new engine still giving me grief

[123-jn]

There is no denying that most of them seem to be nice and quiet when running but I don';t get this really quick bleeding down and always starting with a rattle for a few miles. This was never the case with the old ones. With these it would be 4/5 days before one would bleed down enough to really knock on start up.
These look very similar in construction to the roller tappets employed in most big American V8's. Same sort of metering disc to feed oil up the pushrods etc. You don't hear much said about theirs rattling every start up? I can only think that it is either parts needing to wear-in or poorly manufactured tolerances. Ratwell seems to suggest that I should detect the slightly soggy ones and open the gap to 0.06 and run the engine for 15 mins to make sure they are pumped up, then set the preload. I am a bit concerned about the rather weedy clips that may then ping out of the groove. But once this weather has cooled off abit I will give it a try. There is definately at least one that is playing up but even with a stethoscope I can't track it down. Going on softness at the rocker is hit and miss as any lifter with the valve spring against it seems to go a bit soggy in minutes, even if they then pump straight up when the engine starts.
I have good oil pressure around the engine, on start up maybe even a bit too much!!!! 80-90PSI at the main gallery. On hot tickover I have 20-30Psi depending on how hot!!! and at a steady 2500 rpm I have over 60 PSI Hot. My dash Gauge is quite accurate up to about 35 then it over reads gradually more as it climbs. It reads 100Psi cold start when the draper gauge reads 80. Still plenty of pressure to pump up a couple of rows of tappets. Once I have re checked the lifters I intend doing another compression test with a different gauge to see if that is illuminating!!!

[CJH]

An update on Itchy's diagram, based on some rough and ready measurements:


So firstly the disk isn't gripped by the pushrod socket because there's approximately a 1.4mm gap between the pushrod socket and the lip inside the plunger. Also, the disk diameter is about 0.5mm smaller than the plunger diameter, which must be to allow oil to bleed past the edge. This means the disk floats inside that gap.

Secondly, there isn't a 'flat' side to the disk - each horseshoe sits slightly proud of the plane of the outer edge (and the central disk is on the same plane as the outer edge). On reflection I think this means the disk can go either way up, since the centre of the disk can never sit flush against the pushrod cup to block the hole, and the gap in each horseshoe is enough to let oil reach the hole in the pushrod cup.

[CJH]

Contrary to what Ratwell says, I'd say there is the potential for the oil holes in these lifters to align perfectly when the lifter isn't loaded. Here's a shot of one where the plunger spring is pushing the pushrod cup hard up against the clip at the top, and you can see that apart from a small rotational misalignment the holes are at exactly the same depth. So if these two holes were aligned like this, and pointing down, with hot watery oil, then the internal cavity could certainly drain down very quickly. And then I assume the first time the check ball opens the valve when the engine starts up, the important cavity in the bottom of the lifter will get some air in it. So maybe it would be wise to make sure these holes are 180 degrees apart during assembly, but I can't really see them staying that way.



The other style of lifter has a completely different arrangement - there isn't a single hole in the plunger, but rather 4 grooves cut into the base of the pushrod socket, so although oil can easily reach the centre of the plunger it seems like it would be less likely to drain out through aligned holes.

[MGP]

What oil are you running? 85psi cold is getting on for 6 bar I would have thought most of your oil flow is going straight out the pressure relief valve.
The other thing I found a bit alarming reading through was that you are seeing 120 degrees plus oil temp, with a cooler!!!
Is it possible that there is a flow restriction in the system somewhere and that the problems your having with the tappets is a result of this.
Tappets only need a few psi to pump out but they do need a good flow of quite thin oil as the galleries inside them are quite small, your very high cold idle oil pressure would suggest that your oil is quite thick.

Sent from my SM-G920F using Tapatalk

[CJH]

I thought I'd investigate replacing the paperclip-type retainer with a proper circlip, as per the Febi version mentioned on the Ratwell page. Looks like I'll need a 17mm or 18mm circlip, but it's difficult to measure the internal bore where the circlip will sit. No problem, I'll try both sizes from a kit that I bought a while ago, and see which one fits best....



I'm sure the people who put these kits together do this on purpose

[itchyfeet]

are you sure the groove is the right shape for a square edged circlip?

[CJH]

No, I'm not. It's virtually impossible to tell by eye. I thought I'd fit a circlip and then see how flush it sits next to the lip of the groove. If there's a gap, then the square edged circlip is probably sitting against a rounded groove corner. But how bad would that be, given that it's only oil pump pressure that will be pushing against this clip? If a paperclip is good enough, how critical would the seating of the circlip be?

[itchyfeet]

why risk it?

[CJH]

When I disassembled the 2.1 that I picked up from a scrapyard, I found the mangled remains of two of those paperclip-type retainers inside the oil pickup strainer. A circlip just seems more secure. Anyway, I only said I'd investigate

[itchyfeet]

When I disassembled the 2.1 that I picked up from a scrapyard, I found the mangled remains of two of those paperclip-type retainers inside the oil pickup strainer. A circlip just seems more secure. Anyway, I only said I'd investigate

yes I said above I found two clips half out on two different engines, so worth investigating
You probably need to cut one in half to see and measure the groove

how does a loose clip get into the sump unless by human error, it can't get past a tappet.

[CJH]

You probably need to cut one in half to see and measure the groove

Yeah, won't be doing that. The groove outer face is flat/parallel, so the only unknown I think is whether the corner of the groove is radiused or square.

how does a loose clip get into the sump unless by human error, it can't get past a tappet.

Good question. I guess it could work it's way along the pushrod tubes into the rocker area, but there's no way into the sump from there I think. Dunno - I'll take another look. If there isn't a route, then it would have to be a fairly careless error - like a clip pinging out during a rebuild and not being found.

[tobydog]

Try pushing a piece of plasticine or something similar into the groove to see what the profile is.

[CJH]

Good idea - I'll try that.

[itchyfeet]

Try pushing a piece of plasticine or something similar into the groove to see what the profile is.

why didn't I think of that

[CJH]

Here's the route back to the sump for a stray retaining clip.



It's surprisingly direct, and on the 'lower' side, so a stray clip would simply 'fall' into the sump.