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How far are you willing to go on reducing crank pin size to gain stroke? At some point (2.100, 2.00, 1.889,) there is a loss of strength that is too much. My one shot at a 2.100 size to get 4.00 stroke lived quite a while at 600 hp, 2100 bob weight, 6200 rpm. That was an RB with custom aluminum rods. Without having much experience, I would assume it would be application specific.

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I recently saw both a SBC and a SBF circle track motor, that the jouranals were ground down to Honda size, and they broke. These are asphalt speedway deals, and only about 400HP 2 BBL motors.
Whats funny is they are not allowed to do this, so when they broke, some people found out that they were cheating...double whammy,.....

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How far are you willing to go on reducing crank pin size to gain stroke? At some point (2.100, 2.00, 1.889,) there is a loss of strength that is too much. My one shot at a 2.100 size to get 4.00 stroke lived quite a while at 600 hp, 2100 bob weight, 6200 rpm. That was an RB with custom aluminum rods. Without having much experience, I would assume it would be application specific.

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I recently saw both a SBC and a SBF circle track motor, that the jouranals were ground down to Honda size, and they broke. These are asphalt speedway deals, and only about 400HP 2 BBL motors.
Whats funny is they are not allowed to do this, so when they broke, some people found out that they were cheating...double whammy,.....

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That doesn't surprise me in the least. Those cranks just don't have enough material to go that far. I bet they learned a valuable lesson.
Even on a BB mopar crank, there are limits on how far I'll move the stroke. Back when I was doing the welded strokers from OEM cranks they were pretty strong and would hold up to 700 HP and 7500 rpm for many years of service. anything above that back in the day IMO really wasn't worth attempting. 3.75 to 4.15 was a real common one to do although I did do some out to 4.25.
With the availability of decent and inexpensive 4340 cranks available now, why bother with that stuff.

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just had my 4.15 mopar/scat crank done to 4.25 2.20 chev rod, what are you folks doing about .060/.070 side clearance, some people leave it alone?

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Side clearance isn't an issue as long as you have some. The oil hole in the crank is the restriction.

There are countless engines running around with way more than the factory specified side clearance.

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.009" to .017" is whats specified from the factory. I would tend too think 0.07" is too much....I bet you would have lots of oil flying around and getting excessive oil on the cilinder walls, leading maybe to oil control issues with the rings, specially if running low tension oil rings????....

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Side clearance isn't an issue as long as you have some. The oil hole in the crank is the restriction.

There are countless engines running around with way more than the factory specified side clearance.

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.009" to .017" is whats specified from the factory. I would tend too think 0.07" is too much....I bet you would have lots of oil flying around and getting excessive oil on the cilinder walls, leading maybe to oil control issues with the rings, specially if running low tension oil rings????....

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Side clearance isn't an issue as long as you have some. The oil hole in the crank is the restriction.

There are countless engines running around with way more than the factory specified side clearance.

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.009" to .017" is whats specified from the factory. I would tend too think 0.07" is too much....I bet you would have lots of oil flying around and getting excessive oil on the cilinder walls, leading maybe to oil control issues with the rings, specially if running low tension oil rings????....

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My Duster motor had from .054 to .032 rod side clearances, it also had .0033 to .0035 rod bearing clearances. I never saw smoke, used oil or had any other issues with to much oil on the cylinder walls The rod bearing clearances dictate how much oil gets out of them, not the rod side clearances I did use a crank scraper in that motor to start with The last crankshaft in that motor started out as a six bolt flange forged import that was 4.150 stroke with Mopar rod journal sizes, I had it offset to 4.300 stroke with 2.200 (BB Chevy) rod journal sizes I have three more 4.150 stroke cranks with Mopar rod journal size throws on them that will get offset stroked like that also As far as costs of grinding and reheat treating check with your local shops first before deciding, it may be cheaper to buy the stroke you want to start with , maybe not depending on how much you pay for the cranks to start with

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How many hours does this take?

Sheldon

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19 hours and counting I guess

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Side clearance isn't an issue as long as you have some. The oil hole in the crank is the restriction.

There are countless engines running around with way more than the factory specified side clearance.

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.009" to .017" is whats specified from the factory. I would tend too think 0.07" is too much....I bet you would have lots of oil flying around and getting excessive oil on the cilinder walls, leading maybe to oil control issues with the rings, specially if running low tension oil rings????....

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My Duster motor had from .054 to .032 rod side clearances, it also had .0033 to .0035 rod bearing clearances. I never saw smoke, used oil or had any other issues with to much oil on the cylinder walls The rod bearing clearances dictate how much oil gets out of them, not the rod side clearances I did use a crank scraper in that motor to start with The last crankshaft in that motor started out as a six bolt flange forged import that was 4.150 stroke with Mopar rod journal sizes, I had it offset to 4.300 stroke with 2.200 (BB Chevy) rod journal sizes I have three more 4.150 stroke cranks with Mopar rod journal size throws on them that will get offset stroked like that also As far as costs of grinding and reheat treating check with your local shops first before deciding, it may be cheaper to buy the stroke you want to start with , maybe not depending on how much you pay for the cranks to start with

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...and I was worrying because I had like 0.025" side rod clearance on one jouurnal on a stock 383 I just rebuilt... ... well, one less thing to worry about now!!!

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Dan, I'm pricing a 1.850 rod stroker Olds smallblock for a '65 Cutlass S that I've owned since 1977. (there aren't any olds stroker cranks that I know of). What would be a ballpark price for you to grind mains to standard undersize and offset grind 2.125" rod journals to 1.850"?
Here, I'm looking at $400 or so. The guy does custom work on an italian crank machine. It sounds pretty fair to me. What to look out for?
Thanks,
R.

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$400.00 dollars is a very fair price for quality work IMO. The most important thing is the guy doing the work, Not the machine he's doing the work with unless it's a worn out pile of scrap.
It's real easy to mess up the indexing when your taking a lot off of the journals. On top of that, some cranks will relax and loose their straightness. That's an easy fix if you know what your doing and do things in the right order.
In other words, it's just a little bit more involved than just grinding some metal if you want it done right.

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How many hours does this take?

Sheldon

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19 hours and counting I guess

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Hey, don't you have some Chevy heads to port or something. Get back to work and pipe down.

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Dan,how's the cost compare to take a stock(no radiused) and offset grind it to purchasing a budget radius fillit crank and is there a trade off for strength.And are the cut cranks re-hardened after cutting and what method is use?

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