[Jromaine87]

I had a 535 all aluminum block built. IA2
And after 12 passes I spun a rod bearing.
I have been told that a lot of you guys are opening up the Main journals and doing work to the bearings themselves? Has anyone not done this and was successful? Looking for info on what I should do.

If not I’m selling it and building a new one.


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[lust4speed]

525 IA2 aluminum block engine has survived over 7 years with nothing special done to the bearings that I don't do with a standard block. Refreshed last year after a roller lifter came apart and main bearings still looked new. Several 7,200 shifts against the rev limiter at first until we got things straightened out.

[25stevem]

Assuming that the bolts in that rod are good and where torqued up to the needed preload, then with the improved oil feed layout in these blocks I would be looking for partial blockage in the Crank passage that was feeding that rod and also looking for signs of detonation on the plug and signs of Bearing getting pounded out before it spun.

[blaktopr]

As a side note, there could be another issue. I have nothing special done to my Al block and been good..
But my last engine stock block lost the bearing after 5 seasons because 1 cylinder went lean from an issue in the head and pounded the bearing.

[Jromaine87]

Originally Posted by 25stevem

Assuming that the bolts in that rod are good and where torqued up to the needed preload, then with the improved oil feed layout in these blocks I would be looking for partial blockage in the Crank passage that was feeding that rod and also looking for signs of detonation on the plug and signs of Bearing getting pounded out before it spun.

The bearing was completely destroyed. It came all the way out and was shredded. Nothing left if it.


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[mgarblik]

A few things that might help us with your unfortunate engine failure. 1. How do the main bearings look? Pics please. 2. Which rod bearing/bearings failed, cylinder number? 3. What connecting rods were you using? Were they tightened using stretch, angle or torque? Did the fasteners fail or were they loose? 4. If the connecting rods were new were they checked for housing bore size and then for actual oil clearance with a dial bore gauge before being installed? (especially Eagle). This info and some pictures of the failed bearings would be helpful. In general, a single failed bearing with the other 12 bearings in good condition points to a specific issue with a rod/bearing single issue, not a lubrication failure. A number of distressed bearings might indicate a lubrication failure.

[25stevem]

It's not unknown for a rev limiter to near Hydro lock a cylinder or two.
Just puttin that out there!

[Jromaine87]

Originally Posted by mgarblik

A few things that might help us with your unfortunate engine failure. 1. How do the main bearings look? Pics please. 2. Which rod bearing/bearings failed, cylinder number? 3. What connecting rods were you using? Were they tightened using stretch, angle or torque? Did the fasteners fail or were they loose? 4. If the connecting rods were new were they checked for housing bore size and then for actual oil clearance with a dial bore gauge before being installed? (especially Eagle). This info and some pictures of the failed bearings would be helpful. In general, a single failed bearing with the other 12 bearings in good condition points to a specific issue with a rod/bearing single issue, not a lubrication failure. A number of distressed bearings might indicate a lubrication failure.

Wow, this helped me a lot, it was a single bearing. Cylinder 6, and from what I am told now the rod is bent as well, so we’re looking into a hydro lock issue. It was a brand new carb. No water in the oil.
Thanks A lot


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[Gary H]

Originally Posted by Jromaine87

Wow, this helped me a lot, it was a single bearing. Cylinder 6, and from what I am told now the rod is bent as well, so we’re looking into a hydro lock issue. It was a brand new carb. No water in the oil.
Thanks A lot


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Sorry for the issues you had with the new engine. No reason to get a new block. If the other 7 rod bearings and main bearings looked good, I would suspect that the upper and lower rod bearings were mistakenly swapped. Or, it could be that the clearances were off on that particular rod/bearing assembly. I recently had a set of Sealed Power bearings that varied by .001 from side to side. It was just a flaw from the factory, and I was lucky to have caught it by mic'ing each one first.

Lastly, the rod was probably bent from the bearing seizing up.

[mgarblik]

Originally Posted by Jromaine87

Wow, this helped me a lot, it was a single bearing. Cylinder 6, and from what I am told now the rod is bent as well, so we’re looking into a hydro lock issue. It was a brand new carb. No water in the oil.
Thanks A lot


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Once again, some pics would be very helpful. I didn't mention in first post about looking for discoloration in the rod big end, crankshaft and other parts. Black/blue coloration indicates excessive heat from possible lubrication failure prior to failure. Little heat transfer would indicate a pure mechanical failure, for example, loose rod bolt, bolt failure, metal failure, pure hydraulic lock. (very unlikely but possible if it was coolant). Virtually impossible to hydraulic lock a single cylinder with a carburetor situation in a common single plane manifold. Coolant, however, could do this from a head gasket leak/block/head crack. Look for a single combustion chamber, valves that look different from all the rest. One final time, lots of pics might help us sort this out.

[aaronman]

I had a similar issue recently. We had a combination of issues which we found on the dyno. We had a water leak (from the head) on #2. We had a oil leak (from head) on #6. Both of these issue caused detonation (Oil/Water do not compress) and caused both rod bearings to show signs of detonation. We fixed the heads and issue was resolved.

[cgeise]

Is the engine restricted to the top end to keep the oil down low ??

[Jromaine87]

Originally Posted by cgeise

Is the engine restricted to the top end to keep the oil down low ??

I have 8an drainbacks


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