: Need Northstar Advic



dcooksley
02-14-04, 04:56 PM
I have a 1998 Seville STS - the dealer tells me my engine is beyond repair cause it was bored too big.. The Wynn's extended warranty is a joke- they want to replace the rings... alot of good that will do. Has anyone had any luck with Cadillac or Wynn's with this same problem. The engine has 85,000 miles.

zonie77
02-14-04, 05:40 PM
Did you get to look at the block? Did they measure it while you were there?

Yours is the first I've heard anyone complain about the block being machined wrong. Except for the occassional case leak.

growe3
02-14-04, 07:10 PM
Never heard of a Northstar being bored to big. It may have just had sticky piston rings which can be fixed.

What were the trouble symptoms?

BeelzeBob
02-14-04, 11:00 PM
I have a 1998 Seville STS - the dealer tells me my engine is beyond repair cause it was bored too big.. The Wynn's extended warranty is a joke- they want to replace the rings... alot of good that will do. Has anyone had any luck with Cadillac or Wynn's with this same problem. The engine has 85,000 miles.

What do they mean when they say the engine was "bored to big..." ...??? This implies that the cylinders were machined too large. Impossible basically. If the cylinders were even a few ten thousandths too large the engine would have been noisy with extreme piston slap from the very beginning. This diagnosis sounds like utter BS and is a means of convincing you to go elsewhere (they don't know how to work on it) or to just give up and trade it in for a new car.

What exactly is the problem that you took it in for??

dcooksley
02-16-04, 04:21 PM
Some of the holes are actually oval they are so out of shape. The engine had been slapping for quite sometime. The Cadillac dealer tells me this is not so uncommon, but that it usually doesn't show up until after 100,000 miles.

Yes, I saw the engine with the dimensions.

BeelzeBob
02-16-04, 04:32 PM
Some of the holes are actually oval they are so out of shape. The engine had been slapping for quite sometime. The Cadillac dealer tells me this is not so uncommon, but that it usually doesn't show up until after 100,000 miles.

Yes, I saw the engine with the dimensions.


It is extremely uncommon I would say. Every high mileage Northstar engine that I have ever seen had the original factory honing marks still in the bore. For a cylinder bore to wear is very very rare and there would have to be some reason for that like unfiltered air, a vacuum line sucking salt off the winter roads, etc.... something in the inlet loose and pulling unfiltered air. That is the ONLY time that I have ever seen cylinder bore wear.

If indeed the cylinders are worn like that then you are a candidate for another engine. Simply replacing the rings will not effect a repair. While the engine is designed to be re-manufacturable there has never been a program started to do such...nor are there OEM oversized pistons available as there has never been any demand for them.

If you have a warranty then I would say the problem at this point is with the warranty coverage...and finding out how the cylinders could wear like this. It is NOT very common.

If the engine is accessible look at the bores carefully with a flashlight. Make sure the piston is at the bottom of the travel or removed. By holding the light at an angle to the cylinder surface you should see the original hining marks in the bore at some points. Follow them around the bore and see if they exist where the wear would be greatest, along the skirts of the piston travel..or 90 degrees from the crank shaft centerline. If you can see the honing pattern still in that area then there is no wear and you have to suspect the cylinder bore measurement techniques...which, if not done correctly, can easily "prove" an out of round bore. Also, if the block is worn that badly, then there should be a ridge at the top of the cylinder at the 90 degree (from the crank centerline) above the normal ring travel. Check for that also.

Sinister Angel
02-16-04, 05:16 PM
Some of the holes are actually oval they are so out of shape. The engine had been slapping for quite sometime. The Cadillac dealer tells me this is not so uncommon, but that it usually doesn't show up until after 100,000 miles.

Yes, I saw the engine with the dimensions.


So you visually saw the out of round condition then? If you can, you definately have some issues. See, this is why removeable cylinder liners are nice. If it's still in spec, punch out the cylinders and find someone to manufacture oversize pistons?

