RB30: wot pulls, BANG, comp test = perfect? Lol

[ST240]

Hi guys. It's me again. Lol.

So me and my broski are taking the ol' rb30 for some tuning. We work up to 15 psi conservative as hell, monitoring knock ever so closely. We get to taking out any knock and flattening out the AFRs to around 11.5 ish in our 3rd gear WOT pulls.

So we were doing a pull, feeling like a couple of badasses, and around 5000 RPM there comes this LOUD sound that was a cross between a bang/pop/hiss.... Mother of god. I didn't hear anything fly into the turbo or out the tail pipe.The engine wasn't pulling any vaccum after I let off. There was no power under foot at all so I slowed down to a crawl and the engine died. I tried to start it back up and it didn't start without any throttle. When it did start, I could rev it up once or twice but then it would forcibly die on me. The engine wasn't making any knocking or abnormal sounds. Sounded fine actually, aside from it dying.

The head gasket is right buggered or maybe the ring lands are on the way to the moon, we're thinking. I don't know about that, Scooter, because the compression test came back 150 across the board. I couldn't believe my eyes. The cylinders were SO wet, presumably from me trying to start it so much, and they reeked of fuel.

So we're trying to figure out what the hell is going on. Now Carl (or anyone else that's done an RB30), when you did the Tbelt, did you get the notches EXACTLY lined up? Reason im asking, is i had to get that Tbelt so unbelieveably tight to get the marks to line up upon inital assembly, and after starting it up, the tensioners/belt were making some ungodly whine, and so I had to loosen one of the tensioners on the fly (and silly me, i didn't take note of the alignment marks). Now, when i look at the marks, the two cam marks line up, but the balancer mark is on the 5* mark. I'm wondering if thats a result of me loosening the tensioner, or did the sucker jump a tooth and thats what caused this whole kerfuffle? Although I don't imagine 5* having that kind of impact. I think the belt jumping is a long shot actually. I also had to slot the CAS a bit to get 15* BTDC...

I thought the whinebro255 might have crapped out on me, but it seems to prime fine. That would explain the dying. Maybe I should take a closer look at it? Are the injectors somehow pinned open? Wtf? I seriously have no idea.

One thing is for sure, after the emotional gauntlet this engine has put me through, I can say, with great confidence, that I am fully able to handle any woman out there.

Thoughts? Lol.

[brizanden]

im thinking valves got bent maybe? i just messed around with a ka that had similar issues you described. i know they arent at all the same engine just mechanically speaking.

[noodl35]

Same thing happened to me while on the highway one day. Turns out, an intercooler coupler popped off. Your issues sounds like exactly what I experienced. Check all your couples and for any leaks.

[ST240]

im thinking valves got bent maybe? i just messed around with a ka that had similar issues you described. i know they arent at all the same engine just mechanically speaking.

Certainly that would show with a comp test no?

And thanks I'll check my rats nest of couplers! I didn't even think of that!

[Carl H]

definately sounds like a boost leak to me...the fact that the plugs were wet and it didnt want to fire says its seeing air across the maf but the air isnt getting into the engine.
i used the gates 291t timing belt and it lined up very well, i marked the belt for the cam gears against the old rb20 belt and had the crank at tdc lined up with the mark on the timing sprocket and the oil pump.
the belt slid on no problems using dual tensioners and just required minor adjustment to get correct tension.
there is a bit of belt whine but it appears to be from the longer belt not the tension.

I too comptested my motor and came back with 150 across, dodgy gauge so who knows if thats accurate or not...

I found to get a proper 15* base timing that the cas was advanced abit further than it was on my rb20, dunno why but that seems to be the case.
as long as the timing light is accurate and agrees with a proper consult stream then all should be well.

what is your exact setup on the engine?
sounds like you need a tune baaaaaad.

[ST240]

291t?? Not sure what that is. I used dayco 95291, 152 teeth, 47.88 in. effective length, 1.00 in. top width. Seemed to be the same one the SAU guys were talking about. But like i said, I had that thing SO tight, to get it to line up. I just had to loosen it off, so i know it isnt perfectly aligned anymore.

Yeah to get 15* i had to slot the cas lol.

I'm running RB25DE head, holset hx35 7blade, DW 740ccs, z32 maf + supporting.

I know i need a tune, thats what we were doing! Lol.

[WhatsADSM]

Sure sounds like an intercooler pipe (post MAF) coming off. Simple easy fix.

[Carl H]

yeah, the gates belt i used was readily available here stateside and only cost 20$
the timing marks lined up perfectly and i did not need to stretch the belt...
also you may want to check tdc (if possible) using a degree wheel and a piston stop, i found that when my front lower timing cover was bolted on if i set the crank pulley to 0* on the mark it was actually 8-9* advanced, not good.
for my engine the leading left edge of the mark is 0* spot on so thats how i set timing.

dunno if you'd be interested but i can proly sell you a map that will be almost (if not exactly) spot on for your setup, i have the calibrations for the deatchwerks 740s from when i set up a set on my car for a customer.
pm or better yet email me if you're interested.

[ItzGenX]

Seems like a blown couper or intercooler pipe to me. I remember the first time it happened to me with a MAF setup. It sounded like a tire blowing out followed by one hell of a bog.

[ST240]

It most certainly was a coupling. Thanks guys. I tried to bead roll them all, and first WOT pull, bang, again.

Piece of s***.

Anyways, is it possible a coupler blowing off like that during a 15+ psi WOT pull could damage the bearings in the turbo? My brand new holset is now emitting a "whine" similar to other videos on youtube of guys crapped out turbos, which i just noticed after this incident. That would just be great. Theres less than 400 km on that thing.

[Shocker]

Get some t-bolt clamps on those couplers and crank um down. That plus bead rolled pipes will be solid.

[wakotow]

when you get t-bolts...don't go too overboard on them, you'll make your aluminium piping look like an egg, and it won't seal for beans...and if you don't have extra piping laying around...pretty frustrating...

I've probably done this a dozen+ times between blowing couplers off and blowing them up...my stocker was fine when I pulled it off and my hx35 was fine when I had it off this summer. I can't imagine the turbo knows any diffrence between that and a blow off valve opening.