White smoke after RB26 rebuild

[wombatau]

you shouldn't mess with your emissions setup. besides, it won't give you any power increases

your pcv has to be venting, you can't just block it off. bring it back to stock and i bet it fixes your problem.

-wombat

[vspecv]

you shouldn't mess with your emissions setup. besides, it won't give you any power increases

your pcv has to be venting, you can't just block it off. bring it back to stock and i bet it fixes your problem.

-wombat

provided you engine is venting its fine to block you pcv.

[yamaha227]

blocking the pcv valve and rear turbo line on the intake boot isnt about more power, dont have problems in that area,its makin heaps. this is done to stop any intake of oil mist back into the intake under decent boost which can clog intercoolers and cause detonation.

checked out the cylinders with the boroscope yesterday and all is good, no scores and the cross hatching hone marks look good. will definately try hooking the pcv system up again to see if this helps, worth a try. with it disconnected i realise the venting system is working against atmospheric conditions (14.7psi) at idle and decell, so maybe hooking it up to both the pcv and intake boot might help (giving it vacum and helping to releive some of the pressure in the rocker covers). see how it goes...

[yamaha227]

hooking up pcv system made no difference, took it for a good run and still the same. so will do the valve stem seals mid next week, start with the easier fixes first and see what happens. any idea on what sort of pressure i need in the cylinders while changing the seals to keep the valve in place?

[Cubes]

Make sure u slap a bit of vaso or engine oil on the valve stem seals before you put them in. Don't use grease.

[vspecv]

Make sure u slap a bit of vaso or engine oil on the valve stem seals before you put them in. Don't use grease.

did u fix it

[yamaha227]

after much thought, trouble shooting and resistance (so didnt want to pull the fu#@ing engine out again), i pulled the engine and box out yesterday. this came about after many visits to the engine shop and i finnaly got to the bottom of what he actually did wrong. found out he used the standard 400 grade of hone on my cylinders instead of reading the instructions that came with the total seal rings which says to use between a 240 and 280 grade. great, wasnt i excited, so my cylinders are probaly glazing up nicely and the rings will never get a chance to bed in properly. made me feel really confident when he seemed to be comparing my RB26 to a standard engine he rebuilds everyday

So didnt want to bother with wasting a day on doing the valve stem seals when the cause of my problem is likely to be something else. talked to SK who had some good advice, and ben at race pace who used to tune the car when it was in melb. ben suggested it was prob a good idea to pull the engine, re-hone to suit the standard nissan rings, check everything else and bang it back together.

stripped all the bits of the engine today and found number 3 and 4 exhaust ports to be saturated with black oil and quite a few of the inlet valve stem seals to be also letting oil down the stem, so seems to be combination of both poor ring seating and the majority of the valve stem seals leaking.

so off with the engine and back to the engine shop, didnt he seemed shocked when he sore the evidence of what ive been trying to convince him off over the past couple of weeks. he was convinced it was a turbo issue and all the work they did was perfect.

Dean, can you remember which turbo got the new core and which one didnt, forward one seems a little bit suspect so its of at the turbo shop getting checked out. hopefuly i have some luck with the second go??

[markr34gtr]

your engine builder may have not cleaned up the end of your valves where the collets clamp to the valve . when i pulled my valves out of my head there where small marks very sharp edges from the collets clampnig to the valves..

if you dont clean up these marks on the valves you will stuff the new valve stem seals like what happened in your case i would say....

some of my valves had no marks on them but some did...

hope this helps....

also i used cheap valvaline running in oil an ran it in on the dyno.. dont drive the thing too carefull..

or it will glaze up again...

hope this helps....

[vspecv]

after much thought, trouble shooting and resistance (so didnt want to pull the fu#@ing engine out again), i pulled the engine and box out yesterday. this came about after many visits to the engine shop and i finnaly got to the bottom of what he actually did wrong. found out he used the standard 400 grade of hone on my cylinders instead of reading the instructions that came with the total seal rings which says to use between a 240 and 280 grade. great, wasnt i excited, so my cylinders are probaly glazing up nicely and the rings will never get a chance to bed in properly. made me feel really confident when he seemed to be comparing my RB26 to a standard engine he rebuilds everyday

So didnt want to bother with wasting a day on doing the valve stem seals when the cause of my problem is likely to be something else. talked to SK who had some good advice, and ben at race pace who used to tune the car when it was in melb. ben suggested it was prob a good idea to pull the engine, re-hone to suit the standard nissan rings, check everything else and bang it back together.

stripped all the bits of the engine today and found number 3 and 4 exhaust ports to be saturated with black oil and quite a few of the inlet valve stem seals to be also letting oil down the stem, so seems to be combination of both poor ring seating and the majority of the valve stem seals leaking.

so off with the engine and back to the engine shop, didnt he seemed shocked when he sore the evidence of what ive been trying to convince him off over the past couple of weeks. he was convinced it was a turbo issue and all the work they did was perfect.

