Old setup got killed by spun rod bearing from detonation. Replaced crank, piston rings with fresh hone, and crank polish.

Just got new motor in the car and started tuning. Car runs really well with the exception of smoking on decel. Motor has about 75 miles as of now. I turned it on, let it idle for 15 min, changed oil then started driving it. Started getting into it almost right away, no issues.

Doesnt smoke any other time accept high rpm decel, cant really tell if boosting is a factor, just rpm at this point. Im thinking valve stem seals. Seems to have gotten a little better with time.

Turbo is almost new, like 2500 miles maybe, good drain angle with restrictor. Entire setup is reused, just fresh bottom end.

Ideas?

 

Did you even seat the rings?

 

huh? I went out and started beating on it right away which is the correct way to go about it.

 

I think the valve stem seals may be gone on the "Wet" one lol. This was when I initially tore the motor down. I wasnt sure if it was oil or water but it had been sitting the entire summer so probably oil

 

Get the valve guides checked as well now your at this stage.

 

how is the catch can set up is it on and working

 

I beat the **** out of my engines as soon as i get them. I would think its in the head, but weird how it didnt do it before the rebuild?


decel vacuum is pulling oil in some how? pop the IM off to see if u can see anything before a complete head removal.

 

I think the vacuum in the motor is pulling oil from bad valve guide/seal.

 

Catch can is 2 -12an lines off the VC to open breather. Its sufficient.

Car pulls over 25inHG at high rpm decels

 

You should at least heat cycle it a few times before tuning.... if its the same head as before and it didn't have these symtoms before this new bottom end then I would suggest steadily putting miles on it and see if the problem disapates on its own.

 

x2 followed by retourqe of the head studs and compression and leak down check

 

Come to think of it i'd be pulling that and another piston out and comparing them. But yes a compression and leakdown test would be a good idea.

Lightning Teg, is there any oil inside the actually ports ? i.e. before the valve head/lower stem ?

 

I heat cycled it twice come to think of it before going out. I also started slowly upping revs and load. Its not like I just took it out and immediatly went to town. I also need to note that it seems to only do it once the oil is up to temp

Im thinking something happened to that one cylinder prior. Why would be all wet?

I just found it odd because the car wasnt smoking when I pulled into the garage for the knock.

Im going to keep driving it and actually start really boosting it since I've just been doing 5psi atm to check things. If it doesnt go away I'll check the head.

How would a leak down help check valve stems/seals?

 

this is what you said....

"I Started getting into it almost right away"
"I went out and started beating on it right away which is the correct way to go about it"

had you said this lol then you would have gotten different answers

"Its not like I just took it out and immediatly went to town"

 

Well what I meant was lol.

Im not babying it lets put it this way. But it hasnt seen more then 5 psi or my true redline yet.

 

damn Chris! not having the best of luck it seems. Hopefully you get it fixed and have this beast back out on the road!

 

Well I guess it was the rings seating because I havent seen or smelled anything in the last few days of driving and tuning.

 

usually when your experiencing smoke out of the exhaust on decel it's going to be valve seals. CM or DP rings?

 

I normally will run the motor up to operating temp,shut it down and re-torque the studs 6-8 hours later. Good to go.

 

I've gone to recheck the tq a few times in past years and never had them get loose. Overall its still worth checking if you have symptoms that lead you to believe the hg is leaking

 

sounds similar to what mine was/is doing. i think its just the rings seating. no smoke during driving unless high rpm decel, and it would smoke if idled for a while. i did a couple wot pulls to 5500ish rpm and shut it off after to help seat the rings. cranked it up the next day and no smoke, but like you it seems to do it after the car has reached operating temps, good luck hopefully its resolved and mine too!