Rebuilding a Northstar engine

[BeelzeBob]

So.. What does it take to rebuild one of these things? One of the things I used to worry about on my ETC was the engine going.. I mean.. Isn't is like $8000.00 to replace the engine? So, are there any rebuild options? What would something like that involve?

[elwesso]

In researching this engine, we discovered that few rebuilders are overhauling Northstar V8s - not because these engines are lasting forever (they're not) but because the Northstar V8s are such expensive and complex engines. Cadillac has no reman program for Northstar V8s (if one fails, replace it with a new one). None of the major production engine rebuilders are doing Northstar V8s, and some rebuilders told us certain critical internal parts are unavailable (such as oversize crankshaft bearings). Add to this the fact that the cylinder liners can't be replaced or overbored and it doesn't leave much to rebuild.

Even the heads are throw-aways, according to Cadillac. If the valve guides are worn, Cadillac says the cylinder heads need to be replaced. The heads have hard powder metal valve guides, but we don't see any reason why the guides can't be replaced with new ones or repaired with bronze or cast iron guide liners.

[playaman]

Ack. That's a bummer. Do you know if the cadillac parts are forged or not? I heard somewhere that the pistons and rods were forged. I've been wanting to up the shot on my nitrous but I'm not sure how much it can take. And, nope, no detonation yet *knock on wood* *crossing fingers*.

[elwesso]

They are forged

[playaman]

Gracias. I just saw that mechtech motorsports (www.mechtech-ms.com) has ran 9psi of boost no prob. Sounds good to me.

[elwesso]

9psi doesnt sound too bad. I have heard that any cadillac engine just doesnt hold up well to forced induction. I dont know, i would assume that it could handle it, thats what ive heard.

I personally wouldnt add a supercharger to an engine that didnt come stock with it. Isnt 300hp enough?

[playaman]

I'd like to hit the 650hp range they were hitting, however I don't see that happening anytime soon. I'd like 500 fwhp then I'd be satisfied Looks like we're both forum addicts.

[elwesso]

TRUE

[BeelzeBob]

A new Northstar engine costs what - $8000.00 plus installation?

[elwesso]

ive heard more than that, more like 10k. Im not sure, you could probably get one for much less from a salvage yard. But i think that cadillac built these engines well enough that rebuilts arent necessary.

[Devil_concours]

they said engine costs 8500 when they replaced the engine in mine. Anyways, I heard that cylinder walls are made out of steel is that true?

[elwesso]

Actually, there cast iron sleeves. They stick them in there, because the aluminum would expand too much.

[Brett]

cadillac has shown a few supercharged applications of the northstar in their concept cars...same northstar to your knowledge or different?

[elwesso]

Well they are contsantly playing around with it, trying to make it smaller but as powerful if not more. not sure if they are the same or not FOSHO.

[Concourson20s]

Well they would have to run a way lower compression ratio for one. No engine with a 10:1 will last long with any kind of pressure added to it. I beleive the sc version had something like 8:1 compression ratio and a tighter oil clearance as well.

As it goes for rebuilding these engines, it's perfectly possible. Don't listen to that quote from that article which was posted above. There is alot of false statements in it. First off northstar heads are only throwaways if they are cracked. Sure why spend the money on parts and labor to replace valve guides? (Which they make replacement ones btw). Any good technician, will throwaway a head with worn guides, if they are looking for a good reliable rebuild. Your better off buying heads with good guides, than messing with the worn tired ones on yours. Whether you have a 305 chevy or a 5.0 mercedes engine. Chances are if the guides in your heads are worn and cracked, the rest of your heads are probably in the same condition. Better off rebuilding a cleaner, lower mileage example. As for the bottom end, true there isn't undersize or oversize "main bearings" available, but you can find rod bearings to all type of specs (the ones that go bad the most). Chances are if you spin a mainbearing the engine just became a good boat anchor anyways. Now true these engine's arn't commonly rebuilt, ofcourse! Parts are expensive as hell, and the price of rebuilding one is almost as much as just buying a long block and putting it in. Thats the only reason they are commonly just replaced. Now if your a tech or a do it yourselfer and you have the knowledge to rebuild one you can do it and save yourself a decent amount of money.