will it come outta there??

[blown84]

as a few of you know, im obsessed with makin room inside the cylinder for a big cam, so that valves arent rejected and/or ejected by the pistons. would it work worth a damn if i had, say, .020 milled off the top of the pistons (with a ceramic coatin, maybe i could take a little more?), and had shorter con rods, or would they come outta the hole? if i can use shorter con rods, how much shorter? .001? .500? 1.00? side effects?

 

[Black dawg]

I think it would be easier to look at valve timing

 

[blown84]

I think it would be easier to look at valve timing

thats just the problem. the 6.9/7.3 is an interference motor. the valves HAVE to close and open at a certain time, or they will get a face full of piston. my goal is to get as close to eliminatin this as possible, for more ideal timin.

 

[icanfixall]

Sounds like your going to need a head thats been cut down soyou can actually watch the valves and piston and how they interact with each other. A set of adjustable pushrods and a degree wheel will complete the tools for this cam project. A junk head should be easy tofind. Then finding a machine shop with a large enought band saw to cut down a head is next. Mel has some really great looking pics of the head typ4 cut down for him. Mel painted them to show all the differant passages thru the heads. The intake is yellow. The exhaust is red and the coolant is blue. Remember the exhaust seats are stellite so they will need to be cut with a cutoff grinder thin wheel. Then superglued back in the head.

 

[88beast]

pm me i got some specs ya mite like

 

[Black dawg]

thats just the problem. the 6.9/7.3 is an interference motor. the valves HAVE to close and open at a certain time, or they will get a face full of piston. my goal is to get as close to eliminatin this as possible, for more ideal timin.

Im sure that there is room for improvement, and it doesnt take much timing change to make a big difference.

my hotrod motor has huge friggin domes that mirror the combustion chamber and 2.19 intake valves. quench is right at .035. I have run some pretty wicked cams without any issues (.600 lift [email protected] 102lsa) at 7k and better.


what is the quench distance in an idi?