Thread: Building a ZZ430 clone. Question about quench, compression ratio, etc.

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Hello,

I am in the process of building a ZZ430 clone engine. In case you are not familiar, this was simply a limited edition engine built by Chevrolet I believe over 10 years ago. It was simply a ZZ4 shortblock with Fast Burn aluminum heads, LT4 hotcam and 1.6 Roller Rockers. Anyhow, I have the ZZ4 short block and am getting ready to bolt on the heads. I am going with the GM performance headgaskets. But I have two choices: 10105117 or 12557236. Now the ZZ430 apparently came with the 12557236 gaskets which are 0.051" compressed thickness. The ZZ4 crate engine piston deck height is apparently .025 which would net me a quench of 0.076 correct??? I would assume this is far from ideal quench goal of around .040? Anyhow the 10105117 gaskets are 0.028" compressed thickness. I would assume this would net me a quench of .053 which would not be perfect but much closer. Am I looking at this all wrong??? I want to use the thinner gaskets if I can get away with it. I do have 93 octane out here so I have no issues using that all the time. I would assume that my engine is similar to the new ZZ5 crate engines which use the thicker 12557236 head gaskets and are 9.72:1 compression. So I would imagine I would have no problem using the 10105117 gasket depending on how much it bumps compression??? Any help would be appreciated. I'm ready to bolt on the heads but need to make sure before I assemble. Thanks everyone in advance!

The ZZ-430, Fast Burn 385, and ZZ-5 all use the same head gasket (12557236), short block (12561723), and heads. The ZZ-430 difference is in the camshaft and rockers, as you mentioned. I'd be careful with a thinner head gasket, because, as I remember, when I added the the hot cam/roller lifter combo to my FB-385, the valve/piston clearance was OK, but just about the minimum recommended.

I'm not qualified to evaluate your quench inquiry, but I will guarantee that that engine/cam combo will make serious horsepower when properly tuned. Mine is in a 2,500# car, and it flat moves.

Originally Posted by Henry Rifle

The ZZ-430, Fast Burn 385, and ZZ-5 all use the same head gasket (12557236), short block (12561723), and heads. The ZZ-430 difference is in the camshaft and rockers, as you mentioned. I'd be careful with a thinner head gasket, because, as I remember, when I added the the hot cam/roller lifter combo to my FB-385, the valve/piston clearance was OK, but just about the minimum recommended.

I'm not qualified to evaluate your quench inquiry, but I will guarantee that that engine/cam combo will make serious horsepower when properly tuned. Mine is in a 2,500# car, and it flat moves.

Was this with the 12557236 head gasket? Or did you go with a thinner one?

Originally Posted by v6underpressure

Was this with the 12557236 head gasket? Or did you go with a thinner one?

I kept that head gasket. This may sound like blasphemy, but I was not trying to extract the last half-horsepower from this motor. It runs extremely well, and in a 2500# car with 3:70 gears and a 700R/4 trans, it's crazy fast.

Use 14096405 Composition Head Gasket.
This composition gasket has stainless steel on one side and graphite on the other side with a compressed thickness of .028".
Next time you build a motor, begin with the stack of parts, then cut the block decks to the stack and use the head gasket of your choice to set the squish.

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Originally Posted by techinspector1

Use 14096405 Composition Head Gasket.
This composition gasket has stainless steel on one side and graphite on the other side with a compressed thickness of .028".
Next time you build a motor, begin with the stack of parts, then cut the block decks to the stack and use the head gasket of your choice to set the squish.

.

Thank you for the feedback. What would be the difference between your suggested 14096405 and 10105117??? They both have graphite and stainless fire rings. Not to mention they both have a compressed thickness of 0.028". This is a ZZ4 crate engine and I don't have the tooling to cut the decks etc. so I'm only doing the top end. So you are also saying that a 0.028" gasket will work with my combination?

Originally Posted by v6underpressure

So you are also saying that a 0.028" gasket will work with my combination?

I would think it would be prudent to check your valve to piston clearances with modeling clay, especially based on Jack's recollection,

Originally Posted by Henry Rifle

I'd be careful with a thinner head gasket, because, as I remember, when I added the the hot cam/roller lifter combo to my FB-385, the valve/piston clearance was OK, but just about the minimum recommended.

Originally Posted by v6underpressure

What would be the difference between your suggested 14096405 and 10105117??? They both have graphite and stainless fire rings. Not to mention they both have a compressed thickness of 0.028". This is a ZZ4 crate engine and I don't have the tooling to cut the decks etc. so I'm only doing the top end. So you are also saying that a 0.028" gasket will work with my combination?

