Valve Guide Seals for Big Block

[Clem Z.]

Re: Valve Guide Seals for Big Block

Larry------

I would not use both the stock umbrella seals (attached to the retainer) with positive-type seals. For one thing, the 2 seals might "collide" and destroy each other. For another thing, the double seals might cause too little oil to get to the valve stem. Some valve stem lubrication is necessary.

For the past 40 years, or so, the stock umbrella seals have proven to be pretty effective at oil control on these engines. However, GM did finally go to a positive type seals on the last big block, the 8.1L. These are GM #12555601. If I were going to use positive-type seals on a big block, I think these are the ones I would use. However, I don't know what valve guide OD they require.

if oil consumption is the problem and i was doing this job i would stick with the positive seals,that is why they are called positive seals and remove the plastic shield from the GM retainer. i would replace the positive seals that are there now with new positive seals. JMHO

[Wayne M.]

Re: Valve Guide Seals for Big Block

While on the title subject, did all big blocks, or just aluminum head big blocks (see thumbnail) come with the valve guide already machined to accept the standard Chev valve stem oil seal.

The machined valve guide OD shown on these early '68 L88/L89 "842" heads is 0.53" and the height from the bevelled tip down to the step is 0.35".

To Joe L. -- in my 1971 BB Chev book, there's reference to a seal package # 3998265, consisting of 8 seals, plastic capsules to temporarily put on end of valve stem so seal slides past keeper groove without damage, and an installer that pushes the seal into position. Is this the equivalent to the # 12555601 that you quote ?

[Clem Z.]

Re: Valve Guide Seals for Big Block

While on the title subject, did all big blocks, or just aluminum head big blocks (see thumbnail) come with the valve guide already machined to accept the standard Chev valve stem oil seal.

The machined valve guide OD shown on these early '68 L88/L89 "842" heads is 0.53" and the height from the bevelled tip down to the step is 0.35".

To Joe L. -- in my 1971 BB Chev book, there's reference to a seal package # 3998265, consisting of 8 seals, plastic capsules to temporarily put on end of valve stem so seal slides past keeper groove without damage, and an installer that pushes the seal into position. Is this the equivalent to the # 12555601 that you quote ?

as far as i remember none of the over the counter alum heads i bought were cut for seals.

[Joe L.]

Re: Valve Guide Seals for Big Block

While on the title subject, did all big blocks, or just aluminum head big blocks (see thumbnail) come with the valve guide already machined to accept the standard Chev valve stem oil seal.

The machined valve guide OD shown on these early '68 L88/L89 "842" heads is 0.53" and the height from the bevelled tip down to the step is 0.35".

To Joe L. -- in my 1971 BB Chev book, there's reference to a seal package # 3998265, consisting of 8 seals, plastic capsules to temporarily put on end of valve stem so seal slides past keeper groove without damage, and an installer that pushes the seal into position. Is this the equivalent to the # 12555601 that you quote ?

Wayne------


All big block heads originally used on Corvettes, aluminum and cast iron alike, did not originally have valve guides that were machined for positive valve seals. This also includes SERVICE-only head GM #14011076. Current GM SERVICE-only aluminum heads for big blocks do have the valve guides pre-cut for positive seals. Also, the 8.1L heads (not retrofitable to earlier big blocks) are pre-cut for positive seals.

I don't know very much about the GM #3998265. It was once shown as applicable to 1971-74 big blocks. 1973-74 big blocks could not use the integral valve stem seal because these years used valve rotators on the exhaust valves, a different extra-thick retainer on the inlet side and shorter valve springs compared to earlier on all valves. I expect that the 3998265 included valve seals that were likely all neoprene or Viton. They may have either fit over the stock valve guide or were simply umbrella seals that fit tightly on the valve stem.

GM #3998265 was replaced by at least 2 other part numbers but I don't have any information that the 12555601 was ever one of them.

[Larry T.]

Re: Valve Guide Seals for Big Block

Joe,

I am about to order the 12371061 form GM Parts Direct ($211). On another site that has it for a few more dollars it says "use steel retainer 3964264". Am I correct that the steel retainer is part of the 12371061 kit, or is it just springs. Does the kit come with keepers? If not, what is the P/N for the correct keepers? I want to get everything at once if possible.

Thanks for your help.

