Guru Needed, New 25/30 Engine Startup Problems!

[Black_R33]

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?

[Craved]

take the car to the builders and get them to check it, they built it they should look after it..

sounds like what i had when i bent a valve installing cams, its easy to do.

[Cubes]

Bugger.. Always depressing when this happens.

I'll be interested to see what the problem is.

[RB30-POWER]

Its not exactly rocket science, i don't know how so many people f**k up...

[Cubes]

Its most likely ppls doing the same thing day in day out become a little blazay and miss/forget something.

But your definitely right.. There's no reason for the stuff ups.

[wrxhoon]

My guess is a bent valve, do a leakdown test and should be able to hear where the leak is .

[Black_R33]

OK, did a leak down test and when you pump some air into the cylinder you can hear the exhaust at the back whistling a sad tune........not good......exhaust valve issue.........bugger... :

[Mesmer]

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

[Black_R33]

ta guy's, spoke to engine builder. We both agree before we start pulling the thing apart i am going to pull the loom off the injector on the cyl so i dont wash the bores and run it for 5 mins to see if thats all it needs.......hmmmm.

[Black_R33]

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!

[Cubes]

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.

[Black_R33]

Cheers! Anyone else....?

[StockyMcStock]

convert to solid lifters.

oh wait you said "cheap". my bad.

[RB30-POWER]

how do lifters hold valves open?

if they weren't pumped up, wouldn't they not open the valve enough?

[Cubes]

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.

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.

[Black_R33]

Thanks guys, still looking for a cheap supplier of lifters to help me!!!!

[StockyMcStock]

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.

bah - get a twincharge up ya. changing cams is for pussies!

[Cubes]

bah - get a twincharge up ya. changing cams is for pussies!

lol... Twincharge would be awesome....

I consider you to be the

[Black_R33]

anyway....back to the topic....

SUPPLIER of lifters other than Nissan??????ANYONE?

[darkstar]

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.