BeelzeBob
02-16-04, 11:18 PM
this is why removeable cylinder liners are nice. If it's still in spec, punch out the cylinders and find someone to manufacture oversize pistons?

Sinister...

I don't quite understand your comment, here. What all aluminum engines do you know of that have "removeable" cylinder liners?? The 4.1/4.5/4.9 engine had true, removable liners but other than that the other engines have cylinder liners that are not designed to be removed for service.

Other all aluminum engines can have the existing cylinder liners "removed" by destroying them via boring them out completely and installing new ones...but...you could do that with the Northstar engine, too. So, what is the real difference??

The Northstar cylinder liners are designed to be boreable by 1 mm oversize (1 mm on the diameter..... 0.5 mm on each wall. All you need are the custom oversized pistons...same as any other all aluminum engine with iron liners. Just bore the cylinders with them inplace much like any other engine would.

The Northstar is a little more compact than some other all aluminum engines since it was designed for a transverse V8 arrangement...length was very critical so the bore centers were kept at 102 mm to keep the block short enough to fit in the car sideways. This is what limits any overbore for displacement increase....not the fact that it has cast in place iron liners.

What port in Michigan are you at??

Sinister Angel
02-17-04, 03:58 PM
Yeah, I know nothing about Northstars really, that's why I just threw that idea out there. Right now I'm working on a GM EMD in diesel lab, and the nice thing about those is you just pop the liner out, if it isn't in spec, throw in a new one and have the old one remanufactured.

I'm from Traverse City.

BeelzeBob
02-17-04, 11:22 PM
Yeah, I know nothing about Northstars really, that's why I just threw that idea out there. Right now I'm working on a GM EMD in diesel lab, and the nice thing about those is you just pop the liner out, if it isn't in spec, throw in a new one and have the old one remanufactured.

I'm from Traverse City.

Yea, Ok, big difference between the construction of the big diesels and gas engines. Those are called free standing, wet liners since the coolant contacts the liner directly. Interestingly, the 4.1/4.5/4.9 engines are constructed the same way...with an aluminum block or engine case with the free standing, wet cylinder liners that drop into the block. The majority of the current aluminum block engines have either castin place liners or liners that are installed by freezing or heating and slipping them in. The construction lends itself much better to engines that are in high volume production. Big difference making 50 engines a day and 5000 a day....

I assume you are Coast Guard?? Do you guys go out in the winter at all or not?? I see the ice breaker from the Soo when we cross the Mack Bridge in the winter but I don't know if any of the other ships go out at all...

Sinister Angel
02-18-04, 01:18 AM
Nope, Not coast guard. I'm going to the Great Lakes Maritime Academy

Actually, diesels use a variety of liner styles, not just wet. Wet/dry/jacketed(water runs into the liner).

At least you answered my question of whether any car engines used a wet liner setup though :D

Where you from?

BeelzeBob
02-18-04, 12:59 PM
Nope, Not coast guard. I'm going to the Great Lakes Maritime Academy

Actually, diesels use a variety of liner styles, not just wet. Wet/dry/jacketed(water runs into the liner).

At least you answered my question of whether any car engines used a wet liner setup though :D

Where you from?
Detroit area.

Sinister Angel
02-18-04, 05:51 PM
cool, I have an uncle in ypsi

BeelzeBob
02-19-04, 03:38 PM
BTW....I should have mentioned in the earlier post that there are several production gasoline passenger car engines with wet cylinder liners. I mentioned the obvious one, the 4.1/4.5/4.9 engine family in the Cadillacs. The early Dodge Viper V10 engines were also wet cylinder liner engines although they switched to cast in liners I believe in the later models. Also, the older ZR1 Corvette engine, the one that had the all aluminum, 32 valve design had wet, aluminum cylinder liners in it. There have been a couple of European engines with wet liner construction also many years ago.