Blue smoke for 15 minutes

[TucsonK5]

Confirm my fears...

The problem: recently rebuilt Toyota 22RE smokes on startup and won't stop smoking until running (idling) for ~15-20 minutes. Blue smoke, no water in oil or vice versa. I am thinking it is the rings because bad valve guides wouldn't cause this duration of smoking and I can't think of anything else that would do it. Agree or disagree?

Background (sorry it's so long but I want to provide all details):
So, recently I rebuilt a Toyota 22RE that I bought on Craigslist for $100 (long block). The guy said it had ~115K miles, smoked on startup (I think valve stem seals at the time) and he decided to just buy a long-block stroker motor instead of working on it.

Pulled it apart, everything looks good, main and rod bearing journals are well within stock specs (miked), neither block nor head is warped, cross-hatch pattern still visible in cylinders. I did not mike the cylinders because I saw the cross hatch, don't have an inside mike, and the reported mileage was so low for a Toyota engine. Rings looked good, no carbon build-up, and rotated easily. I didn't hone the cylinders and used the original rings. All seals and bearings replaced. Runs well except for the smoke. I haven't really gotten to get it up to speed on the street because it is not registered or insured.

Cold/dry compression was below spec (all about 125-135 PSI, minimum is 142, standard is 178 PSI), cold/wet added about 10 PSI to each cylinder. I haven't done a warm compression test yet because I smoke out my neighborhood and have people showing up to see if everything is OK.

Thanks for the help.

 

[blazinzuk]

I would say valve guides they heat up and expand rings would keep smoking.

 

[Sandman]

Sounds like really bad valve guides. Rings would be black smoke.

Can you get umbrella seals for it?

 

[TucsonK5]

I hope you guys are right. I did replace the guide seals during the rebuild with new ones and there wasn't any lateral play between the valve stem and guide. Do you really think it could smoke for that long only due to valve guide seals? I'm only used to the 30 seconds after startup. I didn't put it in earlier, but there is enough smoke to create a decent haze in my entire yard.

 

[tRustyK5]

I'd do a leak down test on it. It's apparent there is compression loss somewhere, and that is most likely going to be the same area oil is getting past. ~40-50 psi loss is significant on a motor that is relatively fresh...

Is it possible it was slightly overbored but the stock pistons re-used?

Rene

 

[TucsonK5]

I'd do a leak down test on it. It's apparent there is compression loss somewhere, and that is most likely going to be the same area oil is getting past. ~40-50 psi loss is significant on a motor that is relatively fresh...

Is it possible it was slightly overbored but the stock pistons re-used?

Rene

I will try to do the leakdown today if time allows.

The rebore is one thing I am worried about. Maybe the cross hatch was due to a rebuild gone wrong .

 

[Fordum]

Either I misread your post, or there is something screwy.
You said crosshatch still visible.
I did not see where the other guy had rebuilt it, but he must have bored or honed it. I certainly would not expect to see a pattern after 115K<G>.

Problem is, the main reason you do the crosshatch pattern is to help hold oil while the engine is breaking in and the rings are seating.
By the time the rings seat, the pattern is mostly worn away. It sounds like your engine has never broken in.
Either this guy went WAY overboard with the crosshatch hone, and cut grooves in the wall instead of light scoring, or you have the wrong pistons.

I have seen this with certain types of rings. Hard chrome is often so slick that it takes a long time for them to seat if I remember right.

Also, almost every maker of synthetic oil warns against using it at first on a new engine because it is so slick it can cause problems with break in. Or at least they used to. I know every mechanic I know still does.

You need a certain amount of wear during the break in period. That is why I changed the oil in my rebuilt engine at 500, 1000, 1500 miles to get the wear particles out.
I am going to let it go to about 2500-3000 before the next change, and then may go to synthetic.
I should be doing an oil analysis to check on how much wear so as to know when the break in is mostly done, but I have gotten lazy in my old age.

But,in your case, I'm afraid that it is going to take an inside miking to find out for sure. Were the pistons stamped as to size do you remember? If so, that may save you some time. You could just pull a head to mike the cylinder, and would not have to pull a piston to measure it.

BTW, while valve guides and stems do heat up and seal better, so can pistons and rings. And they might take longer than valve stems.

J.

