I'm of the understanding that desired Squish is .039-.045".

I'm building a 383. The block is a #010 4-Bolt that has been decked to 9.010".

Hind sight would say that I should have gone to 9.000 which is the same dimension as my Eagle crank assembly (w/Flat tops), in other words zero deck and therefore the Fel-Pro #1003 at .041" thickness (nice gasket) would fit the squish range nicely.

Well, to late (damm it!) and now what?

Recommended to me, by a respected source, is the SCE (Pro Copper) #011063 gasket 4.060 x .032", Copper sprayed on both sides. These are avaiable through Summit.

That would give me my desired Squish (.010 Deck + .032 thick = .042 Squish).

I have on the bench the Fel-Pro #1003 composite gaskets (.041" thick) which look just fine to me, but yields a Squish of .051".

This is my first engine build and I'll go to most any length (within my $$means) to do a proper job. Time is not a problem but I don't cherish the thought of stripping the block again to re-machine to zero deck.

Now more to my point, the Copper gaskets mentioned above would seem to be a good solution, mathmatically. But, for some reason I feel that I need another experienced opinion. Help keep my head on straight.

Correct me if I see it wrong but Copper strikes me as a solution to tue more hi-perf applications and it's associated maintenance.
The proper squish however could alleviate some detonation concerns.

In my case I'm looking at no more than 400HP and intend to see the track only occaisionally (depending on how respectable I run -- Hmmmm?).

The 383 will be going into an 87 Camaro which will not be the primary daily driver but I do want some driveability and dependability.

What do you guys think? Should I throw the Fel-Pro's on and forget my squish concerns or try the Copper and deal with it?

Actually, for all I know the Copper could be a very fine gasket as well??






[This message has been edited by Changa2 (edited July 24, 2001).]

 

To use a copper head gasket properly you need to o-ring the block.

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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block

Best ET on a time slip: 11.242 altitude corrected to 10.89
Best MPH on a time slip: 121.52 altitude corrected to 125.89
Altitude corrected rear wheel HP: 497.9
Best 60 foot: 1.546

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

No you don't. We run copper and steel gaskets with flat decks. Just be ready for the copper gasket to leak after a while. What are you using this engine for? If this is a ***** out race engine, you need to know how much your rods are going to stretch at redline. You can probably ask the guy who machined your engine what he recomends, because he's been building engines for a long time, or you can calculate it by knowing your average integrated cross sectional rod area, alloy type, Poisson's heat expansion ratio, and modulus of elasticity as well has piston mass and acceleration. Then you can build your engine to have 0 clearance at redline. The piston should barely kiss the head. I mean BARELY. If this is just a street engine you want a little more clearance than that just to be safe. When my engine was built I think I had at least .060 to .080 piston to head clearance.

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'89 Red Formula 350- 350 .060 over forged pistons 232* @ .020 cam Performer RPM Holley 750 DP Vortec 1.94 1.50 Accel Coil and dist. Hedman shorty headers Dual Exhaust w/ cutouts 1LE WS6 suspension, wheels, and brakes, 9 Bolt 3.27 Posi Edelbrock LCA's & Track bar subframe connectors 700R4 Harwood snorkel scoop Eclipse Head Unit Delco Bose Speakers 2 12" Pioneer subs w/ 400 watt/chanel amp

 

There are regular gaskets less than .041" out there. For example:

10105117 GM Composition Head Gasket, .028" thick compressed.

.038 might be a tad close if you are going to turn over 6000RPMs.

 

ATO, you raise some interesting points.

My crank assembly is EAGLE ductile iron (4340) with SRP flat tops. Rods are 6.0" H-Beam.

No this is not a *****-Out racing engine. My intentions are for Street use with occaisional Bracket Racing. I want to get as much out of it as possible, of course, but within $reason$.

A pre-programed maintenance plan such as eventually leaky head gaskets is not in my plan. Same reason that I didn't go with solid lifters.

So, I think I'll right off the Copper gasket which leaves me SOL, as far as the .039-.045 quench bench mark goes. Other than the Copper I haven't been able to find any composite gaskets in the .030-.035 thickness range, which is what I need to get to the bench mark with my .010 deck.

If I hear you right (maybe it's just what I want to hear) by using the .041 Fel-Pro gasket that I already have (giving me .051 quench) will be no big deal.

Thanks for your feed-back.

 

I had a talk with my race machinest you can go down to cold piston to head clearences of .040 to .028 inches. For a head gasket a ordinary stock steel shim head gasket for a SBC has a squish height of .017 inch. If you want to go even smaller Fel-Pro has one that has .015 squish height. This would put your piston very close to the head but you may be able to get away with it.

DO NOT RUN COPPER HEAD GASKETS. The only people who should ever run copper head gaskets are all out racers. These ALWAYS leak. When I worked in a machine shop I never pulled apart a engine with a copper gasket that did not leak. The racers just put up with it for the improved blow out protection and better sealing.

Do not worry to much about having to much clearence. If you measure what the factory does it is not unusual to see .060 to .080 piston to head clearence.

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84 Z28 383
Stripped w/Cage back halved w/ladder bars and coil overs and 9 inch
700R-4 3.73

 

Of all the parameters that have a measurable effect on engine output, .010" of difference in squish height would have to be somewhere near the end of the list... certainly not worth using fragile head gaskets for, and risking future trouble in that somewhat labor-intensive area. Also, if this is your first engine build, you're leaving all kinds of things (including lots of free or nearly free ones) on the table that you will only learn through experience, any number of which will have a more significant effect on how the engine runs. For instance, you'll get about 10 times as much increase in horsepower by using lightweight piston pins than you will from any manipulation of the squish height, as long as it still works.

Copper head gaskets are not for the street. They will not stand alot of heat-cool cycles. The same goes for steel-shim gaskets.

Use the regular FelPro 1003, 1004 or 1014, stay out of trouble, and enjoy your car a whole lot more. (unless of course you enjoy regular maintenance of things like head gaskets)

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"So many Mustangs, so little time..."
ICON Motorsports

 

Man you guys have hit the nail on the head and I have no choice but to pass on my thanks, to all.
I just experienced a big Brain Fart, which means relief. I waisted the entire day muttering over this question and how best to proceed. I am not an engine builder by any stretch, but I wasn't born yesterday and I do have a semi-educated comfort zone. Something was messing with my mind but you guy's spit it out very specifically.

I'm now comfortable and will proceed with my F/P 1003's. Thanks again to all the above and Thirdgen.Org as well.

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87 Camaro with 700R4 and 3.23 posi, impatiently awaiting 383cid, 4-bolt #010, Int. Balanced Eagle crank assembly, 4340 crank and H-Bean 6.0 rods with SRP flat tops.
DART IE 200/72cc heads (10:1 C/R) with Harland Sharp 1.5 full rockers and Guide Plates
Comp Cams XE274H (230/236 .487/.490 110LSA 1,800-6,000 RPM).
Edelbrock RPM manifold with 750 (Vac/Electric) Holley.
MSD Pro-Billet (Vac) with 6AL box.
My best guess (Dyno 2000) is about 400HP and 430TQ??