Intake Plenum Gasket Broken

[Primordial]

My intake plenum gasket has developed a leak. obviously the deteriorated part of the gasket would have been either sucked into the engine, or blown out (if there was positive boost at the time that it went!)..

Would a small part of a rubber gasket be enough to do damage to the engine internals?

Is there anything wrong with driving the car while effectively there is a small leak in the plenum? I'm thinking a lean situation if it's sucking in more air than is being read by the AFM.

[Dobz]

the car will probably run a bit rough if its only a small leak.

the bit of rubber gasket won't do anything to your engine if it was sucked in, it would burn up pretty quick.

[Primordial]

Yeah spot on... it currently runs quite rough when on idle or decelerating.

Cool, thats good news about the rubber burning up!!

[202.3rwkw]

The car will go lean under cruise ie vaccuum but should go rich under positive boost pressure...........look for black smoke

gc

[Guilt-Toy]

there are 2 types of gaskets.. there is one that is completly rubber and one that has metal inside so when you replace it get the one with metal inside so this wont happen again. Common problem.

[Abo Bob]

I've got a spare Nissan original one lying around if you need it mate. Will swap for beer or bj's.

[Primordial]

Ahh too late. Sorry Adam, I got the gasket in there yesterday - Shame you couldnt offload the gasket to me and get it out of your garage! Unfortunately I only had beer in stock anyway!

It turned out to be the rubber washers that space the bolts off the plenum - the washers had deteriorated and you could actually move the top of the plenum around because these washers were stuffed. Changed the plenum gasket, throttle body gasket, and all nine of these washers while I was in there too... Problem solved!

Thanks for your help guys

[BAMR33]

Just interested, are gaskets for skylines over the counter items from like repco and places?

[-_-StRyDeR-_-]

Kudos motorsports supply full gaskets, standard and aftermarket, send him a PM if ur looking for one

CJ

[neshgtr]

just a side question, my r32 gtr has a noticeable whooshing noise around the middle of the inlet plenum.. this is around the same time by rear turbo's exhaust wheel went n i was thinking it was a vaccum leak/inlet manifold gasket leak until i found out bout the broken exhaust wheel - no boost.. after replacing my turbo's, the noise is still there.. upon closer inspection, the one of the nuts on the plenum was slightly loose, but after tightening the noise is still audible.. has the gasket blown while nut was not tightened properly and does it require a change? not sure if the noise is normal as never noticied it before..

thanks nesh

[Primordial]

just a side question, my r32 gtr has a noticeable whooshing noise around the middle of the inlet plenum.. this is around the same time by rear turbo's exhaust wheel went n i was thinking it was a vaccum leak/inlet manifold gasket leak until i found out bout the broken exhaust wheel - no boost.. after replacing my turbo's, the noise is still there.. upon closer inspection, the one of the nuts on the plenum was slightly loose, but after tightening the noise is still audible.. has the gasket blown while nut was not tightened properly and does it require a change? not sure if the noise is normal as never noticied it before..

thanks nesh

Be careful... There is a specific torque setting that the bolts need to be done up to.. The reason for this is that you dont want to completely squash the rubber washer that sits below it. The rubber washer works as a buffer to allow the inlet plenum to sit flush with the gasket. If you over-tighten the bolt, then the plenum wont sit flat and flush. Once the rubber washers are deformed, you increase your risk of losing a seal with the gasket.

Get your hands on the service manual, it shows the torque settings for the bolts, and shows what parts should NOT be re-used when dismantling/reassembling the intake. The parts that should not be re-used are the plenum gasket, throttle body gasket, and the nine rubber washers (on the RB25DET).

Are you sure there is a leak there? The sound might just be induction noise? At idle, try dripping a small amount of water over joints in the intake. If there is a leak, you will see the water get sucked in, and the engine might skip a beat quickly. Dont use too much water obviously...

[neshgtr]

Thanks for the great info dude, i already have a tomei inlet plenum gasket and throttle body gasket but no rubber washers.. where can i get these from ($$) and do i need 9 rubber washers (r32 gtr)?

i tried testing the leak with some engine cleaner spray.. there was bubbling although it could have been due to heat.. ill try again tonight with some water on cold start..

[Primordial]

Ahh sorry mate, upon looking at the service manual it seems that the RB26 has a different method of attaching the intake, I was talking about the RB25DET.

I've attached the service manual for the R33 RB26DETT, which should be exactly the same as the R32 for this kind of thing anyway. You can see that there isnt in fact any rubber washers on the RB26 like the ones I was talking about!

I would have a go with the water initially to see if you can locate a specific location for a leak (if any) and go from there.

Skyline_R33_RB26_Intake_Service_Manual.pdf