205 turbo crank pressure problems

[ninjacost]

Hi i have a 205 turbo sprint car and im getting major problems with crankcase pressure , if i give the car full boost it blows the dipstick out and sprays engine with oil ,checked all breathers for blockages and all ok, plugs all ok no signs of oil, turbo seals seem ok no oil in pipes to intercooler or in air filter ,im aware that you can get pressure from worn rings but i have no loss of power at all , just wondering if a stuck wastegate could cause this problem ie excess boost pressure leaking past rings ? any advice gratefully received regards steve

[stevieturbo]

If all the breathers are clear and functional and in no way connected to the intake that would allow boost into the crankcase, you've most likely blown it up

Probably melted a piston

What do the plugs look like ?

[ninjacost]

plugs all fine and no loss of power going to try a compression test to see if that gives any clues thanks for reply

[jimbob82]

i'd say it's blowing past the rings. either because it's boosting too much or your rings are borked,

[ninjacost]

i think you may be right engine not done many miles at all going to do compression test and check wastegate

jimbob82 said:

i'd say it's blowing past the rings. either because it's boosting too much or your rings are borked,

[ian_uk1975]

Any PCV? Just trying to be optimistic.

[D_G]

The boost pressure will mask a loss in compression, I'd be pretty confident an engine rebuild is coming your way.

[Evoluzione]

You do have loss of power, you just don't realise it.
Could also be a cracked piston and ring if not using forged items.

[ninjacost]

just done compression test 170 180 150 and ........... 50 !! head coming off now :-(

[stevieturbo]

Told ya so.

And make sure after any mechanical repairs are done, you tackle the cause so it doesnt happen again.

Far too many people just blindly replace parts, for it just to do the same thing again !

[ninjacost]

just taken head off head gasket perfect bores look ok just a case of a bad ring ?

[jimbob82]

ninjacost said:

just taken head off head gasket perfect bores look ok just a case of a bad ring ?

maybe, get the piston out and inspect it properly, ring land may be cracked which sometimes isn't visible without removal. It may look OK from above but the ring could have even broken and gone into the sump if it went that bad.

[stevieturbo]

ninjacost said:

just taken head off head gasket perfect bores look ok just a case of a bad ring ?

You need to pull the pistons out and inspect properly.

[anonymous-user]

Anyone else betting the 2nd Land is cracked??

[Evoluzione]

Max_Torque said:

Anyone else betting the 2nd Land is cracked??

Is that a 66-1 outsider?

I'm just playing it safe with cracked piston and ring at 5-1....

[ninjacost]

ha ha hope you won on grand national ! to be honest i didnt build this engine it was built in holland, cars a griffe maxi turbo i know its got forged pistons its in a diesel block and its a t28 turbo heads nicely ported but apart from that not sure of spec i know its a stressed unit putting out 290 bhp so i guess somethings got to give at some point any suggestions on rebuild spec appreciated :-)

[jimbob82]

better forged pistons

[ninjacost]

to be honest i think pistons will be ok we shall see when i strip it down :-)

[jimbob82]

ninjacost said:

to be honest i think pistons will be ok we shall see when i strip it down :-)

i doubt it...unless your very lucky...

where are you located?

[Evoluzione]

ninjacost said:

ha ha hope you won on grand national ! to be honest i didnt build this engine it was built in holland, cars a griffe maxi turbo i know its got forged pistons its in a diesel block and its a t28 turbo heads nicely ported but apart from that not sure of spec i know its a stressed unit putting out 290 bhp so i guess somethings got to give at some point any suggestions on rebuild spec appreciated :-)

Lol, no, only a crystal ball would have seen me putting a tenner on Auroras to win and I didn't have one of those.

Please keep us posted, it will be interesting to find out what it is.

Now there's a question for anyone, do forged pistons ever crack? I've seen plenty melted and mashed, but not a cracked one yet.

This was one of mine (cast)from a few years ago:



After pushing it a bit too far, personally I think it suffered from over-revving (missed a gear) as they normally come out like this:





Either way, it did ok to put up with an extra 160bhp over the standard 200 for a fair few trackdays and various thrapings before crying enough - similar issues as yours, blowing oil out the crankcase, but did sound a bit off-beat too. Rings were in pieces, but held in the grooves until I pulled it out.