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Author Topic:   offset ground 460 cranks
Mike_R
Gearhead

Posts: 142
From: Indianapolis, IN 46237
Registered: Feb 2001

posted 05-11-2001 10:34 AM     Click Here to See the Profile for Mike_R   Click Here to Email Mike_R     Edit/Delete Message   Reply w/Quote
First off I know there alot of cast steel 460 cranks available, but this question pertains to an offset ground stock 460 crank.

Has anybody here had any experience with an offset ground 460 crank positive or negative? I sometimes hear people say they will break, but I haven't been able to find a person yet who has broken one. I'm just curious what your experiences have been.

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S/Q 2204
Journeyman

Posts: 89
From: Ozark, AL(again after a year of being deployed)
Registered: Feb 2001

posted 05-11-2001 02:28 PM     Click Here to See the Profile for S/Q 2204   Click Here to Email S/Q 2204     Edit/Delete Message   Reply w/Quote
Mike ,
Oh, boy do they break. When I first started running a stroker that was all that was available short of billet (which I now run).
1) first break was in water box, loud slap only took out one rod , did not kick just a larger than normal chamfer.
2) second break about the same, no other damage.
3) third broke in front of #2 main; what a mess. It removed the #1 main cap (block scrapped).
4) fourth, Ford came out with a forging, 6415 material I think ( also think it was a bad choice) Crank Shaft Specialist finished it out ( I wonder about their quality control). Broke snout at front main. Looked like a hand grenade went off in the engine. Installed one from Crower, same forging, in another engine that is still going strong(not my engine). Currently run a LA billet. It has more runs on it than the above shafts combined.
Some people have good luck with the offset ground stuff but not me.
I know of some around here that run the cast steel with no problems. Looking at the price I would opt for it. You will not be starting off with a crank that only God knows how many miles it has on it. In the long run new crank is probably cheaper.
If you have any other questions feel free to contact me. I like my strokers.
Mark J.

[This message has been edited by S/Q 2204 (edited 05-11-2001).]

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Mike_R
Gearhead

Posts: 142
From: Indianapolis, IN 46237
Registered: Feb 2001

posted 05-11-2001 03:10 PM     Click Here to See the Profile for Mike_R   Click Here to Email Mike_R     Edit/Delete Message   Reply w/Quote
Thanks alot for the deatailed info.

I'm curious about how many RPM you're turning and was this turned to 2.200" size journals?

What I've been considering is using the 2.375" (Mopar) size journal just because I have the parts to do it already (490 cubic incher). I would be using steel h-beam rods and turning about 6500 maximum RPM. This is a mostly street and occasional strip car. I don't want to put together a ticking time bomb though. That's the last thing I want.

It's really hard to find guys who have been there and done that so I appreciate the information you can give me.

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F551
Gearhead

Posts: 157
From: Manitoba, Canada
Registered: Nov 2000

posted 05-11-2001 07:55 PM     Click Here to See the Profile for F551   Click Here to Email F551     Edit/Delete Message   Reply w/Quote
Mike/Mark - Welcome to M&M

I run a 68 Mustang with a 500cid/PG.

This will be the third season on the offset ground cast crank. The crank was ground by a local shop to 2.200"- it came from the "pile". We use Eagle rods with Arias pistons. The motor is taken apart at the end of each season crank is magged - so far so good. Also use a TCI Rattler - good damper is important.

Only problem we had was the rod caps walked, appears to have been cured by upgrading the bolts per Eagle and using stretch gage.

Made 645HP @ 6250 and 650ft/lb @ 4250, was turning 6,900rpm in the eyes, now converter has been tightened so hopefully that will go down a bit.

We recognize that the crank won't last forever - but we can have a lot of cranks ground for the cost of a steel one. This will likely be the last year for this one. Sure beats tearing truck rods in half with the old 460 combo!

------------------
Fred
68 Mustang 500CID/Powerglide - "No Tubs"
86 Mustang GT Cobra

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Mike_R
Gearhead

Posts: 142
From: Indianapolis, IN 46237
Registered: Feb 2001

posted 05-11-2001 10:26 PM     Click Here to See the Profile for Mike_R   Click Here to Email Mike_R     Edit/Delete Message   Reply w/Quote
Thanks Mark,

That's nice info.

My thought was with the larger meatier 2.375" journal (and consequently shorter stroke) along with my relatively low RPM 6500 that I may be able to get away with an offset ground crank (with h-beam rods). Mine really would only see the strip maybe 10-20 runs per year maximum.

I am very concerned about getting a good damper, because I feel that could be a key.

