Chevy Nova Forum banner

1 - 20 of 27 Posts

·
Registered
Joined
·
733 Posts
Discussion Starter #1
I have been helping my buddy get his 71 nova running.We installed a "rebuilt'400 small block.Rebuilt means everything in the lower end is fresh.The cam and lifters,Oil pump,crank,Bla bla bla.I did not assembled the lower end.Besides the cam and timing chain.So I don't know what the clearance's are.

Anyway I spent last night and today installing 3 inch exhaust.And we got it all lined out.Changed the oil to some 20w50 valvoline Vr-1.And let the motor warm up.

We took off down the road and he laid into it a little bit.(5000Rpms)And a biggo trail of blue smoke was right behind us.We came back home and pulled the valve cover on the passenger side and check the rockers.Found one of them to be loose.Adjusted it and refired.Seemed to help.But still smoking....

Do you guys think it's ring?Would a compression test tell us?

I didn't install new valve seals on the motor.Could that be the problem.At idle it smokes very little.But when you rev it up she does it pretty bad....


Any advice would be awesome.It felt pretty good.But I think my old truck has got it though!
 

·
Premium Member
Joined
·
1,342 Posts
you got on a engine that wasn't even broken in yet?:confused:


and its probably the rings imo
 

·
Premium Member
Joined
·
15,966 Posts
Is the engine ventilated?
Have a valve cover vent & PCV valve?

Engine must be vented!

Is it oil or transmission fluid from modulator valve?

Intake leak maybe?

Just some things to check

Al
 

·
Registered
Joined
·
168 Posts
Sounds like rings. Especially if they're moly. But I'd still check everything big al suggested.
 

·
Registered
Joined
·
733 Posts
Discussion Starter #5 (Edited)
Yes big al the motor has a pcv valve going to the carb.And a vent on the passenger side valve cover....



The engine probably has 3 hours on it.So if you call that broken in....We ran it for 30 minutes to break in the cam.Adjusted the valves and he took it up and down his road a few times.Not getting on it hard.To dang loud!


Thanks for the tip on the intake leak.Oil leaking into intake valley maybe..I don't like that single plane anyway.We will have to maybe pull the intake and see what happens.

If we do a compression check we have to hold the throttle wide open when we crank the motor over right?

When we started it we used rottella T.I believe it was pretty heavy oil.Maybe we should go back to that.
 

·
Premium Member
Joined
·
8,405 Posts
Lot's of possibilities.
New rings on a worn bore will burn oil. Taper faced rings installed upside down will pump oil into the chambers.
Didn't replace seals? Burn oil. Stem to guide clearance worn? Burn oil.
Intake sucking oil off the galley? burn oil
Vacuum modulator diaphragm ruptured? It will burn ATF.

Like I said too many possibilities to guess what it is.
 

·
Premium Member
Joined
·
1,342 Posts
Yes big al the motor has a pcv valve going to the carb.And a vent on the passenger side valve cover....



The engine probably has 3 hours on it.So if you call that broken in....We ran it for 30 minutes to break in the cam.Adjusted the valves and he took it up and down his road a few times.Not getting on it hard.To dang loud!


Thanks for the tip on the intake leak.Oil leaking into intake valley maybe..I don't like that single plane anyway.We will have to maybe pull the intake and see what happens.

If we do a compression check we have to hold the throttle wide open when we crank the motor over right?

When we started it we used rottella T.I believe it was pretty heavy oil.Maybe we should go back to that.
nope

just disconnect the coil and bump it over 3 times while a buddy is watching the guage. what ever it reads on the 3rd time is the compression
 

·
Registered
Joined
·
168 Posts
I'd get a leak down tester.
 

·
Registered
Joined
·
733 Posts
Discussion Starter #9
nope

just disconnect the coil and bump it over 3 times while a buddy is watching the guage. what ever it reads on the 3rd time is the compression
Thanks.We will do this tommorow.Just not sure if the oil ring would show up or not...

Yes paul wright your right way to many variable.I can almost for sure count the vacuam modulater out though.We where watching the smoke come out of the tailpipe.

The heads where off this car and it didn't smoke before.I didn't take the heads apart.Just cleaned them as best as I could.Made sure all the gasket mounting surfaces where perfect.Looked for cracks.And made sure they where flat.I also drilled steam holes in the heads.I "loaned my valve spring compressor to a guy I used to work with and never got it back.So I couldn't take the heads apart.