Larry

[Clem Z.]

Re: Valve Guide Seals for Big Block

Joe,

I am about to order the 12371061 form GM Parts Direct ($211). On another site that has it for a few more dollars it says "use steel retainer 3964264". Am I correct that the steel retainer is part of the 12371061 kit, or is it just springs. Does the kit come with keepers? If not, what is the P/N for the correct keepers? I want to get everything at once if possible.

Thanks for your help.

Larry

the valve keys you want are 3947880 and you need 32 of them. every spring kit 12371061 i ever ordered came with retainers . i have not ordered for several years and i would guess there has been no change

[Joe L.]

Re: Valve Guide Seals for Big Block

Joe,

I am about to order the 12371061 form GM Parts Direct ($211). On another site that has it for a few more dollars it says "use steel retainer 3964264". Am I correct that the steel retainer is part of the 12371061 kit, or is it just springs. Does the kit come with keepers? If not, what is the P/N for the correct keepers? I want to get everything at once if possible.

Thanks for your help.

Larry

Larry------


The GM #3970627 is a valve spring KIT. The GM #12371061 is a valve spring UNIT that GM says contains 16 of the 3970627 KITS. If the 12371061 is actually what GM says it is, it should contain 16 of the 3970627 KITS which includes spring and retainer with integral valve seal. It does not contain locks ("keepers") so you need to get those separately as clem described.

[Joe L.]

Re: Valve Guide Seals for Big Block

While on the title subject, did all big blocks, or just aluminum head big blocks (see thumbnail) come with the valve guide already machined to accept the standard Chev valve stem oil seal.

The machined valve guide OD shown on these early '68 L88/L89 "842" heads is 0.53" and the height from the bevelled tip down to the step is 0.35".

To Joe L. -- in my 1971 BB Chev book, there's reference to a seal package # 3998265, consisting of 8 seals, plastic capsules to temporarily put on end of valve stem so seal slides past keeper groove without damage, and an installer that pushes the seal into position. Is this the equivalent to the # 12555601 that you quote ?

Wyane

I erred a bit in my previous post and I've corrected it. I must have been a little bit "rummy" from the medication I'm taking for an allergic cold I seem to have developed.

Anyway, the years of applicabilty for the shorter valve springs, rotators and thicker inlet valve retainer were 1973-74. Those parts were not used for 1971-72.

Several GM P&A references show the GM #3998265 as being applicable to 1971-72, also. I think this is an error. I do not see how and other sort of valve seal could be used with an engine that used the retainers with integral seal. As far as I know, all 1971-72 big blocks used this type of seal.

As I mentioned previously, I do not see how a secondary umbrella or positive type seal could be used with an engine that also used the valve retainers with integral seals. Strangely, the 3998265 first appeared in the 1972 parts catalogs as being applicable to 71-72 with 454. However, as I mentioned previously, I'm almost sure that the 3998265 was just a black rubber seal which was either functional as an umbrella or was an actual press-fit on stock OD valve guides. GM went to this type of seal for small blocks in 1981.

Another interesting aspect is that the 3998265 went through several successive supercessions with the last one being GM #460527. The GM #460527 also replaced the 1965-E69 big block valve seal, GM #3866612. I'm almost sure that the latter is a black rubber, umbrella-type seal.

GM also shows the GM #3970627 as being applicable to L69-72 with big block and also SERVICE for 1965-E69. However, when used to SERVICE 1965-E69 applications, the old retainer and separate seal, GM #3866612, are discarded and replaced by the retainer and integral umbrella seal supplied as part of the 3970627 kit.

Addendum: as it turns out, I checked my inventory and I have many examples of the 3998265 and 460527. However, I just don't feel like going out there and digging them out right now. The more I think about it, though, the more I am convinced that they are just a black rubber umbrella seal. The 460527 is now discontinued and I can't find any new number for it, but there may be one. I don't think it's the 8.1L seal I mentioned previously, though.

[Larry T.]

Re: Valve Guide Seals for Big Block

Larry------


The GM #3970627 is a valve spring KIT. The GM #12371061 is a valve spring UNIT that GM says contains 16 of the 3970627 KITS. If the 12371061 is actually what GM says it is, it should contain 16 of the 3970627 KITS which includes spring and retainer with integral valve seal. It does not contain locks ("keepers") so you need to get those separately as clem described.

