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ProfChaos
02-22-2008, 09:13 PM
Does anyone know if it is normal after an engine rebuild for the engine to emit white smoke for a little while as the rings, valve seals, etc. are seating? The engine in question was just completely rebuilt: cylinders honed, rings replaced, main bearings and rod bearings replaced, and both heads reworked, including new lifters, valve guides, and valve seals.



In short, even though a total reworking of the engine was just completed and it has less than 50 miles on it, I get a constant-but-light trace of white smoke coming from the passenger's side exhaust. Drops of water also drip from the end of the exhaust as it emits the white smoke. I notice this constant white smoke and dripping of water at idle. The driver's side exhaust emission is fine, so I am puzzled by it all. :scratch:

Thanks for your help.

--Professor Chaos

dewone
02-25-2008, 10:25 AM
If before the rebuild you had a blown head gasket it could have dumped water (radiator fluid) into the muffler system so it in turn is turning to steam when the car warms up and can last a while. That could be the white smoke you are observing. It could also be an indication that the present heads are not seated properly or there could be a crack in the head or heads, and the white smoke or stream you see is being produced as you run the car. 1)Do a comprersion test on all your cylinders to verify that your getting the proper compression. 2) check the radiator fluid level to see if it is escaping when running. Hope it is the first senario.

ProfChaos
03-03-2008, 10:08 PM
Thanks for the input.

To be cautious, I drove the car to an SVT-certified dealership to verify that the smoke was not something serious enough to merit having the heads re-torqued, or the bottom of the engine re-worked. The Service Manager saw the smoke, and his theory is that the smoke is due to the new rings not being fully seated. He claims that this sort of thing is fairly common with freshly rebuilt engines, so I'm not too alarmed at this point.

At any rate, I have a 12-month/12K-mile warranty on the engine rebuild, from a fairly reputable builder of Ford modular race engines, so we are going to keep an eye on things, and if the passenger-side of the engine still smokes after the next two oil changes (at ~150 miles to each change), we will explore the options. (I don't think it is anything too serious, as the smoke seems to be diminishing somewhat, even though I can still smell burning oil at this point.)

The good news is that if there is a serious issue, it won't cost me anything but more than time.

I'll post a follow-up message when the smoke stops.

Thanks again for your input.

:cheers:
--Professor Chaos

SuperG
03-04-2008, 08:45 AM
After my rebuild, there was absolutely no smoke, so hopefully if it is a little something in the exhaust, it burns away quickly!

ProfChaos
03-11-2008, 12:30 AM
After my rebuild, there was absolutely no smoke, so hopefully if it is a little something in the exhaust, it burns away quickly!


I think that it is indeed something in the exhaust: The guy who re-installed the rebuilt engine went completely ape with Permatex Ultra-Copper high-temp silicone sealant when he re-installed the Bassani header collectors: He smeared way too much sealant onto the header tubes, at the point where they slide into the collectors, and I think that this excess sealant dripping down into the collectors is what is causing the smoking, especially since the smoke keeps killing my front O-2 sensor(s) by contaminating them. I get a "Check Engine" error code of P0153, "Upstream heated O-2 sensor circuit, slow response (Bank 2, Sensor 1)."

Further, when the transmission was re-built (shortly after the original post in this thread), the mechanic in question had to remove and replace the header collectors again, in order to get the transmission in and out more easily. Now, both sides of the exhaust emit smoke, not just the passenger-side. Thus, I'm thinking at this point that too much Ultra-Copper high-temp sealant at the header collectors is the culprit, both for the smoke and for the failed O-2 sensors.

