Rod bearing failure (again)

[1972ho]

This is how most of the other bearings look like when 5 are 8 fails,and I haven’t broken any crankshafts

[rustbucket79]

Timing yes but also oil supply as you’re winging it up to 8000 is the major issue.

What’s your engine and oil system mods on this engine? The decent rods are why it doesn’t look way worse than it does.

I believe one hit on the dyno would have you scratching your head why you’re turning this engine 1000 to 1500 higher than it wants to spin.

[m880]

This is how most of the other bearings look like when 5 are 8 fails,and I haven’t broken any crankshafts

Not fixing the problem but may make it live longer by running full groove mains?

[BCjohnny]

The big port 4v small valve 2.05 / 1.65 OC D3ZE heads, are commonly machined to take the earlier 4v big valve 2.19 / 1.71 pieces (or bigger) because the throat allows more leeway with shape ....... as you know

The only trouble is with a std stroke you end up with a lousy combustion chamber 'shape', because large pop ups are needed to get the compression back, cue lots of timing and 'bad' combustion ...... not helped by the production based manifold

The timing requirement is a symptom of this, and a big red flag

Some change, probably quite minor, has tipped it over the ragged edge, recently

You're still chasing a 'bottom end problem' when you most likely have a 'top end' one

JMO

[BillK]

I’ve been running the timing like this for about 6 years now running the same fuel and timing

So can you think of anything that has changed in the combination right before you started having the problem ? Has the crank been checked or reground since the first episode ? How about the rod big ends and small ends ?

[jsgarage]

Clevelands are known to rotate the outer ring of harmonic balancers, progressively moving the timing mark toward retard. Worn cam chains do the same, and cam chain life is unusually short compared to other small blocks. Dyno runs on mine usually show best power at 29-30 degrees max advance with closed chamber heads and far less rpms. I would verify the true cam-to-crank timing before throwing more parts at it.

[1972ho]

My harmonic dampener is from innovator west so I don’t think that thing moves the timing chain is fairly new but I’ll check it anyway and verify the ignition timing.

[1972ho]

The main bearing someone wanted to see

[tuffxf]

Gday,
You’ve had several people on here offer to help you, but you aren’t giving them any info.
Oil system Setup, clearances, bearing type and brands ,piston to head etc etc
If you are going to post pics of bearings, put all the mains out on a sheet of paper marked 1-5 and upper and lower, same with rods,
You need to help yourself
Cheers

[Danoh1]

My 72 HO set up for vintage road racing had similar problems. You probably have too much timing, however, I think it’s oil related too.

Are the lifter bores sleeved? You must reduce the size of the oil supply hole in the lifter bores. It cannot support that RPM. Your oil pressure will get pissed away through the lifter bore holes.

Do you run the external line from above fuel pump to back of block? This will help distribute the oil more evenly and reduce your oil pressure drop to the rear.

Get the blueprinted oil pump. And make sure you are not sucking the pan dry.

Assume roller lifters and solid flat tappet. Did I miss the cam set up?

The intake is fine. I made 550HP with that intake. It is pretty good. Strip dominator is better. Scorpion is also pretty good. Torker good.

[1972ho]

Danoh1 I have the restrictors in this block .060 to the lifters and a set of light weight 60 gram solid lifters and do not have the external line installed I think this set up must be having a timing issue over another set I run that I had not a lot of problems with beating up a bearing.I’m going back to the set up I ran prior to these problems when goes back together and I also run a 3 qt accumulator.

[Danoh1]

You might consider bushing the lifter bore. Even the oil restrictions aren’t enough to stop the severe bleed off at the lifters. Look at how big the supply hole is in the lifter bore. It’s way too big. This is where the Cleveland looses its oil.

There is a DIY kit available. I did it the hard way. I installed copper pipe through the lifter supply lines on both sides. Then beat the lifter bore copper down. Then honed to fit. Then I drilled a small oil feed hole in the lifter bore. I can’t remember how big. I’d use the off the shelf kit now. This method described came out of a mopar modification book. Worked good. Ton of work.

[BobbyB]

Danoh1 I have the restrictors in this block .060 to the lifters and a set of light weight 60 gram solid lifters and do not have the external line installed I think this set up must be having a timing issue over another set I run that I had not a lot of problems with beating up a bearing.I’m going back to the set up I ran prior to these problems when goes back together and I also run a 3 qt accumulator.

I might have missed it...but are you running a factory crank? My understanding is that aftermarket cranks address the oiling problems with the cleveland.

[Steve.k]

I think your issue is timing. Your way to high on timing. Every oc head I’ve Dynoed quit making power at 36* and at 34 it was the same. An ol super stock racer told be once you can advance ignition till you hit compression lock. His term for so much advance that it fights against itself. I think thats your issue. Its basically hammering itself apart. The oiling mods you did are typically Cleveland mods and the Cleveland will run all day everyday at rpm this way. The high timing is giving you a false conception of throttle response and pull out of gate. This will only last a short time on say a quarter mile pull. Might be a good option once back together to dyno this engine. Steve

[1972ho]

Hey Steve what about at race tracks where the DA and Barometric pressure is 28.75 and lower with DA’s above 3000 plus ft .A friend of mine he runs his cleveland around that amount of timing but his car at less weight than mine is .25 slower and about 2 mph less but his bearings always look better than mine.