Hot Rods Does anyone really do offset cranks anymore?

Just wondering if there are still crankshaft grinders around that still do this?

 

Mile high cranks in Denver.

 

Jack's Machine Hooper, NE

 

Mile High is where I'm sending mine.
It was recommended by my machinist.

 

I was reading an old magazine story about a 414 CID Cadillac motor. I was trying to figure out how they got there.

Looks like you would have to bore one to 4.030 and have a crank stroke of 4.045" as opposed to the stock stroke of 3.875" a difference of .170"

What kinda cost are you looking at for something like that?
I do have a message into Mile High. I'll let you know what I find out.

 

You're also going to need to find out what con rod/bearing they went to.

 

it was pretty common back then to build up the outside of the journal with weld bead, then grind it with the new stroke, keeping the rod journal original size.

seems like a lot of work! now we just get a 1-800 stroker crank

 

The one advantage of offset grind with a smaller rod bearing makes for slower bearing speed.

 

I will take a guess on crank work
$800 -$1,000.02 ?

 

Not for a 390 Cadillac you won't.

They usually use the BBC rods, which is quite a bit longer. Still has to be narrowed. Not sure it would be worth it for 24 cubes.

 

4.140 offset cranks are still sort of common place for the Ford 385 series big block. Lots of aftermarket cranks nowadays but some still grind good original cores.

 

This maybe slightly off topic, but I asked a Laser Welding outfit for a quote on welding up the#1 rod journal on a 455 Olds crank and machining it back to std size, the quote was about €2000 plus shipping back and forth. I bought a new one from summit. Maybe other welding methods like arc welding would have been cheaper. It was a cast crank, not sure if that would have worked...

 

It’s still done some in our part of the world. C.A. Simmons of West Point Ms used to weld his own up and turn them down. ( and I mean with normal welding methods not anything exotic). Not aware that he ever lost an engine due to the crank. They did a lot of such things in the dirt track wars in the south here. I have a couple of 400 cranks that have been turned down on the mains and offset stroked to 3.82 They are neutral balanced. These were of course cheater cranks. I got them when a local guy sold out. With 5-7 slugs of heavy metal I’d say they had a pretty penny in those days coin for all that was done. But in some engine families it’s cheaper to pick up the phone. Is it better. Who’s to say. I saw a lot of guys that did very well with welded up cast cranks back then. Amazing what you can do when you don’t know any better. Kinda like stock rods.

 

Roothawg, You should ask the question, "Why do I want/need a stroker motor?"
More cubes does not necessarily equate to faster. Sure, with a blower to supply additional air it will.

I'll relate a story from when I was in the Engine Performance Development Group at FoMoCo.
We had a 4-valve DOHC 4.6L V8 for the Mustang GT. We also had a 5.4L 2-valve SOHC V8 for trucks.
One of the engineers was going to put the 4-valve 4.6 L DOHC heads on the 5.4 L 2-valve engine. He asked how much more HP did we think the engine was going to make?
I guessed "ZERO".
The reason for that was the ports were sized for the 4.6 and they were going to be limited in airflow on the 5.4.
It made the same horsepower - at 1000 RPM lower.
I mention this O/T example because unless you have sufficient airflow to support more cubic inches, putting more cubes under an overly restrictive set of heads will yeild the same power, only at a lower RPM. Adding a forced induction system will help of course. That's why most AA/GS cars ran big cubic inch motors.

Cam timing and other factors also need to be considered. In short, adding a stroker crank will likely necessitate other changes to the engine and drivetrain to take advantage of the additional cubic inches.

 

I looked into that a few years back. It was cheaper to go with a 4.15 Scat 9000 series brand new crank. There’re supposedly good for 800+ hp.

