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Author: Subject: Oil pressure while cranking over
David Jenkins

posted on 27/7/03 at 09:25 PM Reply With Quote
Ho hum

Still no joy... I took the oil sender out and cranked the engine over - no oil came out.

Now I don't know whether to risk the engine start, or look into it deeper...

cheers,

David






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Rob Lane

posted on 28/7/03 at 11:54 AM Reply With Quote
Trying desperately hard to remember the details but as i recall the sender is on the same gallery as the camshaft feed. Common problem is that there's crud blocking the gallery or exit hole to sender.

Have you commoned the output to low pressure switch and oil pressure guage?

As I recall it's, oil from sump up through pickup to filter then pump, on to galleries feeding crank journals and cam bearings. Then out to rocker shaft and rockers then drizzle return via camfollowers to sump.
It's not a pressure fed filter but a suction fed one.

If you have oil at rockers then it's doing the rounds. Could be partial blockage of gallery.

Rob

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timf

posted on 28/7/03 at 12:05 PM Reply With Quote
dave

just a thought, you said that 12 v start wont get the oil flowing

try 24v though the starter they can handle them for a little while( used the 24v start method on rs2000 rally car)

failing that you shortend the oil pickup. could there be a hole in the pickup thats sucking in air at all.

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David Jenkins

posted on 28/7/03 at 12:15 PM Reply With Quote
quote:
Originally posted by Rob Lane
Trying desperately hard to remember the details but as i recall the sender is on the same gallery as the camshaft feed. Common problem is that there's crud blocking the gallery or exit hole to sender.


The block was supposed to have been fully cleaned by the reboring company (and it WAS squeaky clean! Had to oil it to stop it rusting) . It is possible that there's a blockage somewhere though, as they may have loosened some crud.

quote:
Have you commoned the output to low pressure switch and oil pressure guage?


Yes - I have a splitter in the oil sender hole.

quote:
As I recall it's, oil from sump up through pickup to filter then pump, on to galleries feeding crank journals and cam bearings. Then out to rocker shaft and rockers then drizzle return via camfollowers to sump.



AFAIK, it's oil pump gallery -> crank journal gallery (and senders) -> up to top of engine.
Various orifices along the way for spraying oil on the important bits. This sort of matches what you describe.

quote:
If you have oil at rockers then it's doing the rounds. Could be partial blockage of gallery.


I'm not sure about the oil in at the rockers any more... - I'll have to get the cover off (again...) and have another look.

I'm really reluctant to start the engine until I've got this sorted. Once I'm sure that the oil is circulating then I can put the water in, some petrol in the tank, then crank it up!

At the moment though, I'm nervous. Sigh...

cheers,

David

Note: I put the old oil pump on yesterday, just in case. The rotors were a bit scored, but otherwise it was within tolerance. Same result.

[Edited on 28/7/03 by David Jenkins]






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David Jenkins

posted on 28/7/03 at 12:28 PM Reply With Quote
Anybody know...

...where I can find a good diagram of the x-flow block? Something that will show the layout of the galleries, so I'll know which way to poke (Ooer, missus!).

Cheers,

David

[Edited on 28/7/03 by David Jenkins]






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Rob Lane

posted on 28/7/03 at 04:17 PM Reply With Quote
Sorry David, original reply was very rushed as I was just signing off to visit a client.

If the block was done professionally then they should have removed the plugs at end of block to the oil galleries as well. This then allows the chemical cleaner bath to penetrate throughout.
It's always recommended that the oilways are cleaned out with pipe cleaners afterwards as well. This is because when the block is immersed, the waterways are also cleaned out and in many cases they carry the casting sand and sludge around the tank, some of which 'could' enter the oilways.

Sometimes just poking a piece of soft wire into sender hole will unclear it.

Gallery is common, so no oil coming out is worrying, it might as you suspect mean theres no oil to bearings!! If when you check there is oil from rockers, then it means it is getting up to there via cam bearings at least because it feeds from there up.

The Xflow is usually difficult to get up to any pressure when cranking due to low running pressure anyway.

I wouldn't recommend anything more than a second or two of trying to get the pressure up by starting it. I ruined one engine by running it for 10 seconds that way! If pumps primed it should build up pressure virtually immediately on a new engine.

Rob

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Stu16v

posted on 29/7/03 at 07:39 PM Reply With Quote
David, just some ideas for you.....

I noticed from another thread that you have shortened the sump (on the car?).

How did you shorten the pick-up pipe? There is no risk of a pin hole in the pipe anywhere?

Did you shorten the pipe enough? I've seen cars loose oil pressure in the past because the sump has been 'bashed' into the pickup pipe, and blocking entry hole.

In fact, the very reason I was prompted to reply to this thread is because we will be rebuilding a Pinto out of a Robin Hood this weekend. that was taken out because of oil pressure problems. When it was cold, it was extremely slow to put the oil light out and build up pressure. Strangely, when warm, oil pressure was actually better, and the light would go out instantly. We have found the problem, the oil pickup pipe was squashed agianst the bottom of the sump. When the engine was warm, the oil was thinner, and must of found it easier to get into the little gap available between sump and pipe. Luckily, there initially looks to be no damage to the engine......





Dont just build it.....make it!

