The Stovebolt Site Forums The Shop Area Engine Shop Oil in all exhaust ports

My 235 is newly rebuilt but smokes a lot and has oil in all exhaust ports. The leak test showes no leaks. Any ideas on what will bring oil into all exhaust ports?

Valve guides ??

Hello Jon and welcome!
If it is newly rebuilt and it was good machine work it may simply be that your carburetor is running too rich. This will leave unburned gas in your exhaust ports and the gas may dissolve oil left in the ports from previous days. Do you have the Rochester carburetor? Has it been rebuilt?

I have Weber carb on a Clifford intake. The head was rebuilt too and should be clean.

Ok, that helps. Can you tell us more about the carburetor (1 bbbl, 2bbl?) and the intake type (single carburetor, double carburetors?).

Jon Arvid,

First off, Welcome to Stovebolt!

That being said, can you take and post a couple of pictures of your engine?

That can give us a better idea of the engine in question and possible suggestions to check further.

Dan

Note: If you need help posting pictures, click on this link How to add pictures... for how to get that done.

"Newly rebuilt"- - - - -how many road miles does the fresh rebuild have on it, and what kind of honing and cylinder preparation was done during the overhaul? Was the engine rebored and new pistons fitted, or did it just get a re-ring job? It's vitally important to run the engine under load, like several long uphill pulls, to seat the rings to the cylinder walls. A no-load run to break in the camshaft does not load the rings sufficiently to seat them. For many years, the seating procedure recommended by Perfect Circle was 10 full throttle uphill pulls from 30 MPH to 50 MPH in top gear. Other ring manufacturers required a similar break-in procedure.
Jerry

Could you have the wrong rockers in the valve train like I had on my 235? I was getting too much oil in my top end which caused my newly built engine to smoke. Once I put the proper rockers on my smoke stopped. I even had oil in my tail pipes. Now they are dry.

How did you "leak" test it? When the head was rebuilt, did you use new valves or re-use the old valves? Did you replace the valve guides, or line them with bronze liners or were they reused as is or knurled? Did you use the crappy stock o rings, or no o rings or did you have the head machined for Teflon seals?

"All exhaust ports", indicates that all rings aren't seated yet, or are too small to seat properly ever, or there are no o-rings on the valves , ot the valve guides are sloppy.

A Toyota engine one of my employees assembled back in the late 1970's had an improperly packed set of piston rings in the overhaul kit. The oil rings were .75 MM smaller diameter than the compression rings. It burned massive amounts of oil from day one. He had neglected to notice that the pistons would drop into the cylinders past the oil rings without using a ring compressor. The guy had moved on to another job before we discovered the cause for the problem, so I ended up redoing the engine rebuild for free!
Jerry

Have you checked your crankcase vent?

Thank you everybody, here are some answers:
Yes, it might be valve guide or valve stem seal leaks. Need to check.
Its a 2bbl weber 38/38 on a Clifford single carb intake.
Will post some pictures soon.
It has not hit the road yet. It was rebored with new pistons and rings. Interresting with that ring run in. I haven't heard about that before.
I suppose rockers are correct but can investigate that. But how can wrong rockers lead to too much oil in the top end??
The leak tester adds pressure in the cylinders and messure the leak rate at a certain pressure.
It is new valves, springs, guides, retainers. The head was milled for higher compression. But i need to check the valve stem seals.
Yes, crankcase ventilation is good.
Thank you again for your comments, keep on!

Read my post on 235 rockers. It is what I found on my 235. Too much oil get past the valve guides.

If the rocker shafts are installed upside, you will have a mess too. The bottom holes of the shaft are bigger than the top ones, causing too much oil to the rockers if the shafts are upside down.

Any idea what year the block is?

Here's the pictures of engine and intake:

That is a 5913 head so that indicates 54-55 head. The more important question is what year is the block. If the block is also 54-55, then the rocker arms should have a groove inside each arm that directly intersects the dribble hole on the arm. The reason this is important is that in 59, GM made its last changes to the oiling system for the 235 and 261 motors. Instead of bleeding pressure from the rear cam bearing to feed the rockers, the rockers in the 59 and up blocks were fed from a direct passage from the main oil galley. This increased the oil pressure and volume to the rockers. At the top of the block, an orifice metered the amount of oil reaching the distribution tube/connector on the rocker arm assembly. On the 59 and up blocks this orifice was larger then on the 58 and earlier blocks to allow a larger volume of the now higher pressure oil supply to reach the rocker arm assembly. To control the oil flow at the rocker, so that oil dribbled out of the rocker arm dribble hole, GM offset the groove in the rocker.

Here is where the issue appears. Lets say you have a 55 block that goes south. A friend gives you a 59 and up block, either regular production or service replacement. If you bolt on the 55 head and rockers, you will get an increased amount of oil to the rockers that is not metered correctly and can flood the valve stems so to speak. GM supplied a plug and a special drilled head bolt that was used for these situations so that the oil could be redirected and metered in order to use the later block with the earlier valve train.

