Jump to content
SAU Community

Recommended Posts

Brand new RB25/30 long motor built by RB specialist, installed it last night and it has no comp on cycl 5! Holy shite. Very confident nothing got in it during installation and don't doubt the builders skills but what could it be? If I had to guess I assume it must be stuck valve but how? How does the hydraulic set-up work? Could they be not yet pumped up? After getting oil pressure up (took the inj fuse out and cranked) I started it for about 1-2 mins thinking the plugs where fouled and it would fire up on all 6 after a bit but no good... I don't want to run it anymore as all the fuel in the cylinder will be washing the bores clean and that would be bad.....Any ideas before I have to pull the rocker covers off and start to investigatagtion the top end first?

:)

This happened to my 25 when i rebuilt it. We got a little careless at the end of the rebuild and didn't check the lifters as they where fine when i pulled the engine down.

At least 5 or so where locked up and not letting the valve close all the way. Replaced them and its been running fine until now.

So that may be your problem too.

John

  • 2 weeks later...

Important Update!!!!!

Did a leak down test and found exhaust valves open on cyl 5 ! AHA! Pulled the cams out and wacked 2 new lifters in it (OW!$100 each from nissan). Put it back together and cranked it.........Beautiful-No 5 no probs.... but now no comp in 1 and 4.....WHAT THE? We chopped one of the old lifters in half and found some carbon in it so we think that the lifters must be sucking that crap into them when they pump up and can't bleed down thus holding the valves open. Looks like I need to replace them all!! We have been bleeding them down before assembling the head, this is the right procedure yeah? If we have to replace the lifters does anyone know of a cheaper supplier than oem? Anyone rebuilt heads with similar probs got any stories or techniques to share? Would love to hear your thoughts!

Cheers

P.S Still pretty happy its not terminal though....phew! :)

It has been suggested to me that this 'may' be the cause of my valve float, as occasionally on startup i get the lifter pump up miss. :)

I'd be interested if there is a cheaper than nissan way out of it.

Similiar year VG30 lifters are the same part number so that may be a start, well for myself with the R32 head anyway, possibly the US may have something aftermarket.

No idea...

Black_R33 has experienced a bad lifter holding valves open and now I'm being told that my problem may be partially my lifters due to a couple of symptoms; the all of a sudden valve float and lifter pump up i'm experiencing and the occasional same valve float lifter pump up miss.

No idea.. Will find out when the head comes off. I had planned to pull it off this mid term break, it won't be happeneing as I'd prefer to have a little extra money stashed away just incase it gets expensive. :S

Lifter pump up miss cannot be mistaken, its a different sound to an ignition or fuel miss.

I'm sure black_r33 agrees. :domokun:

Mc. Stocky... believe me I have fantasized about a nice solid lifter conversion + a set of gtr high lift cams... high lift = lots and lots of mid range. >_<:ph34r::)

Try a Wrecker.....

Could also be something trival like swarf (tiny filings) either on the valve seat or in the valve guide causing them to stay slightly open.

The head should have been pressure/vaccum tested before assembly - this would have detected it before you installed.