At this point I've just been trying to get all the info I can so that I don't screw it up.

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Mike_R
Gearhead

Posts: 142
From: Indianapolis, IN 46237
Registered: Feb 2001

posted 05-11-2001 11:13 PM     Click Here to See the Profile for Mike_R   Click Here to Email Mike_R     Edit/Delete Message   Reply w/Quote
Oops I meant to say thanks Fred.

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S/Q 2204
Journeyman

Posts: 89
From: Ozark, AL(again after a year of being deployed)
Registered: Feb 2001

posted 05-12-2001 12:42 AM     Click Here to See the Profile for S/Q 2204   Click Here to Email S/Q 2204     Edit/Delete Message   Reply w/Quote
Mike,
Usually no moe than 6800. 2.1 crank pin, aluminum rods, BRC piston, bob weight low. The metal removed, because of it's location, did not contribute to the failures as it cracked in a different area.
In reality our problem was probably a result of excess H.P. and weight.
You will probably have good luck. Just keep it under 6500 & when you do race it don't torture it in the water box; this is said to kill them.
I was thinking the Scat crank at $730 was not alot more than getting a good core & paying to have it ground.
If the stock stuff is more financially obtainable then just check it over good. I would suggest at least getting that mile long snout shortened to a BOSS 429 length & using a spacer from Engine Systems. I don't like that long arm.
One other thing to keep in mind is that when they do break they will not always treat you nice. An example is when the snout breaks it cause the valve train to take some hits. Roller lifter needle bearings play havoc to rods & pistons ,not to mention 16 custom lenght push rods and valves.
Sorry to ramble just never had anything to contribute till now.
Good luck which ever way you go.
Mark J.

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Ryan Wilke
Gearhead

Posts: 1115
From: Stanton, Michigan 49707
Registered: Oct 2000

posted 05-12-2001 09:30 AM     Click Here to See the Profile for Ryan Wilke   Click Here to Email Ryan Wilke     Edit/Delete Message   Reply w/Quote
Mark J:
In your post you mentioned,

"I would suggest at least getting that mile long snout shortened to a BOSS 429 length & using a spacer from Engine Systems. I don't like that long arm."

What did you mean by that? Is the BOSS 429 snout different from the OEM 460 crank snout? Or, isn't the stock 460 crank spacer any good in a HiPo engine? I'm on the starting line of the learning curve with those 385 motors..... Thanks, Ryan

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S/Q 2204
Journeyman

Posts: 89
From: Ozark, AL(again after a year of being deployed)
Registered: Feb 2001

posted 05-12-2001 11:09 AM     Click Here to See the Profile for S/Q 2204   Click Here to Email S/Q 2204     Edit/Delete Message   Reply w/Quote
Ryan,
Yes, shorter. It is not any larger in diameter.
Got to go. Be back in around 9 central.
Mark J.

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TomP
Gearhead

Posts: 4637
From: Delta BC Canada
Registered: Dec 99

posted 05-12-2001 07:22 PM     Click Here to See the Profile for TomP   Click Here to Email TomP     Edit/Delete Message   Reply w/Quote
I know a guy that has two Boss 429 steel cranks for sale, i think he also has an SFI Damper for one.

[This message has been edited by TomP (edited 05-12-2001).]

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BobMacD
Journeyman

Posts: 2
From: Ayr, Ontario, Canada
Registered: May 2001

posted 05-13-2001 10:35 AM     Click Here to See the Profile for BobMacD     Edit/Delete Message   Reply w/Quote
This is my first post to this board. I have been following the discussions for some time. Allways enjoy the topics and I learn something everytime. I do not run a car but a flatbottom ski boat with a 501 BBF. This motor uses an offset ground crank (2.20 journals) with 6.8" Crower rods and Probe forged pistons. I normally run the motor at 4500-6000rpm. I spend a lot of time at 6000rpm which is the limit the motor will turn given the gearbox ratio and prop size. The motor is making approx 500hp. So far this crank has been in the motor for three seasons now with no problems related to crank strength. The motor is equipped with a Fluiddamper. Bear in mind a boat environment is potentailly harsher than drag racing because the motor runs at high rpm's producing full power for minutes at a time.

I have discussed this subject at some length with Jimmy Fischer at Engine Systems and his rule of thumb is to limit the stock offset ground cranks to a max of 650hp and 6500rpm. He feels the SCAT cranks can handle 750hp.

