offset grind crankshaft

[speedbump]

Hi, Matt, I recently posted a question pertaining to my 394 olds crankshaft as far as, anyone on the forum recommending a good reliable shop to do an offset grind to my crankshaft. the shop that i had sent it to has had it for over a year and never touched it. I recently went to that shop and picked it up undone and untouched. This gives me time to re-think my plans for building this mtr. My question to you is what will i Stand to gain if i decide to offset grind this crank. I can only stroke it up about .260 That would bring my new stroke from 3.690 to 3.950 .   What other things are involved if i was to do this. I understand the throws need to be cut down because of the bal. it would need to be checked for straightness and it would need to be nitride for hardness.  do you have any idea what the cost would be and would i really gain much in hp and performance. My new thought is to just keep the stock stroke. Bore the block to around .120  use dome pistons for more compression rebuild the mtr. the heads are fairly stock use in 2.020 intake and 1.700 ext.  and be done with it. I am running hilborn fi and a power glide trans.in a #1800 car. The car is being build as a  120" wb fed running in nostalgia racing, very limited use. Something to enjoy and have some fun. Maybe you can help me in which direction i should go. Thank you and will be waiting for your reply. Thanks again Mike

[jeff/21]

you should talk to tony at ross racing engines, you don't have to buy from him just pick his brain.
when you stroke a motor check to see what is available in rods and pistons  to get the right deck height stroking usually helps a lot the limiting(HP)factor will be the heads
how are you mounting your power glide that motor has a long over hang short bell housing i made a plate that bolts to the block and shortened and welded the trans housing
good luck! keep us posted

[George]

The Oldsmobile engine has how many off the shelf parts available? My guess is a small amount. Anything can be custom made. It's always a question of how much do you want to spend on your combination ? I got tired of " a little bit here and a little bit there " and put a blower combo together. Just my 2 cents. George

[speedbump]

i been in touch with tony. he has been very helpful. but my question is should i go ahead and do the offset grind and whatever goes with that comb. or just bore the shxxx out of it and be done. will i gain that much hp offset grind. over over bore and have 4oo plus ci. getting the parts is not the problem.

[Paul New]

the old saying there is no replacement for displacement!

I have always went the other way well I can't say that in the mid to early 90's we built a 422" SBC for my dads car. But other than that we have maintained the smaller CI engines compared to others we are currently running our second 387" SBC 4.125 bore 3.625 stroke but we are blown so that helps out

[jeff/21]

stroking normally helps there is one class i built motors for and we where allowed to stroke 3.48 to 3.50 it showed on the dyno we spent a lot of time on the dyno trying to get the most from a limited motor.

[Van]

i been in touch with tony. he has been very helpful. but my question is should i go ahead and do the offset grind and whatever goes with that comb. or just bore the shxxx out of it and be done. will i gain that much hp offset grind. over over bore and have 4oo plus ci. getting the parts is not the problem.

 I ran the 394 olds on blown gas & had a lot of fun with it. Back then every one off set stroked and used the 57-58 journal size, which is the same as Pontiac & 354-331 Chrysler. Today every one that strokes a big block typically uses Big block Chevy journal & so should you. The 394 is a fun & cheap motor to build, best head is the #23  1964 head. To run big valves you will need to use offset guides to move the valves apart.  use the 64 front cover as its aluminum, unless Tony makes a race cover.  If you want to do this on the cheap  use a 400 SBC stroker piston & do the math on rod length & stroke to go with the piston. All you will need is a flat top or small dome.  I don't know why all this Olds info is still stuck in my head ?

[Frontenginedragsters]

Mike:
 It always comes down to being cost effective.
It sounds like a lot of work to do what your asking. Then the added cost of custom pistons.
I agree that cutting it down to BBC size makes the most sense.
You also have to look and see how much mass the crank throws have between the rod journal and main journal. You don't want to weaken it.
I do not have an Olds 394 crankshaft to look at.
Is it a forged steel crankshaft? Most of the older engines used forgings. You would not want to use a casting.
I will guess that between straightening the crank, Magnufluxing, the mains will get cut .010 to establish a perfect centerline. Then off set grind.
Send it out for nitride. Might have $900 or more.
I like the idea of large bore size. Have the cylinder walls sonic tested first.

