Jeep Strokers

Guys,
Last year my 3rd 4.7 Stroker bit the dust due to a failure of the Melling HV pump. During the teardown other than a few scratches in the bearings we found the #6 piston had decided mate with the wall. The reason for this failure was having my machine shop run .0055 P/W clearance per the morons at 505 Performance who sold me the pistons and rods. Turns out according to Race-Tec who builds the pistons that this is nearly 2x the maximum and will end up in piston failure. Guess what they are correct it does destroy your engine. So at this point I need to change the slugs out for a fresh set and either bore the block farther than the .060 it is already at or find another block then bore/line hone/deck etc and transfer all the parts into it. To save coin as long as the wall thickness will be sufficient for the turbo use I would like to retain my existing block and just knock it out to .080 and install a set of .080 pistons. Thoughts on how much over bore and wall thickness we need to be safe? They are sending the block out today for a sonic check.

-RM

Can you buy +0.080" pistons off the shelf?

No I am having them made, but even my .060 were made. First one had the Icon 944's they are in perfect shape about 1200 miles on them but are balanced/hung on a set of reconditioned stock 4.0 Rods with ARP bolts.

Had my block sonic checked and while I have to admit I don`t have the numbers in front of me .080 was not a problem.

Been running a set of Diamond Racing forged, again a plus .080 with no problems.

Curious on what failed in the Melling HV.

There was nothing locked inside the pump or gears. What appears to have happened is Melling had the hole in the upper pump body where the shaft passes through setup without enough clearance. It fused the drive shaft into the upper pump housing, then sheared off the tabs that lock it to the base of the distributor shaft. Sadly that was part of my issue but not all of it. The P/W clearance was obviously a problem from the start.

BTW has anyone sleeved a 4.0 ? Maybe I can make 9 liters out of this 4.0 yet rofl..

superstingray77 wrote:BTW has anyone sleeved a 4.0 ? Maybe I can make 9 liters out of this 4.0 yet rofl..

I had a 4.0 block sleeved and it worked fine

Did you sleeve it for displacement or just a cylinder to repair the block? Figure another block would be cheaper but if I want to get larger slugs into it then perhaps sleeving it would be a good option. Although I am installing a turbo and targeting 14-15psi.

Thrust side for me I would like to see .160" and above. Non thrust or side walls no lower than .110". I have ran many motors in race trim at these levels with a true 4.000" bore and have only seen one failure after three seasons of beating and it did split down the cylinder wall. Yeah, Melling HV pumps do SUCK!!! I run standard melling pumps worked and blueprinted and there easier on cam gear wear. Good Luck!