: Questions On Rebuilding a Northstar Engine

Q Ball
05-03-08, 06:20 PM
I have a 1994 Cadillac Eldorado Touring coupe withe the 295 hp 4.6 Litre Northstar. The car has 211,000 miles or so. When I bought the car I had a feeling it had a bad head gasget, however I had no idea about the typical head bolt issue. The Car has all the standard signs of a bad head gasget. Here are my thoughts. I feel it's a bad idea to remove the engine and trans, go thru all the trouble and put good heads on an old short block. I want to rebuild the engine. I have already removed the engine, trans and cradle from the car. The engine is on an engine stand and that's were I left the job. I still have not torn down the engine yet. My Questions are this. I have rebuild many engines before but this is the first all aluminum engine I will do. Can the block be bored and honed like a standard Iron Block or does it need to be re sleeved. I will be getting an original Cadillac Service Manual. Just looking for advice from sombody who has rebuilt one of these motors before.
Thanks for any Advice.

05-03-08, 08:03 PM
There are numerous threads on rebuilding N* here, generally for headgaskt issues.
I have never seen anyone advocate boring the block or sleeves unless there is a severe oil consumption problem. The majority of the time nobody fools with the pistons or crank since the problem is in the block casting holding the bolts. Do the Timeserts and replace the seals on the lower end if you're feelling froggy but I would not dissect the pistons and crank unless you have diagnosed a problem there. The guy who is doing my HG job claims to have bored an N* block and put oversize pistons in because he had a 98 STS that was eating a quart every 500 miles. I actually saw the car and heard it run - purred like a kitty. That said, I would not let him do it on my car since I am unsure how much tolerance you have to play with on the block.

Guessing from your screen name - are you an APA member?

Q Ball
05-04-08, 11:27 AM
Here's why, It has 212,000 niles. An old Chevy motor is beat and worn down by then. I am leary of all the time and effort so far, to put it back together and have lower end issues in a year from now. This isn't a quick repair. I can get a engine in and out of my suburban in less than a day. This took 2 days just in the removal. The motor ran strong, burned little of no oil. It has an Oil pan leak but now that the engines out thats easy to fix but I'm worried about all the miles.