Don Terrill’s Speed-Talk

Maybe the oil isn't drained fast enough. Have seen numerous head gaskets where the drain hole is off and partly closes the drainback hole in the head.
Just a thought.

Chevyfreak.

I don't remember any issues with the gasket blocking the oil return hole, but next time I have my airboxes off I'll certainly check.

Just asking, but I have a HV pump with high pressure spring in there. I'm thinking that I might need to go to a normal volume, normale pressure pump.

OP Belgian

If SBC, pull valve covers off heads & check that drainbacks from heads to valley are free & clear.
Next, refit std vol op.

I've been thinking about this some more. One other explanation could be that it's sucking oil through the bolts of the pedestal for the shaft mounted rockers. I've used blue RTV on them, but I've seen before it doesn't hold up well against oil.

Kevin Johnson wrote: ↑Sun Jun 07, 2020 12:39 am 11/32

versus

12/32

ypost

But he wrote 3/8(or 6/16) vs 11/16, not 11/32. That's why I asked. I'm guessing 11/16 is a typo?

My buddy had such a issue with a fully brand new motor that we built.

After a ton of checking things out and playing with the Carb and pulling valve springs to look at the seals it was found to be oil / temperature related and the bottom line was found to be that the heads where assembled from the supplier with valve seals for 3/8" stem valves, and not 11/16" ' and yes even though they where for 3/8" stems, they still did drag on the stems, but only very lightly.

"ypost" was not meant to be shorthand for "why post [this]"; it is a deliberate typo of "typos" made by transposing a letter.

Sorry about being too obtusely abstruse.

midnightbluS10 wrote: ↑Mon Jun 22, 2020 6:32 am

Kevin Johnson wrote: ↑Sun Jun 07, 2020 12:39 am 11/32

versus

12/32

ypost

But he wrote 3/8(or 6/16) vs 11/16, not 11/32. That's why I asked. I'm guessing 11/16 is a typo?

My buddy had such a issue with a fully brand new motor that we built.

After a ton of checking things out and playing with the Carb and pulling valve springs to look at the seals it was found to be oil / temperature related and the bottom line was found to be that the heads where assembled from the supplier with valve seals for 3/8" stem valves, and not 11/16" ' and yes even though they where for 3/8" stems, they still did drag on the stems, but only very lightly.

Belgian1979 wrote: ↑Mon Jun 01, 2020 6:30 am I have numerous threads out here about a smoking problem while under deceleration. I did a lot to combat this and recently used a smoke machine to check for intake leaks and such but found none.
I was ready to pull the heads next winter to have the guides redone, but today I started particularly paying attention to what it did on slow speeds. It seems to also blow some blue smoke while taking a corner. Some speed, just not hard cornering.
Is this something that is tied to the guides?

https://www.clearvueconcepts.com/

Use a couple GoPros to observe what is happening in the valve covers on your motor. I am not sure if Belgian authorities would mind you driving around a bit minus your hood (for better/inexpensive lighting?).

Science!

Well, our government doesn't allow alot, so no. We live in a part of the world that is becoming more and more communistic in nature unfortunately. Personally freedom is in serious decline here.

Belgian1979 wrote: ↑Thu Jun 25, 2020 1:47 pm Well, our government doesn't allow alot, so no. We live in a part of the world that is becoming more and more communistic in nature unfortunately. Personally freedom is in serious decline here.

This Winter's project: https://www.autoevolution.com/news/niss ... 39689.html

I tried resealing the bolts with loctite 542. No luck however. Same results.

So I'm left with either the valve guides or a problem with the piston rings.

If having the guides done, what would be an excellent wear resistant guide that works with SS valves?

PS : any idea how much oil can be used with worn guides?

Belgian1979 wrote: ↑Sun Jun 21, 2020 3:15 pm ...t I have a HV pump with high pressure spring in there. I'm thinking that I might need to go to a normal volume, normale pressure pump.

With the HV pump and high pressure spring, you could be flooding the valve train with oil and under load, vacuum is making the oil seep through the valve stem seals. Get a Chevy standard volume pump and put the correct spring. The old Chevy Z-28 engines ran a standard volume pump with a high pressure spring from the factory as well as some of the high output Chevy Corvette engines with the 6 quart OEM pan.

I have experienced this issue with some engines to the extent I had to use restrictors on the cylinder head oil feed to control a hemorrhage of oil on the cylinder head.

Not debating that you might be right, but I always had the idea that it was not possible to flood the top of the engine (unless return holes were not good) since the pump with a higher volume would just run into the pressure limit soon and pump all the oil back to the inlet of the pump. Might be wrong though.

BTW : what is a good quality standard volume pump these days?

I just did a small test, where I took of the valve breather cap on one side of the engine and placed my thumb over the hole and held my face close to it. I do not have anything I would consider an abnormal pressure. This was a test when cold. Considering that my compression test was also very good and even on all cyls, can I conclude that the piston rings are ok? Or is there more to verify than a compression test and feeling for abnormal crankcase pressure?

What I could do next is take away the plate that is mounted below the hole of the breather to shield it from oil splashing. That way I could look at the head below and see actual oil levels in the head when revving it to about 2000 rpm, which should be plenty to have the pump provide maximum volume and pressure. Just a thought before being parts and not finding a solution.

Belgian1979 wrote: ↑Tue Jul 21, 2020 12:52 pm Not debating that you might be right, but I always had the idea that it was not possible to flood the top of the engine (unless return holes were not good) since the pump with a higher volume would just run into the pressure limit soon and pump all the oil back to the inlet of the pump. Might be wrong though.

BTW : what is a good quality standard volume pump these days?

Before I can make a recommendation for an oil pump, what is the size of your oil pump pickup? 5/8" or 3/4"?

It's 5/8" as far as I can remember.

An update to this: I did a couple of tests while my son drove behind me with another car:
1. I deactivated the accusump and lowered the oil level to the low mark and this seemed to improve somewhat the smoking although this may just be our impression.
2. I then set all fuel tables to an AFR of 14.7/1 and shut off the acceleration enrichment. This made the smoke almost completely disappear.

Oil level remained stable.

I did still have some smoke on decel but this is an area in the fuel tables which is (i) extremely hard to tune and (ii) when not rich enough creates backfires. So the smoke could be oil or not ignited fuel which ignites in the exhaust. My son found it hard to tell whether the smoke was grey, blue or white. He thinks that on decel it was a little blue, which would indeed point to my guides.