Smoking after overhaul

[Rulebreaker]

Just finished a fresh overhaul on a 2.3L and after it's first day on the road (100 miles) it is still smoking so I pulled the plugs and checked the compression. All 4 are around 130PSI but #2 's plug is coated with oil. How do i determine if it's a valve seat or oil ring problem? I'm so irritated I cant even begin to explain.

 

[adsm08]

Probably a valve seal if you have good compression.

 

[Mark_88]

Are you sure it's not sucking oil in from the valve cover? Pull the valve cover hose off and check it for oil on the TB end. If there is oil there, then you may not have either ring or valve issues...but just old oil coming in from that tube...unless you cleaned it before installing it that is.

A good test for valve or ring issues is to simply drive at highway speeds and let off the gas...as you slow down the engine will have high vacuum and if the oil is getting by the valve seals then it will smoke during this period. If it smokes otherwise then it could be rings...

With a fresh engine build you shouldn't have too much blow-by so the oil won't (shouldn't) be forced up into that TB vent from the valve cover...if that tube is getting too much oil then you may want to consider putting an oil separator on the tube to remove most of the oil from getting back into your intake.

 

[Mikel89us]

If you over oiled the rings on install, you may have prolonged the ring seat time, i had a racecar engine (2.3L) that smoked for 6 months untill it finally seated in the rings, then quit pulling oil around the rings, and it also smoked out the crank case breather, which yours could be doing back into the intake and pushing oil back into the intake.

 

[snoranger]

Sorry... off topic.

Hey Chad, 130 PSI seems low for a purpose built propane engine. What compression ratio are you running? I'd be running 10:1... Maybe even a little better.

 

[Rulebreaker]

A good test for valve or ring issues is to simply drive at highway speeds and let off the gas...as you slow down the engine will have high vacuum and if the oil is getting by the valve seals then it will smoke during this period.

This is the only time it smokes. RB

 

[Rulebreaker]

Sorry... off topic.

Hey Chad, 130 PSI seems low for a purpose built propane engine. What compression ratio are you running? I'd be running 10:1... Maybe even a little better.

I told the machine shop that i wanted 11:1. I figured it would be higher than 130 myself. I paid them to rework the head as well, so if it's a head problem I'm really not happy.

 

[kimcrwbr1]

You did put a new PCV valve in correct?

 

[Rulebreaker]

You did put a new PCV valve in correct?

The PVC is not new, I'll pick one up for it as that skipped my mind. I have it hooked to a vacuum port above the butterfly valve, should it be manifold vacuum instead?

 

[Mark_88]

I meant to update my answer when I read that #2 plug was covered with oil...mine was too and it turned out to be valve seal on that cylinder...but you could still be sucking oil in under high vacuum.

I ran mine for about a year with the wonky valve seal until I finally got a head redone with new valve seals...then the engine started sucking oil in from everywhere and especially into the intake...resulted in smoke under vacuum that looked like the valve seals where still wonky...

That's when I discovered the oil was burning from high vacuum and it was coming in from the pcv...so I rerouted mine into a catch can and through an oil separator that almost licked the problem...except my engine needs new rings to reduce the blow-by...

If I reroute the PCV to just the catch can and no intake return I get a huge amount of smog blowing out the back end...

These engines are, apparently, notorious for blow-by and the associated oil burning through the intake from the PCV...so...that's why I mentioned that you shouldn't have blow-by on a new rebuild...but if the rings haven't seated properly then it might clear up quite a bit (and when you get that valve seal replaced)...

But at least you are farther ahead by having a rebuild on the engine...maybe try a can of that engine restore stuff...I've been using that and it is pretty amazing...reduced blow-by for a while but it always returns due to my wonky rings

 

[kimcrwbr1]

Yes you want the PCV on intake manifold. I find it fulnny the PCV is the cheapest part of preventive maintenance and the most neglected. Is your breather tube also clear and the breather filter clean the crankcase needs to be at atmospheric pressure neithe plus or minus pressure in mercury. Evcess blowby goes into the carb and minus pressure pulls in fresh filtered air into the crankcase. Just run the engine with the PCV out will tell you if there is excess blowby.

 

[Rulebreaker]

If I put air pressure to cylinder 2 and I have both valves closed, wont I get air up threw a bad valve steam seal? RB

 

[snoranger]

If I put air pressure to cylinder 2 and I have both valves closed, wont I get air up threw a bad valve steam seal? RB

No.

 

[Rulebreaker]

I've got the valve cover off and I really have NO desire to change the seal. I dont know how the rocker comes out, I dont have a spring compressor, and I can just see a keeper ending up in the oil pan and a valve dropped in a cylinder. I didnt want to do it when i had the head off so why in the heck would i want to do it now. I'm half tempted to buy a box of plugs and just drive it, or park it in the barn and forget I own it. What pisses me off is the old oil seals didnt leak, and I'm not convinced me changing them again will even fix it.

 

[Rulebreaker]

One more question, the stud that holds the rocker, is it a hydrolic lifter? & if so can it be compressed?