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I have to replace intake gaskets on a rb26 tonight due to a constant miss at idle, un noticable at higher rpm.

I diagnosed it as cylinder 2 plenum gasket leaking. U should see the thing plume smoke out of the gasket when i have the smoke tester on it.

That smoke tester must come in so handy despite its pricetag and save you so many headaches trying to disgnose issues.

YESSS!!!! :rofl2:

Have found the problem, i sprayed the WD40 around the top of the intake manifold where it bolts down and that gasket in there looks wasted, theres about an inch wide section that looks like its gone, and the wd40 was getting sucked inside ,

that must be what was making the noise under boost , what a relief,

Thanks DVS!!! :worship: :worship: :worship: Saved me alot of $$$

Just one last question, if this leak was there when the car was getting tuned, does this explain the turbo being a bit lazy ? and does this mean my mixtures will be out and need checked again????

Just one last question, if this leak was there when the car was getting tuned, does this explain the turbo being a bit lazy ? and does this mean my mixtures will be out and need checked again????

Any sort of leak will be causing some issues. Get it fixed up and get it on the dyno to make sure everything is fine would be the best idea I think.

You might make more power as well, which is never bad!

Edited by Mitcho_7

YESSS!!!! :rofl2:

Have found the problem, i sprayed the WD40 around the top of the intake manifold where it bolts down and that gasket in there looks wasted, theres about an inch wide section that looks like its gone, and the wd40 was getting sucked inside ,

that must be what was making the noise under boost , what a relief,

Thanks DVS!!! :worship: :worship: :worship: Saved me alot of $$$

Just one last question, if this leak was there when the car was getting tuned, does this explain the turbo being a bit lazy ? and does this mean my mixtures will be out and need checked again????

Awesome buddy. Fark i should have a workshop or something aye.

Once u fix the leak dont drive it hard. Get it

Checked just incase.

These shitty RB25 plenum gaskets are big trouble. I've never seen one fail on an RB20.

Here's hoping the NEO ones are better.

Also, SilverS2.....there is a hell of a lot of mechanical clatter in your engine bay. Are your lifters alright?

i have no idea about the lifters, i just droped the new cams in, and now im thinking about wether they should of been bled or somthing,

the camcorder tends to pick up sounds abit different to real life, the exhaust is louder than what that video showed, but yeah i guess there is a bit of noise there.. what do you suggest? new lifters or somthing?

Any sort of leak will be causing some issues. Get it fixed up and get it on the dyno to make sure everything is fine would be the best idea I think.

You might make more power as well, which is never bad!

yeah im really hoping that when this gasket goes on, when i put it back on dyno it puts out another few kw's and the boost will come on harder... but probably not much difference..

Before i get it checked on the dyno, should i try some sort of decarboniser to clean the engine? that might allow some more timing to be put in and bring me up to 300kw, or even adding 10L of ethanol to tank to bump up the octane?

my injectors are on 78% so can i add 10L ethanol to a tank and get away with it so i can get into the 300Club??

Edited by SliverS2

New lifters is the easy but expensive approach. The cheaper but much more effort approach is to remove them all, dismantle (keeping everything in the correct order - so no mix and match at all), clean, reassemble and re-install/bleed to give them the best chance of doing what they're supposed to do.

If you hadn't found the leaky gasket, I would have been tempted to think that your fluffy idle could be caused by the lifters. Given that you would have "disturbed" that part of teh car when changing the cams, and that the problem started when you put the cams in......you get the idea.

Clattery lifters suggest excessive clearances which is not good for cam/lifter longevity and can lead to catastrophic failure in the long run. I'd not want to run an engine like that for too many miles without getting the noise checked out by someone whoe knows what they're listening to and then fixing it if required.

cheers

Thanks mate, thats food for thought, ill mention that to the tuner and maybe get a few opinions too,

It could still be the problem, ill wait and see what happens with a new gasket then look into the lifter issue. :yes:

New lifters is the easy but expensive approach. The cheaper but much more effort approach is to remove them all, dismantle (keeping everything in the correct order - so no mix and match at all), clean, reassemble and re-install/bleed to give them the best chance of doing what they're supposed to do.

If you hadn't found the leaky gasket, I would have been tempted to think that your fluffy idle could be caused by the lifters. Given that you would have "disturbed" that part of teh car when changing the cams, and that the problem started when you put the cams in......you get the idea.

Clattery lifters suggest excessive clearances which is not good for cam/lifter longevity and can lead to catastrophic failure in the long run. I'd not want to run an engine like that for too many miles without getting the noise checked out by someone whoe knows what they're listening to and then fixing it if required.

cheers

Just wondering, you say that when cleaning the lifters to keep them in order but what about when the New tomei cams get dropped in, does this mean that the lifters have to "bed in" against the new cam??

If after getting more opinions on the lifters and i decide to take the head off, should i get some porting done to the head at all or will that make the turbo more laggy? Maybe some exhaust porting and then exhaust manifold to match?

Just wondering, you say that when cleaning the lifters to keep them in order but what about when the New tomei cams get dropped in, does this mean that the lifters have to "bed in" against the new cam??

Somewhat. But not significantly enough that you worry about it. My comment was more to the effect that each lifter is somewhat bedded in to its lifter bore, and all the components in a lifter stack up to provide a certain thickness. You just need to keep each lifter separate from the others and put everything back where it came from, in order to avoid possible problems.

If after getting more opinions on the lifters and i decide to take the head off, should i get some porting done to the head at all or will that make the turbo more laggy? Maybe some exhaust porting and then exhaust manifold to match?

Properly done, porting will never make more lag. You will only ever increase gas flow, which can only ever improve response.

Just wondering, you say that when cleaning the lifters to keep them in order but what about when the New tomei cams get dropped in, does this mean that the lifters have to "bed in" against the new cam??

If after getting more opinions on the lifters and i decide to take the head off, should i get some porting done to the head at all or will that make the turbo more laggy? Maybe some exhaust porting and then exhaust manifold to match?

Did mine recently, pretty straight forward but very time consuming. http://www.speed-industries.ch/wordpress/2011/02/15/inside-performance-clean-your-lifters/

Did mine recently, pretty straight forward but very time consuming. http://www.speed-ind...n-your-lifters/

Thanks mate, nice info on that site, so it looks like the head doesnt need taken off to get at them which is great news,

looks like i might have some work ahead of me, im still trying to decide wether E85 or water/meth and with taking the intake manifold off to replace the gaskets its a great time to replace injectors if im going E85.. decisions decisions

The modification bug has hit me.. :yes:

Yeh you can do the springs with the head on also, you need a few special tools though.. Absolute worse job EVER!!

Yep its a dog to do tried it then got through changing 20 and all of a sudden air spun the crank and dropped a valve so head came off to finish the job.

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