Hi Guys, got a few probs that i need help with, i rebuilt my 93 cdb with forged internals, run in and mapped at 1500mls, and it has now run for 3500 miles with no problems, lately it seems to pop under hard accelerating with boost it will pop and bang and hesitate then clear, does not do it when smoothly accelerating, also has some blue smoke from the exhaust not too bad on tickover or when revving engine, if turn off when warm and restart after a few mins, then lot of smoke for a couple of light revs, also see blue smoke under boost, could it be turbo ?. done a compression test today with a cold engine these are the readings i got.
No 1 - 140
No 2 - 125
No 3 - 120
No 4 - 138
i have a catch can fitted with two inlets and a small filter on top, seems to be a lot of oil residue on componants around it, and oil leak which just started cant find from where but dripping from the cross member, coild it be rear crank seal. ?
any advice greatly recieved......

 

I had a petrol smell in the sump when my engine let go, checked by smelling the oil on the dip stick. Petrol passes the rings into the oil so petrolly oil.

I never did a compression test so could comment on the figures you provided. The massive cloud of blue smoke behind me gave away the failing engine lol. Did you have the block honed and skimmed ect properly?

The leak sounds like rear crank seal but would get under there and have a really good for other possible places first, oil drain from the turbo ect

 

engine block was bored and honed and woosner pistons supplied by enginetuner, no problems there.

 

Might just be some over fueling never the less check with alan to be safe

 

Did you stroke it by any chance?

 

The first thing I'd be looking at is the poor running, very rich mixture can cause backfiring in the downpipe. Just in case, change the engine oil to eliminate fuel contamination, then immediately get the management looked at.

 

For a new build should your compression not be up beside 150-155?, I thought any more than 7 PSI between cylinders was a bad sign

Funny enough mine has similar symptoms

 

Compressions are lower than i would expect too see after the engine has been run in.
Could be a result of bore wash due to over fueling but would change the oil as suggested above as a safeguard.
Process of elimination tbh to pin-point any potential problems.

Mick

 

from what iv heard is that the figures must have no more a difference then 10% on each cylinder..

 

i had a leaking injector which i fixed about 1200 miles ago compression test then showed between 148/152 which was fine this problem only occured two months ago, will need to work through it from basic and get it checked out by diagnostic i think, or take it somwhere to get it checked, im in wiltshire anyone know anyone local to run a quick diagnostic on her for me ?