Anyhow, I have allways wondered just how strong the new "cast steel" cranks really are. They say they are 30% stronger than an offset ground stocker but how does that compare to a stock stroke stock(whew) crank?
Also, how does the new Eagle crank compare tp to SCAT crank given the price is about half? Are they internal or external balanced?

------------------
69 Mandella

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SG236
Gearhead

Posts: 344
From: Jasper, TN, USA
Registered: Dec 2000

posted 05-13-2001 11:33 PM     Click Here to See the Profile for SG236   Click Here to Email SG236     Edit/Delete Message   Reply w/Quote
Hey Fellas,

Since I'm new to the BBF stuff too, keep the great info coming!

Thanks,

------------------
Russ Hood
70s Maverick S/Pro

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Ryan Wilke
Gearhead

Posts: 1115
From: Stanton, Michigan 49707
Registered: Oct 2000

posted 05-14-2001 09:13 AM     Click Here to See the Profile for Ryan Wilke   Click Here to Email Ryan Wilke     Edit/Delete Message   Reply w/Quote
Bob MacD: I can answer ONE of your questions; the Eagle 4.14" stroker cast-steel crank I bought two months ago arrived externally-balanced. I asked my machine shop to do their Mallory Metal magic work & make it internally-balanced - which they did.

The Eagle crank is in my yet-to-be-finished first 385 engine build-up. It has ARP main cap studs, ARP rod cap screws and a SFI-approved dampener (I've sprung for the pricey ATI Super Dampener), with the hopes that their extra cost is worthwhile insurance against crank flex/breakage.

If you were to change your gearbox/prop, would you feel 'safe' to take your combo to a higher RPM level - say 6800 or more?

OK - I gotta ask: is a "Mandella" your boat manufacturer's name?

Later, Ryan

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BobMacD
Journeyman

Posts: 2
From: Ayr, Ontario, Canada
Registered: May 2001

posted 05-14-2001 08:37 PM     Click Here to See the Profile for BobMacD     Edit/Delete Message   Reply w/Quote
Thanks for the info Ryan. First some answers then some more questions. Yes Mandella is the name of the manufacturer of my boat. It was built in 1969 and I have restored it, much like restoring an early car. Since this boat model has not been made in many years, owning one provides a certain satisfaction.

At this time I am not entertaining running this motor any higher. I have already lost one crank to low oil pressure problems(not breakage) so I am somewhat leary at this time. Also, I have noticed that most buildups of stock architecture stroked BBF's have HP peaks right around 6000rpm. My strategy is to add more horsepower but maintain the limit of 6000-6200rpm and increase boat speed by changing the gear ratio. Since these motors are basically modified stockers, I do not want to run them too hard.

How much mallory metal did you have to use to balance the crank? Too much kinda drives up the cost. What is your first impressions of the crank? Good luck on your buildup. It may interest you that I belong to the Michigan Hot Boat club. I routinely cross the border to boat with club at places like Houghton Lake and Oscoda.

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Ryan Wilke
Gearhead

Posts: 1115
From: Stanton, Michigan 49707
Registered: Oct 2000

posted 05-15-2001 08:59 AM     Click Here to See the Profile for Ryan Wilke   Click Here to Email Ryan Wilke     Edit/Delete Message   Reply w/Quote
BobMacD:
I'll find the build sheet on the crank to see how much mallory metal was used and what it cost me...so I'll get back with you on that.
What are my first impressions of the crank? Well, it looks nice and it went into my filled D1VE block just fine... but I can't say much else about it as it currently bagged and just hangs on the engine stand I'm still collecting/picking up beer cans so I can order the roller cam gear and Edelbrock cyl heads!
You mentioned that you routinely cross the border to boat with the MI Hot Boat Club at places like Houghton Lake and Oscoda... Houghton Lake is about 1.5 hrs from me. It's a good sized, but not so deep lake. I've been there for their January Ice-Fishing Festival - which is a great time, but no boats! Folks race & tear around on the frozen lake during the festival with trucks or snowmobiles! Now if you also go to Oscoda, then you must be boating on the big lake - Lake Huron right?

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Ryan Wilke
Gearhead

Posts: 1115
From: Stanton, Michigan 49707
Registered: Oct 2000

posted 05-15-2001 09:00 AM     Click Here to See the Profile for Ryan Wilke   Click Here to Email Ryan Wilke     Edit/Delete Message   Reply w/Quote
F551:
You said you were going thru the eyes @ 6900rpms? Dang-Man, That's Ballsie, Dude!

