Fresh Twin Cam 30 Gone Pop During Run In :(

[DVS JEZ]

Alot of things could have happened.

Spend the time to investigate the problem and the cause

[abr33]

Any news on this??

[bubbabooga]

I'll be going to see the tuner and engine builder tomorow morning and il relay info back to hear ASAP!

Cheers

[The Dan]

Due to the absolute precision manufacture of rings these days, most of them are almost bed in before you even start the engine. Bearings will knock off the high spots but apart from that your run in can be done in as little as 10 minutes just to put the engine under load and cut the rings in. The varying revs is usually a good idea too but not always necessary. Every engine is different and every ring is different.

If the tuner is competent, he should hear detonation before it becomes a problem and should see things much sooner.

[NoFigJamHere]

Okay first up I previously had a built 25/30 running 356kw using the same head and custom intake manifold.

Only changes this build were to the oiling system, 0.5 higher comp ratio, total seal rings, cam change from 232 duration 6.5mm lift cams to 262/9.1mm with appropriate springs and port tidy up and match the intake manifold ports.

Now I had discussed with the tuner I only wanted it ran off spring pressure in the wastegate so I can learn to drive it at that power level First, made it very clear I wanted a super safe tune and wasn't to concerened with the power level.

So he apparently he had it up and running, bedded the rings In on the dyno for around 10kays, changed out the mineral oil to redline oil ready to get into tunning.

Then he tells me he's ran it up for a power run without touching anything with the tune or boost, where it pulled only 320wkw on 21psi. Down considerably on the old setup and boosted well past where I wanted.

Now apparently Afr's were safe the whole time.

After fixing a small coolant leak the car wasn't idling right and had smoke pluming out of the catch can. Comp test revealed front 2 cylinders down around 50psi and the rest were at about 110psi (which I feel is extremely low for a brand new engine).

Now the engine builder and tuner are unsure of why this has happened but only suspects are the custom intake manifold which kinda points the throttle body towards cylinders 1-2.

I would post a pic of intake manifold but I'm posting from iPhone away at work.

But it's the intake manifold off dahtone racings old 2GUUp candy red r32 skyline.

Now I'm curious if anyone has had similar issues due to a plenum? And who should kind of be at fault here?

I'm far from happy so far!

Specs of the build as follows: rb25/30

Custom je pistons with total seal rings and spool rods, usual block and crank prep, nitto oil pump, lewis engines race sump, r32 rb25de non vct head, ported, springs, cam tech 264/9mm cams, custom intake manifold, sard 700cc injectors, twin entry rail, walbro lift pump, 044 feed pump, haltech e11v2 ecu with boost control. Twin scroll t04z, 0.8 rear housing, turbo smart 50mm gate.

Sorry about big post! Cheers all

The second line in your post explains it pretty obviously IMO.... 0.5 : 1 up in comp ratio, bigger/different cams and he does a FULL power run without even atleast putting 15-20% fuel trim into tune is asking for trouble!!! Surely they checked ignition timing before even starting the run-in....(but i bet they didnt) Also what was the comp in previous set-up? Engine builder must know...If i was you id do as Elite says about not being to raggy...But if they start trying to baffle you with BS i would be going for them to repair at they're expense..

[Dahtone Racing]

The second line in your post explains it pretty obviously IMO.... 0.5 : 1 up in comp ratio, bigger/different cams and he does a FULL power run without even atleast putting 15-20% fuel trim into tune is asking for trouble!!! Surely they checked ignition timing before even starting the run-in....(but i bet they didnt) Also what was the comp in previous set-up? Engine builder must know...If i was you id do as Elite says about not being to raggy...But if they start trying to baffle you with BS i would be going for them to repair at they're expense..

This was my explanation for the failure as well.

[femno]

Yeah was also just about the mention the same thing.

Especially with more comp how could you not wind things back a little before trying to squeeze numbers out of it??? If thats what really did happen then its careless on the tuners behalf. Would have most likely knocked its face off! Didnt you say they found signs of detonation?

Sucks dude I know your feeling.

[bubbabooga]

Called up the tuner today but their still waiting on flow benching of the intake manifold which is with the engine builder, who unfortunately had his workshop broken into over the weekend with a shitload of tools and parts stolen.

That's what I would have thought the tuner would have done straight up to. Not too happy with his approach to it especially after I clearly specified I wanted to run no more than 16-17psi.

Previous cr was 8.2, this time around its up at 8.8 to 1.

I asked the tuner about wether a knock monitoring device was used on the run, he said yes of course and no worrying amount of knock was seen.

The waiting game continues..

Unrelated but I bought myself a turbo gsxr1000 to keep me occupied till this damn rb is sorted

Cheers guys! Appreciate the wise words.

