I have two cranks I can pick from. I can only keep one. Both engines are in my garage but I have to ship one of them back to the rebuilder as a core. I am trying to mix and match parts to build a daily driver quality motor.

Crank #1: out of a rebuilt early 70s 225 that spun a rod bearing. Crank was turned .010 undersize on all bearings when it was rebuilt. #3 bearing seized then spun until it disintegrated and damaged rod journal #3 to the point that I feel ridges when I drag my fingernail across it. Other bearing surfaces look OK.

Crank #2: out of an unrebuilt early 70s 225 that lost oil pressure and had a knocking rod, also on #3. #3 rod journal also has ridges I can feel with my fingernail. #3 bearing didn't spin or disintegrate in this motor. Motor was a runner with a knock when I pulled it.

I am leaning towards crank #2, mainly because it hasn't been cut undersize. What do the more experienced engine builders on the site say?

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Casually looking for a Clifford hyperpak intake for cheap.

A micrometer will be needed to be sure, but #2 is probably the winner.

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Joshua

Thanks. I am hoping to get both cranks on the bench and measure them with a micrometer this afternoon/evening.

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Casually looking for a Clifford hyperpak intake for cheap.

I am going to go with #2. Not only are all the bearing journals thicker, but just about every single journal on crank #1 has visible damage and palpable rippling on the journal surface. Crank #2 only has palpable ridges on the journal for con rod #4. Even if it requires machine work, crank #2 hasn't yet been cut undersize.

The odd thing is that on crank #2 the #3 rod was knocking but rod journal #4 shows far more visible damage and wear than rod journal #3.

Fingers crossed that I can get away with just polishing the journal on the #4 rod journal on crank #2. Time to button the core motor back up, put it in its shipping crate, and ship it back to the rebuilder.

Thanks Josh!

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Casually looking for a Clifford hyperpak intake for cheap.

Both cranks need turned if you want to do the job correctly.

FYI, a crank that has already bern turned ends up with a slower surface speed on the bearing and also gives a thicker bearing. Nothing at all wrong with a turned crank.

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Official Cookie and Mater Tormentor.

I would budget for having the crank reground. You could very well have an out-of-round journal. It doesn't take all that much debris going through the bearings to wear the journal oval.

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Joshua

You will needs some rods resized too.

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Official Cookie and Mater Tormentor.

Argh. Sounds like I should have just kept the undersize crank and gotten it reground and not wasted my time swapping parts around.

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Casually looking for a Clifford hyperpak intake for cheap.

If you have rods where the rod bearings did not spin in the rod big ends, I see no need the get the rods reconditioned. I've built plenty of race and stock engines with the rods just inspected and the ends checked.

If there are no signs of the bearing spinning, just have the big end size and roundness checked if you want maximum comfort; it is not all that hard to measure accurately in your shop. Done it here a dozen times; just torque up the rod bolts properly and measure the ID with accurate tools.

Inspect the rod big end: Any machining lines in the machined surfaces inside the big ends will be cross hatched if nothing has spun/turned, and there should be no heat markings on the rods ends. A spun rod bearing in a rod big end will be obvious in the form of lines parallel to the big end sides; any sign of this, even very short lines like this, indicate the bearing shells have moved and the need for the end to be resized.

And agreed, I would turn either crank if you can feel the ridges like it sounds. I do tend to like to keep the crank with more meat in it, but other items are important, like the width across the journals (for proper rod side clearance) and no damage to the journal sides.

Thanks for the input. I ended up keeping the stock crank that has not been machined undersize. I did that because the undersize crank showed far more wear on more journals than does the stock crank. Five of the rods from the motor that spun the bearing did not show signs of overheating, but one of the rods did.

I will add the crank to my pile of parts I am gathering for a "hot" motor. I will either cheap out and put the motor together checking clearances and tolerances and doing as little machine work as possible, or I will save up and drop the whole pile of parts of at a machine shop and have them do it right.

In addition to salvaging the stock crank, I also traded the early 70s head on the core motor for a unrevised combustion chamber head I have had on a shelf in my garage for years. I also grabbed the stock early 70s cam out of the core motor, even though the fuel pump lobe shows some wear. I figure it is a fine cam for an engine running an electric fuel pump. I kept all the lifters in order so the cam and lifters can be dropped in an engine and run without breaking them in.

Now I need to find a source for cheap bearings, including cam bearings.

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Casually looking for a Clifford hyperpak intake for cheap.

There are a fair amount of /6 bearings that show up on fleabay. See what an EngineTech kit will cost if you need a wide ranging set of parts....$111 for rods, STD mains, rings & gaskets if your pistons are good. Just get the cam bearings elsewhere.

How are the pistons and bores? Look at #1 closely for wear/taper.

The block I intend on using was rebuilt by Jasper about 7 years ago and was a daily driver until the Melling 5 hole oil pump lost pressure and the #3 connecting rod bearing seized and spun. That took out the #3 con rod journal as well as about four other rod journals and three of the four main crank journals on the crank.

I haven't had a chance to do anything but drag my fingernail across the top of the cylinders to check for a ridge. I didn't feel one. Someday I will get a telescoping gauge down the bores and check for wear. The engine was bored .060 over by Jasper. The pistons and bores look pretty clean for a 7 year old motor. I am hoping I don't have to do anything but clean up this "new" crank, have the #3 con rod checked for stretch, and install new bearings. That won't be for a while though. I need to save up some money and find a truck to put this motor in.

I also have a 1983 slant in pieces that I intend to build into a fuel injected and supercharged truck motor, but that is REALLY far down the line.

Best part? The short block was free and the crank was free. I already have a rebuilt head I plan on running and most of a fully gasket set. If I can just clean up the short block I will have a running motor! Most of the issues are the crank and bearings.

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Casually looking for a Clifford hyperpak intake for cheap.

Did you have the cranks magna-fluxed? That is the first step I take.
The slant crank can exhibit cracks around the oil holes.
Of the last five cranks I've checked, two had cracks. One of my good cranks went to a fellow racer, as his stock take out was cracked in that location on a journal.

CJ

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Part of Tyrde-Browne Racing

Uhhh, no. I don't have the tools to magnaflux at home, and I don't have the time or funds right now to take it to a shop. This is really a back burner project. When the time comes to assemble this mess, I will get the crank checked out by a machinist and have him/her check for cracks and wear. I am just trying to assemble the best selection of used parts I can in hopes that they will all be useable. I'm not building a race car or anything.

I already have a rebuilt crank for the 83 motor. It also just needs shortblock work, and a new head done up for it.

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Casually looking for a Clifford hyperpak intake for cheap.

I hear you Reed. A clean and mag costs about $50 down here. Not sure about prices in your location.

CJ

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Part of Tyrde-Browne Racing