Help diagnosing a noise

[SilverXJ]

Well, I guess I'm going to do a rebuild. I will never be confident of this piece of crap unless I pull it and wipe the last traces of Titan off of it. I fix one thing and then something else breaks.

[FrankZ]

Yeah it sucks,,,but atleast yiu don't have to deal with one of these....

[SilverXJ]

Yeah.. I would have flipped if that happened as I have 6o hours in polishing and porting my head and intake manifold, and a 5 angle valve job.

[SilverXJ]

Its out. The front most mail bearing had some major scratches (gouges more like it) in the lower bearing shell. Appears it came from the oil hole in the crank as it is centered on the lower bearing and the upper is un touched. A few other bearing had some light scratches. Piston skirts had some scratches and the coating was heavily worn.

[Mgardiner1]

You said you've had a cam lobe failure in that engine? If so, then the damage to the bearings you see is most likely from the failure.

I still haven't seen you mention anything that would make the noise you described. Maybe the proof would be in the piston/cylinder clearance?

[SilverXJ]

You said you've had a cam lobe failure in that engine? If so, then the damage to the bearings you see is most likely from the failure.

I didn't get around to checking these cam lobes(they look ok), but even if it did I don't think it would do this. Its not from shavings. These scratches look like something larger got in there.

I still haven't seen you mention anything that would make the noise you described. Maybe the proof would be in the piston/cylinder clearance?

I haven't either. It reminds me a lot of the sound my 4.0L made before it lost piston #5 though.

[SilverXJ]

Clearances were around .002-.003 on the main bearings, worse on the #1.

[FrankZ]

Have you pulled the distributor and inspected the drive gear yet?

[SilverXJ]

Have you pulled the distributor and inspected the drive gear yet?

Yeah, nothing noticeable on it. Spins freely.

[Mgardiner1]

pulled the front cover yet? maybe the timing chain is out of alignment and chewing itself apart?

[SilverXJ]

pulled the front cover yet? maybe the timing chain is out of alignment and chewing itself apart?

Yes, the engine is completely apart (besides the head). Timing chain seems a bit lose, but not falling apart. No rub marks on the timing cover.

[amcinstaller]

have you checked the rod bearings yet, or are those measurements in the .002-.003 that you listed above?

[SilverXJ]

have you checked the rod bearings yet, or are those measurements in the .002-.003 that you listed above?

Yeah, they were about the same.

[dwg86]

Just curious...What piston/rod combo was used? How many miles?

[SilverXJ]

They are Silvolite 3241HC .040 pistons and 707 casting rods. Crank is the 3214723 heavy.