PDA

View Full Version : 2300 ford deck height



r3tracing
02-18-2012, 07:21 PM
does anyone know how much pistons can protrude out of the block and still be ok. this is a steel rod 5.2 length motor.

let-r-eat
02-18-2012, 09:26 PM
Alot depending on the head gasket thickness. With a standard .042 Felpro 8993 gasket around .010.

r3tracing
02-19-2012, 03:12 PM
So .013 or .014 would probably be too much with the 8993 gasket

car62
02-19-2012, 06:23 PM
how much is milled off the head?

r3tracing
02-19-2012, 07:53 PM
Don't remember for sure. We changed rods from stock to crower 5.2 and now they protrude farther than I was hoping. It was at zero with stock rods. Just concerned about the pistons smacking the head

84Dave
02-20-2012, 10:09 AM
What rpm do you intend to buzz the engine? If you're going to spin it 6500+, probably should have a bare-bones minimum of .030". And check/measure, at the outer circumference, how much the piston 'rocks' @ TDC. With a marginal piston-head clearance, piston rock/clearance can be a problem on the cam overlap cycle. PLUS...... if the clearance is marginal, quench 'pump' can suffer & cost you some minor TQ/HP. You want the burn pattern clear across the top of the piston. If in doubt, 'dimples' in the piston crowns will help. -Dave-

r3tracing
02-20-2012, 04:51 PM
Thanks for all the info. We cut top of pistons about .010 and we should be good now. This motor should see about 8000 so we wanted to be safe

Racedad
02-20-2012, 07:44 PM
We have run .027 Cometics with 0 deck on a 2.5 with stock pistons.No signs of contact at 7600.I built a 305 Chev back in the day with 0 deck and .017 steel shim head gaskets.That car ran like a shaved ape but the pistons were hitting the heads some. That was too close but it never broke........
I know some ofeS this is waaaay out there and flame away but here are some things I like about a minimum squish clearance:
Running on the tight side I think you get awesome turbulance and so are less likely to suffer detonation damage under extreme conditions.
The piston slows dramatically near TDC so if you cross the line and get contact at high RPM it's not as violent as you might think.
I also think MAYBE under extreme over-rev that we get protection from rod cap/rod bolt stretch with a tight piston-head clearance at TDC. Especially now with low tension rings.I don't have the rod and rod bolt failures I used to have since I have been building tighter side squish but that is also probably due to less detonation.