Stroker cranks

pcmenten · December 18, 2009, 06:11:14 PM

Has anybody taken a closer look at using a Ford crank in the Buick/Rover block?

I have some Ford cranks I can try.

roverman · December 18, 2009, 06:25:22 PM

Paul as long as their raw castings or forgings, "no-problemo". It's been done before by changing the "off-sets" of the raw crank to suit the Rover. I'll need need to make a whole-lotta-hp., from 907 heads to need one. Not likely excepting I add a blower? roverman.

hoffbug · December 18, 2009, 08:08:29 PM

What is involves with machining a ford crank for use in a Rover crossbolted block?
is it the 302 crank?

mgb260 · December 18, 2009, 09:35:46 PM

The bore spacing is probably close,but it would be expensive. Like making a custom crank from a blank.

hoffbug · December 18, 2009, 09:46:26 PM

Ive read somewhere that some sort of raw forging of a Ford crank could be finish machined to Rover specs.. I believe this is what Wildcat and some others used to do before they had dedicated forgings designed with neutral balance in mind.
anyone know specifics?

mgb260 · December 18, 2009, 10:02:13 PM

I don't know, you could ask Wildcat. It is probably a 302(3"stroke) or it's stroker variants which use small block Chevy rod journals,331(3.25" stroke) or 347(3.40" stroke) displacement based on 4" bore +.030 oversize.

pcmenten · December 18, 2009, 10:51:49 PM

I laid a Cleveland 351 crank on the bottom side of my Olds 215. The spacing is fairly close. The crank could be whittled down to fit the block by cutting back the front journal. The problem is that the Cleveland journals are wider than the Olds journals.

So, a raw 351 casting could be used to make a 3.5"-3.7" stroker crank.

BlownMGB-V8 · December 19, 2009, 12:11:27 AM

But why would you do that? Is there some advantage over using the Buick 300 or 340/350 cranks?

Jim

pcmenten · December 19, 2009, 01:05:32 AM

Jim, To use a 300 crank in a Buick 215 block or a Rover block requires a custom flywheel. The total cost of that lash-up is $425 for the crank, requires a flywheel that costs something like $250, and has a max stroke of 3.4".

I see Ford 347 cranks selling for $200. Even if a specialty Rover crank costs $350, you'll be getting a 3.5 to 3.75 stroker crank that will clear the cam and uses stock flywheels, dampers, timing covers, etc. Seems cheaper to me.

NixVegaGT · December 19, 2009, 12:11:05 PM

What doesn't line up? The Mains? I suppose the most critical part would be the thrust bearing in the middle... THen again. With the "Honda" rod you can get as much as 3.52" with the Rover 4.6 crank and that will drop right in without the same modification s that the 300 crank needs.

Your point is that the Ford cranks are cheaper than the Rover spares?

hoffbug · December 19, 2009, 03:41:18 PM

NIk..
you can get a 4340 forged Ford crank finished for $450.. The cheapest forged Rover crank Ive found is $2000.. if anyone knows of a cheaper "forged" Rover crank.. post it up!

roverman · December 19, 2009, 04:27:15 PM

Tony and clan, I seriously doubt anyone will finish-up a forged crank,(Chinese or otherwise),to fit a Rover for anywhere close to $450. That price is based on sbf. volume which dwarfs any conceivable forged crank volume for Rovers. Are we having a crank breakage problem from making too much hp.? Maybe with Honda journals. I think we have a long way to go before that happens. In the mean time, we can get better bang -per -buck elsewhere. My 2cents, roverman.

hoffbug · December 19, 2009, 06:21:44 PM

Art.. Woody says they havent had any problems with the cast cranks to 7000 rpm... Im just throwing it out there.. 2K for a forged crank is insane.. especially if the Ford blanks are plentiful and could be finish machined to "our" specs...

pcmenten · December 19, 2009, 07:27:03 PM

I was cleaning my Olds 215 block this afternoon and thought I'd grab a Ford y-block crank to see how it lines up. Wow! It's pretty close, much closer than a Ford 351, especially on the front journal. The counterweights will have to be milled down to clear, but the spacing of the main journals is pretty close. The main journals are wider than the Olds journals. I don't know how that effects the ability to machine it to fit.

After I warm up, I'll have another look.

Edit: Yes, it's a lot closer, but the sides of the rear counterweight and the front counterweight would have to be shaved to fit into the block, and then the rear flange for the flywheel would be another problem. Short answer, that's not a good fit either.

I don't have a 302 crank handy, so I can't try that.

Wotland · December 20, 2009, 05:34:35 AM

Why not try to find an Terrier crank ?

http://www.youtube.com/watch?v=VxmbGBx0Ybg

roverman · December 20, 2009, 12:03:19 PM

Proper perspective, WHY? The reworked stock cranks, are and will-be, adequate for 99.5% of the builds within this forum. My Huffaker 3.5L, with the"puny" crank will run to 8K rpm's with no problems ! Jim and I are asking why?, and don't seem to get any answers. Just because you can...doesn't mean you should. We're chasing a crank problem that does'nt exist ! roverman.

mgb260 · December 20, 2009, 12:59:28 PM

They are looking for long stroke, big displacement.

roverman · December 20, 2009, 02:37:15 PM

Oh-ok. 3.52" not enough with a 4.6L crank or 3.85" not enough with a 340/350 ? I must be missin sumthin here?

mgb260 · December 20, 2009, 02:48:53 PM

Roverman, I agree with you and Jim . Remember I said it would be expensive.You could get the core cheaper but, when it is done with all the machineing, I don't think so. Maybe more availability?

mgb260 · December 20, 2009, 02:48:54 PM

Roverman, I agree with you and Jim . Remember I said it would be expensive.You could get the core cheaper but, when it is done with all the machineing, I don't think so. Maybe more availability?

v8ian · December 24, 2009, 07:52:17 PM

I would think the bigger problem with the engine would be the dreaded cap walk on any pre X bolted block, my JE 3.9 has been run to silly revs, 8,2k on a missed shift, has ARP rod bolts and stock Injection rods, when I pulled the engine apart, there was clear signs the caps were moving, but the caps were still tight, I assume the problem gets worse the longer the stroke gets??

roverman · December 25, 2009, 04:08:33 PM

Personally, Unless rules would prohibit ther use, I see no good reason not to use a x-bolted block unless you must have the increased deck height of a 300/340 or 350 block.I think the "small journal" cranks will wiggle more than later ones to accellerate the problem. Wer'e all waiting to see how "Mike's 4.02" bore holds-up. I believe 2010 is going to be "interesting", roverman.

pcmenten · December 25, 2009, 04:56:39 PM

On a slightly related subject, I laid the 4.2 crank in the Olds block. The only possible issue is the lack of an oil slinger. I haven't opened the gasket set yet to find out if there's a neoprene seal in there. If it's neoprene, I might be ok.

Other than that, the hole where the input shaft pilot bearing lives, that hole is flanged out a bit more than the stock 215 crank.

roverman · December 26, 2009, 12:46:52 PM

Paul, If your using a 215 Olds full set it should have "rope" for both ends of the crank. I suggest up-grading to TR8/lateRover seals.This will require machining a suitable "counterbore" in the 215,rear main cap/block. An older style, auto cylinder "boring bar"(machine), works well for this purpose.I used to charge $50 for the mod,(old school). Good Luck,roverman.