I am sure well found out more tommorow.I am going to call the guy that built the shortblock and see if he remember anything about what he exactly did.He builds engine's all the time and seems to know what he's talking about.


Thanks for the advice.Hopefully it's not to bad.If we have to take it back down for the rings we will.It would suck though!:(
 

·
Registered
Joined
·
103 Posts
did u cut the baffles on your valve cover? cuz if u did i bet your sucking oil through the PCV and into the carb, thats why your getting the smoke
 

·
Registered
Joined
·
733 Posts
Discussion Starter #12
No we didn't cut those baffles.But we did fill the oil up through the same hole as the pcv valve goes into.I wonder if there was still oil in that baffle and we sucked it into the carb?

HMMM.Maybe....
 

·
Registered
Joined
·
2,146 Posts
how bad of smoke are we talking? like filling up the street like you just did a burnout or alittle wisp of smoke like when header paint is burning off? Sometimes what you see is stuff burning off the inside of you new exhaust, and if the rings were done and the builder used too much oil when installing the pistons it can smoke. I've seen it where a guy will hone the block for new rings but not use a torque plate so when you go bolt the heads on the bore gets distorted and lose ring seal. Good luck let us know what it is...:cool:
 

·
Registered
Joined
·
508 Posts
not trying to jack your thread but why do some of you guys think that if there are molly rings in a motor it means they need a long time to break in??? ive never gone any extra time on any motor build that ive done for molly rings and never had a problem with them sealing. i break motors in how i drive them. get it running good enough and do the biggest burn out i can!!! hahaha:yes: i think if the hone was good as far as the right patern of the cross hatch goes the rings would have had no problems sealing in the first to second heat cycle. thats asuming the clearences were good between piston to wall. i would def look into all the options listed above before going into the motor. JMO. good luck, and i hope its something simple!!
 

·
Registered
Joined
·
2,146 Posts
why do some of you guys think that if there are molly rings in a motor it means they need a long time to break in??? ive never gone any extra time on any motor build that ive done for molly rings and never had a problem with them sealing.


thats what Im sayin!!!!:yes:
 

·
Premium Member
Joined
·
4,612 Posts
new motor with "loose rocker" after a rebuild sounds like a cam lobe has gone south........
just my opinion.there are some very astute engine guys on here as you know,but i've lost a cam after a rebuild and this sounds strangely familiar.
leftcoast carl.
 

·
Registered
Joined
·
508 Posts
new motor with "loose rocker" after a rebuild sounds like a cam lobe has gone south........
just my opinion.there are some very astute engine guys on here as you know,but i've lost a cam after a rebuild and this sounds strangely familiar.
leftcoast carl.
it is common to have to adjust a rocker or two after a break in. if you have one that is way out it might need to be something to look into, but to have to snug a couple up on a new cam and lifters is almost always going to happen. if you run with an excess on a new cam for too long before checking will sometimes cause a lobe to go.
 

·
Premium Member
Joined
·
4,612 Posts
it is common to have to adjust a rocker or two after a break in. if you have one that is way out it might need to be something to look into, but to have to snug a couple up on a new cam and lifters is almost always going to happen. if you run with an excess on a new cam for too long before checking will sometimes cause a lobe to go.
thanks for the clarification.i realize that small adjustments may be required,but i was intending to bring his attention to excessive rocker arm play...i just didn't communicate my thoughts very well.
thanks,
leftcoast carl.:)
 

·
Registered
Joined
·
733 Posts
Discussion Starter #19
Well we still haven't torn into the motor yet.Or even worked on it anymore.You could tell he was very discouraged.Just like any engine build ALOT of time and effort was put into this motor.I was just glad to get the motor and tranny back in the car and the car able to move under it's own power again.That's a big step in the right direction.

As far as how much smoke it was pretty dang bad.Like I said we had a trail behind us coming back to the house.

I looked up a new set of rings and they look to be about 50 dollars.I do not think the cam went bad.We used rottella T and did the whole break in procedure correctly.The rocker was barely loose.But loose enough to make slight noise.I have had poorly adjusted valves cause my motor to smoke before.Just went back to the same thing again....

Thanks for the advice and I hope to know more later this week.
 

·
Registered
Joined
·
761 Posts
Your PCV valve can suck in a surprising quantity of oil when you get on the gas, especially if you don't have baffles (or have crummy ones, like I do). Take the line out and clean the inside of it, that way you can see if there's a bunch of oil in there. It's an easy thing to check and doesn't cost anything.:yes:
 
1 - 20 of 27 Posts
Top