Steel shim head gasket sealant

General engine tech -- Drag Racing to Circle Track

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rfoll
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Re: Steel shim head gasket sealant

Post by rfoll »

They bear no resemblance to the picture.
So much to do, so little time...
pamotorman
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Re: Steel shim head gasket sealant

Post by pamotorman »

rfoll wrote: Sat Jan 06, 2018 7:13 pm The gaskets are in hand, and are in fact shims. The deck is freshly machined, the heads are nearly new and very heavy. First time I have heard if putting it together with the paint wet. Interesting thought.
i used hi temp aluminum paint for years and never had a failure and i put them together with the paint still wet. clean the surfaces with thinner before applying the paint
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Re: Steel shim head gasket sealant

Post by Newold1 »

Just focus on good machine work to achieve good straight flat deck and head surfaces,with a 20 RA or better finish after surfacing, good head bolts or studs, proper torquing and sealer just becomes a non-essential crutch. Concentrate on good machine work with shim gaskets and not on sealers.
DON'T BUY CHEAP OFF BRAND SHIM GASKETS ITS NOT WORTH THE PROBLEMS AND RISK!
The Older I Get, The Dumber I Get :wink:
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Re: Steel shim head gasket sealant

Post by user-23911 »

It's different if you're playing with boost.

Eventually they let go.
That's when you really need sealant.

Good bolts and studs don't even factor into it because they're not the weak link.
But they look pretty.
Momus
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Re: Steel shim head gasket sealant

Post by Momus »

Good bolts or studs allow a higher clamping force between the surfaces and that is what makes the seal. Good fasteners are a critical part, not bling.
digger
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Re: Steel shim head gasket sealant

Post by digger »

Yeah let's use crap bolts :roll:
Schurkey
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Re: Steel shim head gasket sealant

Post by Schurkey »

Last sets of steel shims I installed, I used Permatex brush-cap Teflon pipe thread sealer.

I don't think it makes a bit of difference what sealer you use. Hylomar is expensive. Gasgacinch works just as well most of the time, and costs 1/10 as much. CopperCoat, High Tack, Indian Head...any of 'em work just fine on steel shim gaskets.


I've never installed them dry. Might have to try that someday.
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Re: Steel shim head gasket sealant

Post by pdq67 »

Schurkey wrote: Sun Jan 07, 2018 2:09 am Last sets of steel shims I installed, I used Permatex brush-cap Teflon pipe thread sealer.

I don't think it makes a bit of difference what sealer you use. Hylomar is expensive. Gasgacinch works just as well most of the time, and costs 1/10 as much. CopperCoat, High Tack, Indian Head...any of 'em work just fine on steel shim gaskets.


I've never installed them dry. Might have to try that someday.
Two things here.

1. The only steel shim head gaskets I ever heard of were either MrG's or GM's..

2. I read one time years ago about somebody using no more than gun grease as a gasket sealer!!

Now that to me is almost like installing them dry.

Personally, I use , "Indianhead", but have used aluminum spray paint and both dauber bottle and spray CopperCoat fine through the years.
pdq67
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Re: Steel shim head gasket sealant

Post by naukkis79 »

Modern steel gaskets are Viton-rubber coated and are installed dry. They provide excellent sealing properties.
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Re: Steel shim head gasket sealant

Post by roc »

Steel shim and MLS (Multi-layer Steel) are very different deals.
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Re: Steel shim head gasket sealant

Post by Newold1 »

The internet and online ordering markets are being flooded with some cheaply made and not always in spec.head gaskets. They are really cheap like $50 for a PAIR for stainless MLS head gaskets!

As a test, I bought a pair online and when I got them they were poorly packed and damaged and came 2 weeks later from an address in Hong Kong. made a direct comparison of them to a set of Cometic I have in stock. NO COMPARISON, finish sketchy and uneven, raised embossing not even and I would not risk thousands of dollars invested in an engine with those gaskets.

Just my personal experience so far but I would recommend all here be careful with these types of cheap head gaskets. My suspicion is the steel shim and composition gaskets some importers make are just as bad. I am sure their are other import brands that can and some do make good nicely priced head gaskets, just be careful finding and using them.
The Older I Get, The Dumber I Get :wink:
naukkis79
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Re: Steel shim head gasket sealant

Post by naukkis79 »

roc wrote: Sun Jan 07, 2018 8:55 am Steel shim and MLS (Multi-layer Steel) are very different deals.
Nope, MLS is just couple steel shims stacked. Usually 3 layers, center layer is smooth and only to support other two, one pressed steel shim to face block and one to face head. Preparation to both SLS and MLS gasket is exactly same, if they are coated with Viton or any other coating they are assembled dry, if not cold-sealing will be much improved with some coating.

For some engines SLS gasket are not easily available so I have disassembled MLS gaskets to have one, actually two from one MLS gasket.
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Re: Steel shim head gasket sealant

Post by rfoll »

The compression ratio is about 9.3:1, no nitrous, blowers, extended high rpm usage. The only thing this engine will do is run on the stand to break in the cam, and then a season at the drag strip to give us some idea how the vehicle will behave with some larger cubic inches. All of our prep work on the block and crank was done with the idea that we would need to do this anyway when we get serious with some real compression and bigger cam later on. As it is, things like gear ratio, converter, and tire sizes would be pure guesses, and the cost of a mistake in any of those areas could kill the budget.
So much to do, so little time...
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Re: Steel shim head gasket sealant

Post by PackardV8 »

Anyone have an opinion if one-layer steel shim gasket on aluminum head/iron block requires different sealant than iron head/iron block?

FWIW, both the Studebaker V8 and the Packard V8 used .023" steel shim head gaskets. The aftermarket replacements from Felpro and Best are both .035" composition.
Jack Vines
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Re: Steel shim head gasket sealant

Post by engineguyBill »

PackardV8 wrote: Sat Jan 06, 2018 1:33 pm
engineguyBill wrote: Sat Jan 06, 2018 11:24 am When installing thin, steel shim head gaskets, I have used high temperature silver paint that is made for barbecue grills (both spray and brush on) for 50+ years with no issues/failures. Installation procedures are of utmost importance, i.e. gasket surfaces must be clean and dry; head gasket threads and threaded holes in block must be clean (I use thread chasers, NOT tap and die); coat head bolt threads with very light coat of thread sealer; coat the gaskets with silver paint and install heads while the paint is slightly tacky; torque the heads bolts in recommended sequence - in at least three steps.
Bill, agree with all the above but one, "(I use thread chasers, NOT tap and die)" in fifty years of chasing threads in blocks with standard taps, I've never had an issue I could trace to same.
Hi Jack,
The main reason for using thread chasers instead of tap and die is the fact that most common bolts/nuts (including those used in automotive applications) only have about 70% contact between the bolt and nut threads. Two reasons for this are 1 - economical manufacturing and 2 -ease of assembly. Even quality fasteners such as ARP will typically follow the 70% rule, however many specialty fasteners, such as aircraft applications use "tighter" fit fasteners, but these fasteners are more expensive than the "standard" fit.

When a tap or die is used to clean existing threads, there is a possibility of removing additional material from the fasteners thereby making the fit less than the original 70% and this may reduce the effectiveness of the fastener.
Bill

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