How Much Crank to Buy

D

Dennis Jarrell

Senior Member
I have been looking at new cranks for my 8BA and I was wondering since I'm buying all new stuff would I be wrong in buying a 4.25 stroker?

Thanks,
Dennis
 
Dennis, really need some more information. Are you going racing? Are you familiar with the Ford flathead engine? Putting a stroker crank in there changes everything........
 
The plan is for a very hot street motor for my 35. 3 5/16 bore by 4.25 stroke. Edlebrock heads, three 97's, either a Isky 404 or the biggest comp. thumper cam.
 
I have a 4.25 stroker in my 46 Merc.[59] block.It becomes a torque monster.It does not seem to rev as quickly as a stock stroke engine,and is not quite as smooth
.It has a Scat crank with "H" beam rods.It was a bear to ballance.
 
Dennis Jarrell said:
The plan is for a very hot street motor for my 35. 3 5/16 bore by 4.25 stroke. Edlebrock heads, three 97's, either a Isky 404 or the biggest comp. thumper cam.
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Don't stop at 3 5/16 bore as long as you are going to a 1/2 inch stroke.
Go 3/8. That will still leave you at least 2 cleanups for later rebuilds but the chances are the first bore job will outlast you.

You don't want a 404 cam. It is not economically feasable for a street engine. Granted the 404 is probably the best street cam for a "big" flathead but there are other issues such as cost of lifters and machine work to install the valve train properly. I'm saying this as the last one in the world making lifters for the 404.
A Potvin Eliminator would be my choice. Uses stock lifters and easy to install.
 
The reason I wanted the 404 cam is because a good friend of mine has one in his and runs so good and has had no trouble with it. It has been running for many years. The reason I was going to stay at 5/16 was also because of my friends first flattie that was 3 3/8 had worn the cross hatch at the studs in the bores after a just a few miles so we thought the bore was too much.
 
Dennis Jarrell said:
The reason I wanted the 404 cam is because a good friend of mine has one in his and runs so good and has had no trouble with it. It has been running for many years. The reason I was going to stay at 5/16 was also because of my friends first flattie that was 3 3/8 had worn the cross hatch at the studs in the bores after a just a few miles so we thought the bore was too much.
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As I said, the 404 is a great street cam but it was primarily designed as an all out race cam. I have run them on the street many times in several different size engines and they always perform great. They are also a big maintainence item that needs to be looked at periodicly.
I have reground many of them and never seen one that ran on the street that wasn't worn badly at 5000-7000 miles. They have a lift rate of .010 per degree² and that equates to WEAR at low rpm's.

The reason your friend's bores wore at the studs is the block was not honed with a torque plate so the bores were not round.
I have been running flatheads with 3 7/16 bores since 1952 and never had any indications of distorted bores. We ran some of these with 100% nitro. Even ran picric acid and hydrazine in one of them.
 
I agree the 404 cam is a uninformed decision for any engine which will be street driven. In fact, the wear issues are very significant for even a competition engine. And, the list of cams better suited for street applications is long.

With regard to bore size the 3-5/16 is appropriate for a street build.

Regarding the crank there is no suboptimal points to the 4.250 stroke if purchased as a balanced assembly, except, the pistons will be forged and provide some minor noise until warmed up and careful clearancing examinations are necessary where the rods pass by the block and cam.
 
The reason your friend's bores wore at the studs is the block was not honed with a torque plate so the bores were not round.
I have been running flatheads with 3 7/16 bores since 1952 and never had any indications of distorted bores. We ran some of these with 100% nitro. Even ran picric acid and hydrazine in one of them.[/QUOTE]


Pete or JWL:

Do you have an actual torque plate made from a steel plate or do you do it another way; meaning cutting holes in stock heads and using them as the plate?

I'm getting ready to finish bore and hone and want to use a torque plate, but currently don't have one. I had planned to use an old head and cut holes in it with a hole saw. Never cut cast iron before but I'm assuming it is going to be a messy job.

I know Red's use to rent one when Red H. ran the business. I guess I can always call them to find out if they still do.

Thanks.

Tim
 
Lawson Cox said:
<LI class=sa_wr>Depends on how high you want to get. lol




<LI class=sa_wr>Urban Dictionary: crank


www.urbandictionary.com/define.php?term=crank
Slang, noun. “Crank” is slang for a low purity, crystallized Methamphetamine that is administered in a powder form. Crank, like all other Methamphe...
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I have to admit, this was the first thing that came to my mind...
 
Tim, I use heads which have been modified. As I wrote in my book, I use the same bolts/studs, washers, gaskets, and torque values and sequencing that will be used in the final assembly. After both head plates are on I also torque the main caps in place.

I will lend you my modified heads if you pay shipping both ways. Probably more cost than we would ever guess.

JWL
 
Tim Ayers said:
The reason your friend's bores wore at the studs is the block was not honed with a torque plate so the bores were not round.
I have been running flatheads with 3 7/16 bores since 1952 and never had any indications of distorted bores. We ran some of these with 100% nitro. Even ran picric acid and hydrazine in one of them.
Click to expand...


Pete or JWL:

Do you have an actual torque plate made from a steel plate or do you do it another way; meaning cutting holes in stock heads and using them as the plate?

I'm getting ready to finish bore and hone and want to use a torque plate, but currently don't have one. I had planned to use an old head and cut holes in it with a hole saw. Never cut cast iron before but I'm assuming it is going to be a messy job.

I know Red's use to rent one when Red H. ran the business. I guess I can always call them to find out if they still do.

Thanks.

Tim[/QUOTE]

I had a solid steel one but sold it about 5 years ago.
 
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