Duke Crankshaft (Page 1/1)
omaps JAN 16, 12:56 PM
Is there any difference in the quality of the crankshafts in the Iron Duke. I'm in the process of rebuilding mine and have to get a crankshaft re-ground. I have two, nothing much to choose between them - one is casting number 684 the other is 071.
Dennis LaGrua JAN 17, 09:07 AM
AFAIK, all Fiero Duke crankshafts may be the same. They are all cast units and I've never read that anyone here has broken one. The Duke is a low revving high reliability, high mileage engine. The weak spot appears to be the rods but that was corrected early on during the recall in 1985.
Great info here on the Duke engine from Ira Crummey who is up in New Brunswick, probably not that far from you. He claims to have built a 150 HP version.
Fiero Iron Duke Info site

[This message has been edited by Dennis LaGrua (edited 01-17-2020).]

omaps JAN 17, 10:36 AM
Thanks for the info.
Any way to tell if the rods were replaced in an 85?
Simon
Raydar JAN 17, 04:44 PM
I have read that the 87 and 88 cranks are substantially stronger, due to having the large disk for the crank position sensor, if for no other reason.
The 88 crank was also designed to drive the oil pump / force balancer assembly, but Rockauto lists the same part # for both years, IIRC..
omaps JAN 18, 08:58 AM

quote
Originally posted by Raydar:

I have read that the 87 and 88 cranks are substantially stronger, due to having the large disk for the crank position sensor, if for no other reason.
The 88 crank was also designed to drive the oil pump / force balancer assembly, but Rockauto lists the same part # for both years, IIRC..



I don't think you can use the '87 or '88 cranks in an '85-'86 block.
theogre JAN 18, 07:05 PM
Just take both to the shop to let them measure with one has less damage and grind that.
One Might need polishing vs regrind for under size mains, rods or both.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

Raydar JAN 18, 09:22 PM

quote
Originally posted by omaps:

I don't think you can use the '87 or '88 cranks in an '85-'86 block.



The piece that I read, that said they were stronger (it specifically mentioned the 88), suggested that they were a stronger alternative to the earlier cranks.
Having said all that, I have never tried it myself. YMMV. Just sharing what I have heard, up until now.