Thread: update3 test results

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Hey MainCap: We are going to do that with the intake eventually. My friend and I ran the motor for about 30-40 minutes tonight playing around with it and noticed no "solid blue" color out the exhaust, (maybe a little bit, not much) just "grayish" smoke. (keep in mind our exhaust system has a build up of oil inside). This is the first time ever it has not burned blue smoke on a regular basis out the exhaust. I'm still running on the electric fuel pump and fresh gas. There is a chance we have two problems going on at once. The ring seal is being delayed by the grease, and the chance of oil top side by either the fuel pump, or the holes in the intake. Realizing the ultra rarety of the fuel pump and oil mixing, we are going to go ahead and drive it some on the electric pump. If that doesn't pan out, then we'll pull the intake and take a peak. My friend kinda said what you say, if the holes or crack wasn't too big, the oil going through the hole, or crack, would act like a "flowing seal" where maybe the vaccum loss wouldn't be as great to affect engine running good, but enough to suck oil. I thought I could eliminate the intake altogether when I pressurized it on the motor. (backed off all the intake rockers). The only air loss was by the intake guides to which you could barely hear. Basically the intake sealed up like a tank. I would take the air hose off and plug the hole with my finger, wait for a bit, and when removing my finger, air would rush out like you took your shop hose off an air bubble or the like. (I made a plate to go where the carb is out of 1/4 inch steel, drilled and tapped a fitting into the plate for air. my machinist came up with the idea). Good way to check intake gasket seal or the rate of air by the intake guides. (during test also used my stethoscope to listen in the crankcase, etc. for air loss). Also no air association (or in) the exhaust crossover. One more way to test a motor. If that test shows intake is ok, that leaves me with the rings, or a rare problem with the fuel pump. The only other thing in my mind that is different from stock is the drain back holes behind the oil rings. The stock piston had 8, the new ones have 4 small ones. Most people feel this is not it either when I bring it up. Grease or not, in some 25 years, have I've ever heard of a new motor burn so much oil. My machinist said it this way, with tight clearances you could almost leave the rings off and it wouldn't burn that much oil like ours is. Also said with fresh guides it would be hard to dump such oil. (if guides were an issue ). He just feels the rings can't be that screwed up, grease or not. (especially after two ring sets and fresh cylinders). Even Hasting rings said twice over the phone with me, they can't imagine the grease ever being my problem. If I could eliminate the grease as a problem, does anyone have input on the drain back holes? It would be kinda nice to know what to look for when I get to the tear down. Some 20 pistons I've looked at has at least 6 holes and are bigger holes than on ours. CP piston company said on average their pistons have 6 drain back holes. Federal Mogul said don't worry about that, that's not your problem, even before he heard of what my problem was! Wasn't impressed with talking to him. If I'm not boring you all too much with this problem, I'll continue to keep ya updated. Thanks. Later

You have a very confusing problem here. you are obviously burning the oil evenly across the cylinders or you would be filing the bad hole plug bad. I personally don't think rings are your problem in this case although I have seen it before on a new engine when I was young. I bought a slaughter house engine for a truck when I was in diesel mechanic school because I threw a rod and didn't have space or time to build my own. Within a few thousand rough mud riding miles I got the motor hot and all the ends broke because they touched from expansion. I had sixtie thousanths ring gap or more on 6 pistons. But that isn't your problem. I would eliminate rings and grease and valve stem guides/seals. I been thinking about the intake but it's not all that logical TO ME because the oil really has a long way to go to get there. What I mean by this is the intake is a few inches above the oil for one: It would be just like saying your pcv is burning a quart of oil a minute, it should only be sucking a mist like the pcv. For 2: You wouldn't have all that blow-by because intake vacuum would be sucking it up. The only logical reason I see is the fuel pump blowed a seal because It does have oil access to it in volume. But what thows that theory out is the fuel in the bowls of the carb would be completely full of oil. You could always put the pump back on and let it flow into a bucket while you run the motor off the electric pump to see if oil is mixing with the gas. I wouldn't tear into the motor just yet. Tried that once already and it didn't fix anything. It's somewhere external in my thoughts. Have you checked the carb for oil in the bowls and what kind is it?? Well, you keep testing and we'll keep thinking.....I also don't think the drain holes will do it either, unless they were completely stopped up. Like you said, melting point of grease is to low. You have already burned the grease out the cylinders by now anyway.

A blown fuel pump diaphragm will dilute the oil with gas. Never seen one suck oil into the gas.
I don't remember you saying what happened to this engine to require rebuilding in the first place. Was it a runner, or built up from parts? Did it just get old, or did it break? I'm reaching here, may be a source of a hidden crack somewhere in its history.

the fuel pump cant pick up oil out of the pan and carry it to the carb. the fuel pump can dump fuel into the pan, but then your oil will check overfull. i'm sure you've checked that. if you think about it a motor sitting idleing, with any rings in it at all, the oil cant get on top of the piston. the compression would keep it in the pan. now the compression would blow it out of the breathers. not knowing how bad the blow by is i'd have to say you have a leak above the heads. if you find and fix a problem above the head and you get rid of the tail pipe smoke, i think you're gonna still have the blow by.

