New 4.6L stroker build

[Bodo]

I'd start looking for a new machinist. Is the shop the only common thing?

[SilverXJ]

Roller rockers, head, valve springs are the only common items between ALL engines. I doubt it has anything to do with the actual machining, a bore, hone, deck can cleaning would not cause these problems... incorrectly cam bearings would, but I doubt thats the issue but will check... but I'm not agreeing with his diagnosis.

[Bodo]

What cam bearings have you used? Got part numbers?

[SilverXJ]

Cam bearings - Clevite 77 - SH1980S

[YJason]

Sorry to hear your having major issues again

I'll sell you a good used 4.6L stroker, thinking of parting my heep out and starting over with a 4 dr JK.

[SilverXJ]

The middle two bearings showed the worse damage, then the front with the rear showing the least damage. I don't think that pattern fits an oil problem considering the rear and front are the last to get the oil. Also, I checked #1 and #6 rods bearings. Aside from dirt they didn't look bad.

[Bodo]

Cam bore was checked for straightness and roundness?

[SilverXJ]

Yes it was.

I just checked two cams. One comp I had ran at one point and the Isky. Isky took off about .22" from the diameter of the shaft. The bearing journals measured the same between the two. My digital scale is a piece of shit so I was unable to compare the weights.

[dwg86]

Maybe the cam is flexing from the material that has been removed?

[SilverXJ]

Lee at Hesco thinks its the retainers hitting the valve stem seal. I didn't check that on the Isky cam, but I did check it on the Comp Cam. The comp's exhaust lift is .485" and the Isky is .480". I'm going to check how much room there is on that lift on the head tonight. I'll also check the actual lift on the cam

[SilverXJ]

Meh.. it wasn't the retainer to valve stem seal clearance as it was at least .555". The cam lift is where it should be too.

Out of ideas... the bearing wear doesn't show low oil pressure as the center cam bearings show the most wear and while the rod bearings are dirty they don't show any thing horrible. The comp cam I ran previous had .485" of lift on the exhaust and the Isky has less at .480". And there is no reason its the rockers losing oil pressure. If it was in fact the rockers bleeding off oil pressure then the oil pressure would have been bad to start with.

[the_wrench116]

i would think if a cam was going to flex it would be at the point of most force or in our case the oil pump drive gear and you mentioned that isky takes material off at this point. or your just cursed???

[SilverXJ]

I just don't understand this at all.
1) Engine was fine with the Comp cam, about 1000 miles on the cam. Great oil pressure
2) I kill the Comp
3) Isky and Lunati lifters with slightly less lift than the Comp installed after cleaning engine (using existing bearings beacsue they were fine)
4) Cam bearings die in about 500 miles
5) New block, new bearings, new Isky cam, new Johnson lifters
6) Cam bearings gone once again

-Cam spun fine in cam tunnel
-Block's cam tunnel checks out fine
-First Isky came out bent
-Bearing journals are fine on Isky
-Plenty of lube
-Prime prior to break in
-No binding

Seanyb505 on here is also running an Isky. He has low oil pressure and is replacing his oil pump with a HV. I asked him to check his cam bearings.

[lafrad]

Geeze... its starting to sound like procedural error or something.

Is the oil filter adapter clean? how about the oil pickup tube being far enough from the bottom of the pan... maybe there is just too much preload on the lifters?

[SilverXJ]

Oil filter adapter is clean. Oil pick up tube is about 3/8" from bottom. Preload has varied between .020" to .040", never more. Of all the different cams and engine variations I have run I never had this problem with cam bearings going out like this.