4.7 stroker #6 piston scuffed wall

[SilverXJ]

If you were running a melling pump that failed you could have had the retailer send it back to melling and make a claim.

[danimal]

i did already, it's only been a week, so i'm waiting on a reply.

[superstingray77]

My pump locked up at the actual drive shaft where it goes through into the top of the pump housing. It seized the drive rod and also grabbed the centering dowel/bushing out of the block fused it to the pump shaft. When I tore into the pump the gears were perfect, no debris, no scoring of any kind. It broke one of the engagement tabs off and stopped turning completely.

Few thoughts I have-need to mic a few parts to confirm this but...

The HV pump visually appears to have a larger diameter shaft than the reg volume unit which if there is not enough clearance the alignment dowel will eventually seize to it as parts heat up and expand.

The gasket thickness of the distributor/cam sensor where that meets the block is all that prevents the unit from being literally crushed into the oil pump forcing the gear set to grind into the bottom plate of the pump when the hold down is tightened up. That could increase load on the drive shaft causing cam/distributor gear wear as well as overloading/heating the shaft up.

I am not using an HV pump this next round, I think the additional loads are too hard on the cam gear/distributor and I am not certain the HV really adds any benefit to the engine. Cam etc are splash lubed and the stock pumps work great for 2-300k miles on many 258/4.0 that I have either owned or worked on over the years.

On my #6 piston, I had what I feel was excessive piston rattle (like a marine diesel) when cold but after 5 min it stopped. The manufacturer says after looking at the photos of #6 that he really feels I had a problem on that cylinder from the first start and it just progressed from there. I have a gut feeling he is correct and the culprit might be the machine shop leaving too much P/W clearance causing the piston to rock in the bore too much. RaceTec says that .003 is all i should have and I seem to recall the machine shop telling me the bores were honed to .0055+

[danimal]

i didnt want to tamper with my pump, but the shaft appears to have seized as well, it was solid in the pump housing with both ears broken off. I suspect it was for the same reasons yours did. My motor was all original other than the pump and ran fine and quiet previously. Did you attempt to file a claim? Sorry to take this thread slightly off topic, i just really want to figure out what happened before i throw another melling pump in my stroker.

[superstingray77]

I can file the claim via Oreilly however I waited a year to do it so not certain if worth while now. I will likely try it once i have the written estimate from the machine, shop, parts lists etc. Not certain right now if my block is able to be re-used. I can have the 1 piston remade oversized by .003-4 to ensure accurate PW clearance but if the other 5 are hurt or have excessive PW clearance then I am faced with either getting a whole new set of pistons again (600 bucks) or finding another block and having the 1 piston remade to match that set. My rods and crank are in perfect shape no damage and they are fully balanced (spin etc) I guess i could take the block .090 but ... kinda thin for a turbo engine in IMHO.

_R

[danimal]

I can file the claim via Oreilly however I waited a year to do it so not certain if worth while now. I will likely try it once i have the written estimate from the machine, shop, parts lists etc. Not certain right now if my block is able to be re-used. I can have the 1 piston remade oversized by .003-4 to ensure accurate PW clearance but if the other 5 are hurt or have excessive PW clearance then I am faced with either getting a whole new set of pistons again (600 bucks) or finding another block and having the 1 piston remade to match that set. My rods and crank are in perfect shape no damage and they are fully balanced (spin etc) I guess i could take the block .090 but ... kinda thin for a turbo engine in IMHO.

_R

The paperwork i got from filling out my claim at orileys said 180 days is the limit. I was at about 170 lol.
Good luck man, that would suck to have to replace everything. At least the crank and rods survived.

[SilverXJ]

Melling's warranty is 1 year.

[superstingray77]

Anyone have an opinion on going .090 or larger in the bore. This is of course assuming the block is Sonic checked etc. My fear is with the turbo the walls will be too thin..

[SilverXJ]

I would not do that.. too thin of a wall left.

[superstingray77]

Just got the sonic test results back on the block. Its toast. Machine shop (Precision Machine owner Dennis) here in Austin said that its got so many thin spots even at .060 that it wouldnt have lived long under boost. And bore distortion on #6 already appears to be part of the reason #6 is torn up worse than the rest. He STRONGLY recommended finding a thicker walled block and going .020 for my turbo use if I want it to be reliable and last. He said if the other blocks are this thin then .060 is just inviting disaster.

Now begs the question... what year blocks can I use this is a 99 WJ originally. Forged Scat Crank/K2 Forged Rods - whatever forged slugs I end up buying/having made to go back in. Aftermarket head with major porting/solid cammed etc.

Also were any years or castings known to have less core shift and thicker walls?

[superstingray77]

Deleted Duplicate

[SilverXJ]

Just got the sonic test results back on the block. Its toast. Machine shop (Precision Machine owner Dennis) here in Austin said that its got so many thin spots even at .060 that it wouldnt have lived long under boost.

How thin?

what year blocks can I use this is a 99 WJ originally.

99+ WJ or 00+ TJ for everything to bolt on as stock.
Here is a recent thread on that: http://www.jeepstrokers.com/forum/viewt ... 849#p38849