Tappet reinstallation

[Chimjunkie]

Quick question. Upon reassembly, can hydraulic tappets be reinstalled dry? Will they eventually prime and work properly when the engine is run? or is it an absolute must that they are filled?

[stevieturbo]

Oil gets pumped to them....so dont see a problem.


But some engines can be very fussy....some might want dry...some might want filled.
Some might never bleed down if you fill them up...meaning strip down and empty them.

[rev-erend]

So have they still not pumped up..

How often have you run them and how long for ?

[Chimjunkie]

rev-erend said:

So have they still not pumped up..

How often have you run them and how long for ?

Only had the engine running for several sessions of several seconds due to lack of oil pressure on the gauge (gauge moves a tiny bit. no oil pressure warning light on). Prob need to give it a little rev, but need to play with distributor to improve timing guestimate. Obviously engine very tappety because they are dry. This noise together with my knackered manifolds and the possible oil pressure issue is making me a bit timid! Battery now fully charged again so shall have another play tomorrow.

Assume i would need to run engine a 2500rpm ish for a while to get tappets sorted..

[falcemob]

Assuming you didn't fit the tappets completely dry, you did smear them in oil and squirt oil in the guides didn't you, then you should have no issues giving them a few seconds to fill. I would think around 10 to 20 seconds would suffice. After that if you still don't have proper oil pressure and they haven't filled then start panicking. Fullish pressure should build up on tickover, 2500 may be a tad excessive for a 1st start if it's a new build.
Edited: I would spin the engine over with no plugs in for around 30 seconds to minute with a good battery first to see if they fill.

Edited by falcemob on Saturday 25th October 23:25

[Chimjunkie]

falcemob said:

Assuming you didn't fit the tappets completely dry, you did smear them in oil and squirt oil in the guides didn't you, then you should have no issues giving them a few seconds to fill. I would think around 10 to 20 seconds would suffice. After that if you still don't have proper oil pressure and they haven't filled then start panicking. Fullish pressure should build up on tickover, 2500 may be a tad excessive for a 1st start if it's a new build.
Edited: I would spin the engine over with no plugs in for around 30 seconds to minute with a good battery first to see if they fill.

Edited by falcemob on Saturday 25th October 23:25

Tappets dry inside but oiled on outside. Plus also poured oil all around rocker shafts, down into tappets and over cam shaft. Engine not a complete rebuild. Only took off one cylinder head and replaced new timing chain and installed adjustable pushrods. Also, as said above, the engine has already been run for several sessions of 10-15 secs to see if oil pressure gauge moved. Mostly worried that oil pump is not priming (serpentine).

[stevieturbo]

Chimjunkie said:

rev-erend said:

So have they still not pumped up..

How often have you run them and how long for ?

Only had the engine running for several sessions of several seconds due to lack of oil pressure on the gauge (gauge moves a tiny bit. no oil pressure warning light on). Prob need to give it a little rev, but need to play with distributor to improve timing guestimate. Obviously engine very tappety because they are dry. This noise together with my knackered manifolds and the possible oil pressure issue is making me a bit timid! Battery now fully charged again so shall have another play tomorrow.

Assume i would need to run engine a 2500rpm ish for a while to get tappets sorted..

I suggest you sort the lack of oil pressure, before even thinking about tappets !!!! they will never pump up with no oil pressure !!!!!

Prime the pump manually ( assuming RV8 ), and no not run the engine again until oil pressure has been confirmed.

[Yuxi]

Why do you need adjustable pushrods if you have hydraulic tappets?

Edited by Yuxi on Sunday 26th October 05:04

[Steve_D]

The RV8 is famous for the oil pump not priming.
There are two ways around this.

Take the pump apart and pack it with Vasaline. Then turn over with the plugs out.
or
Take out the dizzy and make yourself a drive shaft to put in an electric drill and spin up the oil pump with that until you have pressure.

Steve

[Chimjunkie]

Yuxi said:

Why do you need adjustable pushrods if you have hydraulic tappets?

Edited by Yuxi on Sunday 26th October 05:04

The preloads still need setting. usually with shims. I always had one or two tappets which were noisy and wanted to set all preloads individually.

[Chimjunkie]

Steve_D said:

The RV8 is famous for the oil pump not priming.
There are two ways around this.

Take the pump apart and pack it with Vasaline. Then turn over with the plugs out.
or
Take out the dizzy and make yourself a drive shaft to put in an electric drill and spin up the oil pump with that until you have pressure.

