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Massive Air Leak

Hanaldo

By Hanaldo,
in Engines & Forced Induction

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75coupe Grand Master

75coupe

Posted
Posted

this doesnt sound good at all...

Ive got an idea why the motor is loosing compression on the power run...

^^^ how do/did you get a hole in the collector?

one would definitely know when they did that...

GTScotT Grand Master

GTScotT

Posted
Posted

If the manifold was shattered and then turned on and revved to redline, debris could be right through the thing and could definitely cause the issues your having right now.

Sounds like a motor out and head off affair. Its not going to be an externally diagnosed issue IMHO.

Hanaldo Grand Master

Hanaldo

Posted
  • Author
Posted (edited)

aaaaah feck NG.

But seriously how does one hole a cast manifold? was it the mech?

I believe it was, but with no evidence at all I won't be saying anything. But I will not be taking my car back to this workshop if I manage to fix it. The luck I've had with workshops in Perth is unbelievable.

The only evidence I have is that when one of their guys called me up, he asked if I knew where there might be a vacuum leak. So I mentioned that I hadn't managed to get a nut onto the very front bolt on the plenum. He said he saw it, and even commented on how we had f**ked the bolt (we had to do it up with vice grips as it sat hard against the collector - will make more sense when I post pictures). So the bolt was definitely there then. But when they showed me the manifold, that whole part of the manifold was shattered off, he wouldn't have seen the bolt if the manifold had been like that.

this doesnt sound good at all...

Ive got an idea why the motor is loosing compression on the power run...

^^^ how do/did you get a hole in the collector?

one would definitely know when they did that...

Absolutely no idea. I'm 110% sure it did not happen while I was installing the plenum. The manifold stayed on the engine, so it was never dropped, and I certainly didn't hit it with anything. The only thing I can think of is that it was cracked, and later gave way. But I highly doubt this as well. I was in and around that part of the manifold doing stuff up, I would have seen a problem. I was also extremely gentle with anything to do with the manifold as I didn't want to scratch the face, because ironically, I didn't want to risk causing a leak...

Edited by Hanaldo
Hanaldo Grand Master

Hanaldo

Posted
  • Author
Posted

dude there is a few neo engines for sale 1100-1500 in drift sales on facebook. Best safest bet.

I'll check it out mate, cheers.

Is there any way a stud or anything could have pulled into where the broken collector is? As in when tightening other bolts its been pushing on the collector

Might be easier with pictures. The part that broke is the very front bolt in this picture:

IMG_0194.jpg

It is shattered about 1.5-2" down from the top of the inlet to roughly the top of the flat mounting plate on the side of collectors there. So that bolt is completely gone. That bolt is the only thing I can imagine may have been pulling on the manifold, but no more so than any other part of the manifold? I don't know. I can't see anyway for it to have broken other than taking a very heavy hit.

GTScotT Grand Master

GTScotT

Posted
Posted

probably huddled in a corner realising they poorly tooled that bolt and cost you a motor. I can picture a moron with a half inch ratchet and a short socket trying to hurriedly do up that bolt with the big ratchet reefing against the runner.

shit shit you guys... fire mizzilez..

Hanaldo Grand Master

Hanaldo

Posted
  • Author
Posted

So just got the car home. It has never idled or driven so nicely in the entire time I've had it. It is like a totally different car. So how can it be so broken :(

This is the manifold:

598507_10150819674997541_519882540_9859496_1717106252_n.jpg

550475_10150819675227541_519882540_9859499_407130937_n.jpg

And looky looky what I found in my boot...

579800_10150819675447541_519882540_9859502_384835976_n.jpg

545796_10150819675697541_761525000_n.jpg

So it definitely broke off while it was at the workshop.

Also spoke to my tuner while I was there. He said it only loses compression when the cylinder temps are really getting hot. Like he could do a couple of power runs and it would be fine, it would go 100%. Then it would start misfiring and he would compression test it and it has 0psi on one cylinder. He didn't specify which cylinder it was, but it doesn't take a fkn rocket scientist to work that out. Then he would let it cool down for a bit, fire it back up and it's all good. Another couple of power runs later, compression gone again.

GTSBoy Grand Master

GTSBoy

Posted
Posted

I would be very surprised if any solid material went into the engine from that break. That piece of flange would have fractured off and dropped onto the floor during a bit of hefty monkey work by the monkey with the spanners. Monkey later says "what's this?" when they get the car off that bit of floor and just chucks it in the boot. Meanwhile, most likely there are no serious fragments of alloy inside the engine.

But if that engine was run with that leak under any load, that cylinder would have been hella lean, and you may have burnt an exhaust valve or seat, or even damaged the piston.

Either way though.......it's not good.

Simon-S14 Grand Master

Simon-S14

Posted
Posted

man that casting is rough on that manifold... but never the less some heavy handed spanner work obviously caused it.

i find it strange that its fine when warm but once hot it reads 0 psi compression... usually takes a hole or a valve stuck open to actually get NO compression.

Hanaldo Grand Master

Hanaldo

Posted
  • Author
Posted

I would be very surprised if any solid material went into the engine from that break. That piece of flange would have fractured off and dropped onto the floor during a bit of hefty monkey work by the monkey with the spanners. Monkey later says "what's this?" when they get the car off that bit of floor and just chucks it in the boot. Meanwhile, most likely there are no serious fragments of alloy inside the engine.

But if that engine was run with that leak under any load, that cylinder would have been hella lean, and you may have burnt an exhaust valve or seat, or even damaged the piston.

Either way though.......it's not good.

Well what gets me is why they would have been tinkering with the manifold. I installed the plenum and everything, all it needed was a tune. But then this issue comes up that the car was revving itself to redline. So if there wasn't this hole in the manifold, why was it revving to redline? But if it was the cause, how did it break? Why would they have the manifold off? This confuses me...

It was also never run with any load while it had that problem. It never moved because it would just rev to limiter as soon as they started it.

I would be tearing them a new one if they broke that and then had the nerve to charge you $1600 as well... Im guessing by the fact that you have the car back that you coughed up the cash?

Yeh I paid. I don't think I had any choice. What I think happened and what I can prove happened are two very different things. I wouldn't have had a foot to stand on if I refused to pay.

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