Valve Springs and Seals Info?

-
B

billsdartgt

FABO Gold Member
FABO Gold Member
Joined
May 12, 2019
Messages
648
Reaction score
366
Location
Puyallup, WA
I started pulling the springs off my J heads to finish some cleaning in prep for the new springs to match the cam I am about to put in, the new comp springs are a dual spring, the umbrella type valve stem seals don't appear right. Am I missing something, this is a new one for me, always had head work done by a shop. Below is what I have. Comp Cams list these seals to go with the setup I have but haven't seen how/where there install, trying not to waste money on something that won't work.

COMP Cams Valve Seals 505-16

IMG_0004.JPG
IMG_0005.JPG
 
I also assume since I am matching the springs to the cam I won't need to reuse these shims?

IMG_0007.JPG
 
Those guides have been cut for a .500 diameter positive seal. That's what you need to get. Any decent half arsed machine shop over there should have some seals to fit that on the shelf. IIRC that should be no more than about .38-.40 cents each if they ain't cornholing you. I haven't had to pay for any in years so I may be a bit off on price but I can't be off by much.

Also, I'm glad you can't use the seals you have. Them is junk. I wouldn't use them on a lawn mower. They pass way too much oil, and oil in the combustion chamber makes detonation.
 
You need to verify your springs to make sure you have the correct load at installed height and open valve lift.

You can't take any chances here or as sure as God made little green apples you'll end up in a world of poo. I try to use at least a hardened .015 shim, even if it puts me a few pounds over what I want for spring load. Those springs move around like Mexican jumping beans and without something under them, even on cast iron, the springs will dig into the heads. And that makes trash in your oil.
 
check top of guide with a caliper- who machined? i would rather have the .530 ones as .500 guides break easier but yoou have what you have
get positive viton seals i prefer over teflon
from what I can see nice guide work
center two exhausts can run hot
you may need to machine spring seats- what yr said
you may need spring locators
you need to hand detail the spring ends
dual springs are not a drop in
check spring length on both inner and outer
retainers must match springs light cr-mo
what cam? all the details why a new thread?
 
Last edited:
Thanks, from the look of the combustion chamber area I didn't think there was any machine work done to these heads, not sure why the guides were worked on and not the rest,

will measure the top and order appropriately.
 
The insides of the guides were knurled to restore them to original inside diameter; see the grooves inside of the guides? So these heads have had a sort of a valve job, at least to correct guide wear, if not other valve seat issues.

The seal change was probably done at the same time. As wyrm says, I'd not use the teflon (PTFE) seals for the street. They can seal too well and starve the guides of oil... BTDT.

Here are vitons in the same size... need 2 sets of these if you are putting them on the exhausts too. There may be others.
https://www.summitracing.com/parts/man-24044-8

Measure the diameter of the 2 steps around the guide. These will determine if you need more machining for the new dual springs you have. If you care to, give the spring PN and the diameters; we may be able to help you look at it.
 
Thanks all for the info, will finish taking off all the springs to make sure no oddities then order as needed, will be doing some more research on the two different types, they are both new to me.

Thanks, again.
 
billsdartgt said:
Where exactly are you seeing the cut to .500, how can I verify?


these are a .500 with the right stem diameter, should work huh?

COMP Cams Valve Seals 512-16
Click to expand...


I put my MaGoo yes on them LOL. I can actually tell because there is a bronze liner in the guide and the cast iron around it is pretty thin.

I'd throw a caliper on it and verify my eyeballs. Looks like .500 to me. And I always did everything to .500 because once you get enough spring the .530 stuff is too big.
 
yellow rose said:
I put my MaGoo yes on them LOL. I can actually tell because there is a bronze liner in the guide and the cast iron around it is pretty thin.

I'd throw a caliper on it and verify my eyeballs. Looks like .500 to me. And I always did everything to .500 because once you get enough spring the .530 stuff is too big.
Click to expand...

you were on the money with the Magoos,measured a .4966, the seals are available in two different outside diameters, a .540 and a .625, inside diameter of new inner spring is .695, I assume the .625 would be the better choice?

need a different spring compressor, 2 of the 3 I have removed shot across the room, still can't find one of them suckers yet, enough spring work today, on to other stuff.
 
billsdartgt said:
found the .500 inner diameter, but as I noted there are two different outside diameters available, looking for which is best
Click to expand...
Look around in the spring department at inner springs I.D and you'll see its splitting hairs for what you're doing. Theres plenty of room
 
In my opinion those heads are not machined for dual valve springs. Do you even have the proper retainers and locks required for the valve stems and dual valve spring retainers? It's highly unlikely the stock items will work. Seals are the least of your potential problems.
 
IQ52 said:
In my opinion those heads are not machined for dual valve springs. Do you even have the proper retainers and locks required for the valves stems and dual valve springs? It's highly unlikely the stock items will work. Seals are the least of your potential problems.
Click to expand...


Good point. I've seen it so much I assumed he is calling a single spring with a damper a double and a double with a damper a triple.

I hope it's not a real double or he needs to machine the seat down unless the inner is shorter and needs that step.
 
Generally the inners are shorter and that is taken up by the proper dual spring retainer.

Or rather, in my experience, the inners are shorter.
 
Last edited:
nothing wrong with that Knurl
I even knurl new guides for oil retention (damn unleaded or alky added gas)
you need some extra lube- and what was said about the all teflon seals
go Viton
check and see if those are dual springs or dual with a dampner between the springs and then check to see if it wants a flat seat or that step\
you do not want to coil bind the inner or extra pressure if step is not wanted, or the lower pressure if it is
I use a lot of dual springs in single spring applications for reliability- sharing the load
did you post the number of those comp springs?
 
Last edited:
So, exactly what part number dual springs are we worrying over? What retainers and locks are being used? And yeah, I have a box each of 5/16 and 11/32 X .500" steel guides with brass liners like those.
 
Good point IQ
OP mike your valve stems, any chance they are chevy valves? Or magnum valves or??? somebody worked on those heads
 
valves have 3/8" stem, retainers on current valves will be replaced, they have a diameter of 1.3X, didn't fit the springs that were in there as they are 1.49, will buy the retainers to match the springs, it is a dual spring, new springs are 995-16s, they will be installed on the heads as they sit,
 
The shims are used to get the correct spring pressure for a given spring height. The cylinder head valve spring seat, valve seat and valve all make up that equation and may not necessarily all add up to the correct spring height, so shims are sometimes needed to compress the spring further to get it to the proper height to achieve a certain amount of seat pressure. It's best you take everything to the machine shop and let them get all of that correct.
 
All - thanks for the info, I will be taking a few measurements with the new installed springs with the tech data available, if close I will go as is, if not, well I will cross that bridge then. I've talked to a few shops, high prices and long backlogs, not like running to jiffy lube. as noted, will see where I end up, this has literally turned into lipstick on a pig with this motor, and this will be the last shot, at least I will actually know what pieces and parts are there, something I didn't know until a few weeks back.

Thanks again
 
If you get a cheaper valve spring mic, you can determine what the installed height is, this is without any shims. This is after you have all the correct parts. Then you add shim to bring the installed height to where you need it. You should check that each spring has the correct pressure at the installed height and at max lift and do the math to make sure you have coil bind clearance and valve seal clearance. It’s not rocket science but you need to pay attention to detail. Trust but verify!
 
You must log in or register to reply here.
-

Back
Top