fresh motor burning oil?

[josh90]

so i bought the car a year ago put about 5k miles on the bottom end the head gasket failed blew a hole in the side of the head in the process found another head took it to a shop and they did a full rebuild on the head  got the car running and its smoking and smells like oil so i figured it was the cheap ebay turbo but  there is oil in the exhaust manifold

if its the oil seal on the piston is there any way to change them without pulling the motor back out? or is it possible im over looking something else maybe something simple?

[DjayS12]

If you can remove the oil pan without removing the engine (you at least going to have to loosen the engine mount), and remove the head, you should be able to remove the rods/piston assembly without removing the engine.

That's what I've read on 240sx forums, I've never changed a piston on an engine inside a engine bay.

[Jeremy]

well i would ask if they truly did a full rebuild as most shops don't change out the valve guides and that is why motor was smoking before my full rebuild.  i would ask about those and do a compression test and post the info back up here so we know what you have and haven't tried or looked at.  hope we can help you get it figured and yes you can pull pistons without pulling the motor out though it makes it much easier if you do.

[josh90]

the guy that did my head replaced them because i forgot to give them to him had 2 make a second trip to the shop to give them 2 him the guy is a hell of a mechanic i dont think its the valve stem seals unless they are just bad

and as for the compression when we tested it about a month ago (if we did it right) cylinders 2,3,4  read 105 psi and # read 110 psi

should i try a leak down test?

[IggyEGuana]

bad break in procedure or incorrect ring gap spacing. assuming the rest of the bottom end rebuild was done/done correctly

[Jeremy]

actually i said valve guide not valve stem seal as guides do go bad mine had over 200k miles on them so yeah they do wear.  those seam like low numbers for a compression test i would read about it and make sure your doing it right then if you think you could have made a mistake then do it again and iggy makes a fair point about improper break in if the bottom end was worked on yet you said it wasnt so unsure n that one.  let us know

[turbo-s12]

105 sounds low to me typically under 150 is bad but im not familiar  with all engines lol

[josh90]

blew another head gasket the other day so i pulled the head and found the colprit the oil ring was folded over ang scoring the cylender wall it cant be honed its 2 deep has to be bored but i cant find any over sized pistons is there anything else i can use

[Jeremy]

yes you can use the ca18det pistons as that is what i have i personally went 1.5 mm over stock because i had a score in the number 4 cylinder wall.  i got mine from supertech. yet im sure depending on how deep the gouge is you can get them from other sources i also changed my rods at the same time as from what i understood the wrist pin is a different size though i didnt measure it as  i wanted to go for a stout rebuild.
Post Merge
sorry and 105 does sound low and i would have them check the block and head mating surfaces as blowing head gaskets shouldnt happen that often.

[josh90]

well im using my other block the one in my car is trashed its scored so bad and as far as me blowing another head gasket i pinchd it by accedent when i put it together it was my own doing oh well live and learn i guess

[Jeremy]

well at least you know the reason behind the headgasket failure.

[josh90]

how do you get the det pistons to work with the larger pin?

[Jeremy]

you also get det rods or have a machine shop oversize the wrist pin in the old rod to the new wrist pin size though you should have them look at it to make sure it has enough material to do that

[josh90]

i thought the det had a longer stroke?

[Jeremy]

both are 1809cc with same bore and stroke blocks are slightly different though from what i understand the UK guys have put an 18et head onto a 18det block though i personally have no knowledge of how to accomplish that feat.

[josh90]

oh for sure sorry for all the questions and thanks for the help

[Jeremy]

no worries bro good luck and keep us up to date on what fixes it

[josh90]

for sure now i just need to talk to the machine shop and get the ball rolling