OK, I'm leaning towards intake gasket leaking. You don't have chrome rings and had proper hone on rebuild?
Here's the side view. Car sure runs good when its warmed up for using a quart every 200. Seems strange to me. I'll try to do the leakdown test this coming week if I have time.
That plug looks like it’s one heat range too hot. A bit hard to say due to all the glazing, but the all important electrode color change over point seems to right at the base by where the threads start. It should be halfway back up towards the tip, like by the 90 degree bend. your motor may be pinging its to death and unseating the rings in the process.
Yes. That's possible it was too advanced with the wrong timing indicator on it before. I do have cooler plugs (NGK UR5) on the shelf.
Yes metal valley pan and no chrome rings. My son-in-law saw smoke on deceleration but no smoke at hot idle or acceleration. I'll try to do leakdown test this week if I have time and also report on the quality of this tester from Amazon.
make sure you are pushing 100 lbs thru the hose to the leak tester, it will give you a better reading. You can do it with 90 lbs of lead air you just have to do the reading on a lower scale. if you put in 100 lbs and you read above 90 on the other one then the engine is ok in that cylinder, it is not going to run like crap there just leak somewhere. If you engine is leaking as much oil as said you should find it with the tester. Make sure each cylinder is at TDC when making each test. I mark the distributor with white paint to make it easier to get to the rest after you get number one up. I just did mine and my lowest one was at 92 lbs and the best one was at 96 lbs with running 100 lbs to the first gauge. not bad for a 25 yr old engine.
I may have a different type of tester. I first zero out with the regular. Results are in percentage. Did 3 so far. 1st 2 were at 5% 3rd at 16%. Air escaping through valve cover and dipstick. Thinking rings. Have to double check it was tdc.
Although it should not be on a freshly bored and ringed motor, I could live with 5% if I had to, but at 16%…… I hate to be the one to tell ya but it’s pull the motor time my friend! If nothing else on whatever bank of the motor you get leakage readings like that, then you need to pull that head and look for scratches in the cylinder walls from broken rings. your wrong timing at the start busted a ring and if there cast pistons you may have also cracked a piston.
Does the left gauge go up to what the air tank says or regulated to 100 lbs? That is how mine works the only thing different the right gauge is the same as your left and I use a chart to read the percentage of leakage. You have to be at least in the green range on your right gauge that shows the percentages. If it is over there in the green and is at or almost 20 % I think that is way high leakage in my mind. If it is reading like I think it should the right gauge should be close to the word Set in the yellow, what does the word SET mean on your gauge in the instructions. It may just mean rings seated in that cyl. that don't make sense either what if the valves leak? I hate gauges like that it says up to 40% leakage is OK? really ?? If cyl # 3 is leaking at 16 % I think it is done and those rings did not seat properly or it has broken. That cyl should read a little lower in the compression test. Stevem probably has it right on that startup procedure with high timing. If other side ok then I would pull head also. Jack up the motor take the pan off, If the hole is ok then shove the piston out put in a new ring set and shove it back in the hole. Done. smoken tires again.
get it over with and pull motor out. put it on a stand a do it right. why torture yourself leaning over fender pulling intake/heads,ect. then laying on your back geting up and down a million times. you will thank yourself in the end for doing it the right way!
I will finish the leakdown test on other cylinders. Strange thing is the 3rd cylinder i tested with leakage had a high compression test result. I will report back when finished. Thanks everyone.
Another reason why I think it's wise to tare the motor down at this point is this. I have seen conditions as yours take place due to the oil ring groove in a few new Pistons out of a complete set have too few, or no oil drain back holes drilled or machined in them at all. Many times new cast Pistons have a lot of casting flash left in oil ring drain back slots making for only partial draining of the groove. This is very easy flaw to miss unless you are use to being very meticulous with inspecting everything top to bottom ! And for others on the board here who have a issue somewhat similar to this, or will reuse Pistons that have sat around a while, note thatv I have seen these oil ring drain back oils clogged off from carbon build up and oil drying out as they sat!
I just have trouble wrapping my mind around the idea I broke aring when I was so gentle on it the first 500 mi even though advanced too much. It used over 2 quarts first 500 mi also.
Maybe a ring is upside down. 2 qts is a lot of oil in 500 miles. All it takes is a distraction/ phone call when you're in the middle of important stuff....
Smoke on deceleration can be from valve seal or guide problems. Does it let out a puff of smoke when first started cold?
Machine shop installed rings and pistons w bearings. No smoke when cold starting.....I've been busy with harvest so I haven't been able to finish leakdown test yet.