 

@THE FRENCHTOWN FLYER While I fully agree that an engine is an air pump and increasing it's displacement without changes to inlet/outlet can lead to restriction, some cases that are not going for max output will still see gains.
In your own words "It made the same horsepower - at 1000 RPM lower." That is a recipe for more usable power on the street, where a lot of engines work. It will probably be a bit less economical (more air = more fuel at same RPM), but more responsive and a lower torque peak too.
It sounds like you've got a lot more real world experience in engine design and testing. I can't keep up with the discussion of port volume, velocity and valve sizing and placement. But grunt is king on the street.
It used to require a lot of work to stroke a crank and get optimized rods and pistons. Having the current choices between a rebuild of old worn stock components VS a kit, it's often the same or less money and time. Even if the top end of the engine is the same, there should be a noticeable difference around town. It might not translate to quarter mile times, but even then ask someone who pays attention to how much 60 foot times relate to E.T.

 

It's more a rhetorical question really. I am always interested in what the guys did back in the glory days of racing. It's probably cost prohibitive for a street driven car. I'm sure it was pricey back then as well.

 

We had a place in Miami Fla., "Andy's Crank Shaft",for many years. He did super good work,but retired near 2000.
About the same time I had to stop racing.

 

Here's a chart I found in a magazine a few years ago. It's only for small block Chevy's though.

 

Yes, Mile High is one of the few who still does welded stroker crankshafts. Cast cranks can be stroked, but forgings are much preferrable.
Yes, custom forged pistons are also required. The complete stroker kit today for an obsolete engine probably can't be had for less than $3,000.
Yes, unless the heads are professionally ported, the result will be more torque and the same power at a lower RPM. That's a good thing in anyone's book.
Yes, more displacement allows more cam duration while maintaining low RPM torque.

jack vines

 

Cadillac increased the displacement of the V8 from 365 in 58, to 429 in 64. This was a 17% increase. But power only went up from 310 to 340, less than 10% increase.

So you're already in the "diminishing returns" realm....

 

That's probably true. I noticed in one of the articles published in HRM they did a rebuild on a 390 Caddy and they did a bunch of crap to it, cam, porting etc and when they were done they were bragging about the HP numbers after the dyno. I was thinking something was odd so, I looked them up and they were exactly the same as the OEM specs.

When I questioned the magazine, they never responded.......crickets.

I think the power band just moved one way or the other in the rpm range. Cadillac engineers were no dummies....

 

The 365 and the 429 Cadillac are different engine designs, so not an apples to apples comparison.....To expand on FRENCHTOWN FLYER and RodStRace's conversation, a stock engine vs a stroker with the same cam/heads/exhaust/intake will both make, within a few percent, the exact same HP, the stroker will just move it down in the RPM range. The torque curve, however, is much improved with the larger stroke. Have seen this on many FE and 385 series Fords, but the big stroke is a helluva lot more fun on the street, and it's always cool to say you've got a stroker. Another advantage to a large stroke is that your vacuum will increase, and it will make any camshaft seem "smaller", so a fella can get away with a larger camshaft and still be streetable. The 552" BBF I built and run in my M****** has a cam that is .604/.630 lift and over 260@.050 for both exhaust and intake duration, and it'll idle all day long, and run power brakes no problem. If it was in a stock 429 or 460, it'd be a rough idling, raspy bitch and need a vacuum canister to run the brakes.... We've got an old school machinist that's in his 80s here in Missoula that still will do offset grinding on pretty much anything you want.

 

That's true, the 365 was upgraded to a 390 and they changed configurations in 1963. With the new 390 and the distributor moved up front. That eventually morphed into the 429. So 1962 was the last year for the traditional Caddy 365/390.

 

The head design is pretty similar, that's what's important, eh? I expect it limits HP considerably.

 

Look at the diesel performance guys as well, especially the shops that cater to the truck and tractor pullers. These guys often offset grind cranks to run smaller bearings and longer rods so they can spin their big CAT's up to and beyond 3000 rpm.

 

The head design on a small block Mopar is pretty similar to a SBC, too

 

You could stroke a 4" Merc crank by simply offset grinding and using early ford small journal rods and end up with 41/8 stroke

 

Yeah, that's .125". I can see that.

 

I have a 427 Chevy crank that has been offset ground to 2.10 small block rod size. I need to have the mains and the counter weights turned down to fit a 409. I have the 2.10 big block rods. This crank could be as much as 3.84 stroke.