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jkilroy
Gearhead

Posts: 1636
From: Vicksburg, MS
Registered: Dec 99

posted 05-15-2001 05:13 PM     Click Here to See the Profile for jkilroy   Click Here to Email jkilroy     Edit/Delete Message   Reply w/Quote
There are other benefits to a 2.2 rod journal size. Lower bearing surface speed, which is a very good thing. The lower the surface speed the less friction, less heat, more power.

A 2.375 bearing has a circumfrence of 7.46 inches which means at 6500 rpm the surface speed of the bearing is approx. 4040 fpm

The 2.2 bearing has a circumfrence of 6.91 inches and a bearing speed, at the same rpm, of 3743 fom which is 297 FEET less than the 2.375 bearing.

It is quite common for BBC racers to use a 2.1 bearing size and most, if not all, NASCAR builders are using tiny HONDA bearings.

------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big"

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Ryan Wilke
Gearhead

Posts: 1115
From: Stanton, Michigan 49707
Registered: Oct 2000

posted 05-15-2001 07:02 PM     Click Here to See the Profile for Ryan Wilke   Click Here to Email Ryan Wilke     Edit/Delete Message   Reply w/Quote
Interesting stuff, Jay.
Now tell me if I'm understanding your #s correctly; a 2.375" journal @6500rpms travels the bearing @ 4040 fpm. But to travel the same 4040fpm with the 2.2" journal, (to obtain the same heat, wear, etc) you'd need to spin it at 7016 rpms? (4040ft/min X 12"/ft X rpm/6.91" = 7016rpms)

Or - When both journals are at the SAME 6500rpms, the heat, wear would be lesser for the 2.2 journal by the 297 ft. or equivalent to 516rpms slower? (297ft/min X 12"/ft X rpm/6.91" = 516rpms).

Which begs to say the smaller the journal the better - less heat, wear, etc; EXCEPT for the trade-off in journal strength. How much stronger is a 2.375" journal vs. a 2.20" journal? -- Depends on what it's made of and how it's conditioned, right? If the same metal/conditioning, the larger is stronger. How strong does it need to be... is like saying 'Do you feel lucky?'

I'd also bet that the HONDA bearings that you referred to are as small or smaller than 2.2" (isn't the SBC 2.1"?) However, I'd guess those NASCAR cranks are made out of some damn good billet steel and get lots of heat treating, etc, unlike a cut OEM cast-iron crank. Does that sound about right, or am I all wet here? Ryan

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jkilroy
Gearhead

Posts: 1636
From: Vicksburg, MS
Registered: Dec 99

posted 05-16-2001 05:01 PM     Click Here to See the Profile for jkilroy   Click Here to Email jkilroy     Edit/Delete Message   Reply w/Quote
Ryan,

Your math is correct. In order to hit the same bearing surface speed with the 2.2 bearing you would need to turn up around 7017 rpm. As I am sure you are aware, heat from friction goes up in an exponential manner, so any decrease in bearing surface speed is good. Also note that SVO NASCAR blocks use the smaller 351C main bearing size, and the 460 prostock blocks use a much smaller bearing also, though I am not sure what size it is.

You are also right on the money that everything is a trade-off. Either way, I think we have all seen BBC motors making big power with a 2.2 bearing, I don't think the drop in size is a major problem. The Honda bearings I spoke of are sized under 2 inches I believe, and yes the Nascar cranks are top notch, probably by Crower or King.

I believe that Alex can provide some input when it comes to bearing sizes. If I remember correctly he was doing some fiddling around with smaller bearings a while back.

------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big"

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F551
Gearhead

Posts: 157
From: Manitoba, Canada
Registered: Nov 2000

posted 05-17-2001 12:15 PM     Click Here to See the Profile for F551   Click Here to Email F551     Edit/Delete Message   Reply w/Quote
Ryan - not "Ballsie" - just the way it is.

Hopefully that will come down as we got the converter tightened up. With the tire/gear it should be about 6600, SAFER!

Find out this weekend - first race is Saturday.

------------------
Fred
68 Mustang 500CID/Powerglide - "No Tubs"
86 Mustang GT Cobra

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Ryan Wilke
Gearhead

Posts: 1115
From: Stanton, Michigan 49707
Registered: Oct 2000

posted 05-17-2001 04:30 PM     Click Here to See the Profile for Ryan Wilke   Click Here to Email Ryan Wilke     Edit/Delete Message   Reply w/Quote
Fred: I hope you come back with a smiling report on your crankin' BBF!! Ryan

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F551
Gearhead

Posts: 157
From: Manitoba, Canada
Registered: Nov 2000

posted 05-17-2001 04:51 PM     Click Here to See the Profile for F551   Click Here to Email F551     Edit/Delete Message   Reply w/Quote
ME TOO!!