 

[TucsonK5]

First off, I want to thank everyone for replying, it has helped give me direction on this.

As far as seeing the cross hatch goes, I guess more experience would have told me something was strange seeing that at *reported* 115K miles - oh well. The guy never said he rebuilt it, though I don't think I specifically asked. He struck me as more of the parts-replacer type car guy versus the rebuild type.

As far as the pistons go, I am pretty sure they were original Toyota stock size because they had the "size classification" markings on them (either A, B, C or 1, 2, 3, can't remember which). No other markings.

Also-

I did the poor-man's leak down test (no gauges-just listening) and the vast majority of the air is going past the pistons into the pan. I may have had a little leakage on intake of #4, but that was about it. Don't know if it makes any difference, but I had ring leakage evident from 5 to 90 PSI. I know its not as accurate as the true gauge-based leak down test, but it still indicates leakage at the piston, whether it is acceptable leakage is unknown. Would the gauge-based test really provide any more useful information in this case?

Correct me if I'm wrong, but this, in addition to low compression, points to bad rings/cylinder wall and kind-of eliminates valve stem seals, doesn't it?

 

[tRustyK5]

The leak down test is just a tool to narrow your focus in finding the problem. A guage isn't necessary really...as you now know that the worst leakage is through the rings.

At this point I would pull the head and properly measure the bore, then (unfortunately) pull the pan, and rod caps, and pull the pistons out of their bores and measure them too. I kinda suspect the block got machined, but whoever assembled it tried to re-use the standard size stock pistons. Maybe the pistons are right but ring gaps are just way off...

The only way to know for sure what was done and what you'll need to do to fix it is to dis-assemble and inspect each part. At least you know it isn't the head/valves/seals or guides.

What kind of oil pressure did it make while running?

Rene

 

[TucsonK5]

As far as oil pressure- no idea. No gauge but the idiot light never came on during running. I would think it should be normal as miking the journals (crank and rod) indicated very little wear versus factory stock and plastigage indicated all clearances near the lower (tighter) end of the tolerances, but within spec (maybe another red flag on a *115k* motor with no measurable wear). Oil pump was also within clearance specs.

One thing I forgot to put in earlier- there was virtually no ridge at the top of the cylinder. It was hard to even feel it with a fingernail and the pistons/rings could be slid past it without any resistance. In hindsight, this should have also tipped me off that the cylinder had been rebored, since I doubt 115K mi would not produce a ridge, even in the hardest block.

Looks like an engine pull is in my future. Should be able to get inside and outside mikes sometime this week from a machinist friend of mine for the pistons and bore. Unless someone has a spectacular solution so I can avoid doing this, I will post up again after I have measured.

Again, thanks everyone for your help!

 

[TucsonK5]

Well, here is the update (although it has been so long that I doubt anyone cares).

Pulled the motor. Pulled exhaust manifold, oil basically running out of exhaust for cylinder #3, the others looked good. At least I found my culprit cylinder.

Pulled head, piston #3 isn't centered in the bore, it is pushed up against the front of the bore (ie toward front of motor). Turns out to be a very slightly bent rod. Switched it out when putting it back together.

Pulled pistons. All look good except for #3 pretty much has the compression rings gaps lined up. User error I am guessing, but maybe the bent rod could have caused them to rotate? Doubtful at best. That is my fault that I somehow phased rings on all other cylinders but forgot to phase #3.

Used a CMM (coordinate measuring machine - extremely precise) to measure the bore, ALL within factory standard spec (Toy 22re blocks are known for being hard and wearing well).

Do a light glaze break/hone on the cylinders, put new rings on, phase them correctly, different rod for #3. Started it up last night, smoked for about 1-2 minutes and no more. This motor is finally done and I am sick of it.

 

[TXblueSS]

Well, congrats. I hate having something gnawing at me like that, and I'm sure you're glad to have that done. How does it run?

 

[TucsonK5]

It runs well, though idle is a bit high, 900-1000, when it should be at 850. It may take awhile to chase that demon, as I guess when the 22re idles high it can be many different things and I have already checked/replaced the easy things like vac hoses, timing, valve lash (somehow this can make it idle high, new one to me).

Yeah, when something takes this long it goes from being fun to being a chore. I have owned this truck for 5 months now and have never driven it out of my front yard!