RD 28 top end strip

[solarman216]

So here we are looking for low compression on my Y60 Patrol

 

[solarman216]

Bores look fine

 

[solarman216]

These are the hydraulic followers, never dealt with them before so got some learning to do, but having extracted 1 exhaust valve and found no fault with it I am seriously considering changing these for new ones as at the moment I cannot see any other reason for poor compression

 

[solarman216]

Unfortunately the turbo has had it, the compressor wheel is rubbing the casing bearings are shot, might look at a replacement module but the waste gate seat is corroded and passing, not sure if I can re seat that at the moment

 

[solarman216]

The head face and no obvious burnt valves, but they will have to wait till tomorrow, Rick

 

[Flying Torquewrench]

Rick, is that also an RD28 engine? If I am correct (wikipedia ) then the only turbocharged engine in the Y60 was the RD28.

I take it that the head isn’t cracked, hence the low compression readings?

Sometimes the tappets can have carbon residue or sludge in them which blocks the oil channel. It could explain why one or two cylinders are down on compression but it would be highly unlikely that all tappets have the same issue.

 

[solarman216]

Rick, is that also an RD28 engine? If I am correct (wikipedia ) then the only turbocharged engine in the Y60 was the RD28.

I take it that the head isn’t cracked, hence the low compression readings?

Sometimes the tappets can have carbon residue or sludge in them which blocks the oil channel. It could explain why one or two cylinders are down on compression but it would be highly unlikely that all tappets have the same issue.

Yes it is an RD28t, I have found some discrepancies with the workshop manual, for instance the valve springs are both 10mm longer but only has steel washers at the bottom instead of what the book calls a "Rotator", it had the head gasket recall in 2000, no cracks in the head but have been playing with two of the followers and I need to use considerable force with a G cramp to push the plunger in and it comes back out by around 1mm so must have a spring, but I think the amount of force needed to compress it is far too much, I am very tempted to cut one open to see what makes it tick, most have been rotating so the flat face wear is negligible, but 3 or 4 have not and have noticeable linear dent in the middle and will have to be replaced so one of those will be a prime candidate for surgery, but I will not do that till I have all the valves out and give it a good clean up, Rick

 

[Flying Torquewrench]

Rick, than it is the same engine as I have. Following your progress with interest.

I have the original Nissan workshop manual and also an ‘Haynes’ manual but from Australia. If you need any information than let me know and ai take some photo’s.

Not sure how easy it is to get hold of a set op tappets. But here is a link to a company in the UAE.
https://magengines.com/product/engine-valve-lifter-set-nissan-rd28-t-2-8-ltr/

Same seller on eBay for £79. Supposedly the last one they have.
https://www.ebay.co.uk/itm/ENGINE-V...OL-CEDRIC-SAFARI-2-8-LTR-DIESEL-/192561589163

 

[solarman216]

Well did a bit more today, main thing being take my turbo to Eastbourne to a specialist, confirmed it was shagged, down side is bits are not available off the shelf so he has to make them so not too bad at £300 for a recon unit.

Here is a pic of a dissected follower, it was full sludge and think it would be nigh on impossible to clean it out, the piston on the right sits against the flat part that the cam passes over, the ball sits in the hole with the sprag cover over, there was a very small spring in there but I lost it, this forms a check valve, the spring in the pic sits on the sprag and the left piston sits over the right one and the chamfered part sits on the valve, what I cannot see is once this is charged with oil it needs even when clean, far more pressure to depress the piston than the valve spring can excerpt, what am I missing?

 

[solarman216]

Here you can see the indent that allows the oil into the smaller piston

 

[solarman216]

The assembly in one half of the follower, to realistically clean these out it would be necessary to extract the piston from the follower and the only way to do that is oil pressure into the small hole in the annular grove, which makes sealing it a bit of a problem, the piston is held in by a spring ring in a groove, much the same as a drive shaft into a CVJ, I will be trying that tomorrow, the other thing I did today was fill all of the ports with kerosene to test the valves and they all passed the test, so will not be removing them, Rick

 

[solarman216]

I have stumbled on another site that gives more info on this subject, and am looking into this further and I am pretty sure I have the answer, but need to confirm it before I post it, but that will not happen till I get at least one new follower to compare, Rick

 

[Flying Torquewrench]

Excellent work Rick.

Looking forward to hearing more!!

I have found a website selling the lifters in the UK if you need it. Not too badly priced either, cheaper than the guy’s in the middle east when you take shipping and VAT into account.

£300 for a turbo rebuild isn’t too bad either. Might be worthwhile for me to have a look around here if there is somebody that could rebuild a turbo in case it is needed.

 

[solarman216]

Not too much done at the mo, but I do have some good news, I have made a tool to dismantle the followers without damage, so all of mine are now in bits and cleaned up, the oil in the piston is probably the same oil that was first put in the engine 22 years ago, it was well thick but did not show much different to that off the dipstick on the glass test, I think that this is due to it not mixing with the rest of the oil, anyway I have ordered a new follower from local factors, should be here Monday so will then be able to do a new and old comparison, Rick

 

[solarman216]

Bits in the process of cleaning up, found a broken stud and another that had been drilled off center

 

[solarman216]

First drilling of broken stud with left hand drill, now for a larger drill and it should wind out

 

[solarman216]

The second one a bit more of a challenge

 

[solarman216]

The tool for removing the piston assembly from the follower, the idea is to strike the hollow cup on a bit of hard wood, it is important to hit it square on, unfortunately some of mine did not want to budge so found a bit of stock ali, they came out first time on that, they were making good round indentations in the wood, so absorbing the shock

 

[solarman216]

1st stud sorted

 

[solarman216]

2nd one, old bit out, now need to find a bit of ali, thread it and screw it in with some stud lock, then drill and thread the original hole, more tomorrow, Rick