318 diagnosis

[megavites]

so...rebuilt 76 block, bored .30 over, whiplash cam. Heads were done by a separate builder and had stem height issues that i sorted out with a few diff length pushrods and adjustable rockers.
Since day one, i've had smoke on left bank exhaust. Also get a cloud on hard accel/decel. Compression ranges 129-140 across all cylinders cold.
All Plugs look good also. No oil on them.(permetex on threads in pic) I pull plug wires and see no difference in oil burning.
Tried replacing some valve seals with no change.
Engine has 1100 miles since rebuild.
One thought was a stuck oil control ring.
Another thought is..heads have unknown milling and Edelbrock performer intake is sitting slightly high and maybe pulling oil into a cylinder? I'm using a .060 intake gasket.
My leak down tester is Chinese garbage and needle didn't move off zero.
I'm leaning intake leak. Maybe use a thinner gasket to bring manifold down into "V" to seal better?
I thought about doing a B12 Chemtrol piston soak to unstick a ring on that side but i'm concerned how aggressive that is and hurting bearings even with changing oil right away. Pistons do have coking.
Any thoughts before i pull intake to check gasket?
See video below.

 

[Ant]

so...rebuilt 76 block, bored .30 over, whiplash cam. Heads were done by a separate builder and had stem height issues that i sorted out with a few diff length pushrods and adjustable rockers.
Since day one, i've had smoke on left bank exhaust. Also get a cloud on hard accel/decel. Compression ranges 129-140 across all cylinders cold.
All Plugs look good also. No oil on them.(permetex on threads in pic) I pull plug wires and see no difference in oil burning.
Tried replacing some valve seals with no change.
Engine has 1100 miles since rebuild.
One thought was a stuck oil control ring.
Another thought is..heads have unknown milling and Edelbrock performer intake is sitting slightly high and maybe pulling oil into a cylinder? I'm using a .060 intake gasket.
My leak down tester is Chinese garbage and needle didn't move off zero.
I'm leaning intake leak. Maybe use a thinner gasket to bring manifold down into "V" to seal better?
I thought about doing a B12 Chemtrol piston soak to unstick a ring on that side but i'm concerned how aggressive that is and hurting bearings even with changing oil right away. Pistons do have coking.
Any thoughts before i pull intake to check gasket?
See video below.


View attachment 1716091974

You used .030 over rings, right?
If you have a small intake gasket leak letting oil in, you should find some oil in the port on the head where the leak would be when you remove the intake manifold.
Before you rip things apart, check the PCV valve and breathers, they can cause issues as well if faulty or not setup correctly.

 

[Icetech]

buy a $25 amazon bore scope that plugs into a phone or laptop and run it down the intake to see if oil is in the intake ports in the hads, alot faster and cheaper than pulling the intake

 

[RustyRatRod]

The intake gasket idea may hold some water. Or oil. Sorry. lol Also, can you tell us about your PCV system.

Lastly, although not related to your problem, you did NOT address the valve stem height issue with pushrods and rockers. That changes nothing about valve stem height. Just to clear that up.

 

[RustyRatRod]

buy a $25 amazon bore scope that plugs into a phone or laptop and run it down the intake to see if oil is in the intake ports in the hads, alot faster and cheaper than pulling the intake

Excellent idea.

 

[toolmanmike]

You used .030 over rings, right?
If you have a small intake gasket leak letting oil in, you should find some oil in the port on the head where the leak would be when you remove the intake manifold.
Before you rip things apart, check the PCV valve and breathers, they can cause issues as well if faulty or not setup correctly.

And even worse if the valve covers don't have baffles under the PCV especially.

 

[Syleng1]

Bore scope is a good start.
Just the valves being different heights scares me about the head work done. I’d be pulling the heads and start there.
Look for knurled guides and worn valves. Valve heights off can cause a bunch of issues. Does it have valve seals?

When a good machine shop does the work you know it and pay for it. Not sure where you got stuff done or bought from but a fresh engine typically does not burn oil just because.
Good luck and keep us posted.

 

[megavites]

to answer above:
1. builder assembled with .30 over rings. Compression is good.
2. running a FRam PCV FV191 valve on drivers side, ported to carb. Valve covers have baffles.
3. diff. valve heights resulted in diff. push rod lengths in some cases with adj. rockers as well to get .020 preload. Engine runs good. Heads/valves/seals all looked good last time covers where off.
4. I have a borescope and didn't even think about going thru intake. Good idea!

Lets say there's oil in intake. My understanding is a thinner intake gasket would help? Current gasket is .060 thick.
If i remember correctly, i trimmed the head gasket tabs and there were no roll pins.