------------------
Fred
68 Mustang 500CID/Powerglide - "No Tubs"
86 Mustang GT Cobra

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SG236
Gearhead

Posts: 344
From: Jasper, TN, USA
Registered: Dec 2000

posted 05-18-2001 08:56 AM     Click Here to See the Profile for SG236   Click Here to Email SG236     Edit/Delete Message   Reply w/Quote
Good luck this weekend Fred! Go gett'em.

------------------
Russ Hood
70s Maverick S/Pro
Looking forward to the 514 or 532!!!

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Mike_R
Gearhead

Posts: 142
From: Indianapolis, IN 46237
Registered: Feb 2001

posted 05-18-2001 11:51 PM     Click Here to See the Profile for Mike_R   Click Here to Email Mike_R     Edit/Delete Message   Reply w/Quote
I was gone for a week on vacation and came back to find this 460 crank discussion still going on. Good deal. This a subject where you can never learn too much.

I have given very hard consideration to the Eagle 4.140" crank like Ryan has. That seems like the most bang for the buck. I am a little concerned that with my pistons I would have to use 6.635" rods (as apposed to 6.700" or 6.800").

My major reasons I was heavily considering the 2.375" journal was so I could use a 6.76" Mopar rod, have a shorter stroke (3.975" easier on mains) and possibly not have to deal with external balancing.

There are just so many pros and cons either way I go. It's a tough decision, but the Eagle crank is awfully appealing for the price.

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Big_blocker
Journeyman

Posts: 50
From: On a rock in the pacific (Hawaii)
Registered: Mar 2001

posted 05-19-2001 10:04 AM     Click Here to See the Profile for Big_blocker   Click Here to Email Big_blocker     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Mike_R:
I was gone for a week on vacation and came back to find this 460 crank discussion still going on. Good deal. This a subject where you can never learn too much.

I have given very hard consideration to the Eagle 4.140" crank like Ryan has. That seems like the most bang for the buck. I am a little concerned that with my pistons I would have to use 6.635" rods (as apposed to 6.700" or 6.800").

My major reasons I was heavily considering the 2.375" journal was so I could use a 6.76" Mopar rod, have a shorter stroke (3.975" easier on mains) and possibly not have to deal with external balancing.

There are just so many pros and cons either way I go. It's a tough decision, but the Eagle crank is awfully appealing for the price.



I am still wondering what crank is stronger out of the two. (Eagle Vs Scat.) I was thinking that maybe the Eagle crank would be a better choice because you could use BBC rods. which are dime a dozen and not too high price for a new aftermarket set. What do you think?


------------------
Drink gas haul a$$ American Racing

[This message has been edited by Big_blocker (edited 05-19-2001).]

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Ryan Wilke
Gearhead

Posts: 1115
From: Stanton, Michigan 49707
Registered: Oct 2000

posted 05-20-2001 09:22 AM     Click Here to See the Profile for Ryan Wilke   Click Here to Email Ryan Wilke     Edit/Delete Message   Reply w/Quote
Mike_R: As you said, there are lots of combinations. Since you have a set of pistons you're trying to use, it limits your options,,,whereas I didn't have ANY parts laying around (good used pistons, Mopar rods, etc.) to work into my package. I've seen a number of folks that love the very package you're considering - so I wouldn't be concerned as to whether it'll work good, it's just a matter of what YOU want.

Big_Blocker: Using rods that have the same dimensions as the BBC does provide the advantage of availabilitiy and lesser cost. This can also be said about using rods with the Mopar 440 dimensions (2.375" journal, 6.76" long) that Mike_R mentioned earlier. I think it all boils down to a matter of what parts do you have, what parts can you get for less $$ and what combo do you want in the end..... Lastly, I think the trick is not to get stuck in the middle of the road with these decisions, but rather pick a package, build it, then go run it and see if it does what YOU want. Good Luck! Ryan

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Big_blocker
Journeyman

Posts: 50
From: On a rock in the pacific (Hawaii)
Registered: Mar 2001

posted 05-24-2001 03:48 AM     Click Here to See the Profile for Big_blocker   Click Here to Email Big_blocker     Edit/Delete Message   Reply w/Quote
Do you know how much he is asking for them ?
quote:
Originally posted by TomP:
I know a guy that has two Boss 429 steel cranks for sale, i think he also has an SFI Damper for one.

[This message has been edited by TomP (edited 05-12-2001).]


------------------
Drink gas haul a$$ American Racing

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