10105117 has a 4.000" bore and the edges of the gasket could overhang into the cylinder bore on an overbored block, creating a "glow plug" that could fire incoming mixture before the spark plug gets a chance to do its business. Pre-ignition equals detonation. 14096405 has a 4.100" bore, so the edges of it are back away from the fire a little.
Either gasket, although not ideal, will work with aluminum heads and prevent the fretting of the aluminum material that occurs with a steel shim gasket.

I would further comment that every good engine build should include claying the piston crowns for valve to piston clearance checks. Actually, there should be 3 to 4 trial assemblies to check different clearances before anything is permanently bolted together.

Next time you plan an engine build, begin with the stack of parts you will use and cut the block decks to that dimension. Then you can use the proper gasket for aluminum heads (Fel-Pro 1003) and have a 0.041" squish. For instance, building a 383, crank radius is 1.875", rod is 6.000" and piston compression height is 1.125". Add these 3 values together and find 9.000". Cut the decks to 9.000" and like I said, use the 1003 gasket. Everybody's happy.

Most of the younguns on these forums seem to go bananas at the thoughts of cutting the block decks. The block is not sacred. It is there for you to alter to your needs and decking costs only about $150, so it's not the end of the world as far as your finances go.

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Originally Posted by techinspector1

10105117 has a 4.000" bore and the edges of the gasket could overhang into the cylinder bore on an overbored block, creating a "glow plug" that could fire incoming mixture before the spark plug gets a chance to do its business. Pre-ignition equals detonation. 14096405 has a 4.100" bore, so the edges of it are back away from the fire a little.
Either gasket, although not ideal, will work with aluminum heads and prevent the fretting of the aluminum material that occurs with a steel shim gasket.

I would further comment that every good engine build should include claying the piston crowns for valve to piston clearance checks. Actually, there should be 3 to 4 trial assemblies to check different clearances before anything is permanently bolted together.

Next time you plan an engine build, begin with the stack of parts you will use and cut the block decks to that dimension. Then you can use the proper gasket for aluminum heads (Fel-Pro 1003) and have a 0.041" squish. For instance, building a 383, crank radius is 1.875", rod is 6.000" and piston compression height is 1.125". Add these 3 values together and find 9.000". Cut the decks to 9.000" and like I said, use the 1003 gasket. Everybody's happy.

Most of the younguns on these forums seem to go bananas at the thoughts of cutting the block decks. The block is not sacred. It is there for you to alter to your needs and decking costs only about $150, so it's not the end of the world as far as your finances go.

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Thank you for the helpful information. This is a fresh ZZ4 crate motor so the bore is 4.00". The main reason I wanted to go with the 10105117 was to tighten up the quench a little bit. The original head gasket for a ZZ4 is 12557236 just seems a little thick in my opinion. Since it was a typical off the shelf ZZ4, I figured the specs would be pretty standard to figure this out. But it seems I have to check my piston to valve clearance. Not only did I want to tighten up the quench, but I have heard numerous people running the 10105117 gaskets with no issues, one of which using nitrous.

Originally Posted by v6underpressure

Not only did I want to tighten up the quench, but I have heard numerous people running the 10105117 gaskets with no issues, one of which using nitrous.

I strongly recommend that you check the piston deck height (distance from the block decks where the heads bolt on to the crown of the piston) before you go any farther. Blueprint PDH is 0.025", which when added to the compressed thickness of the gasket, 0.028", would make a squish of 0.053". Personally, I would not button up a motor with this squish measurement. I'd do it properly by measuring the stack of parts and cutting the block decks to zero so that when using a Fel-Pro 1003, I'd have a squish of 0.041", or if I was in a position of not knowing the fuel quality I could buy later, I would cut the block decks so that the crown of the piston popped up out of the block by 0.006", then use the 1003 for a squish of 0.035".

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You may want to look at Fel Pro's gaskets for the aluminum heads before buying. Decking the block is the only way to correct this, but if this is not possible I would use a composition Fel Pro for the 4" bore and aluminum head and go with it.

aluminum heads go for the thinner gasket and higher compression-if you have any spark knock issues back off the timing some and or then put on the thicker gaskets---------If you don't go for it now you'll always wonder What If I had -------
Have some issues, feel free to contact me--you could bring me your bare block and I could deck it while you wait-----

I think if you look up the Felpro specs, they have an identical gasket as the o03 but with smaller bore size-