Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

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CJH
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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by CJH »

I've done a couple of spot checks on the tappets, and even though it's not the most extensive testing I've ever done the correlation is complete. The tappets under load are the ones that depressurise.

Yesterday morning, #2 Exhaust and #3 Inlet were both open, and by following Itchyfeet's advice to bring each cylinder to TDC (when the corresponding valves are closed) I found that all the tappets were hard except #2 Exhaust and #3 Inlet, which had at least 1mm of play.

I drove the van after yesterday's test, so all the valves had re-pressurised, and when I came to check them this morning different valves had been left under load overnight. This time it was #1 Exhaust and #2 Inlet, and again, all the tappets were hard except the two that were under load.

That's enough to convince me - the tappets in my engine are pants! (unless someone tells me they all do that). In the past, when people referred to tappets 'draining down' I had a mental image of the oil draining out and the cavity filling with air. My experience with these KS tappets makes me think that it's just the oil seeping past the sides of plunger or past the check valve, so that the plunger is just depressed further than it should be. So when the engine starts, it's not a case of having to dispel the air, but just having to put more oil in so that the plunger returns to where it should be.
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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by oilrag »

Hi ,just picked this up and maybe i can help
I use a contractor to apply a surface hardening to cranks and cams ,its called Tuftriding QPQ
heres their abridged explanation
Quote
" Tufftride is a heat treatment process that enhances wear, fatigue and corrosion properties of any ferrous material, but with minimal distortion owing to the low process temperature of 580°C. These benefits result from the formation of an intermetallic compound (epsilom iron nitride) on the surface of the treated component, strengthened and supported by the diffusion of nitrogen.

Q When quenched to develop the full properties, treated parts have a characteristic matt black finish and for many applications no further treatment is necessary.

P When operating against plastic or rubber seals, soft bearing metals or simply because a superior cosmetic appearance is required, the components are polished.

Q Optimum colour and corrosion properties are restored by a short passivation treatment in the quench bath.

Hope this is of help to relates to your queries re cam follower colouring .

Cheers
G
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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by itchyfeet »

I agree with the pants tappets conclusion, I assume its noisy every time you start?
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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by CJH »

oilrag wrote: Hope this is of help to relates to your queries re cam follower colouring .

It does, thank you. So what does this say about the way these tappets have been hardened? Is it a different process to what the polished tappets would have received? Is it a cost-cutting approach that's not as good as the others, or is it likely to have been applied in addition, and therefore an improvement? It'll be interesting to see what Tobydog finds with his testing.
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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by CJH »

itchyfeet wrote:I agree with the pants tappets conclusion, I assume its noisy every time you start?

It is. But not for long. If ever the tappets in my DG became noisy (typically after 3 to 4 weeks standing idle, so not very often) it would take 20 minutes of hard driving for them to quieten down, but with these KS tappets they're usually quiet before the choke has come off, even with gentle driving. I can't decide whether the shorter time is because it only takes a little more oil for them to reset (compared to perhaps the DG's tappets needing to completely refill), or whether it's because the plungers and/or the check valve are a looser fit so the oil gets in quicker.

So unless Tobydog tells us that these CP4L tappets aren't worth fitting, they'll be going in in place of the KS ones. That won't be for a couple of weekends at least unfortunately.
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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by kevtherev »

What are your lash settings on the lifters CJ?
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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by CJH »

Touching plus 1.5 turns.
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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by kevtherev »

Same as me then
Have you tried different settings?
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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by CJH »

I haven't. The 'book' setting is 2 turns I think. If I'm half a turn short, could that mean that the depressurisation that I'm getting is just that half turn of 'slack' being taken out? Maybe they wouldn't compress any further if they were wound in an extra half turn. Worth a try I guess.
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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by itchyfeet »

I wonder if your high lift camshaft could be contributing also :idea
Do you know what the lift was? stock DJ is 8mm if I remember.
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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by CJH »

That crossed my mind, but it's not a particularly 'high' lift cam.

Here it is plotted against an original DJ cam. I'm fairly sure this was the best used DJ cam that I could find, but it's possible it was a bit worn, which might explain the difference between inlet and exhaust. And if there's any wear on the inlet, which is only a fraction of a mm less than the new cam anyway, then I think that means the tappets should be fine with the new cam.

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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by ajsimmo »

I've gone back to 2 turns preload with KS followers. Seem to be much quieter, but that could be down to my new improved priming routine.

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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by CJH »

I'll try 2 turns then. I did the same with the assembly lube and all that, but I'm struggling to see how the effects of that process can survive long-term. I would think that would all get washed away by hot, pressurised oil.
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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by ajsimmo »

Yes, eventually, but it must help reduce that initial wear rate at first start up, then they bed in better leaving closer tolerances from then on. Maybe.
I just know I've had fewer (as in no) problems since.

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Re: Early 1.9 to 2.1 conversion - stop me if I'm being stupid!

Post by CJH »

I've think I've set the pre-load to 2 turns now, but it was a bit of a saga and I'm not convinced I've done it right. I started by working on the cold engine, so that I didn't burn myself on the exhaust, but it had been 24 hours since I'd driven it, so all the tappets had depressurised. What this means in practice is that the plungers had adjusted to the valve position, and the oil below the plunger was no longer under pressure. When I slackened off the locknuts, none of the adjusters had any preload at all - in fact I was able to back them off with just my fingers.

What I should have done is just add another half a turn, on the assumption that the existing pre-load was correctly set at 1.5 turns. But I wanted do them all from scratch and 'get them right'. So before I twigged what was going on I added 2 turns of pre-load to every one. I know now that this meant a total of 3.5 turns. And it was worse for the two tappets that had been under load over night. They needed to be wound in a bit just to take up the slack from the depressed plunger, and then I added a couple more turns. Goodness knows how much pre-load I ended up with on those two.

Too much, as it turned out. The engine wouldn't start. I'm guessing lack of compression on at least the two cylinders that had the tappets under load over night. So then I attempted to undo what I'd done. I undid each one by 1.5 turns, which should have left 2 turns (except for the two that had been under load, which I attempted to set by matching the length of visible thread on the adjuster). Now the engine started and ran ok, but with a fair bit of valve noise (as usual).

So I took it for a run to re-pressurise the tappets, and then adjusted them all again, and now it starts, runs fine, and is nice and quiet. I'll have to wait till the morning to see if it's had any effect.

But I'm not convinced the pre-load is right. I doubt that the plungers are ever at a fully pressurised 'natural' position from which to start applying the pre-load. I'm pretty sure they just end up wherever the pushrod dictates. How do I get them back to a reference position?

I suspect that what I need to do is back the adjusters right off and leave them overnight, so that the internal springs have a chance to push the plungers back to their natural position. Is that correct? Is overnight enough?
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