[JustinP]

Unrelated but I bought myself a turbo gsxr1000 to keep me occupied till this damn rb is sorted

You are a mad man

[DVS JEZ]

I love those words "no worrying amounts of knock". No knock is good knock

[NoFigJamHere]

I love those words "no worrying amounts of knock". No knock is good knock

Even better is that he was actually looking for it!!! He couldn't "see" it????....... So how could it have been knocking... Must have had the head phones over his eyes!!! I dont want this comment to encourage you into confronting your tuner/builder guys but whats the point of flow bench testing the intake??? From what you have said ALL the cylinders have some degree of damage!!! As with just about any engine, 1 cylinder (rarely 2 go if your paying attention to what your doing) goes bad before the others... Your engine has low comp in ALL cylinders just because 2 are worse than the others just means those 2 were always going to be the ones to keep monitering when tuning... Just about every engine bar an F1 engine would have the excact same type of problem. Being a particular clyinder is most likely to be the 1 to fail...

[Dahtone Racing]

There were no worrying levels of knock yet 1 and 2 had detonation damage??????

[DVS JEZ]

There were no worrying levels of knock yet 1 and 2 had detonation damage??????

Scary to think what they classify as worrying knock.

[femno]

The knock of a piston and rod hanging out the side of the block.

[James_03]

Flow testing the intake is just the builder/tuner postponing the inevitable, which they both know is finding the real cause of the failure and deciding who's going to pick up the tab. It's not going to tell you anything, and it won't be the plennum at fault.

I would be asking to view the det damage personally through the scope, it's pretty easy to see as the crown of the piston will show signs straight away. If there's no det damage then the ring clearances were probably wrong, and you need to do a leak down on all cylinders. If it's a fairly well known tuner, then I doubt there to blame.

You need to get personally involved in finding the cause, otherwise your just going to get fed BS like flowing this intake.

[rob82]

Flow testing the intake is just the builder/tuner postponing the inevitable, which they both know is finding the real cause of the failure and deciding who's going to pick up the tab. It's not going to tell you anything, and it won't be the plennum at fault.

I would be asking to view the det damage personally through the scope, it's pretty easy to see as the crown of the piston will show signs straight away. If there's no det damage then the ring clearances were probably wrong, and you need to do a leak down on all cylinders. If it's a fairly well known tuner, then I doubt there to blame.

You need to get personally involved in finding the cause, otherwise your just going to get fed BS like flowing this intake.

That's a pretty bold statement. Have you seen the intake manifold to make that conclusion. Generally unless you've overheated the crown you won't notice detonation via a borescope. If you dont know what your looking for then get an independent failure report.

[The Dan]

I would be asking to view the det damage personally through the scope, it's pretty easy to see as the crown of the piston will show signs straight away. If there's no det damage then the ring clearances were probably wrong.

How so?

[James_03]

That's a pretty bold statement. Have you seen the intake manifold to make that conclusion. Generally unless you've overheated the crown you won't notice detonation via a borescope. If you dont know what your looking for then get an independent failure report.

Cmon dude, flowing the intake? It's a motor that now has low comp due to an internal failure. It's pointless, and even if it was the manifold, how would you link it to a failure like low comp? Doesn't make sense.

You should be able to see signs of det with a bore scope. Even if the crown has nothing, it has low comp which means rings, which means the bore will have drag marks all over it where the rings lands have failed.

When I said clearances I said probably, which means it may or may not be that. Just about every second failure I have seen has been either:

1. Incorrect ring clearances

2. Incorrect bearing clearances

I would put money on it being either of the above, pending it's a well known tuner, who of course ran it up himself.

[rob82]

Cmon dude, flowing the intake? It's a motor that now has low comp due to an internal failure. It's pointless, and even if it was the manifold, how would you link it to a failure like low comp? Doesn't make sense.

You should be able to see signs of det with a bore scope. Even if the crown has nothing, it has low comp which means rings, which means the bore will have drag marks all over it where the rings lands have failed.

When I said clearances I said probably, which means it may or may not be that. Just about every second failure I have seen has been either:

1. Incorrect ring clearances

2. Incorrect bearing clearances

I would put money on it being either of the above, pending it's a well known tuner, who of course ran it up himself.

If the manifold favors cylinders 1 and 2 then it is likely that these are the lean cylinders - which most likely means you've overheated(melted) a couple of pistons. Hence the comp will be low.

[Dahtone Racing]

Has anybody noticed that he said the engine used to run fine with the old setup which had the same plenum?

Which IMO would mean the plenum is not the problem because obviously it was fine on the old engine nor was it a problem with my old engine.

So how could it all of a sudden be the cause of the failure?

You need to look at the things that have changed since the last build.