Matt

[George]

The Olds engine with a 4.125 bore and 3.95 stroke is 422 CID. A gain of 28 CI. over the stock 3.688 stroke. Is that worth several thousand dollars? I would look at getting the engine to breath better before spending $$$$ on a stroker crankshaft. Again just my 2 cents. 

[Van]

The Olds engine with a 4.125 bore and 3.95 stroke is 422 CID. A gain of 28 CI. over the stock 3.688 stroke. Is that worth several thousand dollars? I would look at getting the engine to breath better before spending $$$$ on a stroker crankshaft. Again just my 2 cents.

  My 2 cents says, He can buy a off the shelf forged 400 SBC piston & a BBC  aftermarket rod & re bush the pin end to SBC size and off set stroke the crank. At .060 over bore & stroking I think 440 is more what can be had.  The stock rebuilder pistons are not cheap and the stock rod is no good for HP use. My local crank shop offsets cranks for me at $250 max, I had him offset a few Cast 460 Ford cranks last year. The Olds crank is Forged, and like I've already said this was the norm back when the Olds was raced. To try and have any success with the Olds using stock rods and rebuilder pistons is not going to work. This is not a SBC  The racing world already has to many of them   

[Roger]

Have you contacted these folks in Ohio? They specialize in early Olds speed parts and might be able to help you out.

https://rossracingengines.oursafeserver.com/c/11/oldsmobile-rocket-engines-early-catalog/

[speedbump]

hey guys thanks for all your advice. it's been very helpful. everyone voiced there opion for both issues stroking or over boring. I will need to figure out in my mind which way to go. the cost is a part of my discion but trying to find forged alum. pistons and reconditioning my stock rods and bush them for floater there really isn't that much of a difference. i still need to find adj. rocker arms. which no one has except to custom make them. so the whole build is going to be costly either way i decide to go. If the mtr. was going into a street rod or hot rod. it would be a no brainer. but i do plan on racing this car and the chassis is already cert, to 7.50.  so i guess it back to the work shop to figure out the pros and cons of each way.  again thank you all for all your help and support. i will let you all know what i decided.  every one keep the nostalgia sport going. memories are hard to lose and we need to just keep on playing. Thanks again Mike

[Van]

Mike  The easy way is to have the rocker shafts ground down and then Hard Chrome back to std. Best to use the 57=58 shafts and stands as they have the extra end stands {if my memory is working}, run the stock rockers and Smith Bros. Adjustable pushrods. I have ran the stock cam core and had it reground into a race grind = solid flat tappet. 

 Almost forgot  before grinding the crank, groove the mains so the rods oil 360

[George]

The Olds engine with a 4.125 bore and 3.95 stroke is 422 CID. A gain of 28 CI. over the stock 3.688 stroke. Is that worth several thousand dollars? I would look at getting the engine to breath better before spending $$$$ on a stroker crankshaft. Again just my 2 cents.

  My 2 cents says, He can buy a off the shelf forged 400 SBC piston & a BBC  aftermarket rod & re bush the pin end to SBC size and off set stroke the crank. At .060 over bore & stroking I think 440 is more what can be had.  The stock rebuilder pistons are not cheap and the stock rod is no good for HP use. My local crank shop offsets cranks for me at $250 max, I had him offset a few Cast 460 Ford cranks last year. The Olds crank is Forged, and like I've already said this was the norm back when the Olds was raced. To try and have any success with the Olds using stock rods and rebuilder pistons is not going to work. This is not a SBC  The racing world already has to many of them


I'm really a Ford guy and my racing partner a Mopar man. We bought a FED with a SBC. It's a very affordable platform. Just 2 cents more.

[jeff/21]

Here is some info that might be use full https://drive.google.com/file/d/0B3JGHlPHcRp1OEozVVduMm9rVWc/view?pli=1