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[90drifter]

I have a 90 240. I just rebuilt the ka used new rings, bearings all gaskets. I had the head milled and the block decked. I even replaced the head bolts. I also had a port and polish done on the head and a valve job.

My question is this, I went thru the break in period and have put 1,000 miles on my car since rebuilding it and it is still burning oil is there any thing any one can think to check? Oh, yeah and just today it started to bog down when I would give gas? Any ideas?

Thanks in advance for the advice.

[JJ240]

did the machinist hone correctly for the type of piston rings you used? If you babied it alot in that 1k mile break in maybe the rings havent seated yet. Drive it harder for the next 1k and see if its still burning oil.

[U12 2NR]

I doubt you want to drive it harder. The break in period is crutial to allowing the piston rings to form a proper seal against the cylinder walls. During this time the rings are submitted to immense heat. Driving it harder will only cause the rings to heat up even more.

Even though it's a freshly rebuilt engine, you never know the oil it's burning currently may not even be because of improperly sealing rings. You should perform a leak down test and see if the cause is something other than the rings.

[RedShred]

Mine is still burning some oil... actually about a qt every 8-900 miles... and I have 3000 miles or so on this. I had CrMo rings installed. My machinist instructed me to just drive like I will be driven... HARD.

[JJ240]

i hear that often too, break it in like you plan to drive it.

[Aries]

yes.we advise anyone leaving our shop to drive it like they stole it.It's the only true test to weather or not the work was done correctly.

[90drifter]

i now have 1500 miles on the motor. still no end to the smoke car is now going through three quarts in 200 miles. Only the first three plugs are oil fouled the fourth looks like normal wear. Is this indication of a problem? How exactly do you perform a leakdown test? I see this term a lot and was just curious. Other than the smoke the car is running great.

[U12 2NR]

leakdown test is very similar to a compression test except that you'll be using compressed air. Get a spark plug fitting, compressor, bring the piston to TDC fill it with compressed air. If there's a leak through the exhaust valves, you'll hear the compressed air comming out the muffler. If there's a leak with an intake valve you'll hear it through the throttle body. If it's the piston rings, you'll feel it in the oil cap, crank case pressure. Remove valve cover and you'll see if it's a valve seal (rub oil around the seals and see if the bubble with air comming out). Bad head gasket bubbles in the coolant. I"m sure you can pay a shop to do it for you, shouldn't cost much.

[90drifter]

where might I find this fitting? would autozone or o'rielly's have it?

[Aries]

yep. they both carry them

[90drifter]

Thanks for the help. I'll let ya'll know the results

[re89240sx]

I had kinda the same problem, but mine wasnt burning oil to bad, it was pumping it into the coolant. Ive been driving it like this for about a year and put 20k on it( flushing the cooling system once a month). Car still ran alright for the condition it was in, but the coolant would be such a thick brown goo. But last week i finially got sick of flushing and replacing hoses, and started the swap. I got a 95 KA with the ecu, uncut harness, and tach. Just having some trouble with the wiring, its getting a lil confusing.

[Altiman94]

My engine is currently in its rebuilding stages. I was going to go with a ka24de swap, but I could get ahold of daunttless to get all my hands on the parts. Oh well

[Asleep Altima]

ive got a question... did you run synthetic oil? and if you did, did you do it from the get-go?

[re89240sx]

I was using 10w-30 and 10w-40

[Asleep Altima]

ok then... that rules out what i was thinking... do you know what kind of rings they were? different types of rings take different amounts of time to seat... just do the leakdown and see what happens.

[re89240sx]

Im done with that engine, I'm almost finished with my swap to the 95 dohc, I ran into a problem today when i was putting the engine in. The damn motor mount brakets are different, i guess people are to lazy to post stuff like this on these boards and i should of checked before i tryed to put it in. When i get finished with the swap i will post up a walk-through, as best as i can.

[aaronsnocker1]

I rebuilt a motor in a college class a few years back and the instructor , who has been racing since the late 50's said it is crucial that you seat your rings. You do this by taking the car out and driving in the top gear and accelerating from 35 to 55 mph. This causes the rings to seat properly against the cylinder wall. If your rings dont get seated eventually they will start to leak and there isn't a whole lot you can do but replace. Thats all I know. sorry

[Asleep Altima]

it depends on what rings you go with. chrome seats instantly, moly rings take about 500 miles and i cant remember the others right off the top of my head. different builders will also tell you different things. when i had my 350 rebuilt, the builder told me to wait 500 miles and nothing over 55. then at 3000 i could go synthetic if i wanted.