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Discussion Starter · #1 ·
Last spring I built a 388ci for my '70 velle and it has been burning oil ever since. I started thinking awhile back that my rings were bad, due to the fact that they were file fit rings and I was second guessing my work. I also thought it may be due to the Keith Black Hyperutectics because I have heard some bad things about them as well.

After doing some tuning with the carb I am getting fairly nice looking plugs on the drivers side head. However I am getting oil on most plugs on the passenger side head especially #8 cylinder. I can put a new plug in and it will be black with a little bit of oil and soot within a couple hours. The heads are factory 996 heads that the machine shop only did a valve job on. They did not replace the guides and Im not so sure on seals.

I have done a compression check on the cylinders and they are all showing 165-180psi. Im wondering if the guides are bad or seals and what the symptoms are for such. The car only starts smoking once the engine has warmed up and I rev it up. Otherwise idling it does not appear to be smoking. It will puff out a little smoke when it's started after it has been warmed up. Any ideas are great !!!

Here are the specs:

Factory 4 bolt .060 over
Keith Black Hyperutectic with file fit rings
Eagle cast 3.75 crank
Eagle H beam rods
Factory 996 heads
Lunati Voodoo 60103 valvetrain
Performer RPM intake
670 Avenger
 

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I would try putting new seals on the valve stems. I have a tool and it is quite easy to do with the heads on the engine. Do you have a compressor ? My small block has both the
" O " ring and umbrella seals and don't burn any oil.
 

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I would try a leak down at TDC to see if you are having a ring seal issues and that being said seeing your block is .060 over hopefully it was plate hone because of such a big bore there is alot more cylinder distortion once the heads are bolted on.

On a new build you should be under 10% leak down!!

I have seen guys buy filte fit rings and not plate hone there blocks which is a total waste of money!!!!
 

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Discussion Starter · #4 ·
I would try putting new seals on the valve stems. I have a tool and it is quite easy to do with the heads on the engine. Do you have a compressor ? My small block has both the
" O " ring and umbrella seals and don't burn any oil.
Yep I have a compressor....Im hoping seals is all it is....
 

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Discussion Starter · #5 ·
I would try a leak down at TDC to see if you are having a ring seal issues and that being said seeing your block is .060 over hopefully it was plate hone because of such a big bore there is alot more cylinder distortion once the heads are bolted on.

On a new build you should be under 10% leak down!!

I have seen guys buy filte fit rings and not plate hone there blocks which is a total waste of money!!!!
Im gonna have to break down and buy a leak down tester....What is the order for doing this? Locate TDC on the piston im working with, then fill cylinder and watch for drop in terms of %?

Im about ready to yank the heads off and take them back to the machine shop but guess I should wait and do this first....
 

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Im gonna have to break down and buy a leak down tester....What is the order for doing this? Locate TDC on the piston im working with, then fill cylinder and watch for drop in terms of %?

Im about ready to yank the heads off and take them back to the machine shop but guess I should wait and do this first....

MaKe sure your on the compression stroke and not the exhaust stroke and do the leak down test first before taking the heads off.

Was the block plate honed???

Also I am not a fan of hyper pistons as I have seen similar threads like this before!!
 

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Discussion Starter · #7 ·
I ordered a leak down tester from Summit today and should be here Weds.

I took more accurate compression test today with engine warm and throttle wide open. Measured 6 revolutions per cylinder and this is what I got:

Cylinder 1: 185
2:187
3:180
4:186
5:185
6:192
7:185
8: 190

I know this doesn't help much right now but I have a baseline at least ...will post results of leakdown when I get them-thanks for the help everyone!!
 

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I would try the easy stuff first. Change the oil seals on the heads and maybe even the intake gasket. Good luck :D
 

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I encountered a similar oil consumption problem with my 383 small block stroker. The motor used 2 quarts of oil in the first 500 miles. I never got an opportunity to observer the car while it was driving so I don’t really know if it was producing oil smoke on acceleration or deceleration. I did observe a large puff of smoke on start up. I fixed the oil consumption problem with new valve seals, intake manifold gasket and a new PCV valve. I did not approach the problem very scientifically, I just change all these parts and the problem was gone. On the valve seals I started with the hard teflon positive valve seals. I added o rings on all the valves and soft rubber positive seals to the intake valves. I changed the intake manifold gasket and sealed the intake ports with a very light smear of high temperature silicon. There was some evidence of oil in the intake runners of the heads so I think that may have been the key issue on my motor. Just for good measure I changed out the PCV valve. The existing one on the motor was 40 years old so it couldn’t hurt to replace it. Over the next 1000 miles of driving the 383 used about 1/32 of a quart of oil, basically no oil consumption.

