Thread: Quench Question

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I've read on here that quench should be between .35-.45. In the Edelbrock installation instructions, piston to head should be a minimum of .50 it says nothing about max - no range. What should I shoot for?
Thanx Ed

Originally Posted by DennyW

.039 is the bulls eye to shoot for.

Denny's advice is dead on. Min. .035", .040" max. for higher CR engines running pump gas.

I just find it odd that E-Brock is saying a min .050
My decimal point is out of place in the first post

My guess is they are protecting THERE intrests in your engine. They have no idea if there stuff is going on a new or a 100,000 mi engine.

Great reading!!!!!! Thanks for the post, Denny!!!!!!

I built one engine which ended up with only .033 clearance and if we buzzed the engine to 7500 rpm, when we got to the pits, the engine was knocking. We thought we had stretched a rod bolt. We were so dissapointed. We went and watched the races and then after 20 minutes came back to hear it but the noise was gone, so we continued racing and kept the revs to 6500 and all was well. So obviously the rods had stretched but after cooling down, shortened up again. Wild

This year we will be taking it apart and installing thicker head gaskets.

Originally Posted by TyphoonZR

I built one engine which ended up with only .033 clearance and if we buzzed the engine to 7500 rpm, when we got to the pits, the engine was knocking. We thought we had stretched a rod bolt. We were so dissapointed. We went and watched the races and then after 20 minutes came back to hear it but the noise was gone, so we continued racing and kept the revs to 6500 and all was well. So obviously the rods had stretched but after cooling down, shortened up again. Wild

This year we will be taking it apart and installing thicker head gaskets.

I've had one do it. Makes pretty little indentions on the heads but didn't hurt anything. Quench was about 30.

Originally Posted by camaro_fever68

I've had one do it. Makes pretty little indentions on the heads but didn't hurt anything. Quench was about 30.

In our case, we believe it caused our heads gaskets to blow. Our machinist decked the block plus .06 and we had told him to zero deck it. I caught it during assembly but he thought a .039 gasket would handle it.

Originally Posted by DennyW

.039 is the bulls eye to shoot for.

Nice tree Denny.

Originally Posted by erik erikson

Nice tree Denny.

Ok, but sorry. Erik, it's all good with me if you like Denny's tree, just don't expect me to chim IN with you.
I'm not saying that I abhor his tree, but, it's just not for me.

Denny Thanks for the answer, Much better than the one that edelbrock sent
"There is no maximum, but too much clearance means that there is no quench, which means no power. Anything tighter than this, or the head gasket thickness, there is potential for piston to head contact depending on the connecting rod or rpm. Thanks." Me thinks the best way to cover your butt is to not completely answer the question.

If you want a maximum number, I believe it is .080, and especially when using the lighter rods which use aluminum.

Originally Posted by TyphoonZR

Ok, but sorry. Erik, it's all good with me if you like Denny's tree, just don't expect me to chim IN with you.
I'm not saying that I abhor his tree, but, it's just not for me.

Well happy Hanukkah then.

Originally Posted by 53 Willys

Denny Thanks for the answer, Much better than the one that edelbrock sent
"There is no maximum, but too much clearance means that there is no quench, which means no power. Anything tighter than this, or the head gasket thickness, there is potential for piston to head contact depending on the connecting rod or rpm. Thanks." Me thinks the best way to cover your butt is to not completely answer the question.

You are talking about something that has way to many variables.
If I build a stock type engine I just make sure you have a min.of .040 and call it good.
On drag race engines you can get by with .030 with good steel rods for good alum. rods you would need at least double that and maybe a little more depending on rpm's.
On a IMCA mod engine we try and shoot for .050 because even with good 4340 h-beam they will grow some.
Like I said it really is an open ended question.

Originally Posted by DennyW

In British Columbia Christmas turkey may be accompanied by either fresh or smoked salmon.
In Canada the traditional Christmas dinner is roast turkey with vegetables and sauces. For dessert it is rich, fruity Christmas pudding with brandy sauce. Mince pies, pastry cases filled with a mixture of chopped dried fruit.

Looks like Thanksgiving Dinner to me.

Stop it Denny, you are making me hungry.
Now where did I put my lunch?