On the photos, it looks like you have a lot of soot and some oil there on your finger. Looking at the gasket, it does not look like you have a very good seal, especially on the headers. This is not exactly uncommon with the Clifford headers. It also looks like you have some wetness in the intake ports. So just as an initial issue, I think you want to consider using a Rimflex gasket instead of the Clifford gasket or stock gaskets. It is imperative that you have a good seal.

I might also retorque the head just to eliminate any loose bolt issues.

So maybe start with finding the casting date and part number on the block, retorque the head and get a Rimflex gasket installed.

Finally, what weber carb are you using? The non-progressive 38/38 or the progressive 32/36? The reason I ask is that I ran a pair of 38/38 webers on my Clifford intake and truth be told I tried my best to get them to run right. They always ran rich, started up rich and with a big cloud of white smoke, had a stumble on hard acceleration, and no matter what I did in terms of jetting or adjusting I could not get them to run right. Jetting was expensive and a pain, and I struggled with weber tuning, or maybe it was just not to be, I dont know. A couple of years ago, I switched over to a pair of Holley 350 cfm two bbl carbs and that solved the issue. You may want to consider that alternative.

Not to say this is your problem but I'm running dual Webers, and shortly after initial startup it started smoking.I went thru a lot of checks until I looked down the carburetors and both were slobbering gas down the throat at idle. My new (Chinese) fuel pump was putting out too much fuel pressure. I put a regulator in and that took care of it for a couple of days. Then it started smoking again and I found both idle jets were plugged. The Webers seam to be very sensitive to small particles in the gas. I have since installed 2 gas filters and it still does every once in a while. When it starts smoking I remove the jets and blow them and it stops smoking.

As others have mentioned, it only requires a very small volume of oil to keep the rocker arms and valve stems lubricated. If the top end is getting over-oiled, some of it will find its way down the valve stems, and there might be inadequate oiling of the connecting rod and main bearings due to pressure loss in the rocker arm shaft. There is a threaded plug in the middle of the cylinder head that will allow you to compare oil pressure between the main oil gallery on the side of the engine block, and the pressure that the cylinder head is getting. Several different designs of rocker arms and oiling methods were used over three decades of engine production, and a mismatch of parts and/or incorrect assembly can result in too much oil getting to the head. It would also be a good idea to run the engine with the valve cover removed and see if there's a lot of oil being squirted out of the rocker arm weep holes. A small trickle is all that's needed- - - -not a stream.
Jerry

The block has casting number3836233 which corresponds with a 1955 truck in the list I found. The rocker arms used now look exactly similiar to the old set used before the engine overhaul. Are there anything that indicates rockers before or after 1959?
I have a 38/38 Weber, and yes I experience it tricky and rich running. Its an expensive carb so I will try to clean it properly again and lower fuel pressure lower that recomended.
It's time to put it together again and check carb function and oil flow to rockers.

One of our own ‘bolters “Pre ‘68 Dave” is an expert on these Stovebolt engines and has a website that show the differences in the rockers and oil supply thru the years these engines were made.

Here is a link.

"Are there anything that indicates rockers before or after 1959?"

The position of the oil groove inside the rocker arm is the best way to identify the early or late design rocker arms. The later model part that was used with full oil pressure to the rocker shaft has a groove that's offset from the spit hole in the top of the rocker. Earlier models that used lower pressure inside the rocker shaft have the groove aligned with the hole. The shafts are the same design for about 30-something years of production, from the 1940's to the early 1960's.
Jerry

I believe the rockers arms have different numbers. Here is a post that Identifies which rockers go on which years. Rocker Arm ID

Could it be possible in the past the orfice was drilled in the block to the top end and that’s why it’s over oiling. My 59 235 is working very well now that I have the proper rockers on it. No oil in exhaust and the plugs look good. There was just too much oil in the valve train and the valve guides and intake seals could not handle it. My engine has a fresh bore job with new pistons, rings, and reground crank, along with a completely rebuilt head. It should not have smoked but it did untill the valve train was corrected.

Last Checks: The rockers have the grove in the middle aligning the hole. Then they are correct for the 55 block and 55 head. Attached is a link to a video of the rockers working.
The carb (Weber 38/38) was cleaned and all jets and passages blown with compressed air. It now possibly smokes less, but still runs rich. I can see fuel driping into one of the carb barrels at idle. The other barrel seams dry.
Rocker video: https://www.dropbox.com/scl/fo/gv07yt529tbir3u23ybaw/h?rlkey=02f507l9hxgceppfaift7qouj&dl=0

In your video the oil connector has the overflow pinched off. In 55 that should be a loop back down to the head. If you look at pre68 Dave's site, it clearly shows the different types of couplings between the rocker shafts. Maybe when you're running at highway speeds you are getting too much oil pressure in the rocker shafts. Thus, it's overwhelming the valve seals and guides. I would correct that coupling and see if it helps.

You have some seriously mismatched parts, and it's unlikely things will get any better until those problems are corrected. Chasing one's tail trying to make a wrong carburetor work can be very frustrating, no matter how much money has already been wasted. It seems you've got some incompatible valve train bits and pieces, also. It seems that you're determined to ignore everyone's well-intentioned advice and press on with Band-Aid fixes. Good luck!
Jerry