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4.2 crank casting number.

CRASH

NAXJA Forum User
NAXJA Member
Location
Foresthill, CA
Anyone know the casting number of a late model 4.2 with serpentine set up?

How about a the earlier model heavy crank?

I'm trying to make sense of a parts store listing.....they sell a myriad of different cranks for $136 with all the associated bearings.

I'm leaning towards the heavier crank for the pure advantage of rotating mass for crawling purposes.

CRASH
 
Well...

I'd be more inclined to take a lighter crankshaft (easier to keep balanced) and go with an intertia ring for the flywheel if you feel you really need it to maintain engine revs. Of course, that's a two-sided issue either way - while the additional rotating mass will tend to keep the engine turning, it will also require more torque to GET turning. Consider carefully.

Of course, that is the advantage of the inertia ring - you don't have to tear the engine to bits to tune it. I'm sure there's a way to determine a mass optimax by application - you might want to check with Ed Stevens, as he seems to be our resident maths guru...

I seem to recall that the principal reason for the shift to the dual-mass flywheel has to do with decreasing mass to allow for more rapid acceleration, but that seems to be generally a non-issue for most of us here... :laugh3:


5-90
 
Which parts store listing were you looking at Crash? I also need a 4.2 crank for the stroker that I'm putting together and at $136, that's a very good deal. I want the '87-'90 lightweight crank with the 2.06" nose for a serpentine pulley.
The crank casting numbers that I've come across are:

'75-'80 #3214723 12 counterweight heavy crank, 2.38" nose
'81-'86 #3235477 8 counterweight light crank, 2.38" nose
'87-'90 #3727 8 counterweight light crank, 2.06" nose
 
Dr. Dyno said:
Which parts store listing were you looking at Crash? I also need a 4.2 crank for the stroker that I'm putting together and at $136, that's a very good deal. I want the '87-'90 lightweight crank with the 2.06" nose for a serpentine pulley.
The crank casting numbers that I've come across are:

'75-'80 #3214723 12 counterweight heavy crank, 2.38" nose
'81-'86 #3235477 8 counterweight light crank, 2.38" nose
'87-'90 #3727 8 counterweight light crank, 2.06" nose

Here's one at Parts America (Kragen/Shucks/Checker), rebuilt by Crankshaft Rebuilders Inc. The part number is 25300:

http://www.partsamerica.com/PartDet...=CRI&MfrPartNumber=25300&PartType=529&PTSet=A

Autozone.com also has them, but the CRI brand doesn't have a price associated with it. It has the same part number as Kragen, CRI 23500, and it specifies a 2.00 length snout: http://www.autozone.com/servlet/UiB...|~JEEP|~WRANGLER+4WD|~1990|~3+MO|~44.0|~EA|~N

CRASH
 
Dr. Dyno said:
Thanks. Unfortunately Parts America don't ship outside the US and Autozone don't have any cranks in stock. :( I'll have to look somewhere else.

If you really want it, you can have it sent to me, or I can pick one up for you, and then I can forward it along to your sandy home.

CRASH
 
CRASH said:
I can pick one up for you, and then I can forward it along to your sandy home.

CRASH

That would be great. I definitely want the '87-'90 crank (#3727) that has the short snout (2.06") for a serpentine pulley. If you can find one, let me know and give me a price plus shipping. :cheers:
I know these guys http://www.newengineparts.com/ have the crank that I need but their site's not working properly.
 
Dr. Dyno said:
That would be great. I definitely want the '87-'90 crank (#3727) that has the short snout (2.06") for a serpentine pulley. If you can find one, let me know and give me a price plus shipping. :cheers:
I know these guys http://www.newengineparts.com/ have the crank that I need but their site's not working properly.

I'll be shopping next week, so I'll let you know what the CRI crank kit from PartsAmerica looks like.

CRASH
 
Their site's working again. Here's the list of crank kits:

New Engine Parts Domestic Crank Kits

At $140, you get a very good deal for the 258 crank kit (includes rod and main bearings) so I'm definitely getting it from there.
 
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