oil priming problem - RV8 (Pre-Serp)

[wedgienauld]

Please can anyone advise me on my Pre-serp RV8 (TVR Griff 500) Oil pump priming problem.

Griffith 500 Pre Serp - 50,000 miles. I’ve had the car a couple of years and used it but occasionally. Anyway – a few months ago I noticed that the oil light would flicker when the engine was warm (after about twenty miles of use). Changed out the oil pressure switch, still the same. Changed out the oil pressure relief valve for a JE Motors tadpole type - still the same. I’ve been using Valvoline VR Racing Oil. It appears that some users of this oil have experienced a lowering of their oil pressure.

I thought I would try a different oil – did an oil change and switched to Mobil 1. Old oil out and new oil in, with replacement oil filter – no oil pressure. Top end rattling, so all stop and prime the oil pump with vaseline. Still the same. Switch off remove oil pump base to find gears badly scored bits of aluminium and a marked front cover oil pump internally. Replaced the gears with new and refaced the oil pump base internal face using wet and dry and a sheet of glass. Clean and remove all debris. Broke the oil pressure sender so this was replced with the correct TVR part. Still all the same! Removed the sump yesterday and examined the oil pick up strainer. Little bit of Blue-hylomar, (from a previous replacement due to a leaky gasket there), so removed flushed/ picked off the residue gasket material and re-assemble. Repacked the oil pump with Vaseline – guess what - still no pressure. What is the problem?

[spend]

Spin the engine by hand and see if the dizzy goes round. Could be that all the damage was from the cam dizzy drive gear..

[GreenV8S]

Is the oil pickup still intact and sealed to the block? If this is cracked or loose it can let air in which makes it much harder to prime. Given the amount of work you've already done and the fact that you're obviously handy with the spanners I suggest you carefully mark the dizzy position and then pull it out. This will enable you to get at the oil pump drive so you can spin it up with a drill. This makes it much easier to prime the pump and also confirm the oil supply in general is all OK before you put the engine at risk. An alternative approach is to back fill the pump via the oil filter housing. If you have a sandwich plate (or don't mind spending a few quid to get one) this is a doddle. Otherwise not worth it unless you're really determined not to remove the dizzy.

I'm a bit concerned by all the debris you're describing in the oil pump and I suspect you may be heading for an unpleasant shock, but hope for the best and get the oil pump primed to start with.

[Number 7]

I managed to shear a distributor shaft close to the oil pump. Try as we might, we couldn't get oil pressure until the distributor was removed and we realised why.

As Pete said, definitely worth removing the distributor to at least (hopefully) eliminate that cause.

7.

[wedgienauld]

Appreciate the replies: the dizzy cap is off and the rotor arm spins round with the engine; of course the fact that the car started previously should have alerted me to the fact that the dizzy is not therefore sheared. The drive from the cam - could this still be damaged and affect only the bottom half of the assemby - the oil pump gears?

Oil pick-up pipe being cracked - good point, also - but too much of a coincidence for it to manifest itself at an oil change?

I believe Ill remove the dizzy and investigate further there. The priming tool for an electric drill start - where can I get one, please?

Regards, G

[GreenV8S]

wedgienauld said:

The drive from the cam - could this still be damaged and affect only the bottom half of the assemby - the oil pump gears?

In theory yes. The oil pump is below the gear, the dizzy is above it. Not saying it's likely but it's possible. While you have the dizzy out this is also a good time to see what condition the gears and oil pump drive are in because all that swarf you found must have come from somewhere. The drive you need is simply a rod with a flat on the bottom similar to the bottom of the dizzy drive. Once you have the dizzy out and look at the oil pump drive on the bottom, it's obvious.

[bigrumbly]

You could use a distributor shaft on the end of a drill to prime the system.

David
Trevor the TVR Rallying

[sax player]

It is possible the roll pin below the gear drive has sheered. this will still allow the rotor arm to turn but will not drive the gear pump.
Suggest if you have had the sump off take it off again and have a look at youe main and big end caps. Sounds as if you have done a lot of turning over wothout any oil pressure.
Hope you find the solution soon
Shaun.

[spend]

I think I'd be stripping the front cover anyway, any damage in the area of the cam / dizzy / oil pump shaft is likely to have knock on effects, and likely require a few new parts. The only way you would be sure is to strip & rebuild, and the impact of cam drive failure if the engine runs is catastrophic.... In reflection simply replacing oil pump gears after an incident was probably a tad optimistic

[wedgienauld]

Thank you for your replies Gentlemen: I removed the distributor at the weekend and it appeared totally in-tact with the gears in fine condition. The corresponding gear on the cam seem in good oder, too. I aquired an oil priming tool from Famous Four and attempted to spin the oil pump gears - removed one of the rocker covers in an attempt to view the oil flowing - but nothing flowed! Removed the oil filter to observe there, but nothing was moving. So again I drained the oil from the sump and removed the sump. Oil pick up pipe where I left it, (only one bolt holding mine to the block by the way), - examined it again, can,nt see any cracking. What is the problem here?

I've just made enquiries to aquire a replacement oil pick up pipe, (and bolt), but although I do,nt want to jump the gun here - whats the next step?

[TVRleigh_BBWR]

One small thing to add, is mobile one has change a lot since TVR 1st started using it. it was 10w40 at the time as this was a bit thin for a Rv8, i think now its 0W40 this will be much too thin for a Rv8.

[wedgienauld]

Hi Leigh - I'm using the 15W50 Mobil 1, which should be fine

[GreenV8S]

Is the oil pickup pipe sealed to the block? An air leak here would allow it to pull in air rather than oil. Also make sure you inspect it closely for any cracks which might be obvious to a cursory inspection.

[TVRleigh_BBWR]

Ok, sometimes you can miss the simplest things.

[spend]

Silicone leftovers blocking galleries? Don't normally like sticking compressed air in the engine, but I'd be inclined to gently blow 'backwards' to check the passages are clear.

[dlewis]

There does not seem to be any circulation so it must tbe the pump or the pump drive (as Saxplayer suggested) the debris from the gears or its connection.

I also agree with spend, curing the pump may not be the end of it all now.

The OP facts did mention faltering pressure, could be the drive/pump on the way out.

The upper bits must be in need of oil now.

Be careful.

Dave

[wedgienauld]

.. come to the same conclusion: compressor organised for Saturday - oil pump base (and gears out), and air-line aimed back towards the oil pick up. See what we'll see...

Anyone got a diagram of the oil-ways on an RV8 please?

[spend]

Best to take the pick up off & catch stuff coming out of the block? Look closely at the oil pump and make your own mind up, but providing you have filled the filter with oil, pumping oil through the pressure release valve or even pressure switch gallery is the surest way to prime the system IMHO.

Rene has a nice one:


There is a more tech one somewhere

[TVR keith]

I had this problem once and solved it by removing one rocker shaft then using the electric drill priming tool. Oil then comes out of the head where it feeds the rocker.
Once I got the oil flowing refit rocker shaft, spin engine on starter without plugs in until the pressure comes up on the gauge.
need to do something to stop fuel feeding through, not sure about that bit, the engine I was working on had carbs

[GreenV8S]

It's overkill perhaps, but the other option which is quick and easy to do is put a sandwich plate or remote takeoff plate on the oil filter and use an external pump to feed oil in. If you feed it via a T piece you can get it going round the engine as well as priming the pump. Maybe not so handy if you don't have one on the shelf, but they're cheap to buy and a heck of lot easier than dropping the sump and so on. If you have / were ever thinking of fitting an oil cooler, now would be a good time to get the sandwich plate.