 

[AJ/FormS]

Hang on, don't take anything apart yet!
IMO
#1 this is not a valve seal issue , and
#2 highly unlikely to be a valley leak into the intake ,and
#3 not a ring seal issue either, nor a an oil-ring.
#4 IDK yet what the problem is, but I suspect the PCV. I'll bet you have it plumbed to one of the intake runners.
Here's the test;
Pull it out of the valve cover and just flip it off to the side. Then fire it up and keep it at a fast idle to clear the oil out of the intake; Then repeat your test as in the first video.
Meanwhile, see what's coming out of the open hole in the VC. If, at idle, you have a stream of blue smoke coming out of the CC, your rings are not sealing. If you have a puff once every revolution, you have a vertical gouge in a cylinder wall. This will not show up on a regular LD test, but the cylinder pressure in that hole will be a lot less than in any other.
---------------------------------------
Now, as to the PCV valve, there is a designated port on nearly every street-carb I have ever seen, which is where you plumb your PCV to. It is almost always on the front between the throttle-bores and enters the carb underneath the throttle blades. If yours is NOT there, make it so.
Do NOT plumb it to an intake runner.
Do not plumb it to the Secondary side.
If you have to; you can drill and tap the intake plenum, for a hose-barb, in such a way that it connects to all the runners.
------------------------------------
Speaking of your compression test results; a pressure variation of from 129 to 140, with just 1100 miles on the clock, is giving me the hebejeebies; that's terrible. Yeah, I know what the sevice manual says, but old AJ here, says that whatever hole scored 129, it has a problem.
Throw out the highest and the lowest numbers, then average out the remaining six, which will then be your mean target. Say you had the loser at 129 and the winner at 140, and all the rest averaged out to 138. Badaboom, that loser is ~7% low, and it is sucking down your average power ALL the time.
Find out why.
But if all the rest average to 132, then your loser hole is only 2% low, and you gotta wonder about the 140psi hero.

Because you have doctored your valve gear in an unconventional way, here is what I would do;
I would remove all the valve gear from the smoking side, then do a Leakdown at 80psi on those 4 holes. When you pressurize those cylinders, the pistons will fly to the bottom of the bores, where the holes are the roundest and, the least worn. So then, your results should be as good as identical in each of those four holes unless the valves are leaking.
If you get a troublesome hole, with the piston now at the bottom, you can bop the valves a few times, and see if the pressure changes. If the pressure comes up or changes at all, then the valves are Not sealing properly ........ and you have a decision to make.
But if the pressures vary less than a few percent, go to step two; which is,
Reset your LD tester to 20 psi, and pressurize a hole. Then take your longest breaker bar and turn the crank over, CW in normal rotation, stopping every 20 degrees or so, to let the LD tester stabilize. Obviously, if the cylinder walls are ok, then the LD reading should Not change from bottom to top. If suddenly the pressure goes away, then most likely, you have a gouge in the cylinder wall. Test all four .
Caution, when you get to the top, your 3.91 bore at 20 psi can generate 240 footpounds of force. your breaker bar might be 18" long max which means the instant that the crank passes TDC, it is able to unleash 160ftlbs of force into your bar. Do NOT let that happen! Have a helper ready to dump the pressure at your command; Do Not try to do this alone; I am not gonna reimburse you for hospital bills, lost wages, broken parts, etcetera. This is the only test I know of that can find a gouge.
I'm not saying you have a gouge in your cylinder wall. Really, I'm leaning towards the PCV valve. But like I said on line #4 above, IDK..... yet

BTW, when I do a compression test, I crank thru as many compression cycles as it takes, to get two successive, about the same, psi numbers; AND, I record the number of cycles.
If I see all the numbers approximately the same (which would be ideal), but 7 holes pumped it in 4 cycles while one took 9, then, even tho the numbers indicate really well, there is in fact, a problem in that 9-cycle hole.

 

[Bewy]

What colour smoke? White, grey or black?

 

[megavites]

@AJ/FormS ,
i thought you were on to something with the PCV. There was some oil on the valve and at end of hose at carb which goes into the center port on my 1406 Edelbrock. I disconnected the valve and ran it out on the highway with no change. Still leaving a decent cloud on hard excel.
I'm thinking my best option is to:
-get another leak down tester and try to determine if i have a head issue or ring issue..although compression test doesnt seem to indicate rings.
-next would be to scope intake and/or remove to look at gasket and possibly install a new one.
-next would be to have another set of heads (302) checked and swap springs to these and install.
I was hoping for easy.
Smoke looks Grey according to neighbor (i'm colorblind) but i'm not loosing coolant, only small amount of oil.

 

[AJ/FormS]

Seeing this second video, it looks sorta normal to me..

