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Help Please! No 1 Cylinder Low Compression And Turbo Failure

fubar

By fubar,
in Motorsport Discussion & Builds

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fubar Enthusiast

fubar

Posted
Posted

Hey All,

I have a r32 with an rb25neo (Come from Japan with this motor in it so not sure what the internals are but there has been some work, like gtr cams)

I was at a drift meet last weekend and i noticed the engine had a little flutter after a few laps. Pulled in and check the spark plugs and found number 1 plug had melted!!! Spark plugs were running a bit lean so upped the fuel mixture and put a new plug in and went back out. Got third place, yeeew so went out to destroy the rest of my tyres and then i lost power, boost (normally 15psi but only achieving 7-8psi, looks like a standard turbo nissan 45v2) and a little blue smoke out of the exhaust when you rev it. Motor seems ok and idles goods

Just carried out a compression test at running temp

1 - 92psi 125psi wet

2 - 125psi

3 - 109psi

4 - 121psi

5 - 121psi

6 - 129psi

No 1 cylinder was oily then the rest when i took all the plugs out so looks like the ring my be gone on no 1??

Turbo is buggered, does not spin smoothly at all and play in the shaft in and out and a little sideways.

Would just like to know my options,

New turbo and see what happens or should I go all out and rebuild the motor or just new rings on no 1???

Any info would be appreciated:)

post-52148-1271167904_thumb.jpg

BezerkR32 Veteran

BezerkR32

Posted
Posted

it will depend on if there is any cylinder damage, but id pull the lot, give it a light hone and then re-ring all 6. most probably will be replacing #1 piston. replace big end bearings while at it. thats cheap but good option.

Hey All,

I have a r32 with an rb25neo (Come from Japan with this motor in it so not sure what the internals are but there has been some work, like gtr cams)

I was at a drift meet last weekend and i noticed the engine had a little flutter after a few laps. Pulled in and check the spark plugs and found number 1 plug had melted!!! Spark plugs were running a bit lean so upped the fuel mixture and put a new plug in and went back out. Got third place, yeeew so went out to destroy the rest of my tyres and then i lost power, boost (normally 15psi but only achieving 7-8psi, looks like a standard turbo nissan 45v2) and a little blue smoke out of the exhaust when you rev it. Motor seems ok and idles goods

Just carried out a compression test at running temp

1 - 92psi 125psi wet

2 - 125psi

3 - 109psi

4 - 121psi

5 - 121psi

6 - 129psi

No 1 cylinder was oily then the rest when i took all the plugs out so looks like the ring my be gone on no 1??

Turbo is buggered, does not spin smoothly at all and play in the shaft in and out and a little sideways.

Would just like to know my options,

New turbo and see what happens or should I go all out and rebuild the motor or just new rings on no 1???

Any info would be appreciated:)

fubar Enthusiast

fubar

Posted
  • Author
Posted
it will depend on if there is any cylinder damage, but id pull the lot, give it a light hone and then re-ring all 6. most probably will be replacing #1 piston. replace big end bearings while at it. thats cheap but good option.

Thanks, ok looks like i have some work to do:)

Any reason why a new spark plug would melt like that? maybe the bit that is missing is mashed all around the piston!

Can you recommend any one in perth to look at my motor internals, get parts off and tune it? Apperently all the ppl that were full bore on the rb motors have gone over east:)

Cheers

BezerkR32 Veteran

BezerkR32

Posted
Posted

thats a high speed lean out. its not a bad one as you can still recognise that its a spark plug lol, but enough to melt the side of a piston which i dare say you have done. you dont have any fuel surge issues when cornering with that car?

otherwise id say it was just a little lean in the tune,

Thanks, ok looks like i have some work to do:)

Any reason why a new spark plug would melt like that? maybe the bit that is missing is mashed all around the piston!

Can you recommend any one in perth to look at my motor internals, get parts off and tune it? Apperently all the ppl that were full bore on the rb motors have gone over east:)

Cheers

fubar Enthusiast

fubar

Posted
  • Author
Posted

yeah she was running a little lean when i checked the plugs, it got tuned about a year ago and it was running really rich. we backed it off a bit but still had it running rich. i've never had fuel surge issues on the track for the last 2 years even if im on empty, it has a gtr tank which prob helps. I was hopeing no body would ask what management i have, its an old school apexi safc 1 with the dials lol come from japan like that:) and i had a look in the spark plug holes and its got flat top pistons, maybe the internals are not stock.

I pulled the turbo out and the exhaust wheel has completely snapped the shaft right at the bearing lol check out the pic. i would have fired an exhaust wheel at the guy behind me cause i've got no mufflers or cat

Im pulling the motor out tonight and will strip it down eventually and check out if there is any damage

post-52148-1271407376_thumb.jpg

BezerkR32 Veteran

BezerkR32

Posted
Posted

thats a pretty standard ceramic turbo failure.........i guess the new one will be a steel wheeled turbo. excessive exhaust temperature due to lean burn will cause this. Definately have some tune issues.

yeah she was running a little lean when i checked the plugs, it got tuned about a year ago and it was running really rich. we backed it off a bit but still had it running rich. i've never had fuel surge issues on the track for the last 2 years even if im on empty, it has a gtr tank which prob helps. I was hopeing no body would ask what management i have, its an old school apexi safc 1 with the dials lol come from japan like that:) and i had a look in the spark plug holes and its got flat top pistons, maybe the internals are not stock.

I pulled the turbo out and the exhaust wheel has completely snapped the shaft right at the bearing lol check out the pic. i would have fired an exhaust wheel at the guy behind me cause i've got no mufflers or cat

Im pulling the motor out tonight and will strip it down eventually and check out if there is any damage

fubar Enthusiast

fubar

Posted
  • Author
Posted

Finally I pulled the motor apart and yeah no 1 piston got a bit hot! its all there but on the inlet side is rough on the edges and top compression ring stuck! Slight scoring on no 3 bore but still haven’t pulled it out yet. No 1 bore is badly scored and in one little 3mm wide section I can feel a slight divot. So looks like a hone wont work on no 1. the other bores have been honed out already so it hasn't even worn in. bore size is about 85.6mm

Any ideas with how far I go with the rebuild? Should I get a full service on the head ($1000) or just a machine ($75), full set of forged pistons or standard, how much boost can the standard take? type of head gasket, prob wont run more than 18psi IF I get a new turbo, etc

I don’t really want any more power, just reliable and I don’t have a lot to spend maybe $3000 max but would like to keep it around the 2 grand mark if possible.

Cheers

BezerkR32 Veteran

BezerkR32

Posted
Posted

i agree, cheaperest option.

maybe do that to get it running and slowly build the existing engine up on the side.

your better off putting in another low km neo motor in there if you just want reliability and less down time
fubar Enthusiast

fubar

Posted
  • Author
Posted
i agree, cheaperest option.

maybe do that to get it running and slowly build the existing engine up on the side.

yeah guess thats what im trying to way up. Im in no rush i have another car and at least if you rebuild it you know its all new. you could by another second hand one and have issues plus its hard to find a neo motor in perth that has low km's and fairly cheap.

BezerkR32 Veteran

BezerkR32

Posted
Posted

yeh they are standard.

Got a pic of the piston and crank i pulled out of the car. Is this standard? the new forged piston i was going to buy dont have the valve prints in them.

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