my rb20 is effed

[j-ran]

so i was driving and all of a sudden i get no power, cant make boost and was running on 4 cylinders.

i pulled out my plugs after doing a coil delete test and found numbers 4 and 5 have the ground strap pounded onto the electrode... 4 was worse than 5

just did a compression test (cold, i know)
1 - 120
2 - 122
3 - 117
4 - 119
5 - 117
6 - 120

so these numbers are low, but i think its because i did it cold (because i cant stand the sound of my car running right now)

I am thinking it may be a bottom end or turbo problem now... i will get to my turbo soon and check it out.

any suggestions? all of the people i talked to so far are fairly stumped

[mcfly]

i agree numbers are low but very consistent which is still good to see.
what sound is it making and is it running on all 6 yet?

[Terrh]

smashed spark plugs is usually a really bad sign. Did you use non-JIS length plugs or something?

[Skym]

But wouldn't sparkplug tips hit piston crowns on all 6 cylinders, not 4 and 5???

Sounds like it might be bottomend bearing problem or conrod bolt problem. Probably a big end conrod bearing failure if it makes a metal to metal wacking sound from bottomend.

[j-ran]

i havent really heard anything for rodnock... and im using NGK BCPR7ES like most other rb20s

[Skym]

Hmmmm.

I saw something similar before with sparkplug tip getting damaged on a BMW engine. It was due to cambelt slipping a tooth and result was piston to valve contact. The valve snapped off and sat on top of piston and got rammed into head + it took out spark plug tip. But when you look at compression on your car it looks ok, so can't be a valve that has snapped off.

[j-ran]

no, plus i had a decent look down the sparkplug hole and no valves sitting there. What about a worn wrist-pin? Would that give me enough play to smack sparkplug at high revs?

[mcfly]

Hopefully it's running by the time i get down there but if it isn't i will more then help out troubleshooting.

after you confirm spark on all cylinders i say checking the turbo wouldn't be that bad an idea. I think you mentioned you had fuel already.
I'm thinking though if you had been testing something and fuel dumped into the cylinders(a substantial amount) it could be possible for it to smack the ground strap up. Just unlikely.

Any smoke coming out in any color?
And just shooting in the dark, but there is no big leaks in the hot/cold piping?

[j-ran]

no leaks as far as i can tell, ive inspected it fairly closely. Fuel and Spark are both good. It will start and idle and drive, but it will not make boost, and feels like shit. I had a bit of blue smoke when i was limping it home, but not a ton. And i have ran it again since i changed the spark plugs that were flattened (although i could not obtain high revs or anything) and checked those plugs again when i did compression test and they are fine.

[Skym]

Hmmmm.

Never heard of wrist pin failure on a RB engine. I would think that the tolerences would be too tight for that to happen.

I remember hybridnut talking about sparkplug failure with RB20DET on his webpage -

"Always use normal copper NGK sparkplugs with turbocharged engines, overpriced iridium/platinum plugs fail and crack at high temps and can cause alot of damage. Cost me 8 valves and one piston to find it out for myself, one valve was completely destroyed/cut off from a blown iridium spark plug."

From here -

http://www.cardomain.com/ride/630659/6

Maybe your engine is running too lean???

Or cambelt timing is wrong and has slipped a tooth or two???

Slipping a tooth or two on cambelt makes engine run rough.

[j-ran]

nice to see you rocking a canadian flag there skym.

ok, well first off I am using NGK copper plugs. I dont think its lean-ness because ive been running that tune for a while and its not so bad. But i will look into cam timing.

[Skym]

Yeap. :D

It would explain the sparkplug damage, rough running, sudden loss of hp.

[j-ran]

so, as far as i can tell, mechanical timing is good, rotated crank by hand as well and feels smooth all the way around 360 degrees.

I guess tomorrow i will start getting at the turbo. If that aint it, I might be looking at a rebuild of my bottom end :(

[mcfly]

I will say right now, there is no way for the spark plugs to be hit by the pistons without the valves taking it very very hard.

[j-ran]

isn't that the area of cam timing when the valves are pretty well closed though?

[mcfly]

Yeah, but the shape of the piston doesn't actually allow it to make it to the spark plug without smashing itself into valves too.

and if the plugs are still good since you changed them then chances are it was fuel or some other incompressible :p

[j-ran]

ya, the compression test really steered me away from valve problems, im really leaning towards the turbo now. Hopefully i will take it off tonight.

[mcfly]

I'll be in town on Thursday looking at some places
so i move as soon as find one.
then we can trouble shoot in person

[j-ran]

well, i stuck a fiber optic camera down in there and had a look, and what i saw made me want to cry... I will be looking for a new motor i think.

[j-ran]

so whats the best way to pull this motor? with or without tranny attatched?

[mcfly]

pulling the transmission with the engine will save a little time

[j-ran]

There is a good chance I will buy Charlie's car and rob the motor, if its worth it. Good news is, we would have a 4 door parts car in kamloops, and one less gts-t being a driveway ornament.