I need to know what the factory piston to deck height is for a 93 5.0 with the hyper- u pistons. I am having trouble with piston to valve clearance with my engine. It's a stock short block with an E cam and 1.7's and I'm down to .011 on the intakes @ 7* atdc. I have checked and double checked all other possibilaties. My deck height is about .003 in the hole, That is good but it does not seam to be what the factory would have set it at. If you have a short block around can you please check to see if the the pistons are close to being flush with the deck at TDC. Just trying to get a feel for what they are from the factory.Any year untoched (unmachined) short block will be fine, also any engine manual info for this dimension would be good. Thanks Dan.
5.0 piston to deck clearance
- Thread starter mach1dan
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With new bearings and UNTOUCHED crank, rods, pistons you will have from approximately .008" to .013" in the hole. It's very rare all cylinders will have the same clearance, and this is the reason for "square decking" a block.
.003" in the hole is a nice clearance... most people in my group would prefer .000" which is common practice to attain a .030" to .040" quench.
It's my assumption you have camshaft timing issues you need to address, and that is the cause for your lack of PTV clearance.
You didn't mention what heads, what gaskets, where your camshaft is dialed in, pushrod length...? These are a few questions to start with.
.003" in the hole is a nice clearance... most people in my group would prefer .000" which is common practice to attain a .030" to .040" quench.
It's my assumption you have camshaft timing issues you need to address, and that is the cause for your lack of PTV clearance.
You didn't mention what heads, what gaskets, where your camshaft is dialed in, pushrod length...? These are a few questions to start with.
The problem appears to be the combo with the stock pistons themselfs. I have tryed different combo's from: stock heads, cam ,lifters ,pushrods and rockers with felpro perma torque gaskets (.055) nets minimum .115 int @7* atdc and .190 exh @ 7* btdc.To edelbrock perfomer set up: edlebrock performer heads 60379 (1.90 int& 1.60 exh) E-cam, 1.7 cobra rockers,felpro 1011-2 gaskets (.045) nets minimum .011 int@ 7* atdc and .040 exh @7* btdc.( And all combo's thier of).My arguement with my local speed shop that I purchased everything from is that the performer package is advertized by edelbrock (and him)to be "bolt on out of the box" for 85-95 5.0 L engines except 86 W/O valve notches. His arguement is that my motor is either decked or has the wrong pistons or crank because he has done this combo to many 93 5.0's and never had a problem. He also admitted that he has never checked the piston to valve clearance on any of them.(my point was ,then how would you know ?) I know that I will need to fly cut the pistons if I expect this combo to work. It just pisses me off that he is insistant that it must be my motor and not the combo that is the problem.That is the original reason for my post, I could not find documented info on piston to deck clearance. He insisted that this was the problem and that it should be at least .025 in the hole from the factory. Their is no evidence of machining of the deck. ( I know what it looks like, I was an engine machinist for 5 years.)The engine was virgin when I disassembled it. All the part number and dates are correct. The performer combo just does not work on the 93 motor with out additional machine work.(fly cutting). I was trying to build this with out spending a lot on machine work, but we all know how that goes. Thanks for your responces, Dan
