Plenum Leaks

[AngryRB]

This is getting really frustrating so im after some opinions on this, i seem to have constant leaks around the plenum gasket and ive tried the stock and at the moment have the cosmetic gasket on.

A few things im not sure about are the actual bolts seem like they bottom out before they really nip up,

the cosmetic gasket is flat and the stock one has a ridge around the cylinder part which maybe is better for sealing, although it seams to squish when trying to really tighten it up.

help please...

[ZRBE]

Stock? Or..?

There was another post I read about changing from stock to forward facing, the bolts were "too short" ??

[Ben C34]

Is it a stock plenum? stock bolts?

In sure the oem gasket is best.

The bolts bottoming out sounds odd. perhaps put some washers on as a quick fix.

[AngryRB]

yeah its a stock plenum, the stock bolts have a unthreaded length on them and i think there bottoming out before its tight enough, but then at the same time im not sure if im over tightening it causing it to push out, ive been spraying it with so much carby cleaner testing it that it might be affecting the gasket now maybe.

should i be using any type of gasket goo/sealent or just gasket by itself?

2 bolts on the outside/fender side keep leaking even after tightening the shit out of them with some different bolts that have thread all the way to the bolt head.

Edited July 9, 2013 by AngryRB

[89CAL]

If you think the bolts are bottoming out, couldnt you try shorter bolts? Or space the bolts with a washer or two?

[AngryRB]

If you think the bolts are bottoming out, couldnt you try shorter bolts? Or space the bolts with a washer or two?

The area that seems to be leaking is where ive replaced the stock bolts, the bolts used have washers on them and nip really tight and still leak, so not sure what to do now.. wonder if the Loctite hardened before it got tightened up the first time and has created some uneven surface between the plenum and gasket..

should i buy a stock gasket and try again?

[AngryRB]

I just opened up a can of worms with this today, after starting it and tightening up the bolts a bit more, sprayed some more carby cleaner and its leaking, closer look and its developed a crack

so, can I just have this welded together permanently, is it possible and any issues that would occur doing that?

Edited July 9, 2013 by AngryRB

[Ben C34]

Can't you just buy another stock manifold?

[AngryRB]

if I did then ill still have this leak issue, just cant seem to seal it off properly..

welding it would be 100% guarantee of no leaks wouldn't it?

[Ben C34]

Are you talking about where the top joins the bottom runners? If you weld that I'm pretty sure you won't be able to get your injectors out.

[AngryRB]

that's a good point, dam this intake leak shit..

[jiffo]

What's this in an Rb25?

No need to split the plenum to remove injectors in a 25.

But for cost to have it welded (properly) you could have bought something 2nd hand.

[Ben C34]

Pretty sure neo have to split plenum to get them out

[AngryRB]

bit of a dilemma, 3gaskets ive tried now and back to square one, if its possible to get the injectors in once its welded it sure would resolve this constant issue, OEM gasket leaks after some high boost runs and this cosmetic ones leaking without boost.

[MrStabby]

I dont know gtst plenums and the gtr ones use studs. First I would take the plenum off and check the bolt length since you mentioned that. To me, bottomed out bolts feel a bit "springy" when they get tight since you're flexing the entire length of the bolt. Measure the width of the plenum then gently turn the bolts into the head without the plenum in place to check the exposed shaft is shorter than the plenum width. Don't get excited about the exposed shaft! (yes folks, i'm here all week)

If the bolt length is good, then you need to check the mating surfaces are perfectly flat. Its very unlikely the head wont be flat unless there some external damage to it, so concentrate on the manifold. Since yours is already stuffed, i'd get a good second hander and start there (still check it for flatness). A straight edge (aka metal ruler) is usually what you'd use to check for flatness.

[Ben C34]

I'm pretty sure his leak is between the top of the plenum and the runners. Seems really odd that it would warp there.

[AngryRB]

yeah its the plenum gasket, the OEM one is a thick rubber style gasket, its interesting how the Neo has a different bolt pattern, it looks like maybe the factory had this issue and so they doubled the number of bolts at that side or swapped the configuration around.

so I have two options

1) get another manifold, gasket and try again which ive lost faith in it ever sealing off for long

2) Pay a fabricator to butcher it up around where the fuel rail goes so I can still fit the top feed rail on and weld it solid shut, so 100% leaks gone forever..

number 2 is a PITA and number 1 is 50/50gamble.

Edited July 10, 2013 by AngryRB

[Ben C34]

You are the first I have heard that has had this much trouble. New manifold would surely solve your probs. Don't weld it together, that would be mental!

[StevenCJR31]

it would be possible to weld it but you would possibly still have it leaking tween one runner and the next runner

[StevenCJR31]

it would be possible to weld it but you would possibly still have it leaking tween one runner and the next runner