Tappet/Rocker Gear Problem - Sigma

[ccpl]

Hey all.

Ok, to follow on from a previous post of mine and making a long story short. In the last couple of months my tappets (being hydraulic) started to get really noisy after 2500rpm. A couple of minutes of idle, and everything would quiet down nicely.

Having thought that my oil gear might have been damaged, i rebuilt the bottom end of the motor (the head was rebuilt 17/03/2003), oil pump, timing gear, pistons, bearings, the whole lot. 1 Day of driving and everything was well, no tappet noise. The 2nd day of driving, tappets started playing up again at bout 2000rpm. 3rd day, tappets noisy as shit no matter what rpm, it couldve been idling and making a racket, i noticed that it only happened once the engine warmed up though.

Having resigned myself to the fact that my hydraulic lifters were cactus, i went out and bought new lifters (after confronting the people who rebuilt my head only to get the reply "oh we dont replace the lifters, we only check to see if they are pitted, and if not, we use the old ones!!", not really a freaking full rebuild then is it). Anyways, having bought new lifters and taking the old ones out, i realised that the old ones indeed were f*cked and put the new ones in.

Now, the lifters did quieten down considerably, but still were quite noisy when the engine warmed up. Having had 20w-50 oil in the engine at the time, i changed to 10w-30. This quietened the tappets to almost normal operation, yet they still follow the same pattern, quiet when cold, a little noisy when cruising and louder when in the higher rpm range.

The only thing that i can think of is

1) have the hydraulic lifters been installed incorrectly, im assuming the oil holes in the lifters are supposed to go up in the bores of the actual lifters??

2) the rocker gear and actual lifters themselves maybe be worn (shouldve been replaced but hey, dont go to barclays engineering!)

Would anyone else PLEASE give a suggestion of whats goin on, cos i am starting to run out of ideas!!

Thanks in advance
a.g

(ps - the whole problem started about 2 weeks before i removed my balance shafts. It was hardly noticeable at the time, but the same pattern was there. The day after i removed my balance shafts, the whole thing got messy - hope that helps!)

[Jim]

did you fit a locating collar to the back of the oil pump when you removed the balance shaft from the pump? if not, the driven gear in the oil pump will be flopping around and most of your oil pressure will be sprayed out the back of the pump.

also, did you block up the oil gallery journal where the balance shaft bearing is? if not, your in trouble. an easy trick used to be to knock the balance shaft bearing out, then refit it 90° thus blocking up the oil gallery.

[ccpl]

Originally posted by Secoh
did you fit a locating collar to the back of the oil pump when you removed the balance shaft from the pump? if not, the driven gear in the oil pump will be flopping around and most of your oil pressure will be sprayed out the back of the pump.

also, did you block up the oil gallery journal where the balance shaft bearing is? if not, your in trouble. an easy trick used to be to knock the balance shaft bearing out, then refit it 90° thus blocking up the oil gallery.

I used a balance shaft removal kit from repco. Came with dummy pole to act as balance shaft in the oil pump, bearing for balance shaft cavity and new chain for oil pump. Oil pressure is more than fine ( around 100psi when cruising and 40-60psi on idle). So as far as i can tell, the oil situation is fine. Everything in the bottom end is new, oil pump, gearings, timing, etc. oil pressure is more than enough, so the only thing i can think of is something to do with the head itself.

[mizone]

Yep I hear ya. Had my Magna's 2.6 rebuilt four months ago. Now the tappet noise intermittently comes back when cold.

It's not hard taking the rocker cover off. Take a look at the valve to lifter faces. Are they pitted ? Mine the number one exhaust valve to tappet faces pitt to hell. Dunno why there's lots of oil and good pressure etc ?

[ccpl]

As far as i can tell, the valve lifter faces are fine. So do the oil holes on the hyraulic lifters go up into the bores of the lifters, or do they seat against the valve face?

[mizone]

From what I can tell the oil comes down from the top. I had the skid type rocker arms but have seen ones with a wheel, so am going by mine in particular.

The manual suggests holding the engine at 3000RPM for a minute to stop the noisey rocker prob. Repeat if ness.

Not sure what it does ( more oil or pressure ?) but it's only worked twice. Give it a try at least.


From my pushrod exp. in the past I know if the noise comes and goes it is actually the tappet turning slowly around.

[ccpl]

running the engine at 3000rpm only makes the problem worse. And yes i have tried that many a time. Well i installed my new lifters with the oil hole facing towards the rocker cover up into the tappet bores, assuming that oil is forced up into the bores and is where the lifter gets it oil from to make the hydraulic pressure. Maybe my actual tappets are warped and the oil is bleeding down out of the tappet leaving no oil for the hydraulic lifter.

[MrBishi]

As I said the last time you asked the question, you need to prime the tappets. Take them out, sit them in a pool of oil with a pin holding down the one way valve and fill them up. Go to the library & read a gregory's manual on to do it (my memory is a bit hazy)

[mizone]

MrBishi. I primed mine but the problem comes back after two or three months.

[karl_2ltGC]

WHy not just get the whole rocker gear from a early astron(solid tappets)???? Adjust them correctly and not have any noise

[ccpl]

Because for one thing, the solid tappet rocker gear off an astron 1 head is slightly different to my knowledge to the astron II rocker gear (different alignments and cam gear etc) And the other reason being astron I stuff sucks

[karl_2ltGC]

Its all totally interchangable, i know one guy with a magna head on his ge sigma racecar that uses solid tappets... theoretically there will also be a power upgrade due to more accurate valve timing.

[MrBishi]

Karl
You are incorrect. The tappets are not directly interchangeable.
It is possible to do it by fitting G160 rocker adjusters (longer) to the tappets but this is far from ideal as the tappet does not then hit the valve squarely. Another option that i am currently looking into is to run tappets off a 2L L300 van (Not 100% sure at this stage). There is also the manual tappet astron 2 found in some late Scorpions and some Pajeros (I haven't been able to find one yet).

As for fixing the hydraulic tappets, I'd try:
-Pulling them out, cleaning, re-priming
-Check the rocker shaft for wear or blockage. The oil is tranferred to the tappets through the shaft then through the rockers. If the oil can leak out between the two then you will be losing pressure. Ideally if you can feel a wear line with your fingernail you should replace them.
-Check rockers for blockage.
-Can you locate the offending tappet/s?

[ccpl]

Thankyou to all who helped, but i think i discovered the problem! After doing an oil change and running some engine oil flush, the tappets are quiet as! even at high rpm, they make little or no noise, i guess they need to be primed up properly now, but the problem seems to have been blocked oil gallerys. As when i dropped the oil out, there was alot of grit and crap in the oil. I spose thats probably from running the engine in as well, but oh well. But thanks to all who helped!