It was said the 442 was factury blueprinted and deck clearanced .02 below the deck maximum,
With the thin steel headgasket what was "Squish" for this engine. The car craft 455 Olds build with Edelbrock heads had 0.065 squish....what gives?
Thanks
joepenoso

 

If im interpreting this right you mean the deck was -0.02, meaning the pistons came up slightly out of the block. At 0.065 "squish", which comes out to the equivilant of a 0-deck block and 0.045 gasket which is pretty much stock if i remember right. Seems to me decking the block down that far would require a larger gasket for clearance. My guess would be the factory was trying to get the pistons as far out of the block and into the gasket as possible without causing clearance issues. Ive been told 0-decking the block and using a 0.02 gasket would cause issues so maybe this is what they were thinking?
Idk, thats my 2 cents haha

 

PS: Using summit's compression calculator -
4.125 bore x 4.25 stroke, 80cc heads (assuming C head) 15cc pistons, -0.02 deck, 0.065 gasket yeilds about 9.87:1 compression. In that case i would second your statement of "what gives" lol

However the same specs with the crazy rare D heads yeild 10.82 compression, and E heads could yeild 10.13. So if this were a D head combo itd be a monster, but other than that i agree with you, it doesnt seem to do much for compression. Unless the idea was to sell it like this from the factory and hint to their customers that they can go home and swap gaskets and make some awesome compression at extremely, extremely low cost

 

... except the factory head gasket was about 0.014", if I recall, though the manual gives it as 0.025", which leaves me a bit confused.

- Eric

 

then 0.014 would be 11.05:1 which sounds like what they'd be shooting for, but wouldnt that cause clearance issues?

 

The way I understand it is Quench greater than 0.040 becomes less effective in reducing engine knock, preignition, gas mileage. Car Craft used the new Edelbrock heads but left quench at 0.065 and compression at 10:1. Thereby increasing chances of preignition and reducing engine efficiency . I wonder if anybody used the Singh grooves on pistons to in crease engine efficiency in an Olds motor. The grooves point to the spark plug ..reduce preignition and increase MPG. Check out this link
http://speedtalk.com/forum/viewtopic.php?t=5907
Thanks
joepenoso

 

What is a safe quench clearance for steel rods and cast iron head?
If you use the .02 in the hole deck cleance plus the stock 0.017 steel factory head gasket combined equals 0.037? Could you go closer without having the head meeting the piston.

 

That is close enough to do the job and not have to worry about collisions. from what I understand .040 to .045 is good anything more starts heading down the detonation hill.

 

Quench is not as much of an issue when using Aluminum heads. They are not as prone to detonation below 11:1 compression so it isn't important that the quench is greater than .040". You don't happen to go to SAM (School of Automotive Machinist) do you?

 

PS...Car Craft is not the foremost resource for engine building. In fact, magazine projects are funded by donated parts and the articles read like a Summit catalog. I had the misfortune of "fixing" a car that Popular Hot Rodding "built" and then sold to the public once the series was complete. Here is one article about paint: http://www.popularhotrodding.com/tec...job/index.html

This car is the biggest POS I have ever seen. The front bumper was not even bolted on, it was set on, the bolts were put in for the picture but no nuts were ever put on the bolts. None of the lighting worked, but if you read the articles they will brag on and on about the painless wiring and all. The speedometer isn't hooked up. The vent controls were just cut and left in place. And there is a 8" round hole in the firewall (unplugged) where the vent fan used to be.

Don't cite magazines, find out what real people are doing to their engines and use that as a guideline. I guarantee I've got more than .040" quench on the motor I just built with Edelbrock heads and I made 492 horsepower without any detonation issues. The magazines suck these days, no longer are they run by gearheads....rather the advertising companies have taken over.

 

The magazines don't hold a candle to this web site. You can't beat the price either!. I was under the impresion it was best to have the quench as tight as possible for turbulance, better fuel economy and resistance towards preignition. There's people who put grooves in squish areas to acheive this (Singh grooves google it) I was just wondering the tightest others have went with steel connecting rods ? I wonder if .030 quench is possible without pistons smacking the head?
Thanks
joepenoso

 

Remember that most Oldsmobile engines have dished pistons, rather than domed pistons, so the Singh groove discussion is not relavent in most cases.
With flat-tops, it would be interesting to do the experiment, but it looks as though even in domed applications, the results have not been conclusive.

- Eric

 

I still wonder what the closest squish would allow before contact............
0.028..........?
thanks
joe penoso