My First TBI Teardown

[Spraynlog]

I have been given a '93 Spirit, 2.5 TBI 5 speed. It was overheated pretty bad, and when I looked at it, the compression was 145,145,60,90. The car has pretty complete records from when it was purchased new. It had a dealer overhaul at around 70K, which was done on the 7/70 warranty. They replaced the pistons and rings, and rod bearings due to an oil consumption problem.

A friend of my wife was needing a car, and I found this on craigslist, and it was purchased for $650, and driven about 2 1/2 years with no problem. The radiator split, and so now it is mine.

I pulled the head today, and the HG looked OK, no obvious blow out. It was a Chrysler gasket, #5281064, with a pentastar embossed on it. I' guessing the head is cracked, but I haven't looked too closely yet. One odd thing I noticed was the #2 cam cap was loose, bolts were finger loose. Is this a sign of the overheating? I have a MP4452005 HG, should I use it on a TBI?
I found a nearly new radiator in the JY today, so I have that covered.

[135sohc]

Theres nothing wrong with using the MP headgaskets on a TBI engine. The 006 mp gasket is actually a closer match to the 528 gasket than the 005 is but use what you've got and dont worry about it.

[Spraynlog]

I had some time to look at the 2.5, and the piston tops and bores look pretty good, no melted aluminum or gouges in the bores. I'll get a reconditioned head and put it back together,it should make a good daily driver for work. What could I expect for mileage from a 2.5 TBI/5 speed combo?

[BIG PSI]

We have a 1993 TBI Acclaim with the lockup auto trans and on the highway at 70 mph we get
25 mpg. You should get close to 30 mpg, maybe slightly more.

That is a rare car you have (being a stick).
Can you post up some photos of it, especially the interior.

Chuck

[Murphy]

while you got the head off, you could mill it down for a bit more compression

[turbovanman²]

Honestly, if its been overheated that badly, I would do a ring job on it.

005 FTMFW,

[Spraynlog]

I wondered if the MP005 HG would lower the compression due to its thickness?
The original EPA mileage for the car was 25/32. Pretty impressive if true!

Here are a couple pictures.

[turbovanman²]

I wondered if the MP005 HG would lower the compression due to its thickness?
.

All replacement gaskets are slightly thicker due to them guessing your going to be milling the head.

[Spraynlog]

All replacement gaskets are slightly thicker due to them guessing your going to be milling the head.

Got ya.

Have you ever seen cam cap bolts loose from over heating? I don't think the valve cover had been off the engine in years, it suprised me to see the bolts finger loose like that!

[turbovanman²]

Have you ever seen cam cap bolts loose from over heating? I don't think the valve cover had been off the engine in years, it suprised me to see the bolts finger loose like that!

Never.

[onerippinturbo2]

i agree with simon, re ring that bad boy before the head goes on!!! overheating takes the tension out of the piston rings causing them to consume oil when put back into service, rings and rod bearings are cheap, replace them both and enjoy the new whip dude!!!!

[shackwrrr]

Ive seen stuff like that come loose when the engine has a knock though. I would check to make sure

[raccoon]

Got ya.

Have you ever seen cam cap bolts loose from over heating?

yes! my 91 shadow 2.5L TBI! 2 bolts backed out till they hit the valve cover baffle.

[Spraynlog]

Ive seen stuff like that come loose when the engine has a knock though. I would check to make sure

No knocking that I heard, it actually ran pretty smooth when cold, I drove it 1/2 a block into the driveway where I tore it down.

With my younger daughter graduating from HS in June, my car stuff is on the back burner. I'll drop the pan, pull the slugs and ball hone it, then put in new rings and rod bearings, along with a reconditioned head. It won't happen for a month or 2.

[contraption22]

Wow... I wish my '93 Clam had bucket seats and a 5 speed!

[BIG PSI]

Wow... I wish my '93 Clam had bucket seats and a 5 speed!

ME TOO !!!!!!!!!

I have a red 93 Acclaim TBI auto with lock up.

I still get 25 mpg with it at 70 mph

[raccoon]

everyones got 93 TBI acclaims, lol.

[Spraynlog]

Well, I got some time to pull off the oil pan on the 2.5 TBI, the good news is there was nothing in the pan, no metal parts or evidence of coolant in the oil.

On the other hand, I was expecting to pull off the rod caps and push the pistons out the top, but the balance shafts on the 2.5 are in the way of that.
I have only torn down 2.2 motors in the past, so I wasn't expecting that. How much trouble is it to pull the balance shafts? I'll have to read up on it.

[Murphy]

depends....do you want to keep them?

results may vary, but it wasn't too bad for me. A little bit more vibration, but livable. If you want to do that, cut the chain, pull the 6 bolts, then tap and plug the oil feed hole. would be a very nice mod for a 5 speed car!

[Spraynlog]

I got the balance shafts off, I didn't want to cut the chain, so I removed the chain gear by jamming a tire iron in the cogs and taking off the chain gear bolt.
It slid right off.

I then took out the two pistons that showed low compression to see if there was any damage. They looked fine, and the rod bearings were almost new looking. That jives with the records I have, the motor was torn down and had new pistons, rings and rod bearings at 50K or so. The pistons were date marked from 1996. The Spirit is a '93. I'll take the pistons in to work and have one of the millwrights mic them to see if they are standard bore. I'll put them in the ultrasonic cleaner too. I'll ball hone the cylinders and put her back together! It looks pretty good to me.

Has anyone used the one piece FelPro pan gasket? Is it any good?