Steel Shim Head Gasket Worth It?

ags290

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I am gathering the last bits and pieces to do a head swap on our early 65 mustang. I bought a C7DE head from a member of the forum and have it at the machine shop being checked over. I have already purchased a Ford head gasket kit with the later style composite head gasket and hard plastic valve stem seals. (C9OZ-6079-A). And then today a original steel shim type gasket has come up on Ebay.

My questions are: Should I forgo milling the head and try to buy the thinner head gasket? I am assuming that Ford made the switch to the composite gasket for better sealing? Also should I use the hard plastic stem seals in the kit or rubber umbrella ones?

The engine is a 170 and the car is used just to cruise around the suburbs. The reason for the head swap is I have a puff of smoke on startup and the plugs on 3 and 4 keep getting oil fouled. The valve stem seals on the current head are fresh so I am guessing bad valve guides. I have performed a compression test and all of the cylinders are within 5 lbs of one another so i don't think rings are the issue.

As always, any help or opinions are appreciated.

Kevin
 
My own thought (probably not worth much!) is that if the head is already at the machine shop, get it milled. It will guarantee that it is trued-up, and if you ever needed to remove the head again, you could easily get the modern gasket. They probably do seal better, also. I milled .030 off of mine (I think you need around .025 to match the old gasket). BTW, Instead of putting in valve guide sleeves, my shop found new valves with oversize stems and just drilled out the original guides. This adds expense, though, for new valves. In terms of seals, it probably doesn't make much difference, and there may be no objective proof, but you might possibly have less chance for the soft seals to crack or become loose on the stem.
 
For what it's worth, I have a copy of the '67 shop manual. For a new gasket it says this:

On the 170 Six engine, apply cylinder head gasket sealer to both sides of a new gasket. Spread the sealer evenly over the entire gasket surface. Do not apply sealer to a 200 Six engine head gasket. Position the gasket over the guide studs on the cylinder block.

Why just the 170 and not the 200? I dunno. It doesn't go into any explanation. Apparently there's something special about the 170 variant. Just thought I'd throw that out there for ya.

Cheers! :beer:
 
my advice would be to use the composite head gasket and forgo the steel shim one. the later gasket tends to seal better and last longer imo. the steel shim gasket requires a little extra care when installing it, and most people dont have the patience for such care, i know i dont.
 
rbohm, could you go into some detail on

the steel shim gasket requires a little extra care when installing it

I have one of those "valve grind" gasket kits that comes with the 0.035" gasket. Not quite as thin as the OEM, but still thinner than the more modern ones. What kind of extra work and I looking at for installing this thing?

Sorry for jacking the thread...
 
you need t make sure that you get a thin coat of sealant on both sides of the gasket, and then you need to take extra care when installing the head so as not to move the gasket around too much. the steel shim gaskets are more prone to damage than the composite gaskets are. dimple the embossing on one, and you make a place for a leak to happen.
 
I appreciate all of the responses. I will go ahead with the composite gasket.
 
Howdy Ags and All:

In reality, it probably doesn't matter too much for your intended use. IIWIYS, I'd mill the head enough to true it, and use the (C9OZ-6079-A) gasket from the discontinued FoMoCo valve job gasket kit. The difference between the OEM steel shim gasket and the later service replacement gaskets will be about .010", and a truing mill cut will be about that also.

On the valve guide seals, neither very good or will last very long, but they are what we have, short of machining for PC of other fitted seals.

PS- I'd sure specify a three angle valve job and a 30 degree back-cut on the intake valves while it is at the machine shop. Those two items are cost effective and worth it at all engine speeds, even with a stock cam.
That's my two cents, for what it's worth.

Adios, David
 
Hi, I'll take a shot at cr bobcat's question about a 170 head gasket using sealer and a 200 not needing it, as per a Ford shop manual. The bore is smaller in the 170 so Ford used an old style steel gasket to match the bore. My guess is on the larger bore 200 they used a new style gasket which did not need sealer, so mechanics who were use to gooping it up needed to be told just install it out of the box. This is just a guess since I was a little to young in 1967. I didn't do my first valve job until I was 13 years old in 1973.
 
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