Coyote gen 3 head gasket thickness ?

[C0y0te]

Hi ,

Does anyone knows what is gen 3 OEM head gasket thickness?

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[C0y0te]

Could anyone who knows reply, please ?

 

[K4fxd]

See post #3
https://www.mustang6g.com/forums/threads/oem-head-gakset-thickness.151554/

 

[C0y0te]

See post #3
https://www.mustang6g.com/forums/threads/oem-head-gakset-thickness.151554/

He said it's .039, some other said it's .050+

 

[K4fxd]

Short of buying one and measuring.....

.039 or .040 sounds about correct. Personally I don't like any thicker than .030 for quench reasons. I seriously doubt the stock gasket is .050

If you find out for sure please let us know.

 

[C0y0te]

Short of buying one and measuring.....

.039 or .040 sounds about correct. Personally I don't like any thicker than .030 for quench reasons. I seriously doubt the stock gasket is .050

If you find out for sure please let us know.

Is it safe to use .030 with cams?

 

[NASteve]

Is it safe to use .030 with cams?

There is no way to answer that without checking the engine first, no builder worth anything will agree to that. As far as not using anything thicker than .030" that is only if the piston is .015" down in the hole, use a .030" head gasket with a 0 deck piston and that engine won't even last through warm up unless it is on kill and been checked and verified multiple times. Usual quench on a street/strip engine is .045" and we tighten it from there provided we've verified nothing is touching but it takes top notch parts to survive and once you do get to .030" quench that engine isn't meant to be ran a long time without coming apart and being checked over again. At .030" quench you will see next to no carbon build up on the pistons and any marks on the valves or pistons will transfer from one to the other because it is that close.


Just for reference NHRA spec head gasket thickness for stock eliminator and super stock is .035" with 0 deck clearance and that will allow 14.28:1 compression, that is for a non supercharged engine for 2019.

 

[C0y0te]

There is no way to answer that without checking the engine first, no builder worth anything will agree to that. As far as not using anything thicker than .030" that is only if the piston is .015" down in the hole, use a .030" head gasket with a 0 deck piston and that engine won't even last through warm up unless it is on kill and been checked and verified multiple times. Usual quench on a street/strip engine is .045" and we tighten it from there provided we've verified nothing is touching but it takes top notch parts to survive and once you do get to .030" quench that engine isn't meant to be ran a long time without coming apart and being checked over again. At .030" quench you will see next to no carbon build up on the pistons and any marks on the valves or pistons will transfer from one to the other because it is that close.


Just for reference NHRA spec head gasket thickness for stock eliminator and super stock is .035" with 0 deck clearance and that will allow 14.28:1 compression, that is for a non supercharged engine for 2019.

it's really enrichment reply, so what do you think about raising compression ratio by using both, pistons and heads gasket ?

 

[NASteve]

it's really enrichment reply, so what do you think about raising compression ratio by using both, pistons and heads gasket ?

If you are going as far to swap pistons then there are a few ways to bump compression but you will always be octane limited no matter what you build. So decide on the octane you will be running pump gas, E85, or race gas, then build around that accordingly. If the engine is a street/strip engine then basically stay with stock type stuff and maybe mill the heads slightly but gen 3 cars already are close to the limit on compression with pump gas and with a dedicated E85 build you can bump up to 13.1, after that race gas is needed. Always remember though when you raise compression the tuning window in what you have to work with gets smaller before you into detonation, pro engines N/A will be in the 15.1 and up range and their tuning window is small, but again these are pros, avg guys don't need that. So unless this is a racecar stick with stock pistons and gaskets, if this is a race engine its best to get with a experienced coyote builder and discuss it with them. Building engines isn't like picking bolt ones or power adders, there is a lot that goes into getting them right.

 

[K4fxd]

So unless this is a racecar stick with stock pistons and gaskets, if this is a race engine its best to get with a experienced coyote builder and discuss it with them. Building engines isn't like picking bolt ones or power adders, there is a lot that goes into getting them right.

I still like a tight quench but I do thoroughly check clearances. It's not "bolt together and forget"

 

[NASteve]

I still like a tight quench but I do thoroughly check clearances. It's not "bolt together and forget"

I won't do a wide quench unless it is for a boost application, but anything less than .045" for a street/strip application is to tight. On a race engine yes because it will never go unmaintained, it will have the heads off often and have its bearings, rings, and gaskets swapped regularly.

 

[C0y0te]

If you are going as far to swap pistons then there are a few ways to bump compression but you will always be octane limited no matter what you build. So decide on the octane you will be running pump gas, E85, or race gas, then build around that accordingly. If the engine is a street/strip engine then basically stay with stock type stuff and maybe mill the heads slightly but gen 3 cars already are close to the limit on compression with pump gas and with a dedicated E85 build you can bump up to 13.1, after that race gas is needed. Always remember though when you raise compression the tuning window in what you have to work with gets smaller before you into detonation, pro engines N/A will be in the 15.1 and up range and their tuning window is small, but again these are pros, avg guys don't need that. So unless this is a racecar stick with stock pistons and gaskets, if this is a race engine its best to get with a experienced coyote builder and discuss it with them. Building engines isn't like picking bolt ones or power adders, there is a lot that goes into getting them right.

if i want to go with high Comp. pistons i'll go with 13:1 or 13.5:1,
what if i went with deep relief pistons to use .030" HG and S2 comp cams ?

 

[NASteve]

if i want to go with high Comp. pistons i'll go with 13:1 or 13.5:1,
what if i went with deep relief pistons to use .030" HG and S2 comp cams ?

You're thinking about it wrong, the valve reliefs affect P to V clearance, but when you go with a thinner HG you end up putting the flat parts of the piston close to the deck of the head which is good for N/A but you have a lot of things to factor in. Block and head growth when they reach temperature, rod stretch, piston pin flex. If you get that wrong even if you have enough P to V clearance the pistons will slam into the head. You need to have a builder lay it all out first, then start measuring before you even get a HG. If the piston is 0 deck then going to a .030" head gasket will not work. Usually a mod motor is .006"-.010" piston in the hole, factory machining tolerances are sloppy compared to a "built" engine so quench can be .045" to .050"+, going to .030" quench without verifying it with the engine running is a sure way to kill it. Depends on the parts used you may not be able to go less than .039" quench.

 

[K4fxd]

what if i went with deep relief pistons to use .030" HG and S2 comp cams ?

You will want good rods also, all rods stretch. You want to minimize this.

I would listen to NA Steve unless you have a real good engine builder, then I would listen to him. I have built many many high RPM long stroke engines with .03 quench and am comfortable doing it.

 

[C0y0te]

You're thinking about it wrong, the valve reliefs affect P to V clearance, but when you go with a thinner HG you end up putting the flat parts of the piston close to the deck of the head which is good for N/A but you have a lot of things to factor in. Block and head growth when they reach temperature, rod stretch, piston pin flex. If you get that wrong even if you have enough P to V clearance the pistons will slam into the head. You need to have a builder lay it all out first, then start measuring before you even get a HG. If the piston is 0 deck then going to a .030" head gasket will not work. Usually a mod motor is .006"-.010" piston in the hole, factory machining tolerances are sloppy compared to a "built" engine so quench can be .045" to .050"+, going to .030" quench without verifying it with the engine running is a sure way to kill it. Depends on the parts used you may not be able to go less than .039" quench.

I really appreciate your time sir
You gave me they keys to go with this project.

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