Bad news it seems, the kit includes only the springs for about $230. The retainers (3964264) are an additional $230. Throw in the keepers and it is $497.00 before shipping. Maybe I should check back with the dealer. They had the kit for $341.00. Maybe their kit included the retainers? Any other suggestions for suppliers?

[Clem Z.]

Re: Valve Guide Seals for Big Block

Bad news it seems, the kit includes only the springs for about $230. The retainers (3964264) are an additional $230. Throw in the keepers and it is $497.00 before shipping. Maybe I should check back with the dealer. They had the kit for $341.00. Maybe their kit included the retainers? Any other suggestions for suppliers?

GM keeps taking standard equiptment out of their cars every year and making it a extra cost option and i guess they are doing the same with parts.

[Joe L.]

Re: Valve Guide Seals for Big Block

Bad news it seems, the kit includes only the springs for about $230. The retainers (3964264) are an additional $230. Throw in the keepers and it is $497.00 before shipping. Maybe I should check back with the dealer. They had the kit for $341.00. Maybe their kit included the retainers? Any other suggestions for suppliers?

Larry------


How did you determine that the kit did not include the retainers?

[Wayne M.]

Re: Valve Guide Seals for Big Block

..... I'm almost sure that the 3998265 was just a black rubber seal which was either functional as an umbrella or was an actual press-fit on stock OD valve guides. GM went to this type of seal for small blocks in 1981.

Here's a pic (thumbnail below) out of that 1971 BB Chev book, which shows 3998265. I notice that the OD of the valve guide is NOT machined -- I missed that before .

The GM #460527 also replaced the 1965-E69 big block valve seal, GM #3866612. I'm almost sure that the latter is a black rubber, umbrella-type seal .......

Joe --- yes, # 3866612 is stamped in black ink on the paper back of those two packs of 16 rubber seals shown in my pic of post #7. Amazing how soft they are, after 40 years.

[Larry T.]

Re: Valve Guide Seals for Big Block

Larry------


How did you determine that the kit did not include the retainers?

Joe,

I made two contacts. GM Direct did not have a phone nimber so I sent an e-mail. They responded with a picture of springs but no real answer. Then I contacted Crateenginedepot.com as they had a good online price. Speaking with them on the phone they indicated that it only included springs and that retainers were seperate. I know they did not pull a box off the shelf but I assume they know what they are taliking about. I also called Jegs and they said the same thing. I am having a hard time swallowing $500 for these parts.

Larry

[Joe L.]

Re: Valve Guide Seals for Big Block

Joe,

I made two contacts. GM Direct did not have a phone nimber so I sent an e-mail. They responded with a picture of springs but no real answer. Then I contacted Crateenginedepot.com as they had a good online price. Speaking with them on the phone they indicated that it only included springs and that retainers were seperate. I know they did not pull a box off the shelf but I assume they know what they are taliking about. I also called Jegs and they said the same thing. I am having a hard time swallowing $500 for these parts.



Larry

Larry------



Then GM's description of the 12371061 kit is incorrect.They describe it as containing 16 of the GM #3970627. However, as I pointed out before, GM #3970627 is NOT a valve spring. It's the part number of a KIT that includes the valve spring + retainer. I'm sure the spring, by itself, has its own part number. But, it was never published because it's an internal number and has no SERVICE relevance since its not available separately in SERVICE.

For example, GM #12368082 is a rocker arm KIT. It contains a GM #3959182 rocker arm, a GM #12338047 rocker ball, and GM #3896648 nut.

GM #12368085 is a rocker arm unit which contains 16 of the above referenced GM #12368082 rocker arm kits. I purchased one of these units quite some time ago. It was a box which contained 16 individual GM boxes with the 12368082 part number on them.

[Clem Z.]

Re: Valve Guide Seals for Big Block

Here's a pic (thumbnail below) out of that 1971 BB Chev book, which shows 3998265. I notice that the OD of the valve guide is NOT machined -- I missed that before .

Joe --- yes, # 3866612 is stamped in black ink on the paper back of those two packs of 16 rubber seals shown in my pic of post #7. Amazing how soft they are, after 40 years.

i have some of those metal bodied seals around and yes they did not require the guide to be machined