advice on blowby isssue

[gsxr141]

ok guys, i need some advice..... i recently threw together a motor and put it in the car. everything looked good except the crank and lower end bearings. i threw a mint crank in and all new bearings, along with a new shimmed oil pump... before the swap i was having issues with smoking on decel. since the swap i still have the problem, but worse.
i added a baffled catch can the other day and the smoking went away.... just yesterday though, i did a long pull on the highway only to find the dipstick pushed up and oil everywhere... this was not happening before the catch can install. is there anything i can do do prevent this? i added a spring to the dipstick, and after a pull today it was ok. will this cause any problems? i've seen this done on numerous cars, so i thought i'd give it a try.
at this point any suggestions would be appreciated.
thanks......... kevin

 

[hvyman]

Better to have the dip stick pop out then one of the mains.

If this is a 7m I would check the make sure the baffles in the valve covers are clear and the port in the throttle body is clear. And the hose that goes from block to valve cover by the alternator.

 

[gsxr141]

yeah. it's so weird. before the catch can hookup the dipstick never did that. maybe the catch can isn't free flowing enough. has anyone ever hooked up the can directly from the block hose? other than this issue, the engine runs mint. i was hoping that some of the smoking was the turbo, but i'm thinking it's the engine now. how do you clean out the baffles in the valve covers? also, if they were plugged up wouldn't the dipstick have pushed up before?

 

[jetjock]

... i recently threw together a motor...

Could be the problem right there...

 

[gsxr141]

thanks for the help. as usual your posts offer an abundance of useful info and no sarcasm.

 

[Suprapowaz!(2)]

thanks for the help. as usual your posts offer an abundance of useful info and no sarcasm.

Now that was funny. But I'm sensing sarcasm in your post as well.
The last time you posted about this I advised you to do a leakdown test. What were your results? Did you even do the test?

Sorry, disregard. I was thinking about the wrong person. It was Sebas that had the same issue as you.

Regardless, do a leak down test and see where this blow by is coming from.

 

[SeeUSmile]

Sounds like a PCV problem. How's yours currently hooked up?

 

[gsxr141]

i have a baffled catch can hooked up inline with the stock system...

 

[Suprapowaz!(2)]

Does that catch can have a one way check valve, and you possibly hooked it up wrong?

Why don't you do a leak down test? Just to rule out if it's severe blow by past your pistons? If you just put this motor together that would be important information to know.

 

[jetjock]

uh oh, I detect sarcasm...

 

[Suprapowaz!(2)]

I was just wondering is it bad advice to ask someone to perform a leak down test? Because every time I suggest it nobody ever does it.

 

[gsxr141]

i did a leakdown test. cyl 1 was 4%, cyl 2 was 9%, and cyl 3 was 14%. i stopped right there.
funny thing is....... with the catch can hooked up it doesn't smoke, but it pushed the dipstick up after a long pull. without the can, it smokes a ton on decel.
i'll be tearing the motor apart again to see what's what.

 

[Nick M]

thanks for the help. as usual your posts offer an abundance of useful info and no sarcasm.

My response was going to be similar. For example this statement.

everything looked good

So you can measure sidewall clearance (honing) with your eyes? What is smoking a ton on decal? Oil smoke? Thick black compression bypass?

 

[Grandavi]

There is far too much wispy description in what was done to really advise properly. Why don't you give a much fuller description of what you did.

I thought you bought a "new" engine for your car. Confused why it would need the crank and bearings redone. Having said that.. have you cracked the head? (as in took the head off?) Also, you should avoid using descriptive words like "mint" crank. There is no such thing. There are new cranks (Not sure if they exist for 7M's anymore) or ones that have been through a machine shop. Mint means nothing other than it looks good.

So, after running through a whole mess of "possibles", if you could, you would be better served by describing your build better. It may be tedious to type it out in a highly detailed fashion, but guessing isn't the best route.

 

[gsxr141]

sorry for the lack of detail....
to start, i picked up a rebuilt shortblock from a member here about a year and a half ago. upon further inspection, i found the pistons had some marks on the tops of them....
then this past spring i bought a complete motor that i was told was rebuilt some time ago....
i pulled the oil pan off and found the crank and bearings very scored.
at this point i took the new bearings and good looking crank out of the shortblock and put them in the second motor.
i never did pull the pistons out, as the cylinder walls looked great. i know i should have now.
the head was just cleaned up and installed on the motor. i reused the turbo setup and intake manifolds from my current running motor.
the guy that helped me put it together thought the smoking was from bad valve seals, but we did a leakdown test anyway.
as i stated the first 3 cylinders we did didn't look good. our next thought was that maybe one of the rings had a small piece missing. at this point i installed a baffled catchcan as a bandaid, just so i could drive it. with the can installed there is NO smoking on decel BUT after a 0-100 pull on the highway the dipstick was pushed out and oil was everywhere.
with the can unhooked there is a ton of smoke on decel. i was still going to try another turbo just in case that's the problem.
as i said before........ i'm baffled here. i don't know what the problem is. if i have to, i will tear the motor apart again and install new pistons and rings, etc....

 

[Grandavi]

The one time I had a lot of blue smoke on decel was my turbo seal going. Yours sounds a bit more severe.

I pumped a lot of money into my car to avoid band aids. Your motor sounds like a huge hurt locker. To me the hint is that with the catch can on your not smoking. However it sounds like your not venting which is what pushes the oil out the dip tube. So what your doing is creating a elwhole new problem rather than diagnosing the initial problem.

I'm not a mechanic but I will wager nobody wants to do too much guessing because of the list of possibilities. Should eliminate the issues first by doing a proper compression/leakdown test first. I only see 3 cylinders tested. Why stop?

 

[gsxr141]

i stopped because of how bad the 3rd cylinder looked. at that point, the guy that helped me with it said that i should pull it all apart and "build" it right over the winter. i know i cut some corners, but i was just looking to be able to drive the car while i put together a proper motor. i still have the complete engine that came out of the car and the extra shortblock.

 

[Grandavi]

The only problem with that philosophy is that if your engine dies, you have a car to tow (at best) or could put yourself in a dangerous situation (at worse) depending on where you drive.

Most Supra owners will advise against having a MK3 without having a secondary "daily driver". Unless your car is in really good driving condition, I would suggest you may want to just park it and find a 500.00 beater to drive while you rebuild the drivetrain properly. You can always sell the other vehicle when your done, but at least you wont have to hunt down gremlins that shouldn't exist.