1G G4CS questions. Piston protrusion, head gasket thickness, knock sensor etc

[93xsg]

Hey guys,

Bought a pre built G4CS motor that had been sitting for a few years. With the amount of dirt and crap on the motor decided to tear it apart and clean it at the minimum.

Found out the block deck was awful and had that done. I had a local machine shop assemble the head for me. Bearings were scratched so I ordered new ACL race bearings and got the crank installed today.

Being as I don't know exactly what was done to it, and I'm a little new to the stroker platform I have a few questions.

The pistons protrude ever so slightly from the top of the block, I've attached some pics of the head and the block to get opinions on headgasket thickness. Wiseco catalog says 1.1mm gasket and 0 deck clearance.

I've been reading about quench height and people say 0.035 - 0.060 range. Both head and block have been shaved, unsure of amount. STM has a .040, 0.045, 0.056, 0.060, 0.080, and 0.120 inch Cometic MLS available.

From piston part number below I've determined it's a Wiseco 4g64 87mm piston for 4g63 head, with 1.3785" compression height. (Answered my own question here about bore size for headgasket).

Also, the knock sensor, I've read you need to drill and tap a hole. Would this be where that bolt is installed with RTV? (picture)

I tried measuring the crank to find out if it is 100mm or 88mm. (Guy said it was a 2.2l stroker but he was wrong on other things). With crank laying flat, from the outside (right of crank journal) to outside (left of rod journal), I got 100mm. Center to center of journals was around 50mm. Assuming that's a 2.4 crank?

A few things about it.

Oversized valves, beehive springs
Delta regrind 272 cams, AEM cam gears
Wiseco pistons 6564M87 2556J
G4CS block
6 bolt rods with ARP rod bolts
Stock 6 bolt crank i believe 100mm (see above)
ARP mains with Kiggly Girdle
ARP head studs

Main question is about the knock sensor and the quench height for gasket thickness.

Sorry I couldn't get a measurement of piston protrusion. I broke a piston ring removing them and just slapped in a piston to see what it was looking like. Wouldn't get an accurate measurement without the rings in. (Didn't have a piston compressor and it's late).

Any insight would be great. IDK if someone with experience will be able to tell just from photos what gasket to run. I'd like to be able to order gaskets and replacement piston rings (doh) at the same time.

Any other G4CS tips would be appreciated. I know about the different timing belt. I plan on using the 4g64 belt and adjusting my cam gears to get proper timing. (Advance both gears 3.5°). It's looking like I should probably invest in degreeing the cams tho as well.

Any issues with flywheel? I have a 6 bolt Fidanza aluminum wheel with steel surface area. I've used the supra ARP long bolts with the auto trans spacer for my normal 63t 6 bolt stuff.

Thanks,
Taylor

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[DSMPT]

Guy said it was a 2.2l stroker but he was wrong on other things.

I think he meant a 2.2 de-stroker since the G4CS is a replica of 4g64.

I tried measuring the crank to find out if it is 100mm or 88mm. (Guy said it was a 2.2l stroker but he was wrong on other things). With crank laying flat, from the outside (right of crank journal) to outside (left of rod journal), I got 100mm. Center to center of journals was around 50mm. Assuming that's a 2.4 crank?

If the engine is disassembled and you already know what pistons you have, just measure the rod length (Big end center to small end center distance) then you can know what stroke the crank has.
Since 4g64 deck height is 235mm and you have 1.378" compression height pistons :
If the rod length is 150mm, the crank is 100mm stroke.
If the rod length is 153mm, the crank is 94mm stroke.
If the rod length is 156mm, the crank is 88mm stroke.

Also, the knock sensor, I've read you need to drill and tap a hole. Would this be where that bolt is installed with rtv? (picture)

No, that's a balance shaft inspection hole. The factory knock sensor location is usually between cylinder 2 and 3 in the center of block.

the quench height for gasket thickness.

You would need to measure with a deck bridge tool to know how much exactly above the deck, but you don't need to worry much about that unless you have removed too much material from the deck. The common 1.3mm/.051" thickness head gasket would probably be just fine.

 

[93xsg]

I think he meant a 2.2 de-stroker since the G4CS is a replica of 4g64.


If the engine is disassembled and you already know what pistons you have, just measure the rod length (Big end center to small end center distance) then you can know what stroke the crank has.
Since 4g64 deck height is 235mm and you have 1.378" compression height pistons :
If the rod length is 150mm, the crank is 100mm stroke.
If the rod length is 153mm, the crank is 94mm stroke.
If the rod length is 156mm, the crank is 88mm stroke.


No, that's a balance shaft inspection hole. The factory knock sensor location is usually between cylinder 2 and 3 in the center of block.


You would need to measure with a deck bridge tool to know how much exactly above the deck, but you don't need to worry much about that unless you have removed too much material from the deck. The common 1.3mm/.051" thickness head gasket would probably be just fine.

Hey thanks man. It has the stock 6 bolt rods in there so it's a 100mm crank. I came across one of those stroker threads a bit ago with all of the combinations you can make with these motors, pretty sweet.

And thanks, I'll have a look tonight for the knock sensor location and compare it to my 4g63 6 bolt block. I'll have a better idea what's left when I assemble the motor mounts and JMF coil pack holder etc.

From what I've gathered, a stock motor has 0 deck clearance and a 0.051 thick head gasket. So I take it, I would measure the protrusion and add that to the stock gasket thickness for my headgasket?

I think with my buddies Cornwell straight edge and dial indicator we should be able to figure out how much it protudes. It was getting late last night.

After I posted this I found the stock head from factory is 132mm tall. I'll see if I can measure that and determine how much has been removed.

Thanks for the info