Any major issue going with thicker head gasket??

427L88 · Feb 13, 2006

I'm thinking of going to the slightly thicker FelPro head gasket for an added measure of "pump fuel" safety. Any durability issues with these? I know my quench will go from .046 to .057, which isnt good, but other issues?

Tired of running on the ragged edge of pump fuel. That stuff won't get any better, I'm quite certain.

( found out why it was detonating. Carbon buildup in the chambers. THat stuff will take your " DCR calculations" and throw them to the wind. PO'd that I didnt take a can of GM Top ENgine CLeaner to the motor before I pulled it apart. Bet the detonation would have gone away with the carbon!)

Busted Knuckles · Feb 13, 2006

According to the experts, it'll probably have worse detonation with a wider quench. Try dripping water thru your carb sometime to get rid of carbon. Edelbrock has a system that does that but it has a purpose other than keeping everything clean. Ever notice how clean a chamber is with a head that's cracked into the water jacket?

71454Chevelle · Feb 13, 2006

Gene,

Not an expert here, but I'd bet you would be better off leaving the quench distance alone. IMO, you would probably detonate as bad or worse with the larger distance.

What will your DCR be with the new heads? Is there anyway you could open the chambers abit?

BillsCamino · Feb 13, 2006

71454Chevelle said:
I'd bet you would be better off leaving the quench distance alone. IMO, you would probably detonate as bad or worse with the larger distance.
What will your DCR be with the new heads? Is there anyway you could open the chambers abit?

I agree Gene...lay some specs on us so we've got more info.

427L88 · Feb 13, 2006

Running the SRP medium dome jobs 29cc dome, 3.76" stroke 4.311" bore, slugs are down .007", standard gasket is .039" compressed, heads are at 116cc. Harold's old cc grind, 276/284 seat, 110 LSA.

I'm sure the carbon was a major factor in the detonation.

Sure glad I polished those chambers!

Dont have the DCR calculator here at work. I'll stick to a standard FelPro anyhow. Only thing I like thicker is Oreo cookies anyhow.

10secBu · Feb 13, 2006

427L88 said:
Running the SRP medium dome jobs 29cc dome, 3.76. .060", slugs are down .007", standard gasket is .039" compressed, heads are at 116 cc.

I'm sure the carbon was a major factor int he detonation.

Sure glad I polished those chambers!

Gene, any chance you can chuck the pistons up and mill some of the dome off to lower the compression ratio? Are they a solid dome or a hollow dome? JE/SRP might be able to tell you how much you can safely take off if any.

I'm not sure increasing quench by head gasket thickness is the right way to solve your issue.

Maybe Mike Lewis or CNC can give you their thoughts.

GRN69CHV · Feb 13, 2006

Carbon build up and the fact that you run a solid flat tappet cam. No way to cut it, solid flat tappets have the shortest "actual" seat-seat timing of any cam. I would bet a large flat tappet hyd cam would have taken care of things and if you wanted to drop the R's down into the 6200 max range, a hyd roller would have defnitely solved the detonation issue as well as kept (maybe even upped )the power level.

71454Chevelle · Feb 13, 2006

427L88 said:
Only thing I like thicker is Oreo cookies anyhow.

Especially the Double Stuff Oreos. :thumbsup:

71454Chevelle · Feb 13, 2006

Gene,

Don't you have that cam advanced quite abit? What about taking a couple of degrees advance out of it?

Troy70SS · Feb 13, 2006

Hey Gene - what about going to the 288/296 solid cam instead. That's what I was thinking of doing if I have problems when I put the 155cc chambered Brodix heads on my motor. I'm running the 276/284 solid now.

Just a thought....

Troy.

BillsCamino · Feb 13, 2006

427L88 said:
Running the SRP medium dome jobs 29cc dome, 3.76" stroke 4.311" bore, slugs are down .007", standard gasket is .039" compressed, heads are at 116cc. Harold's old cc grind, 276/284 seat, 110 LSA.

Using the above figures...
CR is 10.16 :thumbsup:
Quench is .046"
DCR figures at 8.17 (intake c/l at 106)

Looks right on to me!!

Guest · Feb 13, 2006

Gene,

Try a couple of cans of Seafoam in your tank after fast idling her and dumping some down the carb's while she is running.

I know, I know, she will smoke like a STEAM ENGINE breaking the crap loose!!

Should decarb her good tho, imho..

Then do like I do and every third oil change add a half a small bottle of good old MMO to the oil and the rest in the gas tank at fill-up!

The darned old, "snake-oil" named stuff is probably made out of high purity oxygenated esters that are documented to act like "steam" in the chambers running under load to clean them..

Can't hurt anything, so what do you have to lose??

Come back and tell us how she runs after the Seafoam an a tank or two of gas has been ran through her..

pdq67

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540Hotrod · Feb 14, 2006

Any chance you can do a little chamber work and add a few CC's as well as helping breathing?

That's how I'd go about it.

JIM

71454Chevelle · Feb 14, 2006

Question..............when doing a little chamber work (i.e. laying back the chamber walls), what kind of cc increase do you typically see?

427L88 · Feb 14, 2006

Guys, I running 55+ hours a week running a biz, and raising kids on my spare time. The short5 block is NOT being disassembled. It would never go back together, see point one.

I wouldn't mill the pistons anyway. I'd get some 118-120 cc heads on there.

And to think that solid cams somehow effect detonation is quite spurious I think. My last solid cam was more like a old GM with wide seat durations AND 114 lsa. So to say my current cam builds more cylinder pressure than an old outdated design, yes, but to say solids over hydraulics is like saying all Italians are in the mafia.

Well, I'm hopeful 116cc-117 vs 112.5 and dropping running temps will do it.

540Hotrod · Feb 14, 2006

You can do a lot...for example my BB heads were 119cc before porting etc. They ended up at 129cc before we started angle milling to get them back in line.

I recently did a set of old iron 461's for a small block. I got them out to 70cc (from 64cc) without too much work just by unshrouding around valves etc.

JIM

427L88 · Feb 14, 2006

Yeah, I hear ya 540, but life gets in the way. I just want the car together and running. No time for such mods and can't waste money to pay anyone.

Mr. 4 speed gets by with 10.4 and a slightly bigger seat duration. 10.2 should be fine. And if it isnt - oh well.

DO appreciate the thoughts gents, but your suggestions are just not doable unless I get fired and have an additional 50 hrs a week to play. Maybe next year when a get a car club monkey off my back., I can get back to tinkering and enjoying it.

I just wanted to know if anyone had run the thicker .051 FelPro.

Guest · Feb 14, 2006

You mean you don't have time to try my "shade-tree" trick with the Seafoam and good old MMO??

Try it, it might just clean enough carbon/ash out of her to fix you right up??

Then either come back and say it worked OR pdq67's fulla sh-t!!

he, He!!

pdq67

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BLT4FN · Feb 14, 2006

Gene I'll throw my 2cents worth in.

It will not get a chance to carbon unless you drive like a little old lady

SO

DRIVE IT LIKE YOU STOLE IT!

:beers: :thumbsup: :beers:

bowtie6872 · Feb 14, 2006

Any major issue going with thicker head gasket??

427L88

Busted Knuckles

71454Chevelle

BillsCamino

427L88

10secBu

GRN69CHV

71454Chevelle

71454Chevelle

Troy70SS

BillsCamino

Guest

540Hotrod

71454Chevelle

427L88

540Hotrod

427L88

Guest

BLT4FN

bowtie6872

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