i'm losing a quart of oil every 500 hundred miles or less.
there are no leaks to be seen. this engine was just rebuilt last jan. the compresion test reads 120 150 150 150
1-4. lokking at the cylinder walls you can still see the honing marks. and the piston are already coking. what do ya'll think. i sure as heck don't want to get into this engine again im going to check the valve lash to see if there set the same. im using Q state syn 4x4. fixing to stop that it is going expensive at the rate i'm adding oil. not much smoke from the exhaust. you do see it in the morning when it is cool and humid.

thanks.

93 p/u 22re/street rv head/street rv cam/ kn filter charger/
lce header and exhuast.

Does it smoke? Did you replace the valve seals when it was rebuilt?

That's lower than I'd expect on a completely rebuilt engine, & that 120 is *way* lower than it should be, I believe there should be no more than 10% variation from highest to lowest cylinder.

Did you use sythetic oil for brake in?

Dave

it smokes some but not much. i did use syn on brake in.
id didn't like thase comp numbers either. actually it made me pretty pissed. i wonder is the used to small of rings for what they bored

Did you rebuild it, buy it as "rebuilt", or have the rebuild done?


How many miles have you put on it since rebuild?

i had the lower end done at a local machine shop and had the head checked there too. the head was farely new; about three years old. there is about 6k miles since the overhaul.i drive a 1k a month.

you still see the honing marks in the cylinders. i don't know how long it takes for it to look smooth. i checked the valve adjustments and the #1 exhaust was set to tight probably # .oo5 <img src="/forums/images/graemlins/scared.gif" alt="" />. #3 exhoust was to loose @.o10. all now set to 7&9. i'll redo the compression check sometime this week or monday. i think the will all be the same. i don't likethe 150 readings on the compression check but i was not to concerned since the where all the same untill recently.
i wonder if the rings are the right size are not? the shop assembled the lower end

I'm wondering if the synthetic oil kept the engine from breaking in properly. Hopefully EB will see this & weigh in.

My other thought is that the ring gaps are lined up on the piston; they're supposed to be staggered. <img src="/forums/images/graemlins/cyclops.gif" alt="" /> My brother learned that one the hard way on his first rebuild.

>>>*Apparently you do have the head back off since you say you can still see the hone marks and one or more of the pistons are showing signs of buildup?

The 150# reading is exactly what we see with a rebuilt engine, new head, aftermarket cam and a block that has not been decked to establish quench. The 120# reading is very low.

I would suggest you keep going, drop the oil pan and pull the low cylinder. Possibly a ring was pinched or damaged during install, now is the time to correct. I would be replacing the rings and setting on a new set of seals while the head is off, just in case.

We had one case of an inhouse engine that smoked worse than anything I ever saw, 155# on all four. I drove in and took that one apart myself, even though the customer had assembled it. I found an oil expander ring in #4 cylinder that was .020" instead of .040" and that is all it took. Something like that is darned hard for a builder to notice, I found it after the fact so I got to pretend I would have... <img src="/forums/images/graemlins/smile.gif" alt="" />..

Replacing the seals while the head is off is a 10 minute job, insurance there, things happen. It isn't possible to make my son Tod get in a hurry building these heads, he just won't rush. (Even when I yell at him, all that does is slow him down) But still a seal can be pinched, or even a possible hard to spot defect can cause small amounts of oil useage.

But the low compression number tells me it isn't a seal or even an oil ring, something isn't correct with a compression ring and likely the top one.

Synthetic oil can be used during breakin, I know some say otherwise but they are wrong...*LOL**...I know this having done it literally dozens of times with racing engines. Of course our breakin procedures with competition engines are less than gentle.

Just remember that with synthetic, there is no margin for error, the stuff is slick. If there is any flaw or concern, you will use way more synthetic than you will a dino oil type, so we do not suggest it for breakin with a normal street engine..

On honing patterns, if the bore was properly prepped with a good plateau pattern, it will show for many thousands of miles, this is normal....*EB

A truck with a newly rebuilt motor rolled out of Burt Toyota, the owner put synth in it to break it in. He brought it back complaining of similar oil usage.

They put dino oil in it, and 500 miles later he had sharply reduced consumption and a bit more pep. They concluded the rings had not seated properly with synth.

Just sayin'. Some engines come from the factory with synth; perhaps they are machined to tighter tolerances? Dunno.