btharbold

Hi Everyone,

Trying to track down an oil usage and smoking issue on a fresh 327/365 build that has maybe 1500 miles on it.

Background: 327/365 build, completely went through everything in the motor. All new parts, heads redone, new bronze guides etc. Engine runs strong. It smokes out of the pass bank, not really at all when cold, but once warm at idle you will see it smoking. Plugs on pass side show evidence of oil fouling after running for a bit. Ran a dry cold compression test and most all cylinders were in the 200-215 range. Have not run a leak down test yet, gauge is ordered.

I put another set of valve stem seals in it thinking that might help, used the positive style teflon seals, no real improvement.

Pulled the entire top end of the motor, pass side head intake valve stems above the head were all crudded up, intake runners seemed wet. Cleaned everything, all valves chambers etc. Installed heads with new 1003 gaskets. Dry fit the factory intake to see if there was a rocking issue etc, seemed fine. Bolt holes line up, when dry the intake sits on the head surfaces and leaves a minimal gap at the china walls of the block.

Installed new Fel Pro 1205 intake gaskets and even RTV'd the intake ports which I never do. Reassembled everything and ran it, still smoking out of the pass bank. I had the wife drive the car and I followed her, no real smoke driving until she winds it up and shifts, you get the puff of blue I guess when the motor unloads and loads again. Noticed it from both banks, but only get the smoke from one at idle.

I spoke with the tech rep at Total Seal who swears it is oil being pulled in via vacum. Ring problem would not explain the buildup above the intake valve head right?

Before I tear this entire thing down what am I missing? I did not notice any areas where the intake looked cracked. Heads and block were not milled excessively. I unhoked the breather hose going to the carb and ran it blocked, no change. Carb has the correct .090 orrifice 90 deg fitting in it.

If it was a crack in the intake doubt that would affect multiple cylinders. Looking for any other ideas here guys.

Thanks,

Brad

LSUvetteguy

???? Have you checked the pushrod / guide fit? Or the pushrods? Just guessing, since that's about the only thing you didn't mention.

Pop Chevy

Sounds to me like the guides were fitted up too loose. Easy to pull a spring and check em though.

btharbold

Not sure what you mean by pushrod/guide fit. When I had the heads pulled apart, I did not feel any slop in the guides, I do not have any way to measure ID of the guide, but it would see, even if the guides were a little loose the new stem seals would stop it even for a little while?

LSUvetteguy

That "slop or wobble" was what I had in mind. I agree that the new seals should stop things at least for a while but at this point????

kcust62

This may be reaching for straws, but, late valve timing will keep the intake valve closed too long after the intake stroke has started, and will increase the vacuum in the cylinder. The high vacuum will have a tendency to suck oil up past the piston and rings into the upper part of the cylinder where it will be burned. This condition could still yield a positive cold compression check. Are you absolutely sure you checked everything?

Dan Hampton

Did you measure the guides? Maximum clearance is probably in the neighborhood of .0015-.002. A little more for the exhaust since they grow where the intake does not.

APV

Hello, I'm watching this thread very close. I have a similar situation on my rebuilt 66 327/300 less than 500 miles. Thanks!
Al

Ironcross

May be nothing but are the valve seals installed correctly....and as you know PC seals require some guide work and the 'O' ring style uses a different procedure

wonderful

Do a compression test on all your cylinders, it will tell you a lot. You have blow by. Who rebuilt your engine? Did you get a guarantee? Check for bent or stuck valves.

Frankie the Fink

He did a compression test...read the original post.

btharbold

The guides were machined to accept a positive style seal and have the groove cut in the outside. The seals fit nice and snug, i had to push them on the guide with a socket to seat the ring.

Ran a compression test already cold and dry. I am going to do a leak down test as soon as the gauge arrives. I keep coming back to rings, but how would that explain all the build up above the valve head, especially on the intakes?

There are no bent or stuck valves, just had both heads off and had every valve out of the heads to clean everything up.

With regard to valve timing, cam is an original grind 30-30 lashed to .026 .026. I have played around with lash at .028 and .030 with seemingly no change in anything except valve train noise.

Guess I will pull rocker studs today and reseal just in case. Sure thought they were all in blind holes, but you never know I guess.

Thanks,

Brad

LSUvetteguy

Rocker studs? How would pulling them change anything, given your symptoms and what you've already tried?

Bluestripe67

Very high vacuum occurs at mid shift as stated above. Since this happening only on one side, what do you know of the honing and ring install on that side. Could the shop have changed hones in the process of honing or how certain is it that the correct rings and gap are on those pistons. Dennis

btharbold

Rocker studs are screw in style and may go into intake ports if the port job went a little too far, I agree its far fetched, but worth a try.

The machine shop that did the machine work is a small local shop, does decent work. I did all assembly, ring filing etc myself. Checked everything with a bore gauge, used total seal max seal gapless top ring set, end gaps per their specs.

Really cant say if he would have changed hones, nothing stood out during the assembly that would have looked different one side to another.

65 fi

When I was 19 I had a similar problem with a 70 Z/28. It turned out to be the valve seats.

btharbold

Were your heads cut for replacement seats? Had the valve job done on existing seats, we didnt want to chance getting into water with cutting the heads for the hardend seats

65tripleblack

If you're using 461 heads, or a later version of double humps, like 462's, 291's, 186's, then when drilled for threads the machinist will routinely go into water on all 16. They will not intersect any intake runner, in general. They must be sealed with teflon thread sealant or pipe dope. Coolant seepage when mixed with fuel and/or oil will create a gummy, soft black/brown muck. If it's hard, black and crusty then it's carbon deposits from fuel.

In any case a cam like the 30-30 with 26 degrees overlap @ 0.050" lift will cause significant backflow to other cylinders. A problem in one runner will be greatest at the offending cylinder, but will also be seen in others fed by the same plane of a dual plane manifold. For comparison, the overlap for the LT1 is 16*, Duntov is 8*, and 151 is 5*.

btharbold

Just pulled plugs, marked the bottoms of them with a sharpie first to index. All plugs on pass side show evidence of oil on them. A couple do on the drivers side as well. It seems to favor the side of the plug towards the piston, but they are wet all over so it is somewhat hard to tell.

I am leaning towards rings at this point, but I guess I will do the leak down test first before I tear this thing down.

If the leak down test #'s are good can it still be rings?

mudbone64

I realize you previously spoke of this but after I re-assembled the 454 in my '72 it smoked like mad once warmed up. No smoke at all when the engine was cold started but after it warmed, mercy, did it ever smoke. I removed the intake and several intake valves could be seen with oil standing on top of them. I changed the intake gaskets and the valve stem seals and the problem was solved. Seeing as how I changed two items at once I can't say for sure what the fix was.

I know one thing is for sure, I'd rule out everything possible before I started a complete tear-down. It seems as though you'd almost have to have a problem with nearly all of your ring sets or the way all of them were installed for the problem to be a ring related issue. I'm wondering if the problem isn't the stem seals or the intake gaskets or as 65tb is suggesting a possible reversion problem. However, for the reversion idea to be a possible source for the problem wouldn't the smoking issue have always existed since the engine was built?

If you get it sorted out, be sure and post up the results. I just love happy endings.