Crankshaft replacement (Page 1/3)
Cunnive APR 24, 08:41 AM

Hey folks,

I am in the process of rebuilding my 2.8L and I figured since I am replacing every part in the engine, I might as well replace the crankshaft.

Anyone have a recommendation for a replacement crankshaft? I'm not looking for anything performance-wise but something that is close to or slightly better than OEM.

Ty
Raydar APR 24, 11:21 AM
If you are replacing the crank, do a 3.1 crank and pistons. They're pretty much a straight drop-in. The block and rods are the same.
You'll be pleased with the torque increase.
Cunnive APR 25, 12:38 PM
Unfortunately I already purchased replacement pistons and connecting rods for my current crankshaft so I would need a replacement for what works without needing to get matching pistons.

I see the engine tech crankshaft on rockauto is out of stock so was wondering what other brand or replacement would work.
olejoedad APR 25, 12:47 PM
How many miles are on your engine.
If the crank is not damaged, why would you want to replace it.
A seasoned cast crank is stronger than a new cast crank, simply because it is seasoned.
Magnaflux your old crank to check for cracks, if it's not, then use it.
Raydar APR 25, 10:05 PM
This may not exactly address your question, but here goes....
I don't know what year your 2.8 is, but if it's an 85-87, you can swap in an 88 crankshaft. You will need to also replace your flywheel or flexplate, to a neutrally balanced piece. A flywheel or flexplate for most any FWD 3.1 will work with the 88 crankshaft. The later (neutrally balanced) flywheels are much easier to find than the earlier (weighted) pieces.
Hope that helps a bit.

[This message has been edited by Raydar (edited 04-25-2020).]

pmbrunelle APR 25, 10:17 PM

quote
Originally posted by olejoedad:
A seasoned cast crank is stronger than a new cast crank, simply because it is seasoned.



I don't know how the seasoning helps things, but it is an intriguing idea.

The 80s BMW F1 turbo engine blocks were apparently sourced from used road-car engines.
wftb APR 25, 10:51 PM
Engine blocks as raw castings used to be left outside for a few months before machining. My late Uncle, that worked on WW2 aircraft told me all factories did this and he called it seasoning as well.

------------------
86 GT built 2.2 ecotec turbo
rear SLA suspension
QA1 coilovers on tube arms

Gall757 APR 26, 09:26 AM

quote
Originally posted by wftb:

Engine blocks as raw castings used to be left outside for a few months before machining. My late Uncle, that worked on WW2 aircraft told me all factories did this and he called it seasoning as well.




correct.

Cast Iron is odd stuff. As it cools it builds up internal stresses. If you machine it right away, the part will slowly warp and probably take your machining out of spec. Each part will have it's own requirement for 'seasoning', but a used part has already done all that and will maintain accuracy better than a new part.

[This message has been edited by Gall757 (edited 04-26-2020).]

Cunnive JUL 06, 01:56 AM

quote
Originally posted by olejoedad:

How many miles are on your engine.
If the crank is not damaged, why would you want to replace it.
A seasoned cast crank is stronger than a new cast crank, simply because it is seasoned.
Magnaflux your old crank to check for cracks, if it's not, then use it.



The thrust bearing was eating away at the walls too much and has made it too close for comfort to exceeding the recommended specs. I also found a tictac-sized piece of metal stuck inside an oil galley when I took out the crankshaft so I want to just replace it entirely.

My machine tech told me I need a Cast #817 for my 2.8L 86 fiero engine

Is there any crankshaft out there I can search for that would be a straight replacement?

[This message has been edited by Cunnive (edited 07-06-2020).]

fierofool JUL 06, 07:34 AM
As Raydar said, you can get a neutrally balanced crankshaft for a (Beretta) 3.1 FWD engine and use your old rods and pistons or the new stock 2.8 rods and pistons you just bought. The shorter stroke of the 3.1 will give you much more torque. It's all a drop-in, except you'll need to replace the flywheel or fexplate. In that case, a 91 Beretta piece is readily available through Rock Auto.