Bad week for cars.

Mr. Pockets · #1 07-15-2007, 03:19 PM

A few days ago the MR2's timing belt broke. That's not a huge deal; I just ordered a new belt and oil pump and I'll get it done this week.

What was a big deal was what happened to the '96 Eclipse GS-T I autocross with a friend of mine. It's his car, but we both run it. We have an excellent time competing with each other, hitting the top 5 index times often.

Anyway, yesterday he actually beat me. That's only the second time this season, but it seems he did it at the expense of the car. On his last run, the car was down on power and making a clacking noise like a diesel. Our theory is that it spun a rod bearing.

We're not sure yet what we're going to do with it. The car already ate its original engine at 30k miles, and now it'll be on its third.

I'd like to have a mechanic friend of mine take a look and give me his diagnosis, but I'm sure we're going to need to tear down the engine to really find out what happened.

kcpaz · #2 07-15-2007, 03:51 PM

sounds like another case of 7-bolt crank walk

Mr. Pockets · #3 07-15-2007, 04:12 PM

Quote:

Originally Posted by kcpaz

sounds like another case of 7-bolt crank walk

Actually, yeah, it's a 7-bolt. Ugh.

Royal Tiger · #4 07-15-2007, 06:48 PM

Is that the 4g63? I thought they were bullet proof. What causes it? Too much boost?

kcpaz · #5 07-15-2007, 10:28 PM

They are pretty strong, but the early 7-bolt motors had crankwalk problems. Alot of guys replace their 2G 7-bolt motors for 1G 6-bolt motors when they go bad. It's considered an upgrade.

Mr. Pockets · #6 07-16-2007, 08:04 AM

I don't know a thing about the 4g63, other than it looks a hell of a lot like any other twin cam inline-4. I certainly wouldn't call it 'bulletproof,' though. We run in STX, so there are no real mods to the engine. It has a K&N filter...and that's pretty much it. To spin a rod bearing at 90k miles on the engine is shameful, in my opinion.

We really can't put in a 1g 6-bolt and stay in our class. It has to be another 7-bolt. Yay.

JaySVX · #7 07-17-2007, 06:56 AM

There are two versions of hte 4g63 engine, one with a 6bolt crank, and one with a 7bolt crank. THe 7bolt's are known to develop crankwalk. Either way, the stock engine is capable of handling ~450hp stock, as it's components are solid. If you are gonna build one up though, i highly reccomend starting with a 6bolt 4g63t, upgrade the turbo, injectors, fuel pump, fuel rails, headers, turbo, and ecu, and you'll be running mid 300's in the whp realm possibly more with a good tune, for generally $2500-3000, perhaps less if you know what/where/when to buy.

Why would you have to put in another 7bolt to stay in your class? I would think it would be considered a stock engine even if you tossed a 6bolt in. Either way, is it really worth it to throw the dice with another 7bolt?

Mr. Pockets · #8 07-17-2007, 08:26 AM

Quote:

Originally Posted by JaySVX

Why would you have to put in another 7bolt to stay in your class? I would think it would be considered a stock engine even if you tossed a 6bolt in. Either way, is it really worth it to throw the dice with another 7bolt?

We really don't have a choice. Replacing the engine with anything other than what it shipped with is not allowed in our class. If we did replace it, that would put us in another class. That'd be fine, but we really don't want to spend the money or the time preparing the car for that class (Street Mod).

Zeppelin · #9 07-17-2007, 11:43 AM

The engines look identical, except for the oil pan. I doubt they'd catch that on inspection..

JaySVX · #10 07-17-2007, 01:04 PM

They pretty much are identicle. If you know what your doing, you could even replace the 7bolt crank with a 6bolt in a 7bolt engine, the parts are swapable.

Royal Tiger · #11 07-17-2007, 04:09 PM

Quote:

Originally Posted by Zeppelin

The engines look identical, except for the oil pan. I doubt they'd catch that on inspection..

Must be a strict pre-race inspection if they are running the engine block serial numbers.

Mr. Pockets · #12 07-17-2007, 06:53 PM

It's not a question of pre-race inspection. It's not like there are scrutineers at autocrosses enforcing rules. But it's not out of the question to have things protested at larger events. I went to a National Tour event earlier this month and I'd like to do more. You guys know that there are different blocks and that those blocks have differences. If somebody protested the car, it'd be up to me to prove that it's legal. Usually you do that with a factory manual. That manual is hardly going to back up an engine block change.

Make sense?