or exhaust. the seal just need to stop oil from running down the stem. get some more of the ones that fit, ****on it up and run it. just my 2 cents worth. Chappy
Lots of mid 80's Chevys used a positive Viton seal on the intake and an umbrella on the exhaust. When I worked as a machinist, I would often use the umbrellas on both intake and exhaust when we were out of the others. No one ever came back with a problem. Lots of Fords and other GMs used umbrellas on both intake and exhaust.
Thank you guys. I am just going to order another set of three exhaust seals and call it a day. Sent from my XT1635-01 using The H.A.M.B. mobile app
You should be fine with umbrellas on both .....Looking at the picture though, it appears that the spring seat may not be flat between old and new machine work. Does the outer spring have a consistent contact surface? Inners?
You are correct. The arbor for the cutting tool used to machine the guides down wasn't straight and the seats are not entirely flat, though I stopped as soon as I started into the seat so not by much. Would this pose an issue? Should I run a shim to be on the safe side? Sent from my XT1635-01 using The H.A.M.B. mobile app
Bummer....I guess the question is how bad are they. a few thousands measured down from the retainer might be OK. If you are wary, you might take the heads in and just get the spring pockets cleaned up. You must already have some shims to achieve the recommended ***y height/seat pressure, but that may not square the spring. The extreme worse case might be uneven guide wear and early spring fatigue due to loss of heat transfer. You've probably seen slomotion videos of spring motion, but take a peek. Not that you are running those RPM extremes quoted. . On the seal issue, I wouldn't have any qualms. I began not using any seals years ago when having inner spring clearance problems and only recently started using vitons on the intakes. No negatives, not even upon cold startups.
Well that blows. They aren't the full diameter of the spring and none go very deep, but they aren't even from one valve to the next. I will probably just do shims since this is just going on a mild 327 for a daily driver that will never see any real high rpms. Sent from my XT1635-01 using The H.A.M.B. mobile app
I suppose it is a lesson learned not having the machine shop cut the guides for me while they decked the heads. Sent from my XT1635-01 using The H.A.M.B. mobile app
Yep, so maybe it won't go 100K. I remember using Isky's seat cutter in the 60's with a hand drill....not pretty. The worse thing is probably the mental image held in memory.
Whatever you do don't use the red ones from Compe***ion Products. They break apart and clogged up the oil pump screen. I had to remove all the valve gear and springs while still on the engine and then take off the pan. I found pieces of the spring clips like what is on the lower half of the the dark blue one above. They were on Dart Iron heads with double springs set to #135. I installed a single big block spring #145 and seals with metal only on the guide. So far so good.