Engine rebuild smoking

[emccallum]

Good idea, I have a scope. The head was done a year ago. I am sure they will tell me everything was perfect. I tried to contact them today, and will keep trying.  I think what I need to do is figure out what is wrong, then figure out how best to fix it. Since last year I found another machine shop that I think might be good for a second opinion. Bottom end was honing, rings, and bearings. 

Plugs all look very similar, black. #1 looks a little more normal. Whatever it is, it doesnt seem to be just one or two cylinders. 

I am open minded, maybe it could be fuel, but my nose smells oil. IMO, too much fuel would be more of a black smoke. This is blue, constant and gets worse the more it revs. Whatever it is, its a consistent leak that will be apparent when found. 

 

[bartsscooterservice]

could be burning oil yes, the bores should be bored/honed TO the new pistons, not other way around.

10 or 15w40 is better to use on these engines.

white could also be coolant, but that has a distinctive smell to it

[emccallum]

Replaced the valve seals which looked perfectly fine. Adjusted the valves and still have about the same smoke. Spoke with the engine builder. He is very confident in the head and bottom end. He really thinks it is too rich. We talked over several things. I understand where he is coming from. Good compression, all plugs look about the same. I have triple checked the floats, even rigged up a float sync type tube. 

Ztherapy used .100 nozzles and SM needles. I always thought SM needles were for l28 stroker type builds? Anyone else running SM needles with a stock L24.

I had some old carb pistons that probably had stock needles. I swapped them and no difference.

Engine runs strong and adjusting the mixture changes the way it runs, but has zero affect on the smoke. If it was rings, then it would show on compression, right?

Are .100 nozzles stock?

Are SM needles ok with a stock L24?

I have never had a good or bad z smoke this bad! Argghh

 

 

[Yarb]

Possibly an oil ring,Just throwing that out there.

[SteveJ]

1 hour ago, emccallum said:

Replaced the valve seals which looked perfectly fine. Adjusted the valves and still have about the same smoke. Spoke with the engine builder. He is very confident in the head and bottom end. He really thinks it is too rich. We talked over several things. I understand where he is coming from. Good compression, all plugs look about the same. I have triple checked the floats, even rigged up a float sync type tube. 

Ztherapy used .100 nozzles and SM needles. I always thought SM needles were for l28 stroker type builds? Anyone else running SM needles with a stock L24.

I had some old carb pistons that probably had stock needles. I swapped them and no difference.

Engine runs strong and adjusting the mixture changes the way it runs, but has zero affect on the smoke. If it was rings, then it would show on compression, right?

Are .100 nozzles stock?

Are SM needles ok with a stock L24?

I have never had a good or bad z smoke this bad! Argghh

I'm running SMs on a stock L24. It doesn't seem too rich to me.

[emccallum]

I think its time to bite the bullet, pull the motor and take it to another shop.

I am in the upstate of SC if anyone knows a reputable shop within driving distance I am all ears. 

[Captain Obvious]

Yes, .100 nozzles are stock. And about the suitability of the SM needles, some people seem to have good results with them and others can't get idle to work right.

I think there's a problem with the rings seating, or as Yarb suggested, an issue with the oil control rings.

Why would you take it to a different shop? Wouldn't it be the responsibility of the first shop to make things right?

[Patcon]

It'll be hard to get them to make it right if they dont believe there is a problem...

Is it possible to get a good video of the smoke and post it up? It's not an absolute that a good compression motor wont smoke. It could be oil rings or the ring gaps might be too closely aligned.

Another option would be to keep moving forward. Get it painted and put some road miles on it and see if you can get the rings to seal better.

You could also get a wide band and check the exhaust. Get the mixture dialed in. If it still smokes it's not fuel at that point

 

[emccallum]

9 hours ago, Patcon said:

It'll be hard to get them to make it right if they dont believe there is a problem...

Is it possible to get a good video of the smoke and post it up? It's not an absolute that a good compression motor wont smoke. It could be oil rings or the ring gaps might be too closely aligned.

Another option would be to keep moving forward. Get it painted and put some road miles on it and see if you can get the rings to seal better.

You could also get a wide band and check the exhaust. Get the mixture dialed in. If it still smokes it's not fuel at that point

 

A good video? That made me laugh! Its a real bad smoker. I will get a video, but it won't be good.

Its not going to get better. I would rather pull the motor, get it right, then move on to finish. Sucks, but this car has fought me every step of the way. 

[emccallum]

@Patcon, yesterday I adjusted the valves as they were set a little loose for the initial start. Several were very loose. Fired it up and of course it still smoked. I raised the idle and turned the mixture knobs all the way lean until it wouldn't run, and there was zero change in smoke. If I start the carbs at 2.5 turns, I can go to 3 turns and get the highest, smoothest idle. Sounds great. Carbs seem to be doing what they are supposed to do.  It has to be in the rings and there is only one way to find out.  

I can have the motor out and on a stand in an afternoon. I am thinking of tearing it down myself to see if I can see anything amiss. 

[jonbill]

Have you checked the spark plugs? Might be worth a look to see if its all cylinders or not.

[Zed Head]

18 hours ago, emccallum said:

Good compression, all plugs look about the same.

 I had the same question.  Looks like he checked.

Kind of sounding like the wrong rings were used or somebody made a mistake somewhere.

 

If you're going to swap engines you might just take it out and beat on it for a while.  What harm can it do?  Maybe you'll get lucky and the rings will seat and start sealing properly.