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Have a good condition 85.5 block and crank, was wondering if you guys think I can get away with just polishing this crank and not turning it if I were to build it?
Or get this one that is factory cross drilled unit on eBay. I don't know how much cross drilling helps vs using a crank scraper with a screen for aeration reduction, but I paid $400 ten years ago to have my crankshaft cross drilled and turned one size under on the rod bearings. http://pages.ebay.com/link/?nav=item...obalID=EBAY-US
Good point Spencer. Your comment earlier to me about why not just build it lead me dust the crank off and I realized it really doesnt look too bad, so I might just build it! Would a digital caliper be sufficiently accurate to check or do I need a good micrometer?
Also do you have a pic of that oil pan you're trying to offload? You said something about a broken baffle?
Good point Spencer. Your comment earlier to me about why not just build it lead me dust the crank off and I realized it really doesnt look too bad, so I might just build it! Would a digital caliper be sufficiently accurate to check or do I need a good micrometer?
It should really be checked with a micrometer; out-of-roundness tolerances are finer than the one-thousandth that a good vernier caliper can resolve.
If there are no deep scores in it, just polish it. Depending on what RPM range you run, cross drilling may be a waste of $$. Chevy used to cross-drill their cranks a lot. But esp. in their "crate motors" usually for racing, they don't do it any longer, because the oil was stacking up at the back of the block at high RPM's . Talk to a performance crank grinder and see what he has to say about this. Cross drilling on #2 journal might be a good thing since those tend to go bad first.
No scores, all the journals are smooth to the touch and look good. I was asking about the polish because though it may not be clear, there are some dark areas on some of the main journals, but again you can't feel them. Was hoping to be able to polish it at home by making some kind of jig and hitting it with some rolled up 600-100 grit soaked in oil and then toss it back into the block. The bores on the block look really decent.
Coming back to this, all the journals are in spec, and are concentric near as I can tell. Took some representative pictures to show the mains and rod journals.
They all feel smooth as glass, no scratches but as you can see they all have some discoloration. Should I not worry about it, or is it worth my time and money to have it polished? I'll be using new rod bearings, but the mains are getting reused from my last engine so long as they plastigauge ok since #1 they're expensive, and #2 they tend to get hardly any wear in our motors.
Pictures are no substitute for sliding your finger over a surface and "feeling" it... but, judging by your pictures, I think it needs more than a polish.
All of those discolored areas in line with the oil holes are not normal... I fear that crank has seen some rough times. Perhaps some kind of debris in the oil or a limited supply of oil.
Polishing is a surface finish treatment - it doesn't really remove material. And, the the discoloring you have, and possible scratch marks, you might have to remove material so you have a good surface to polish.
Do keep in mind everything is relative. I know you have your cylinder bore issue and you're trying not to spend a lot of money... You could put this crank in and possibly get years of service and there might be some other part that is the "weakest link". The condition of the parts you start with is purely your call - I just don't want you to think that polishing a damaged crank will solve some sort of other problem.
Pictures are no substitute for sliding your finger over a surface and "feeling" it... but, judging by your pictures, I think it needs more than a polish.
All of those discolored areas in line with the oil holes are not normal... I fear that crank has seen some rough times. Perhaps some kind of debris in the oil or a limited supply of oil.
Polishing is a surface finish treatment - it doesn't really remove material. And, the the discoloring you have, and possible scratch marks, you might have to remove material so you have a good surface to polish.
Do keep in mind everything is relative. I know you have your cylinder bore issue and you're trying not to spend a lot of money... You could put this crank in and possibly get years of service and there might be some other part that is the "weakest link". The condition of the parts you start with is purely your call - I just don't want you to think that polishing a damaged crank will solve some sort of other problem.
it FEELS glass smooth and all the journals mic out in spec. I guess I'll take it to the shop and let them tell me what they think, worst comes to worse I have one other spare crank.
12-12-2015, 06:35 PM
You guys think this crank just needs a polish?
