25 replies to this topic

[minivanman8]

I have just rebuilt my engine (now 1293 with supercharger, 18cc dished pistons and a Vmax sw5 copy cam).

It started up first time no problem and sounds lovely but I had to stop it as the oil pressure gauge struggles to get off the bottom of the scale (I'm talking barely 2mm from the bottom of the scale!)

It has a new oil pump (yes it most definitely is engaged)

I am using the halfords classic oil for the first few hundred miles.

Any suggestions/easy checks/likely causes?

[BennerW]

Got another Oil Pressure Gauge, that would be the first check I would do. Is it a mechanical one or does a sender send a signal to the gauge.

 

Ben

[Cooperman]

With a new engine it is VITAL to build up oil pressure with the plugs removed before installing the plugs and firing it for the first time.
Never run a new engine, or any engine come to that, without a good oil pressure.
You need to now check the pressure relief valve, re-prime the pump, and spin it over with a second battery connected until it reads at least 40 psi. Do not, under any circumstances, fire it up until you have that pressure and just hope that your new engine is not damaged already.

[minivanman8]

It's a mechanical gauge. Was reading fine before the engine work. Spun it over with the pipe disconnected and oil splurged out of the block.

[minivanman8]

How can I check the pressure relief valve? How can I tell if it is faulty? And why do I need a second battery? It already has a new one!

[Stevie W]

Did you rebuild the gearbox at the same time??
I had this problem during initial spinning on the starter with the plugs out and after splitting the engine/box to check I had included the "O" ring I found I had problems with the oil pick-up pipe flanges where it bolts to the gearbox casing.
The flanges weren't very flat on both the pick-up pipe and the blanking plate.
I suspected the oil pump was drawing in air after removing the oil filter and finding it was full....but with very airiated oil (loads of tiny bubbles!).

Re-prime your pump and double check the pressure relief valve is clean and not jammed fully open.
Spin the engine over on the starter and see if you have oil pressure then.

Cheers, Steve.

Edited by Stevie W, 26 August 2013 - 05:56 PM.

[minivanman8]

I re build the box at the same time and included a centre oil pickup pipe. Little o ring was definitely included :)

Second gauge also reads zero and there's now no oil coming through the oil pressure gauge pipe . How can I re prime the pump without ripping the engine apart?

[Stevie W]

Undo the oil delivery pipe that runs from the block to the filter housing. Turn the engine over backwards whilst pouring oil down the hole in the block.
Re-attach the pipe making sure the copper sealing washers are in good nick, then try spinning the engine over on the starter with the plugs out.
Check your oil filter after a few spins and check what the oil looks like...should be bubble free-ish unlike mine was!!!

Cheers, Steve.

[Cooperman]

I always get another vehicle, attach the battery from the 2nd vehicle to the one needing an initial start-up, then run the engine of the 2nd vehicle whilst spinning the new engine over on the starter motor with the plugs out and coil lead disconnected until I have a minimum of 40 psi on the gauge. Then I put the plugs in, re-connect the coil and fire up the new engine, knowing that it won't have its new bearings damaged by lack of oil pressure.
The first few seconds after first start up can be critical and if the pressure has not been built up first, then expect the bearings to be at best slightly scored, at worst damaged.
NEVER do an initial start-up without first getting working oil pressure. This cannot be over emphasised.

[The Principal]

As above pour oil down the hole then put the car in second gear with the spark plugs removed and push the car backwards watching as the oil is drawn down towards the pump, once theres enough oil reconnect the pipe and spin the engine over plugs out may take 20/30 seconds to get some pressure.

[minivanman8]

I've removed what I believe is the pressure relief.....the little plug just below the oil filter housing takeoff....there is the bit you undo and a spring inside. Should there be anything else in there?

[mossy2a]

nope, a plunger and a spring,  i have found spacer washers in there in the past to increase the pressure.  Does the plunger look in good condition?, is it new?

 

i would agree, the best thing to do is to prime the engine correctly as all the posts above.

[minivanman8]

I think I have found the problem then..... There isn't a plunger in there.....I must have left mine in my original block....the one I had machined was done on an exchange basis. Good news as long as I haven't damaged any bearings in the process!

[mossy2a]

make sure you double check, sometimes they can be a pain to get out.  make sure it not hiding in there.

[minivanman8]

Ill double check in some decent light tomorrow, but it certainly looked like I was staring right through the block earlier. I guess it is a solid piece that's in there....so if I poke a screwdriver in and it goes 4 inches in I know there's no plunger in...