Dean, can you remember which turbo got the new core and which one didnt, forward one seems a little bit suspect so its of at the turbo shop getting checked out. hopefuly i have some luck with the second go??

doesnt come as a surprise, time to ditch those gapless rings too.

cant help on which turbo, i just supplied the funds and ben did the work.

i also think running in a properly built rb is not a problem either, when ben builds my engines, they have less than 100kms before we let them rip on the dyno, my last engine made 450kw@the wheels with only 70kms on the speedo and still goin strong.

[surfiemullet]

drive to the top of a large hill and start driving down after getting some speed and take your foot of the accelerator and go down the hill till your high in the rev range with no accelerator pedal. get someone to watch behind you for smoke then nail the throttle and if you get lots of smoke it will be the valve stem seals. with the throttle closed it makes a huge vacume and the valve steam seals will leak if they are worn/damaged. hope this helps

[yamaha227]

thanks mark, will go and check my valves before he throws them back in. they were all brand new valves so unless they are like that from factory they should have been ok. i had the valvoline in it for about 50k then was told by an experienced rb engine builder in sydney it was not a good idea so i changed it, to a straight 25w 50 mineral oil.

spoke to ben about how he runs his engines in and he said he normaly runs them a little while to settle everything in and does a few kays, then leps rip and generally uses synthetic oil straight up. so the engine shop will now be getting a visit from me everyday so i can keep an eye on things and check everything out for myself aswell, not keen to go through it again.

[markr34gtr]

the gapless rings will be okay.. as long as your bore is honed right and run in properly..

i am using the same total seal rings and no probs at all...

they need to be gaped correctly also think 22 thou for the rings to work correctly, being gapless... seems a lot of ring end gap but they make em and test them.....

if the ring end gaps are too tight you wont be getting enough compression past the top ring to make the second ring seal.....

just used valvaline oil drove it for 20ks the 3 hours on the dyno. shes run in quick...

good luck with the engine builder.........again....

[Sydneykid]

time to ditch those gapless rings

Why?

[vspecv]

only based on what i have seen, i have never used them, but this is the second engine i have seen with these symtoms.

why not stick with genuine type rings, whats the benefit of the gapless rings.

[Sydneykid]

whats the benefit of the gapless rings.

On a leak down test they show 4 to 6% less leakage. You can run a wider ring gap for temperature compensation and not suffer like you do with gapped rings. You can run ~10% less ring tension for lower friction losses. The byproduct is you get longer service life between rebuilds.

They are not for everyone though, there are some procedures that you simply have to follow. The first, is set them up exactly as per the instructions, some engine builders find this a very hard thing to do:jk: Plus you have to run them in properly and they don't take kindly to using synthetic oil early in their life, some people find this a very hard thing to do. :headspin:

Bottom line, we have tried them back to back on the engine dyno and picked up 18 bhp in a 600 bhp engine.

[vspecv]

cool, dont sound like they are a good move with yamahas engine builder.

[markr34gtr]

i agree v spec.. when i set up my total seal rings had to file every ring except the oil rings to get the ring gaps as per instructions.. takes time .....and the ring gaps are large for a reason....

cheers...

[yamaha227]

I think that has been my biggest problem, engine builder doesnt know how to set everything up correctly to suit these rings, worked that out when i realised he didnt read the instructions (eg correct hone grade) to suit these rings. so i would just about bet my left aggot he didnt gap them properly as well.

so will go with the standard nissan rings for this reason, less things for him to get wrong hopefuly. have talked to a couple of people about hone grades, ring gaps etc for standard rings, but does anyone have any more info for me to keep in mind so i can keep an eye on things. as far as i can tell, 13 thou is the maximum ring gap i should have for the top and 22 thou for the second ring. 400 grade with a ball hone to finish of the cylinders seems to be what is generally used, anyone heard any different from an experianced RB engine builder?

anyone know the correct way to install valve stem seals? do you put the seal on first then put the valve up through the guide, or valve in first then protect the seal from the grooves in the end of the valve by using a bit of packaging tape wrapped around the end of the valve temporarily, then slip the lubbed up seal down onto the guide? what should he be using to get the valves home on the guide?

thanks, ben

[markr34gtr]

far out man you ve had bad luck..

i would make him get a new set of total seal rings and fit them properly.. there not cheap and work great.... gapped right and run in with running in oil .....

the stem seals is easy.. fit them to the head then put oil on them and the valves and slip them together slowly....

he may have damadged the old stem seals when he fitted them to the head last time...

just dont baby the engine when you get it back together... vary loads and rpms....

total seal recon not to use syntheic oil for 2000klms......

cheers, good luck...

[RB26zcar]

Well... how did the repairs turn out this time? I found this thread intresting, and would like to hear a follow up.....

thanks

joel