Jump to content
SAU Community

Inlet Valve Leaking! Where Do I Go From Here?

Seano93

By Seano93,
in General Maintenance

 Share

Recommended Posts

Seano93 Newbie

Seano93

Posted
Posted

Hi guys,

New guy here looking for some advice on where to go next in my diagnosis.

I have a '96 R33 GTS-T pretty much stock, it started running a bit rough a couple of months back but i only just got off my ass to investigate it.

So i checked my spark plugs, found cylinder 6 was black/ oily. I did a compression test, the first 5 cylinders showed 120psi, but the 6th cylinder showed only 20psi....... yes, 20. We didn't have a proper cylinder leakage tester but i had a connecter and plugged an air line into the spark plug bore with the engine at TDC and air came rushing out of the pod filter.

So obviously there is a problem with the inlet valve/s on cylinder 6?

I was hoping you guys could give me some insight into what the actual problem might be and how i go about confirming and rectifying the issue? And will i have to replace rings as well? Im not sure where to go from here and how much work im looking at. I was planning on selling the car soon so i dont want to spend too much time and money on it.

Your input would be appreciated,

Cheers, Sean.

Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted

Probably be more coat effective to replace motor with a used lump with good compression since you're selling it anyway

Say of you pull the head then find out your piston ring lands are smashed, there's more money gone.

Sad reality isn't it? But these cars are old and they break

  • Like 2
Humbla Grand Master

Humbla

Posted
Posted

Probably be more coat effective to replace motor with a used lump with good compression since you're selling it anyway

Say of you pull the head then find out your piston ring lands are smashed, there's more money gone.

Sad reality isn't it? But these cars are old and they break

Mine only broke due to some one else's boo boo,if you take care of your engine they last,nearly 300000 on second hand motor on my old 33

do 30000 plus a year on mine so they do last. :-)

Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted

Mines probably got 300000 km on it too - judging from the body and car bushing etc. Clock says 140000 lol

Has had a good hair cut from dealers and previous 50+ owners.

I'm too scared to do a compression test on mine in fear of getting sad. It cops a beating on the track and regularly sees 1.5bar through the motor. It's going to pop soon I reckon lol

  • Like 1
scotty nm35 Grand Master

scotty nm35

Posted
Posted

Mine is in a similar condition Johnny, 200,000+ks, goes through 2L of oil in 5k, the bores were very scuffed when I had the head off. It just refuses to die, even my tuner is amazed. It still cops 32psi daily, i'm not tracking it anymore but it survived 8 track days, overheating to 150c quite a few times, and over 200 power runs on the dyno... Some of which caused a head to lift.

The only reason I think it is still going at all is because I have a spare engine waiting to go in. If I sold it the engine would blow the next day. Regular maintenance, good fuel and tuning are my reasoning though.

To the OP, rip the head off, if there is anything wrong it's time for a wrecker motor I think. Make sure you can compression test the s/h motor in the car if possible, and check the oil filler cap and inside the rockers for carbon buildup which would indicate poor servicing with crap oil.

Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted

your motor is just scared of being replaced so it's behaving LOL

it's sad we will never truly know the real KMs on these import unless it's come straight from Japan with authentic japanese deregistration & auction papers

jiffo Mentor

jiffo

Posted
Posted

Just because the engine was at TDC doesn't mean it was firing on No 6.

Could just as easily been firing on No 1 which could explain air rushing from No6's inlet valves.

To eliminate the guesswork, one would rotate the crank another rev and perform the test again.

Then you'd have a better idea if it was a valve or a piston problem.

No matter in the long run, 20psi compression test is a mega fail.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      Yup. You can get creative and make a sort of "bracket" with cable ties. Put 2 around the sender with a third passing underneath them strapped down against the sender. Then that third one is able to be passed through some hole at right angles to the orientation of the sender. Or some variation on the theme. Yes.... ummm, with caveats? I mean, the sender is BSP and you would likely have AN stuff on the hose, so yes, there would be the adapter you mention. But the block end will either be 1/8 NPT if that thread is still OK in there, or you can drill and tap it out to 1/4 BSP or NPT and use appropriate adapter there. As it stands, your mention of 1/8 BSPT male seems... wrong for the 1/8 NPT female it has to go into. The hose will be better, because even with the bush, the mass of the sender will be "hanging" off a hard threaded connection and will add some stress/strain to that. It might fail in the future. The hose eliminates almost all such risk - but adds in several more threaded connections to leak from! It really should be tapered, but it looks very long in that photo with no taper visible. If you have it in hand you should be able to see if it tapered or not. There technically is no possibility of a mechanical seal with a parallel male in a parallel female, so it is hard to believe that it is parallel male, but weirder things have happened. Maybe it's meant to seat on some surface when screwed in on the original installation? Anyway, at that thread size, parallel in parallel, with tape and goop, will seal just fine.
    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      How do you propose I cable tie this: To something securely? Is it really just a case of finding a couple of holes and ziptying it there so it never goes flying or starts dangling around, more or less? Then run a 1/8 BSP Female to [hose adapter of choice?/AN?] and then the opposing fitting at the bush-into-oil-block end? being the hose-into-realistically likely a 1/8 BSPT male) Is this going to provide any real benefit over using a stainless/steel 1/4 to 1/8 BSPT reducing bush? I am making the assumption the OEM sender is BSPT not BSPP/BSP
    • funkymonkey
      Jacks that fit under GTR lips that can reach the subframe?

      By funkymonkey · Posted

      I fashioned a ramp out of a couple of pieces of 140x35 lumber, to get the bumper up slightly, and then one of these is what I use
    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      I wouldn't worry about dissimilar metal corrosion, should you just buy/make a steel replacement. There will be thread tape and sealant compound between the metals. The few little spots where they touch each other will be deep inside the joint, unable to get wet. And the alloy block is much much larger than a small steel fitting, so there is plenty of "sacrificial" capacity there. Any bush you put in there will be dissimilar anyway. Either steel or brass. Maybe stainless. All of them are different to the other parts in the chain. But what I said above still applies.
    • Duncan
      Mistakes were made, my R34 Story

      By Duncan · Posted

      You are all good then, I didn't realise the port was in a part you can (have!) remove. Just pull the broken part out, clean it and the threads should be fine. Yes, the whole point about remote mounting is it takes almost all of the vibration out via the flexible hose. You just need a convenient chassis point and a cable tie or 3.
×
×
  • Create New...