What Ima thinking, is that your smoke is just water vapor. If you see water dripping out of the tailpipe, that would be normal. But if you don't see it, that only means that the water vapor, if that is what it is, is condensing inside the mufflers, and the exhaust stream is just picking up random amounts of it, as liquid water, and then blowing it out the back.
For this reason, your mufflers should be drilled at the lowest hanging points with small holes, one in each muffler, no bigger than 1/8inch. If smaller than 3/32, the water may not drain at engine shut-off. If bigger, you will start to hear them. Be advised that, if you don't drill holes, the natural acid formation in the non-drilled mufflers will eventually rot the holes for you, and they will be neither pretty nor welcome.
Now, to prevent this natural event is not possible. But you can increase the minimum coolant temperature of your engine to minimize this. And, your exhaust system should be somewhat sloped downhill to the mufflers. If that is not possible, then I would drill the pipes at whatever point is the lowest, and then you can see/watch the steam blow out, lol.
However, if where you live, the atmosphere is naturally humid, you will never get rid of it.
If it is water-vapor, this is probably a sign of a pretty good tune, at whatever rpm it is turning, when you see it. Which, with a Whiplash cam at idle, that would surprise the crapoutta me, lol.
So IDK, that's my thinking as of today.

 

[megavites]

@AJ/FormS ,
video doesn't tell whole story. Yes, kinda looks normal, and does have alot of condensation at startup until it gets hot but when getting on it on highway...it smokes enough, people get out from behind me.
I can drive normal speeds and not really see any smoke. This has been frustrating to diagnose.
I believe my best path forward is the steps in post #11...unless someone has another thought.

 

[AJ/FormS]

i thought you were on to something with the PCV. There was some oil on the valve and at end of hose at carb which goes into the center port on my 1406 Edelbrock. I disconnected the valve and ran it out on the highway with no change. Still leaving a decent cloud on hard excel.

I missed that
But-um, if your mufflers do not have drain-holes, and they have an accumulation of oil, from an over-active PCV system condensing in there, then the mufflers have to get pretty hot to burn it out.
Here's a simple test;
flip the PCV out of the valve cover, and seal both of the valve covers, and then put a pressure gauge on the dipstick-tube. Start her up and let her idle.
1) There should NOT be any vacuum in the CC. If there is, then the only place it can come from is the intake to head gasket.
2) at idle, the Whiplash cam does not make a lot of vacuum, so then, you may have to idle it up, to say 1400 ish rpm. But if you do that, watch for pressure, which is what should be happening, and if it does, then, immediately idle her back down.
3) the pressure should be slowly and steadily building up. Do not let it it climb up past 3 or 4 psi, else it can blow seals or gaskets out.
4) if pressure builds up fast, and if you can see your gauge needle pulsing, STOP the engine! The pulsing is a gouge in one of the cylinders.
------------------
I had a single-cylinder dirt-bike come in once that did this, and what had happened is that one of the wrist pin clips, not a spiral-loc, had popped out and the wrist pin had slipped over to one side and was rubbing on the cylinder wall. Whenever the rings passed over the gouge, on the compression stroke, some of the pressure would scoot thru the gouge and end up in the CC. It was also somewhat hard to start, and blew smoke.

How I found this before teardown was by using the LD tester, set to low pressure, and with the valve lash backed off, and then slowly manually turning the engine over with a breaker bar, stopping every few degrees to let the pressure stabilize.
At the very top, the LD was minimal, but as the piston dropped and the rings exposed the groove, the LD changed. Hmmmmmm I said to myself, that's not normal............. The cylinder was beyond repair.
BTW,
after the repair, it still blew smoke ..... until the muffler cooked the oil out of itself. Scary moment? No, I knew it would happen, and advised the customer.
BTW-2
at WOT,
the manifold vacuum is getting close to zero. If your engine is smoking Blue at WOT, it is NOT likely from a vacuum leak into the CC, nor from valve seals.
In order of likelyhood the engine is burning oil that has entered the combustion chamber from;
1) the PCV system, or
2) fuel-wash from a very rich carb
3) a faulty intake to head seal, in the valley, or
4) oil Not being scraped off by the Oil-control rings, or
5) too much oil in the CC, or
6) just oil having accumulated in the mufflers/exhaust system, or
7) a problem in the cylinder walls, or
8) fuel-contamination


BTW-3
Smoke on hard decel is a bit of a different problem.
In this case the engine is creating all the vacuum that it can, in the chambers, and the usual entry point of oil is past the valve seals, but also includes the PCV system which enters the intake below the now-closed throttles; AND the valley seal, and in the case of the Whiplash, the headers are gonna try and evacuate the plenum on the overlap cycle.
If your throttles are also sitting very low on the Transfer slots, this will aggravate the entire situation. ( your Transfer slots exposure under the throttles should be square to ever so slightly taller than wide.)
However, In this case, under high vacuum/low rpm, the engine is Not processing much air so not much exhaust. The exhaust gasses are cool, and so is the exhaust system, and the oil easily condenses and accumulates inside the mufflers. Over time, it will also begin to coat the very ends of the tailpipes, where you can swab it out.
In a normal-running engine the only things coming out the TPs are hot air and water; Not soot, Not oil, Not any glazing. If anything, there might be a whitish to tan baked on finish, impossible to swab out, same as may appear on your sparkplug porcelains.