Confusing problem indeed. Originally the motor just had excessive cylinder wear due to it lived on gravel roads most of it's life. It's my bosses car to which he grew up next to the guy who originally owned it and rode in it as a kid. The motor had never been apart and had 100,000 miles on it. My boss liked the car enough to fully frame off restore it. His other '57 with a 283 I did for him turned out great, so he let me do the second one too. (the first one took runner up in class at a denver super chevy show).
I know the rarety of it being the fuel pump, but obviously want to eliminate everything possible, logical or not. I did a gas comparison in four clean glasses. 1. unhooked line by carb and took sample. 2. took some out of the cars gas tank. 3. got some fresh gas. 4. put some oil in fresh gas. Test inconclusive. The gas from the tank and by the carb look the same. The fresh gas looked lighter in color than from car. The color of gas I put oil in did darken to the color of gas out of the car. Unfortunately, it's winter here and don't know if the fresh gas is treated for the winter, giving it a lighter color. When I drop oil into the gas, it drops to the bottom of the glass. Let sit for days and no oil at bottom or top of gas. Obviously they mix together so well that when I empied the glass with oil in gas, the glass didn't have no oil residue on the bottom of the glass. One would have to have it chemically analyzed to find out for sure. That would explain why there's none in the carb. But why the oil under the carb in the intake plenum I mentioned earlier in one thread? That one makes no sense. (that's why I decided to consider the fuel pump). But I showed myself that oil and gas mixes by my one test in the glass, then how could one explain oil in the intake? Any ideas? (of course the gas is atomized and maybe the oil could stay in the intake for there wasn't full strenth gas to wash the oil down or mix with it well) Boy am I grabbing at straws. I do realize a bit of blow by is normal, ours seems more so. Blow by as standard points to the rings. We'll keep trying. It's snowing here again so I can't get it out yet to put some more miles on it. We did find some fresh oil down under the fuel pump. None seems to be coming out the "breather hole". I wiped it clean and will watch it. It was still positive not seeing much blue smoke last nite. That would be mega rare to have it be the fuel pump, but what if I'm the lucky one to get such a pump? New parts don't always mean they work right. (found that out restoring two cars). What if the case was cracked and the oil could get on the right side of the diaphram to "pull" oil into the gas somehow. I have heard of two storys of oil in gas because of a pourous diaphram, one story from Hasting rings web site. He was loosing oil and couldn't find out why. He took his motor apart and together again, same problem. In desperation he changed the only thing left, the fuel pump, and problem fixed, so the story goes. So I guess I'm not to crazy to consider the fuel pump as part of my problem. I'll keep looking. Honestly want to try everything before I consider taking it apart. I'll eliminate the fuel pump first, and probably pull the intake soon and eliminate any holes or cracks as the problem. Sounds like a plan. Thanks all

There are not many ways for it to get under your carb. Those extra holes, intaked cracked, etc. You may just need to swap it out and try another old one it could even be cast iron or whatever Also, with all the oil in the pipes and mufflers, its going to be hard to know when you find the problem cause it will smoke for a while yet most likely.


Another thought, if the intake was that severly cracked to suck that much oil, wouldn't it have a hellashous vacuum leak? My cars won't run with a simple vacuum line off.

Just an off the wall idea here, maybe the grease used to lubricate the cylinders partially glazed the bored, when burnt it will probably leave a residue, may need clear it out. I would not put a foreign material in there, but if the lubrication system checks out, ie getting oil everywhere, timining is good, no vaccum leaks (that you can find) and no other obvious reasons for the smoke and minimal risk of major damage by running the motor then take it for a drive.

Put the best gas in there possible, ie nice high octane premium fuel, it has detergents in it which may help break down any build up.

Get the engine up to normal operating temperture and then give it a nice hard run under load. Keep it nice and hot, plenty of revs, but no shock loading let it wear any crap of the cylinder walls, bed in rings etc. Air flow will help flush carbon etc out of the combustion chamber, burn carbon etc.

If it does not work then you will pull it down anyway, and you had some fun before hand, or it works and you dont have to pull it down. I would only do it if there is a low risk to the motor, ie running out of oil blah blah, burning a little oil will not hurt to much.

Also oil and gas mixed together will be hard to tell, but mix some oil and gas together in a glass jar, not to much oil then let the gas evaporate. put the same amount of gas in another jar and let it evaporate with the oil mix. The gas with oil should leave a slight oil film on the jar, the gas should be dry feeling.

Justin

Hey camaro fever: I'm allowing my self some room on the oil in the exhaust. That will take awhile to burn out. I should eliminate the intake because my pressure test shows it's sealed tight, and I have good vaccum on the guage, and it runs right. Obviously don't want to leave out any possibilities though.

Hello JL350: It is possible about the glazing. I have decided to drive it for awile and see what happens. As you kinda said, I have nothing to loose driving it. I do use premium gas in all our vehicles. I'll try the gas in oil again soon and see. I did drive it today a bit and it's not burning too bad right now. I'll keep driving it with the electric pump for now. If it is getting better, I'd put more odds on the rings are trying to seal, rather thinking its the fuel pump. I'm going to try everything I can before I rip it apart. Later

Got back from a little drive. Redid the leak down while the engine was the hottest I could get per say. I come up with 10% leakage this time. What do you think of 10%? Some feel it should be 5% on a good strong motor, engine broke in. (ours isn't though yet). The smoke wasn't too bad. Actually seemed to get less a bit by driving it a little bit harder than normal. I'll keep track of my qt per mile and see if it gets any better.