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


  • Similar Content

  • Latest Posts

    • I have been being VERY quiet about what you're alluding to, as it is something that ticks me off... The number of cars from factory that run coil overs is HUGE! Most of them these days do... The other part that annoys me, is people saying "Well all the incabin adjustable suspension is illegal by blah blah blah"... If that's the case, then why can I buy a car brand new that can do it if, FULL STOP in cabin adjustable suspension is illegal...   Also, I could just chuck some aftermarket shocks in my car, throw the stock springs on, after my blue slip, dump my super low springs back in. Same shock and spring style setup... Hell, they could also be the same colour springs etc.     I'm voting, BlueSlipper didn't want to touch the above car for some reason. Whether it be some sort of bias against the car, the owner, them maybe having previously done dodgy shit and now they're being super careful in case they get slapped in the face by the Gumbyment again... Find a new blueslip place.   And can confirm as you had said, yes there are holy bibles of vehicle heights, and all sorts of other suspension stuff. Heck your run of the mill mechanic, and tyre shop has access to all of that stuff. It's how they do wheel alignments...
    • Funny story Heading to Sydney this morning on the HWY there was some slow traffic, so I gave it the beans and midway through my overtaking "power run" I lost all power It seems that I missed a hose clamp,  and the MAF and filter went WiFi To make this more problematic, the little tool kit that lives in the boot, is sitting in the sun room at Goulburn......LOL Luckily for me I found a bit of steel on the side of the road that could be used like a rusty and bent flat head screw driver to tighten it up enough that it got me into Sydney, it is now all tight like a tiger with the aid of a 8mm socket Note to self: Use my brain and double check stuff, and always keep that little tool kit in the car for when I have a brain fart
    • Oh, and as for everyone with their fuel economy changes, I switch between E10 and 98 in the company car. Even do when I had personal cars that could run on E10. You know what changed my fuel economy in any noticeable way? How I drove, and where I drove. Otherwise, say on full tanks of just back and forth from work only (So same trips, same sort of traffic), couldn't notice a difference that I can correlate to the type of fuel in use. In the current vehicle, that's over 42L of USABLE fuel. While 98 is all "more energy dense", it also has higher knock resistance as it takes more energy to get it to ignite too. The longer hydrocarbons, typically more tightly bound. So running the same ignition map, can also produce less power, if there isn't enough time to get it all burnt through properly, as yep, the flame propagation speed is different from lower octane fuel to higher (Higher has a lower flame propagation, due to the more tightly bound and harder to self ignite funs. This is also typically where, a vehicle that is designed purely to run on 91 (Whether it be E10 or normal 91) usually sees absolutely no real world difference in fuel economy for the normal man, woman, or dog.
    • We've got some servos around me that have 91 with E10, 91 (no E10), 95, and 98. At those stations the change from 91 E10 to 91, is typically around 8c/L.   But lets not get started on the price of fuel in Oz. It's ridiculous. All the service stations around me, bar one, the price of fuel has been over the $2 mark per litre for the cheapest, 98 being around $2.45. That one service station is a CostCo, fuel from it comes from the same refineries, and makes no pitstops, it runs great, including the 98. In fact, I've had no issues on CostCo fuel, but plenty of issues at other stations!. The CostCo fuel, was $1.65 roughly this week for 94 with E10. $1.88 for 98. Servos directly across from it, $2.10 for 91 E10, and $2.48 for 98. The part I had to laugh at? If I drive multiple HOURS away from Brisbane, say out near Nanango, or Kingaroy, or even out to Goondiwindi, the price of their fuel, is the same as what it is at the CostCo... Oh, and that BP servo at Goondiwindi is HUGE and goes through epic turnover of fuel, so it's not sitting there for weeks going to shit. And what blows me away, my mate is one of the people who drives the Fuel Tanker all around QLD, delivering to all those places. At the same company his previous role was doing the "local haul" deliveries... Same truck, same driver, same pickup point it all comes from. So you tell me, how the hell it is 60c/L CHEAPER for fuel, when nearly all else is equal, except they require a B-Double to drive half a day out of Brisbane, and half a day back, every second day, compared to the delivery that can be under 30 minutes drive from the fuel pickup point... Not to mention, go five blocks down the road, and Ampol to Ampol will vary 30c/L... And I've had this conversation with my mate... The way it's priced, is just typical, pure and utter rubbish... He also does runs from Brisbane, to all over QLD, down to Newcastle, Sydney, Nowra, Melbourne, Geelong, and even out to parts of the NT depending on the companies needs. His main stuff is all the longer distance away from home for a few days at a time, then when he's back, he loves to just pickup extra shifts wherever he can in whichever truck, hence all the weird different places.   Oh, as for getting E10 into all the fuels in Australia... It was very quickly highlighted, that we don't have enough biomass available to use to make E10 sustainably like they require, and it would dramatically cut into our, and the worlds food chain supply...   I vote we all just start running on liquid methane gas... Plenty of that just getting tapped off at tips from underground decay... (Note, this is pure just stupid commenting. I could very easily highlight the reasons its not a good idea especially on scale...)
    • Am I correct in assuming that the R35's are getting the classic skyline haircut off the odometer?  Quick search on carsales, there are 33 08 and 09 GTR's for sale, only 2 of them have more then 100,000km's on them (116,075 and 110,000 respectively).  And somehow there are about 25 for sale with around 60,000kms? Looks like the classic skyline haircut to me =/
×
×
  • Create New...