New 4.6L stroker build

[SilverXJ]

Got the block back from the second machinist. No problems found. He recommended using coated bearings so he installed those. He thinks that the coated bearings will solve the problem. I doubt that. I'll try to find other issued before I put it back together again.

Possibly an oil issue, like air in the oil. But I hear no weird noised from the lifters and the other bearings show no damage. And where would the air come from? I will test the oil pump for air leaks this week.

[shawnxj]

buddy of mine was telling me that you can sometimes get air through the surface where the oil pump meets the block so i put a little bit of permatex around both edges of the gasket to make sure it has a good seal

[SilverXJ]

That doesn't make sense. Thats the pressure side of the pump. Oil would be pushed out through there. No suction.

[SilverXJ]

I pressure checked the oil pump this evening. Pressurized up to 60psi.. used soap around the joints to look for leaks. Did it cold then heated to about 200*. Where the pick up meets the pump is nice and tight.. no air bubbles. There was some leakage around the gasket for the cover. Don't know if that is to be expected or not. Not the ideal way to check it, but its better than nothing... and I don't have any other methods of checking it.

[I6FAN]

Would you see air bubbles there?....Thinkn it be drawing in...maybe you could see something?

Man, I was pretty sure you had this fixed last time! Did they end up reaming anything from the bearings?

[SilverXJ]

Would you see air bubbles there?....Thinkn it be drawing in...maybe you could see something?

I was expecting to see air bubbles form the pump to pickup seal. Nope. Coming from the oil pump cover really doesn't surprise me. I have never been impressed with the way they sealed.. basically a thin gasket and a thick stamped cover. Most of that would be under pressure any how, which would only leak oil, not pull air in. I'll still try to fix it. Probably lap the bottom on a piece of sand paper on glass just to make sure its flat. Doubt it would help that much as those coutersunk bolts aren't exactly a precision fit with the cover.

Man, I was pretty sure you had this fixed last time! Did they end up reaming anything from the bearings?

Yeah, me too. Nothing was removed from the bearings because it was all in line and clearances no grater than .003". Used stock sized bearings too.

Dale thinks there is some kind of incompatibility between the camshaft and bearings and the coated bearings would fix that. I doubt that. More like band-aiding a problem. I still think there is a real problem someplace but I don't know. I'm also a bit concerned what the coating material can do once it is released from the bearings.

[tigmeister]

I just got through reading all 34 pages of this thread. Holy crap!

My suggestion is, keep it simple, don't over analyze. Why not try a stock cam, lifters, and valve springs? No it won't be as potent as an after market setup, but it's
a proven combination for longevity, at least to see if the bearings fail again. Almost every 4.0 I've seen in the wrecking yard has anywhere from 175,000 to 275,000 miles on them.

I commend you for all the attention to detail and serious thought you've put into this problem, but I don't think it has anything to do with the way the bearings are put in or what type they are or which way they're exactly rotated etc.

You've had multiple brands of bearings and cams and even blocks with the same problem.

What's been the same? Other people have asked too.

The rocker and valve spring assembly has been the constant.

You didn't lose bearings with the comp cam, but you lost a lobe.

To me it looks like it would be worth a try with a less aggressive valve train, at least to test the theory.

Take it for what it's worth, just my 2 cents.

[SilverXJ]

The valve train isn't aggressive. ~110# seat, 250# open. No bind, no contact of any sort. This is a combo many people run, Mopar springs, Harland Sharp roller rockers. I believe the comp cam was damaged due to something I did,even though a few say what I did shouldn't have hurt it. None of the other cams show any lobe wear. None of the valve train shows any significant wear. I know that the bearings can't be at fault. I still haven't heard back from Hesco on testing my pump though.

[Exos]

I've run the mopar springs and retainers/Harland Sharp ajdustable rockers for 18 000 kilometers now, and no signs of cam bearings/lobes wear. I did not pull the oil pan, but the valvetrain noise is constant since the swap, oil pressure too, and performance stays equal.

[SilverXJ]

Since we had such warm weather this weekend I started on assembling the mess. Main and rod bearing clearances are .0018-.0020" as usual. The block deck was flat as possible. Using a straight edge I couldn't even fit .0015" under it. Smallest feeler gauge I had. The head has a slight warp. .003" in the middle, measure over the whole length. It is still well with in spec and I probably won't do anything about it.

First time installing my own pistons... first one didn't go to well. I don't know if the tool wasn't tight enough or if I wasn't holding the right compressor against the deck enough.What ever it was I bent an oil rail. So I need to get a new oil ring pack. Oh well. The remaining 5 went in easy. Made me look like a pro. Aside from #1 that is. Lol.

I also tested a theory I had that the block was flexing differently when supported by the engine mount sin the bay vs. at the end by the engine stand. I supported the engine in the middle with a jack and the deck flatness did not change. I guess it doesn't warp on the stand.

Hesco still has my oil pump and I haven't heard back from them on testing yet.

Aside from the crank I will be installing as many external accessories prior to installing the cam.. just to see if anything moves the cam tunnel. I doubt it will, but just an idea.

[YJason]

I've been absent from the site for awhile and just started checking it again and holy $hit, I can't believe you are still at it with the engine problems. You've got a lot more presistence than me. I think I would have said screw it a long time ago and installed a chevy 6.0 and a 4L65e and called it a day. I hope the new machine shop gets you fixed up and on your way to a happy stroker.

[SilverXJ]

Heard back from Hesco on the oil pump. It checked out fine. Sooo... nothing was found wrong again.

[dwg86]

Everything is checking good? HMMM. This may be a long shot and maybe not even a problem, but could you have excessive cam walk? If you are using a timing chain cover without the bump for the pin to ride on, maybe the cam is walking front and back and peeling the cam bearings. I didn't use the spring on my engine. I made a long pin out of a hardened bolt. I removed the rear cam plug and used a dail indicator on the back of the cam. I kept grinding and polishing the pin until I got .003 clearance. I also installed an aircraft fastener, called a hi-lock, in thr timing chain cover for the pin to ride on.

Just a thought.

[SilverXJ]

How would I check for excessive cam walk?

I do have the pin and spring installed and my cover does have the nipple for the pin to ride against. When installing the cover I can feel resistance from the pin against the cover so I know it is pushing back. Also, I thought that the grind on a flat tappet cam was suppose to pull the cam into the block? But yet that pin and spring setup was added sometime along the 4.0L's production run.

[dwg86]

I have also heard that a hyd cam is ground to keep the cam in the block, but most engines have some sort of cam retainer. And engines that were not manufactured with a cam retainer, have some sort of after market retainer (SBC).

Before you install the rear cam plug...install your cam with pin and spring and timing chain cover with the gasket, put a dail indicator on the rear of the cam, and pry forward and aft on the cam to see how much play you have.

Like I said, it's only a thought (racking my brain trying to figure this out). Maybe Benny at Hesco could tell if this is a valid thought or possible problem?