Dead engine?

[predator]

Yesterday my engine died, and had to get it towed home.

Has been running rougher and rougher last week. Until yesterday it was just stalling, and would idle really roughly. Soon as you put into D it would stall.

Pulled things apart and run a compression test. Cylinder 3 is way down on compression (80psi vs 130psi of the others - on my gauge, which does read a bit low), and spark plug covered in visible oil. So I suspect the worse

Basically engine will start, run for a bit, get gradually rougher and rougher, then die.

Is it definitely the end of the engine, and anything else I can do to check?

damn rb20 crap crap

*sigh*

[Driver]

eek

i think ure gona need to get a rebuild

[Morgs]

Leak down test will confirm it

Great chance to leanr all about RB motors when you pull it out and strip it down

RB20s are cheap

Keep positive

[R32-GTS]

Even if one cylinder is dying it shoudnt stall. Could be something much simpler than that.

[NickR33]

Leak down test will confirm it

Great chance to leanr all about RB motors when you pull it out and strip it down

RB20s are cheap

Keep positive

good advice :uh-huh:

even if all you get to do is unbolt stuff and clean parts... it can be a positive experience

[BHDave]

The dropped compression on one cylinder is the decider. It should still run (if a bit rough) but it won't be making a miraculous recovery.

I enjoyed pulling my old rb20 apart. It's nice to see what sort of damage you have done to the engine after flogging the crap out of it for 2 years. In my case very little, just rings and bearings really, if i hadn't been planning on an rb25 swap it could have been rebuilt and gone back in.

[predator]

Unfortunately, I never have even had the chance to flog the crap out of it See the plan was to do that for another 6-12 months then put in the RB25 I have sitting here. Now I have no choice on the timing of it all.

It's possible its something else, but I have thoroughly cleaned AAC valve, swapped AFM, changed O2 sensor the other week (and it was ok on that), checked all hoses.. checked plugs, cleaned plugs.. coils have no visible cracks or signs of damage. Not sure what else it could be ?

I guess I could try and rebuild the rb20 once its out.. I'm going to have to buy another crapbox anyhow while I do the conversion maybe then rebuilt rb20 could go into that.. hmm.. some ideas!

[boostn32]

im rebuilding my RB20 i cracked a piston, i love the 20. if u want to come have a look im at ashomre. pm me

[R31 POWER]

Hahahaha i broke mine yesterday.It starts fine but knocks abit in the bottom end and after giving it alittle rev it knocks big time.It sounds like a rex when it runs rough so whats with that?

[BBQ]

Hahahaha i broke mine yesterday.It starts fine but knocks abit in the bottom end and after giving it alittle rev it knocks big time.It sounds like a rex when it runs rough so whats with that?

The motor is ment to run on 6 cylinders... When you loose a cylinder the firing order is out.. .. The other 5 cylinder are probaly doing thier job.. and that one cylinder is just pumping raw fuel out...Causing it to give an off note eg... Like a rex..

[Chris32]

Any of you guys thought it could be a dodgy valve?

[predator]

I am not sure now, I have to investigate mine some more.. it won't start now at all.. whereas before it was running for little bits, albeit rough as guts.

Its getting petrol in there (can smell it on the plugs) - think it was actually petrol on the carbon (looking like oil).. but it doesn't seem to be getting spark..

would a dodgy valve cause bad compression?

[Chris32]

shit yeah, if your exhaust valve wont shut, it all gets squeezed out before going bang!

[makaveli]

Hi Gordo,

Im very sorry to hear about your problem man

I really hope you get everything sorted ok...

In my opinion, you have a rb25 and you want to do the conversion so just drop it in.

If you don't have the relevant funds get a shit box to get you round coz if you were rebuilding the 20 you would need it anyway.

Thats just my opinion on the situation.

Take Care

Mark

[predator]

ok, continuing investigation.. CSI eat your heart out..

It may *possibly* be a wiring problem around the ignitor module.. removed it, put it back in, obviously jiggling wires whilst doing so. Now starting and running the same as it always did each and every time.

Also curious, so ran another compression check on cylinder #3.. its back to 120psi ! vs 130psi of the others, close enough to 10%. I did the first lot of checks twice to confirm and it was 80psi both times.

Now would a stuck valve mentioned by chris32 be the problem here? Giving a low reading when stuck open, and back to normal while working fine??

The world confused mother ****er comes to mind! :confused:

[Chris32]

Could be a dodgy or blocked lifter perhaps?

Maybe worth doing a engine oil flush with one of those concentrate type addatives that break down the old oil, and then dump the old oil and put some fresh oil in it?

[boostn32]

Hahahaha i broke mine yesterday.It starts fine but knocks abit in the bottom end and after giving it alittle rev it knocks big time.It sounds like a rex when it runs rough so whats with that?

R31 Power, i put 10k on its a spun big end bearing. that requires a new bottom end, crank and affected rod/s go buy another engine.

[Roy]

boostn32...change yiur avatar, i keep seeing yous and thinking its an old thread as thats my old avatar:) TP for my bunghole?

Bugger to hear about all the RB20 dramas the past week, hope it is just an electrical gremlin...and engine flush is cheap and easy, may not do anything, but then again?

I hope it is something electrical :wizard:

[Cubes]

I've got a dodgy injector plug that tends to play up every so often.

The wiring loom injetor plug has split, water gets in and causes a bad connection.

Every now and again it gets hard to start and runs on 5cyls until its warm.

Playing with the injector will instantly get it running on 6 again.

Looking at the plug the contacts get corroded as all buggery. Clean it up and its all good again for another 6months.

It also tends to play up more often if I park the car on grass overnight.

[predator]

lol @ roy's sparky.. that is now what I need - I think I'm going to have to get in an autoelec to check all the electricals, as I am starting to think that is more what it is. I have done what I can - at least they'd be able to tell me what *is* working fine. ECU reads error "all fine" (useless thing!)

yeah.. this is more *when* it gets warm it goes dodo.

I think there is still plenty of life in this engine! After all its only a 100,000km engine (well on the odometer anyhow) - would be strange if it was packing up so early. There is no sign of a stack of oil in the intake or anything like that, no knocking noises, no oil in water, water in oil - the obvious things.