Steve

This i have heard, but assumed that this only applies to the older oil pump design. The Serpentine engines have a crank driven oil pump which should self prime. It's a 6-7 hour job to remove the timing cover on a TVR Chimaera unfortunately so dont want to take apart again unless i absolutely have to. Have read that oil can be pumped manually back up through the oil pressure sender?

[Pumaracing]

The easiest way to prime oil pumps without dismantling everything is via where the oil filter screws on. Engines usually have a feed into the filter from the pump via the holes in the outside of the filter, the oil then goes through the element and back into the block to the crank via the central channel the filter screws onto. If you get a length of 8mm i/d plastic tube and a small funnel you can insert the tube into the appropriate oil feed drilling from the pump and turn the engine backwards. This will draw oil down into the pump. A cupful should be plenty. Do NOT put the tube in the drilling that goes to the crank obviously.

Starting an engine to "see if the light goes out" is not very sensible to put it mildly. You can ruin the bearings within seconds doing this. I recall an inexperienced mechanic who one of my customers had the misfortune to employ shagging one of my new race engines by just cranking it until he'd flattened two fully charged batteries because he had no idea you needed to prime the pump or how to do so. The engine never even got started but an hour of cranking with the bearings dry achieved similar results. He didn't stay employed for much longer anyway.

[chrispitman]

The early Rover V8 need to be primed via the dizzy drive, but the later serpentine are self priming so unless you have a completely worn pump it should be fine.

check the oil pressure warning light comes on when you turn the ignition and this should go out as soon as the car starts, the gauge on the dash takes quite awhile to react.

The tappets, I assembled mine dry, with a bit of oil on the body, and used the cam oil on the base. This provides enough to start the engine untill oil presure reaches the top of the engine.

I belive Tappets can take quite awhile to prime.

[spend]

Pumaracing said:

If you get a length of 8mm i/d plastic tube and a small funnel you can insert the tube into the appropriate oil feed drilling from the pump and turn the engine backwards. This will draw oil down into the pump.

Since the filter faces downward on the RV8 and the pump gallery is not a round journal I can't see how you could achieve that? There is the LR oil cooler take off on the side (not the bottom one - it would need a much better seal and they are interconnected IIRC) of the Serp cover which could be used to similar effect I guess.

Might as well just pump a load of oil through the pressure sensor gallery (top one) IMHO.

[Pumaracing]

What the specific gallery and filter arrangements on your particular engine are I have no idea. I'm just giving you the general principles. Find a gallery that goes to the pump not the crank and turn the engine backwards is the gist of it.

BTW I do hope when you've been cranking the engine to try and get oil pressure up you've been doing it with the spark plugs out. It'll spin over a lot faster and with much less load on the dry bearings. A continuous 20 second blast like this gets pressure up on most engines. You can hear when the pump has started pumping even without looking at the oil light. The rpm goes down a bit as the pump load builds up and all the mechanical noise quietens down a fair bit. If all you've been doing is cranking for a few seconds at a time and/or starting the engine for a few seconds it's not surprising the pump hasn't primed yet.

[GreenV8S]

If you have an oil cooler or remote filter, you also have the option of teeing into one of the hoses and pumping oil in. That gets the pump primed and also pushes some oil out into the galleries to give the bearings a head start. I use an ordinary cheap small pump powered by an electric drill and it does the job perfectly.

[spend]

Pumaracing said:

Find a gallery that goes to the pump not the crank and turn the engine backwards is the gist of it.

That sounds far more rational to me, I've always been sceptical about the forcing oil up the middle of the filter (which many swear by as a method of priming the pre-serp pumps).

Specifics of the RV8 are that common consensus is that the Serpentine (crank driven pumps) are self priming and the pre-serpentine (dizzy driven) need priming. Generally the serp pump priming problems are down to loose/blocked pick up pipes AFIK. Hence most serp rebuilds are just fire it up & hope, which would really bother me. Personally I put a pump across my oil cooler takeoff and run it whilst cranking the engine by hand, there are still enough things to worry about even when well oiled

[Chimjunkie]

Thanks guys for the input.

How about something like this for pumping oil into and around the engine?

http://cgi.ebay.co.uk/1-2-DRILL-HOSE-PUMP-FOR-POND...

[GreenV8S]

Chimjunkie said:

Thanks guys for the input.

How about something like this for pumping oil into and around the engine?

http://cgi.ebay.co.uk/1-2-DRILL-HOSE-PUMP-FOR-POND...

As far as I can see, that's identical to the one I use. The only slight gotcha was that the rotation/flow markings cast on the outside were back to front so check the direction of flow before you connect it up.