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#1 New engine oil pressure

Posted: Thu Oct 29, 2015 10:42 am
by Wicker
Good day, All

The rebuilt engine is back in in the chassis with all electrical connections.

Before I go any further in building out the rest of the car I wanted to check oil pressure so if there is a problem I can deal with it now. Is is possible to spin the engine with the starter (without spark plugs) and show oil pressure? I can do this with other non-Jag engines. The oil pump will have to fill the oil filter canister which may be too ambitious for this exercise.

Thoughts and comments?

#2

Posted: Thu Oct 29, 2015 10:49 am
by Heuer
Should not be a problem.

#3

Posted: Thu Oct 29, 2015 11:07 am
by Alty Ian
I did that but you will find that you wont get up to full oil pressure just on the starter, mine got to about 30psi approx. But I would still do it and see what it reaches. The other thing to do is keep the oil fill cap off and watch for oil flow onto the tappets and most important of all is watch out for leaks !

#4

Posted: Thu Oct 29, 2015 11:57 am
by Wicker
Thanks David but my question is really can I except to get oil pressure just cranking the starter? Will the starter cranked engine fill the canister or is there a way to prime the lube system?
Appreciate the comments.

#5

Posted: Thu Oct 29, 2015 12:13 pm
by Alty Ian
All I did was fill the oil pump and pipes with oil while it was being assembled but most of that probably drained into the sump but I knew all surfaces had oil on them. All bearings were assembled with graphogem paste which is what I assume you have already done. It should self prime itself mine did so in a few seconds.

#6

Posted: Thu Oct 29, 2015 12:27 pm
by Wicker
I did not fill pump with oil as I thought it would drain out. I did put assembly lube on all bearings. I have cranked 3 times for 20 seconds each but I have nothing on the gauge. I will probably fit a hard gauge to the filter body and not rely on a sender unit.

Make sense?

#7

Posted: Thu Oct 29, 2015 12:37 pm
by Moeregaard
I've always done this on rebuilt engines, using a mechanical gauge. Don't rely on the dash gauge, as these are notoriously unreliable and inaccurate. You won't see more than a few pounds, but oil will get to all surfaces.

As Ian suggests, remove the oil cap and watch for oil flow around the tappets. Since this is the part of the engine furthest from the oil pump, you can be sure that everything as this point will have lubricant.

#8

Posted: Thu Oct 29, 2015 1:10 pm
by Heuer
Did it recently on my Lotus Elan - pressure got to about 30psi.

#9

Posted: Thu Oct 29, 2015 2:03 pm
by Alty Ian
Wicker wrote:I did not fill pump with oil as I thought it would drain out. I did put assembly lube on all bearings. I have cranked 3 times for 20 seconds each but I have nothing on the gauge. I will probably fit a hard gauge to the filter body and not rely on a sender unit.

Make sense?
I fitted a hard gauge before I turned it over once, I took out one of the gallery plugs (1/2" BSP thread) and fitted a male 1/2" to 1/4" hose adaptor and ran a rubber hose to the pressure gauge (which I tested before use with Compair) by the bulkhead for ease of reading.

I noticed it sprang to life ages before the sender unit said anything. However, when the engine ran, surprisingly the sender unit is really accurate.

I have grown so fond of the wet gauge I have decided to keep it until the engine is fully run in :lol:

#10

Posted: Thu Oct 29, 2015 2:32 pm
by Heuer
Personally I would keep it - indeed I have on my OTS. : viewtopic.php?t=173

#11

Posted: Thu Oct 29, 2015 6:06 pm
by jag68
Take out the oil pressure sender from the filter block and using a small funnel or tube pour a liter or more of oil through the hole. The oil will go into the galley and as well back into the filter. Some of it will eventually drain back into the pump/sump but you needn't wait that long to start the engine. The oil filter element absorbs a lot of oil and you can pour oil onto it before putting it into the canister and attaching to the filter block but that is messier. If you use a spin on oil filter pour a least a half liter of oil into it before screwing it on. It's amazing how much oil the element will absorb and you should get little to no spillage if you are quick.

#12 Oil pressure

Posted: Sat Oct 31, 2015 9:46 pm
by cactusman
As others have said absolutely you can. Remove the plugs first as that way there is no compression and the starter can spin the engine a bit faster. You won't get full pressure as others have said but enough to check you do get pressure and spot leaks. I always do this when I have changed oi filters etc....just in case😈. J