Smoke from a newly rebuilt 2.4

[daepp]

This is a continuation of an earlier post...

Had a leakdown test performed yesterday on a 2.4 rebuilt approx 4000 miles ago.

#1: 30%, #6: 40%, #2: 15%,
#4: 40%, #3: 45%, #5: 30%

From what I am told, this is off the scale bad. But the car runs great - it's the stares from the eco-greenies here in so cal that start to get to you after a while

The car smokes a lot - at startup and while driving. The engine had consumed 3 qts of oil in about 900 miles. I keep the oil level between the hatch marks on the dip stick, checked level and hot.

The engine was rebuilt by a very technical Pelicanite. He had the 2.2 p&c's and the heads machined at what I've been told is the best P-Car shop in Chicago.

With fresh plugs, the car pulls strong. It runs well, if a little rich and idles smoothly. However, it will leave an oil splattering on the concrete when the car is left to idle for a minute or two.

The tech who performed the test (who did not build the engine) has 37 years with P-Cars, most of it at a dealership. He is factory trained and I have seen the certificates. He DOES want to rebuild the top end (for $8K with new Mahle P&C's) so I am going for a second opinion from a different tech in a different city. I will not tell him what the first test results were.

BTW, the tech indicated he heard air escaping in the oil tank.

It has been suggested to me that the rings might not have seated yet? Does this seem logical/possible? What else could have gone wrong?

Any advise?

Thanks,

David

[Rot 911]

My guess is the rings didn't seal. After 900 miles they should have by now. Do a compression test.

[Gunter]

#1: 30%, #6: 40%, #2: 15%,
#4: 40%, #3: 45%, #5: 30%
From what I am told, this is off the scale bad. But the car runs great - it's the stares from the eco-greenies here in so cal that start to get to you after a while.
Good point about the polution; I couldn't believe how bad the air is in SoCal on my trip last year.
It's disappointing to have this after a rebuild but I agree with Kurt: The rings didn't seat. Do you have KS P/C's?

[daepp]

I believe the P&C's are used and honed Mahle 2.2's.

[Thomas Owen]

The rings should have seated long ago. The air loss past the rings to the oil tank indicate a ring problem, so either there was a problem with the initial install (gapped wrong or broken) you are looking at replacement P&C's . The fact that only 1 cylinder is really acceptable means that there was a big problem from the very start,
The 8k price seems a bit high though, and you are doing the right thing by going to another shop for an opinion.
Good luck, and post your results.

[addictionMS]

I would pop out a spark plug and shine a light down there, I had this happen a long time ago, and it was cracked rings, right out of the box.

Hope that is not the case, but if it is you should be able to see the scoring with a light through the spark plug hole on number one, when the valve is open

If you have a bore scope I would do that as well.

Jim

[Early_S_Man]

David,

This sounds like a thrown-together, cheap-and-dirty 'rebuild' to me ... no matter what the credentials of the tech who did the work!

When cylinders are honed, you are worsening the Piston-to-cylinder clearance if the previous pistons are reused, and I suspect they were! They were probably out of spec when the engine was reassembled! That means the rings were having to move around exessively in the lands of the pistons when attempting to seat, and seal! There are probably broken compression rings, and worn out/broken oil control rings as well ... hence the bad blowby situation evidenced by hissing heard by the tech at the oil filler opening.

My suggestion is to tear the engine down to the cylinders and measure them, yourself. If they are Birals, and in good enough shape to rebore ... I suggest boring out to 85.0 mm and a set of JE 9.5:1 pistons with clearanced valve pockets for the 85 mm cylinders. Get Wayne's engine rebuild book, and do it yourself.

[daepp]

Wayne: it sounds like good advise, however the rebuild was IMO done very carefully. It IS perhaps merely a small mistake with big consequences. That is, unless I can come up with some other explanation that does not require a whole new set of P&C's and top-end job.

[Bobboloo]

Warrens advice as usual is right on the money.

Whatever the case, if the numbers above are correct then the motor needs to come apart period. Break it down and the root to the problem will be revealed. Probable causes are broken rings, parts past there wear limit or rings installed incorrectly.

Take each cylinder and measure it as well as the pistons. Pistons that have worn lands can actually be re-conditioned and have "fatter" mil rings installed but more than likely in this scenerio the cylinders are past the wear limit for piston to cylinder clearance which would mean replacing the cylinders for the given pistons. Warrens suggestion of using the JE's and boring the cylinders is the cheaper route and the added plus is more power from the increased displacement.

One more alternative is a used "in spec" set of P+C's.

Let us know what you find.