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David Jenkins

posted on 29/7/03 at 08:08 PM Reply With Quote
quote:
Originally posted by Stu16v
How did you shorten the pick-up pipe? There is no risk of a pin hole in the pipe anywhere?


Chopped a piece out and silver-soldered the ends together - ended up as a very strong joint with no apparent pinholes. I also put a good smear of jointing gunk around the oil pickup pipe where it goes into the block when I refitted it.
quote:

Did you shorten the pipe enough?

I believe so - originally I didn't, and had to take the sump off again to do a proper job.

This is all part of my anxiety - did I do a good enough job on the oil pickup pipe...
I believe that I did, and the problem is that the engine doesn't crank fast enough to push the oil around... however, there is doubt...

I REALLY don't want to have to take the sump off again!

cheers anyway Stu!

David






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Stu16v

posted on 29/7/03 at 08:22 PM Reply With Quote
If the pipe has been silver soldered, I wouldnt be concerned about pin holes.

Just the pick-up to sump clearance then....

An idea to try....

Strip one of your oil pumps, clean spotlessly, and pack pump full of Vaseline (ooh-err) or moly grease. Fir to engine, and spin engine over for twenty or so secs. Hopefully, one of two things will happen. Either a) you will get oil pressure, and no more probs, or b) you wont. If b) is the case, take oil pump back off and see if the grease has been replaced by oil. The Vaseline/grease will mix with the oil happily, and help prime the pump far better than oil. If oil hasnt reached the pump, you know the problem lies with the supply side. If it has, then it is the gallery side......





Dont just build it.....make it!

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David Jenkins

posted on 30/7/03 at 07:15 AM Reply With Quote
I would never have known about that technique... I like this forum!

Presumably you mean packing the vaseline around the pump chamber, where the rotor is (not all the pipes & tubes, etc.!)

That's Saturday morning's job lined up...



cheers,

David






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stephen_gusterson

posted on 30/7/03 at 01:35 PM Reply With Quote
David

I have no idea of whats the difference in taking sump or pmp off, but is it not possible to take sump off, and put a pipe on the pickup tube, and blow or pour oil down it so it goes back up to the pump and primes it under gravity / tyre pump pressure.....?


atb

steve






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David Jenkins

posted on 30/7/03 at 02:35 PM Reply With Quote
Taking the sump off is a logistical nightmare!

I had thought about connecting a pipe to the pump's pick-up port on the block and sucking on it with my shop vac - if it goes up the tube quickly then there's not much wrong there!

DJ






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timf

posted on 30/7/03 at 02:48 PM Reply With Quote
david

do you fancy using a compressor to blast a shot of compressed air around the galley ways to see if any crud can be flushed through the system

Tim

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David Jenkins

posted on 30/7/03 at 02:55 PM Reply With Quote
Maybe - I'll hold that one in reserve, Tim

cheers,

David






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Stu16v

posted on 30/7/03 at 05:43 PM Reply With Quote
quote:

Presumably you mean packing the vaseline around the pump chamber, where the rotor is


Yes mate.

[Edited on 30/7/03 by Stu16v]





Dont just build it.....make it!

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timf

posted on 30/7/03 at 08:16 PM Reply With Quote
david

i've dug arround in the books i've got and found a wordy description of the oil system if its any help

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David Jenkins

posted on 31/7/03 at 06:58 AM Reply With Quote
Tim,

That could be very useful - what book is it in? (Just in case I've already got it... )

DJ






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timf

posted on 31/7/03 at 07:35 AM Reply With Quote
rebuilding and tuning for'd kent crossflow engine by peter & valerie wallage
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David Jenkins

posted on 31/7/03 at 09:41 AM Reply With Quote
Ah - got that one...

You are correct, though - it's the only book I've seen that attempts to describe the oil system.

Never mind - and thanks for the thought.

cheers,

David






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paulf

posted on 1/8/03 at 09:40 PM Reply With Quote
The method I have used in the past when having problems with oil pickup is to remove the oil pressure switch and connect a pumptype oilcan to the engine with some hose and fittings , then pump in a pint or so of oil which should backfill the pump and filter.Then spin over with a fresh battery and the plugs removed.
I also found my crossflow to be slow to prime but after a minute or so i fitted the plugs and fired it up and got immediate oil pressure.
paul.
quote:
Originally posted by stephen_gusterson
David

I have no idea of whats the difference in taking sump or pmp off, but is it not possible to take sump off, and put a pipe on the pickup tube, and blow or pour oil down it so it goes back up to the pump and primes it under gravity / tyre pump pressure.....?


atb

steve

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stephen_gusterson

posted on 1/8/03 at 10:24 PM Reply With Quote
I dunno why david is so worried really.

its either gonna work and prime first time, or wreck his engine.

No biggie really!





best of luck


atb

steve






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David Jenkins

posted on 2/8/03 at 09:24 PM Reply With Quote
Thank you, Steve, for that helpful suggestion...

As it happens I decided to go for it today, with the aim of risking 5 seconds of running (every bearing had received a coating of bedding-in lubricant when I assembled the engine).

Unfortunately I didn't get a spark (see the question in another topic!) so the question hasn't been answered yet...

cheers,

David






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