Can't get engine to prime

plastic orange · Post by **plastic orange** » Wed Apr 20, 2011 6:20 pm

I eventually got round to fitting a new cam and lifters due to my engine developing a tappit rattle at constant revs (3500 whilst cruising). Straight forward enough job, but I now can't get engine to prime. I've stuffed enough vaseline in the pump gears to open in Amsterdam

(several times now) , and spun the pump with an electric drill for ages. I'm getting some oil to oil feed to rockers, but no real pressure. I tried starting car (plenty cam lube), and it fired immediately, but no pressure so cut it off.
I've looked at all the oil threads on here, and basically tried everything with the exception of taking the sump off to check the pickup (engine out job).
Pump gears are good (tried another set), but there is some scoring in the front cover, with similar on base cover. I've also fitted an uprated relief valve in case this was a problem.
I'm now at a loss - any words of wisdom?

Cheers

Pete

ChrisJC · Post by **ChrisJC** » Wed Apr 20, 2011 6:44 pm

On what basis do you say 'no real pressure' ?

I have found that the electric drill you are using to prime the pump starts to work noticeably harder once it's primed.

Have you a remote oil filter? I fitted the pipes back to front on mine once....

Chris.

JSF55 · Post by **JSF55** » Wed Apr 20, 2011 6:48 pm

Are u sure it's not the gauge ? had this on the nsra not so long back
http://www.nsra.org.uk/newforum/showthr ... light=pump

plastic orange · Post by **plastic orange** » Wed Apr 20, 2011 6:51 pm

Basically, oil was just pouring out the rocker feed hole when drill was at max speed, plus some air spurting out till I had a flow. No remote filter fitted - SD1 front cover on a 3.9 engine.
I must have 'drilled' for several minutes, and no resistance felt on drill.

Pete

mgbv8 · Post by **mgbv8** » Wed Apr 20, 2011 7:51 pm

Pete!

You wont feel any resistance on the drill if you are priming with no rocker gear fitted.. Which is what it sounds like you are doing.

The oil pressure will be crap if the rocker gear is badly worn. And it will be zilch if you are trying to see pressure with two open 5mm holes on the heads.

Perry

plastic orange · Post by **plastic orange** » Wed Apr 20, 2011 8:08 pm

Rocker gear is in excellent order - I'd thought that oil would be forced under pressure out the hole rather than just flow. I did replace rockers, and still no gauge pressure (gauge was working the day before I did the job, and I've checked it against another one).
My suspicions is the front cover wear.

Pete

JSF55 · Post by **JSF55** » Wed Apr 20, 2011 8:21 pm

Your not sucking air some where? obvious would be the pick up pipe is not sealing or or u missed the gasket off ?

mgbv8 · Post by **mgbv8** » Wed Apr 20, 2011 8:22 pm

Pete!
If the rockers are in good nick and fitted and you still have no resistance on the drill and no pressure then I guess the relief valve is stuck open. I've had many V8's with badly worn front covers etc.. But they all made good pressure when priming from cold. My own front cover is the factory 1975 cover with 130,000 miles on it. Scored to buggery in the noil pump area as well.

When you prime with the drill with the rockers fitted do you see oil seeping from the rockers at all??

With the rocker gear off you will not see any pressure when priming unless you can spin the oil drive at silly rpm and see a 6 foot spout of oil from the oil holes in the heads.

If you had good oil pressure before you fitted the new cam etc. Why would the front cover be the problem now??

Ian Anderson · Post by **Ian Anderson** » Wed Apr 20, 2011 8:24 pm

Fit a new oil filter
No more vaseline

Then spin the pump - you may be blocking everything with Vaseline - everything then goes via relief instead of engine

Ian

plastic orange · Post by **plastic orange** » Wed Apr 20, 2011 9:07 pm

I'll try a new filter tomorrow.

Cheers

Pete

scotb · Post by **scotb** » Wed Apr 20, 2011 9:46 pm

fit the ls1 uncle pete,you know you want to.............

plastic orange · Post by **plastic orange** » Wed Apr 20, 2011 10:06 pm

I know

Pete

ChrisJC · Post by **ChrisJC** » Thu Apr 21, 2011 7:03 am

When I tried it with the rocker shafts not fitted, the oil shot half-way across the workshop.......

Chris.

plastic orange · Post by **plastic orange** » Thu Apr 21, 2011 10:40 am

I'd read that - hence my concern about oil just flowing out.
I'll replace filter and fill oilways via rocker feed hole (again) and try again.

Pete

stevieturbo · Post by **stevieturbo** » Thu Apr 21, 2011 4:24 pm

I used to always have problems with mine after an oil change or similar work on the oil system.
Remote filter and cooler fitted.

You could drill all day and still get virtually no oil pressure, then all of a sudden it would pop up. Or drive it gently for a few days, then it would eventually rise up as normal.
Sometimes I re-packed with vaseline and that worked, others it didnt. Never did figure out the problem.

Then I fitted the Mocal oil pump cover instead of the sandwich plate etc. And it worked properly all the time.

Issue certainly wasnt the oil pump cover itself, as I tried a couple. I also tried the oil pressure booster plate that Real Steel sold, and it made no difference.

SO just fit an LS1, it works all the time lol