No oil pressure.

[JOWETTJAVELIN]

I have just fitted the replacement 803, bolted it all in the engine bay etc after over a week of hard work, and fired it up but there is NO oil pressure. I gave it a few moments to get circulating as we had dismantled it all and had just put fresh oil in, I know it takes a moment to circulate. But there was not even any oil in the nylon pipe to the oil gauge.

I am wondering if this has something to do with the new oil pump and gasket I was advised to fit. It struck me on fitting the gasket that whereas the old one had two tear shapes, like the oil pump itself, the new gasket just had two holes for what I assume is the main feed.

I am really pi**ed off about this after we have gone to so much trouble over it all.

Please help.

[chrisd87]

Did you prime the oil pump?

[JOWETTJAVELIN]

No - not sure how to do this but we turned the engine over many a time to try and start it (timing way out to begin with).

[bmcecosse]

The new oil pump MUST be primed with oil before fitting....... And you NEVER try to start a 'new' engine until there is oil pressure available....... Plugs out and crank on the starter until the gauge shows 25 psi. But if the pump is dry - it will never prime up. Does your block have a blanking plug - on the exhaust side - just above the water drain cock a doodle diddley?? If so - remove it - pour in oil while slowly cranking the engine over on the starting handle (so two person job) - then refit the plug and crank on the starter to see if pressure comes up. I have to say -if you have run the engine with no oil pressure - you have probably damaged the bearing shells now. Were they all new ??

[JOWETTJAVELIN]

Bearings were assured to be in good condition, certainly not new. Probably 40-60k miles on the engine. I am sure there is a plug as you describe in the side of the block in what appears to be a main oilway.

I only ran the engine for about 10-15 seconds but we cranked it over so many times on the starter.

I hope they are ok otherwise I am going to go ape sh1t.

[bmcecosse]

I'm astonished you didn't open the big ends and mains to inspect the condition....... So - prime up as described and see if the pressure comes up on the starter. You're lucky - later blocks don't have that 'priming' plug......but there is a way to do.

[brucek]

Mmm - it may well be a case of learning from the error. As annoying, frustrating (and all those words that mean the same thing) as it will be, I think, given the obvious fragility of the 803 unit, and your past experiences with a failing unit, I would have the engine out again and firstly check whether any damage has been done to the big ends and mains. If they are toast - and to be honest, even if they are OK, I would fit a set of new shells which will at least give you peace of mind that they have been replaced and are in good nick. At the same time, I would take the opportunity to prime the oil pump properly so again, you know its been done.

Yes it will probably take another week to complete the job, but at least you will have more confidence in the unit once done. As it is, you don't know if the bearings are shot now nor whether the oil pump will work as it should. A few too many unknowns for me so I think I'd just get my sleeves rolled up and crack on. Good luck and try to 'enjoy' the experience

[JOWETTJAVELIN]

Thanks for the advice. I will see if I can prime the pump and see what happens. Unfortunately I won't have the time to take the engine out again because next week for the next 3 months things will be getting very busy with me - I'd hoped to have the car ready by this weekend.

[bmcecosse]

The pressure should come up ok with the priming - but do add a good 'cup' of oil - not just s few spoonfuls. Bearing damage - well - the hot oil pressure will tell that tale !

[JOWETTJAVELIN]

I am very pleased and relieved to say that following your advice (it was the first engine I'd ever stripped and I didn't know you had to prime the oil pump) that, after priming the pump with the best part of 2 pints of oil ( ) I started her up when I saw oil going along the tube to the oil gauge, and she sounded good! Hot idling pressure is approx 15 psi (with new oil pump), and there is a very slight knock at high revs, so I am going to purchase a new set of bearing shells for when the time comes.

Right now though I am the happiest man alive to see all our hard work paid off, and no major problems or even oil leaks from the sump. Test driving the car showed a fog of blue smoke in the rear-view mirror, but I expect this is due to the oil I squirted through the plug holes during re-assembly.



Hope to see you all at an event soon to terrorise you with clouds of blue smoke!

[MarkyB]

As long as there was some residual oil on the bearings you will probably be OK, time will tell.

[daveyl]

Might be worth purchasing a new oil pressure relief valve and spring. My newly rebuilt engine would only show a lowish oil pressure until I replaced it with a ball-bearing/spring combo from minispares.

[bmcecosse]

beware the ball bearing... yes - I used it on my competition engines but it can give some 'funny' results. If you have 15 psi idling - and ~ 50/60 psi when running and hot - it's in good enough condition. Leave well alone......and don't thrash it - it's a wee humble 803 - it needs careful handling.......

[David53]

I never take mine above 45 mph unless I really have to.

[bmcecosse]

Oh I never take my 1098 over 45 mph 'unless I really have to ' - which I did, about 20 times this afternoon.....

[JOWETTJAVELIN]

Quick update - that familiar knock has started again. It's not too bad atm and is intermittant but clearly I can't ignore it.

Can I renew the shells with the engine in situ and just take the sump off?

Is the crankshaft likely to need a re-ground?

[bmcecosse]

You can fit big-end shells - and the centre main..... But if there is any crank damage it's just throwing good money after bad, and 80s shells are not inexpensive..... A crank regrind will be required then. What's the oil pressure when hot??

[JOWETTJAVELIN]

Hot idle has just gone down to 10, hot running 35mph, 40psi.

[bmcecosse]

Not TOO bad for an 803........

[MarkyB]

The knocking suggests otherwise