Turning down a crank

hotrod9193

Member
When a crank is turned down from 1 inch to 3/4 on a big block open is it still reliable? I just want to kno what route to go on the crank in a open build
 

PD Power

New member
If you are turning the crank snout down.....that part which the clutch rides on.....then yes it is very dependable and frequently done modification.
Turning down the crank pin to 3/4".....will not run for long. Never heard of anyone doing that. It would require a specially built rod and
unusual bearing set.

Probably better than machining the crank snout, would be to get a 1" drive clutch.....3 discs.
 

hotrod9193

Member
I'm talking about the snout. Was wanting to run my regular clutches instead of having to buy a 1 inch clutch. Just wondering witch would be the smarter way to go and best mod
 

graphic edge

New member
PD,
ARC makes rods and bearing sets for .750 journal. Have built many doing this,you can get about .114 stroke out of the by offset grinding.
 

mikelavite#72

Premium User
mike at VKE uses the Star rod with dipper removed , and offset grinding the 420 cranks . for stroker set up
 

PD Power

New member
PD,
ARC makes rods and bearing sets for .750 journal. Have built many doing this.
That is a very deceptive statement.
I just spoke to ARC and they told me they have NEVER done this.
It wouldn't be so bad had you not added "Have built many doing this."
Fact is, you have built NONE doing this.
 

truck

New member
Be careful pd they (engine builders) are doing this....arc Might not know because all that matters to builder is what length, main journal and wrist pin size the rod has.....I know of at least 3 engine builders turning down crank journal and using different style arc rods.....outside the box and it works....where he was mistaken is that arc doesn't make a .750 rod journal size.....875, 1.000, 1.250, 1.374, and so forth and so on....
 

Jimbo

If you talk the talk you should walk the walk
Mike Clements used to have a .750 rod for the flat heads.
In fact i have one on the shelf.
 
Mike Clements used to have a .750 rod for the flat heads.
In fact i have one on the shelf.
Wasn't that one a one piece rod that the crank had to be pressed together like a bike engine? Been a long time since I saw one , but Im pretty sure someone use to make a setup like that for the old FH.
 

graphic edge

New member
PD,
You for sure caught me brain farting? You are correct on the .875.
Did build several and that was also several years ago and as you well know, sometimes passage of time make details foggy.
 

mikelavite#72

Premium User
guys he is talking about the clutch side of crank . being turned down to 3/4 . i know this couse i sent him the crankshaft...........
 

Jimbo

If you talk the talk you should walk the walk
No it's not a one piece rod. It's just like every other rod you find in a Animal or flat head.
It has a bearing cap and bearing inserts with splayed rod bolts.
 
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