: 94 Northstar with broken valve.



wpg-topsecret
10-16-06, 04:06 PM
I'm looking at buying a northstar for my fiero. Here is the add for the motor on a local forum:


I am selling my northstar v8 out of a 94 cadillac, it needs a valve replaced.
- 300 hp
- v8 32 valve
- all aluminum
Comes with all wiring harness computer, engine is complete. I need it gone asap.
- Great for fiero swaps, hot rods, spare parts, etc.

Asking $300


And here is a response from the seller when I required why it needed a valve replaced:


The car had around 130km, it was a writeoff. I removed one valve cover about a year ago when i got it. One valve was cracked at the top, GM gave me a price of around $60 for the peices i needed. I never got around to doing anything with it. Now its sitting and i need it gone.



With a broken valve can I expect there to be more damage in the motor than just the valve? Are the chances of rebuilding the motor to use for reasonably cheap pretty good, or should it probably just remain a parts motor?

zonie77
10-16-06, 09:08 PM
If the valve broke so the head dropped in the engine it needs a LOT more work. You could take a look at it if it's close.

wpg-topsecret
10-16-06, 10:09 PM
How hard is it to pull the valve cover with the motor out of the car so I can have a look and see the damage there atleast?

chevelle
10-16-06, 11:19 PM
I don't think the "seller" knows what he is talking about......

Maybe you should go over there and look at it and see what he is calling a "valve"....

Since you really cannot see the "valves" by taking off the "valve cover" there is really no way of knowing what he is talking about being "cracked at the top". And no one is going to replace an engine valve for only $60. I suspect he is looking at some other part and calling it a "valve".

The biggest concern is the whole story and what really happened and what the condition of the motor is from sitting all this time....possibly with the cam cover already off as the seller suggests...???

clarkz71
10-17-06, 07:09 AM
No matter what the engine needs, it's worth $300 just for parts.

wpg-topsecret
10-17-06, 10:21 AM
No matter what the engine needs, it's worth $300 just for parts.

That's what I was thinking....

wpg-topsecret
10-18-06, 02:44 PM
Here is an updated response I got from him when I told him you can't see the valves when you take the cover off:


it wasnt runnning when i pulled it out. the car was already cut in half. When you pull the valve cover off on the water pump side ( the one with the little pully) You see the top of the lifter i guess it is. It is cracked. I called the dealer about it and the pricing for the peice was around 40 bux. Sorry i never got around to pics yet, been working long hours. I will try again tommorow.
- Jason

chevelle
10-18-06, 11:18 PM
A lifter cracked..???!!!! There is likely much more damage to the engine. About the only way a direct acting tapped "cracks" is if the engine is severely overreved to teh point that the valves float. This causes a no-follow condition between the cam lobe and the tappet and as the tappet crashes onto the cam lobe it cracks. Not just one will crack..... The engine is still probably good for parts but replace ALL the lifters and/or do NOT consider them "good" parts.

thu
10-19-06, 01:33 PM
I agree 100%.

As the Monty Python Troupe would say, "RUN AWAY! RUN AWAY!"

wpg-topsecret
10-19-06, 05:43 PM
With a cracked lifter, would it be safe to turn the motor over with a breaker bar and socket just to make sure everything's not completely siezed up?

Are lifters for the N* rather pricey?

Zorb750
10-19-06, 09:05 PM
How do you so horrendously overrev this engine? 6500 RPM = fuel cutoff on 1994.

wpg-topsecret
10-19-06, 09:49 PM
So, if I go pick this motor up and plan to use it, what is the MINIMUM work I should do the check/repair and make sure it's good to drive?

Pull heads, check combustion chambers ect (replace head gaskets)
Pull oil pan, plastigauge bearings, check for damage
Rebuild heads, replace lifters

Anything else I should check/rebuild?

Odin8
10-24-06, 11:39 PM
Eh, if something malfunctions in the PCM or EBTCM or whatever controls the rev limiter then I suppose you could over rev it then. My mechanic said I probably threw a rod from over revving it, and that was a result of my EBTCM malfunction. My traction light was on and after the car blew up they found the EBTCM to be shit, and when I was driving it before then it'd revved until I let off the gas, it wouldn't shift at redline. So /shrug, that is one explanation? If anyone knows better let me know, I'm still kind of skeptical myself. Otherwise yah, I'd ask the same question, how the hell could you over rev an engine like this with everything protecting it?

zonie77
10-25-06, 12:38 AM
So, if I go pick this motor up and plan to use it, what is the MINIMUM work I should do the check/repair and make sure it's good to drive?

Pull heads, check combustion chambers ect (replace head gaskets)
Pull oil pan, plastigauge bearings, check for damage
Rebuild heads, replace lifters

Anything else I should check/rebuild?

If you pull the caps you have to replace the bearings. I would do a cyl pressure test on it or do the HG's if you have access to a timesert kit. You might consider replacing the case seal too.

Zorb750
10-31-06, 11:49 PM
EBTCM has nothing to do with rev limiter. Your mechanic is an idiot.

Odin8
11-01-06, 11:41 PM
Pretty much what I thought. What would cause the rev limiter to stop working then?

Zorb750
11-02-06, 12:06 AM
Well, the Northstar doesn't use a phototachometer, so it can't be loss of tach input... It needs the crank signal to activate spark. PCM would be my assumption.