Good Luck

[daepp]

What displacement can the 2.4 be brought up to while maintaining reliability? And will the mfi pump continue to function as is, or would it have to be changed to accomodate a larger displacement e.g 2.7l?

[GIBSON]

Without a displacement change you can increase performance by using the earlier higher-compression 2.2 pistons, minimal work required to make this change. You can go to 2.7 with spigot work, new barrels and pistons and head modifications (though Steve at Rennsport says he does not always do this if using the 8.5:1 pistons in the coversion, it gives a bit higher compression when you don't modify the heads.)
My 2.4S rebuild smoked for awhile after the rebuild, I traced it down to 2 leaking injectors and replaced them, the rings seated nicely after that and now no smoke. I did have to change out 5 of the rocker arm shafts as the old ones would not seal even with the RSR seals installed. Also bumped the torque on the rocker arm shafts (as per Walt at CE) and that seems to have helped as well. No more oil leaks.

[Bobboloo]

A 2.4 can be built out to a 2.7 or even 2.8 reliably but it gets expensive. The cheapest route is what Warren suggested. You can bore your 84mm out to 85mm to give you a true 2.4L as opposed to 2,341cc which is what a 2.4 really is. You might even be able to bore your cylinders out to 86mm to give you a 2.5L ish motor.

To go to 2.7 requires splitting your case and boring the spigots out to 97mm so that you can install larger P+C's. In this scenerio you can install some RS 2.7 P+C's or a 2.8 set from EBS who uses JE's with used 90mm cylinders bored out to 92mm and plated with Nikasil.

P.S. Building out to 2.7 or 2.8 with your current induction, cams and heads will give you a great street motor but it will be limited on the top end RPM wise which means you won't have any dyno bragging rights but you'll have a great torquey street motor. In this scenerio you can probably just adjust the MFI injection pump for the added displacement since the cams remain the same. Should you decide to go this route Tyson Schmidt would be the one to ask regarding the injection pump.

[daepp]

Bruce - how did you find the two leaking injectors? And did your engine (prior to the fix) smoke a whole lot on startup, or just while running?

[rsNINESOOPER]

For $8000.00 you can have the whole engine rebuilt!!!
Definitely take it somewhere else, There are lots of knowledgeable folks on this board that know a repuutable shop or two down in your area. You will work it out, just dont rush your selection process for who's going to do the work.

[GIBSON]

I have an injector testor from the era, it allows for testing of the spray pattern and for cleaning of the injector (I use it in combination with an ultrasonic cleaner, the ultrasonic only goes so far though as you need to get a good injector cleaner through the entire injector and that's done best with the injector open or in spray mode). It also lets me check for pressure inside the injector which tell you if you've got a leak (fuel drips from the injector). I just replaced the 2 bad ones rather that trying to have them fixed. The rings seated right away and I had no smoke (other than a small amount on start-up). To answer your question, it did smoke quite a bit on start-up and when I removed the heat exchangers, the exhaust ports were wet on those two cylinders. I knew the rings were not seating and took a chance that the injectors might be the problem as the other rings seated well. Looks like that was it.

[asphaltgambler]

Did the tech install the rings when he rebuilt it?? 3 qts @900 miles is huge consumption for that size engine.

[Jay Auskin]

Originally posted by Early_S_Man
David,

This sounds like a thrown-together, cheap-and-dirty 'rebuild' to me ... no matter what the credentials of the tech who did the work!
...

Sure sounds like it Warren...but it isn't. I did the work. I didn't have confidence in the head rebuilding or inspection of any of the parts. So, I had Midwest Eurosport do this. The details were sweated when I put this thing together, and it wasn't acting anything like David says when I sold it. I sold it to a Porsche Independant dealer in Chicago, who sold it very quickly after that to David. This car has great power, and runs very well like David mentions. 30%+ leakdown doesn't make sense.

The pistons are 2.2L "T" KS. All were "in spec" and new rings were used.

I've done 3 Track days in the car after break in and it ran absolutely flawless. I then put another 400-500 miles on the car and sold it. There was zero smoke for me except for ~10 seconds of starting. Once a stable idle was acheived--no smoke.

I've been in contact with David since he bought it. I hope to help him figure this out.

[einreb]

This may sound nuts, but any chance at all that the car was resold with a different engine? (what color is the engine tin?)

Up until it left Jays hands, I saw that car run (or was in it) couple dozen times and never saw it smoke other than a puff at startup.

[svandamme]

how was the engine broken in ?
gently , or hard like a bronco?

[PorscheGuy79]

My quick SC, that people who own SC's say has more pull to it than a normal SC, had more trouble than I expected pulling on the little T. There is more than enough power in the car. This bothers me some because it was great last time I saw it.