Vaughan
 

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Discussion Starter · #14 ·
Im hoping valve seals is all it is. I have a compression leak down tester on it's way to determine if rings are the culprits or not.

I just replaced the intake gaskets a week ago. I had originally thought they were the problem, which they were somewhat (the endcap RTV seals failed) so I redid with new gaskets and the "Right Stuff" for endcap seals.

One of the things that is strange, is I notice no oil being burned when the engine is cold, but once it warms up, it starts burning it. Makes me wonder if when the oil is cold, it does not seep past the guides/seals as easily as it does once warm?

Also one of the heads I previously had on this engine was cracked. The machine shop caught it and sold me a "shop" head they had leftover. Reviewing the receipt from them, it appears they only did a valve job but did not do anything with the guides. Im not sure if anything was done with seals either. Im wanting to put AFR's on it but not until later this year.


I encountered a similar oil consumption problem with my 383 small block stroker. The motor used 2 quarts of oil in the first 500 miles. I never got an opportunity to observer the car while it was driving so I don’t really know if it was producing oil smoke on acceleration or deceleration. I did observe a large puff of smoke on start up. I fixed the oil consumption problem with new valve seals, intake manifold gasket and a new PCV valve. I did not approach the problem very scientifically, I just change all these parts and the problem was gone. On the valve seals I started with the hard teflon positive valve seals. I added o rings on all the valves and soft rubber positive seals to the intake valves. I changed the intake manifold gasket and sealed the intake ports with a very light smear of high temperature silicon. There was some evidence of oil in the intake runners of the heads so I think that may have been the key issue on my motor. Just for good measure I changed out the PCV valve. The existing one on the motor was 40 years old so it couldn’t hurt to replace it. Over the next 1000 miles of driving the 383 used about 1/32 of a quart of oil, basically no oil consumption.

Vaughan
 

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Discussion Starter · #16 ·
That was what my machine shop thought. But I installed intake without gaskets and measured endgap at .025 and sides at .035 .....I had the block zero decked and thought the same thing , that with the heads and not knowing how many times they were surfaced that it might throw angles off....



I was thinking more toward the intake/head angles being off ,not just the gasket being bad.
 

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Did they happen to measure the side gaps at the top & bottom of the contact area?
I've seen mis-matches there that cause the oil to suck past the gasket into the port.
Just tossing out more ideas of where to look.
 

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Discussion Starter · #18 ·
Did they happen to measure the side gaps at the top & bottom of the contact area?
I've seen mis-matches there that cause the oil to suck past the gasket into the port.
Just tossing out more ideas of where to look.
On the side rails I pushed the intake over far to one side and measured total gap then divided between 2 for a estimate per side. Then centered intake and measured top of side rails and front and rear end rails. I didn't measure the side rails at bottom of contact area though - how do I measure bottom area, from front and long feeler gauges?

Thank you for the ideas-I'm doing everything I can think of...
 

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I'd set the intake on the heads/block without any gaskets and measure the top & bottom on the intake to head at the ends.
Unless your heads or manifold are warped .that should show if the top/bottom of the intake flange is square to the head/s.
 

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Jason,
Here is my 2 cents worth. .....

1. I have never seen valve stem seals solve a bad oil consumption problem. You have to remember that all of the early small blocks had nothing but an "o" ring and they did not use much oil. The 350 that came new in my Heavy Chevy went oil change to oil change without using a drop.

2. The ring end gap would have to be pretty rediculously big to cause an issue. A few years back we went to a seminar that one of the major ring manufacturers gave. They basically said thet they did not see any significant increase in blowby or oil consumtion until the ring gap was opened over .050"

3. Like Carl said, cylinder wall finish and roundness is very important. Personally I think that the finish is the most important thing. Torque plates are a definite plus, but I dont personally feel that using them or not using them will cause the amount of oil consumtion you have on a fairly new engine. GM doesnt use them and they dont have oil problems.

Last but certainly not least ..... is there any chance that you put one or more of the second rings on upside down ??? I am only asking because I have done it and it caused very similar symptons to what you have. Years ago I put just one second ring on upside down on a 336 (305 stroker) that I built for an 85 Firebird. It kept fouling one plug and smoked just like yours does. Compression and leakdown was fine. I could not find anything else so we pulled it back out and took it apart and sure enough, I had one second ring on upside down :( That one ring was scraping the oil off the cylinder wall on the up stroke instead of the down stroke like it was supposed to.

Just some thoughts,
 
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