I called Bassani, and their Customer Service Department told me that, since the headers I have are ceramic-coated headers, the excess sealant will just bake onto the ceramic coating inside the collectors, and there is no affordable way of removing the excess silicone sealant without also removing the ceramic-coating. Thus, I have a new set of header collectors on the way from Bassani, and the Bozos who did not install the headers properly in the first place will never touch my Cobra again. (They also broke a sensor at my oil pan, ruined my starter, and left greasy fingerprints all over the plug wires and all over the fenders and rear spoiler. It took me over an hour to clean the grease off of my plug wires...They are nice people, but they are also strictly an amateur operation, judging from the way that they treated my car. Thank God that they subcontracted the engine re-build to a true modular motor secialist (http://www.realspeedparts.com/index.html) .)

After I have the new header collectors installed by Injected Engineering (http://www.injectedengineering.com/), I will also have Injected Engineering (http://www.injectedengineering.com/) perform a cylinder leak-down test and a compression test before they also perform an SCT dyno-tune. That way, smoke or no smoke, I will better know if the rebuilt engine is seated properly; I will better know what I have in terms of engine performance, long before the warranty on the rebuilt engine expires.

I'll post a follow-up message when the car stops smoking and stops killing O-2 sensors.

Thanks for the help. :cheers:
--Professor Chaos

ProfChaos
03-26-2008, 09:35 PM
The smoke coming from the exhaust is caused by something inside one of the rebuilt heads--perhaps a valve guide that is not installed properly. Right now, the rebuilt engine burns a quart of oil in fewer than 400 miles. I will know more tomorrow, after a modular motor specialist performs a leak-down check on each cylinder and inspects each spark plug for oil contamination.

The OBD-II error code that keeps occurring is "P0133: Upstream O-2 sensor, slow response: Bank 1, Sensor 1." I think that "Bank 1" includes cylinders 1-4 (the right cylinder head). Thus, I suspect that whatever is causing the smoking lies in the valve train of the right cylinder head.

dewone
03-27-2008, 06:05 PM
Dang the luck on that. Looks as though your on the road to recovery.

Good luck.

SuperG
03-27-2008, 08:19 PM
And hopefully the problem is right below the valve covers!!

ProfChaos
07-14-2008, 11:25 PM
And hopefully the problem is right below the valve covers!!


The problem with the Cobra still ticking slightly (on the passenger's-side head) and also burning oil at a ridiculous rate turned-out to actually be two problems: The head was not rebuilt properly--the valve seals for more than one cylinder were leaking oil into the intake valves--, and the head also had a casting void that was causing the slight ticking noise at rapid acceleration--a ticking noise that was the result of the cylinder head not developing sufficient oil flow.

The head-casting void was the real enigma, as I've never heard of that happening with a Teksid-manufactured Cobra head. (The casting void was almost certainly caused by a spurious air bubble during the casting of the aluminum, at manufacture--way back in 1995/1996. And, that bugger of a head-problem was perhaps the reason that the 51k-mile engine was in a salvage yard before I bought it: The passenger's-side head of the engine always ticked, although intermittently at times, from the time I had it installed after buying it from a salvage yard....The moral of the story: never buy a used Cobra engine from a salvage yard, unless you are intimately familiar with the history of the car from which it was removed.)

Since the Blue Oval Corral (the business who sub-contracted the original engine rebuild) went out of business, I ended-up having to pay twice for the engine rebuild. That stinks, but the person who had the head-work done the second time is an honorable guy and an excellent Ford Modular engine specialist (Walter Drakeford at Real Speed Racing (http://www.realspeedparts.com/)). So, if anything else related to the engine rebuild should come up within a reasonable period, I'm likely covered for everything except additional parts. :) Walter also showed the technical know-how to suggest that we replace the casting when the head was rebuilt the second time, and that move resolved the ever-annoying ticking noise.

The really good news is that the '96 Cobra engine is now completely re-built, with fewer than 2000 miles on new rings, new main bearings, new rod bearings, ARP head studs, and--of course--the twice-rebuilt heads. :bounce:

Thanks to all for the tips and expressions of empathy during this seven-month adventure in Cobra land. I'm zooming right along now, and Lorena the Cobra is better-than-new. :flash:

cheers, :cheers:
--Professor Chaos