Steve126
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| posted on 4/5/16 at 11:52 AM |
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Crossflow Oil Pressure
If you had a freshly rebuilt crossflow engine and you were turning it over with the plugs out, how long would you expect it to take before you got oil
pressure?
I've rebuilt my engine, it has new everything, I've checked the oil galleries are clear, checked the gap between the pick up pipe and
sump, made sure I put the bearings in the correct way, tried different oil pumps and filters, primed the pump, but I get no pressure.
I'm not sure if I simply needed to crank the thing over for longer or if something else is wrong. I did find that if I kept it going for quite
a while the engine would suddenly seem to tighten up, but wasn't sure if this is something that happens when pressure builds or if it was a sign
that the engine wasn't happy due to a lack of oil, so I stopped.
I'd be grateful for any advice.
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David Jenkins
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| posted on 4/5/16 at 01:21 PM |
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I would expect you to see some pressure after a brief spin - but if you have a new cam then you shouldn't be spinning the engine over constantly
with the starter. (see Burton Performance's technical guidance pages about cams to see why).
One thing to look at is the pressure relief valve on the oil pump - sometimes they stick open if a bit of grit has got in there - this is why I
didn't get to my first SVA appointment (sudden loss of oil pressure on the way). If you look at the pump's mounting face you'll
just see the top of a shiny cylinder - if you give that a prod with something non-scratch then you should be able to push it in and out (but it is a
tough spring). In my case, I could see that the piston was stuck in, and a gentle prod let it click back into place. Never stuck again, so I guess
the filter caught the grit particle (10,000 miles ago!).
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MikeRJ
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| posted on 4/5/16 at 02:21 PM |
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On a freshly rebuilt engine if you spin it over on the starter to get oil pressure you can almost always hear it slow down when the pump finally
primes and pressure starts building up.
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rusty nuts
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| posted on 4/5/16 at 06:09 PM |
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Filling the filter with oil helps
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02GF74
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| posted on 4/5/16 at 06:25 PM |
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With no plugs fitted it will turn over briskly. I would expect oil pressure lught to come off easily in less than 30 seconds.
You have correct amount of oil?
Does oil pressure switch work, lamp work?
Check relief valve inside pump?
Gasket fitted correctly so no oilways blocked ( dont think thats possible but hey.....)
Is oil pick up ckear and sitting in oik?
Is the gasket for pickup (its been a while but seem to recall ther being one), fitted correctly and no gaps so air isnt sucked in.
Is pickup not porous, eg tube welded but with pinholes?
Is there oil in the filter?
Is it correct filter, is drain valve not preventing flow? Again unlikely but....
Are you seeing oil on rockers and pooling on top of cylinder head?
Got any other stuff plumbed in such as remote filter, oil cooler, dry sump?
If so, is it c0rrectly fitted?
Is cam chain fitted, seem to recall can drives the pump.
Re priming, should you need this, pack pump lobes with vaseline, not any other grease. At very least if vaseline goes. Then pump is ok.
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sprintB+
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| posted on 4/5/16 at 07:42 PM |
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Yep, you have a problem. Agree with the above
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Steve126
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| posted on 5/5/16 at 01:38 AM |
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quote:
Originally posted by 02GF74
With no plugs fitted it will turn over briskly. I would expect oil pressure lught to come off easily in less than 30 seconds.
You have correct amount of oil?
Does oil pressure switch work, lamp work?
Check relief valve inside pump?
Gasket fitted correctly so no oilways blocked ( dont think thats possible but hey.....)
Is oil pick up ckear and sitting in oik?
Is the gasket for pickup (its been a while but seem to recall ther being one), fitted correctly and no gaps so air isnt sucked in.
Is pickup not porous, eg tube welded but with pinholes?
Is there oil in the filter?
Is it correct filter, is drain valve not preventing flow? Again unlikely but....
Are you seeing oil on rockers and pooling on top of cylinder head?
Got any other stuff plumbed in such as remote filter, oil cooler, dry sump?
If so, is it c0rrectly fitted?
Is cam chain fitted, seem to recall can drives the pump.
Re priming, should you need this, pack pump lobes with vaseline, not any other grease. At very least if vaseline goes. Then pump is ok.
The amount of oil is correct.
The oil pressure switch worked on my old engine, I also have a gauge and the needle on that didn't move.
I would have thought the relief valve would be ok as I have a new pump and I've tried a used one that worked on another engine.
Oil pick up is clear, fitted correctly, in good condition and is in oil.
Filter was filled with oil before it was fitted.
I've tried different filters, all listed as for the crossflow engine and all filters I have seen used by other people on these engines.
Oil doesn't come out of the top of the block and if I unscrew the oil pressure gauge pipe from the union in the side of the block it is bone
dry.
Cam chain is fitted and cam is definitely driving the pump
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02GF74
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| posted on 5/5/16 at 01:55 AM |
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This engine was working before?
How do you know correct amount of oil, used dipstick or volume?
Is it modified sump?
Is sump plug in? 
Would suggest removing oil filter, place bowl under pump and whizz engine over.
If no oil, bad pump, pick up not in oil, blocked or leaking.
Remove pump and wedge a hose into gallery, try to suck on it, ideally using one of those siphon pumps, and or blow into it and listen if you can hear
oil bubbling.
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rusty nuts
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| posted on 5/5/16 at 07:04 PM |
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You did of course fit the oil pick up pipe ? I've seen someone who forgot to fit one when rebuilding an engine years ago that had the same
problem.
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Steve126
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| posted on 6/5/16 at 01:08 AM |
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I did fit the oil pick up pipe, checked it was clear, cleaned the filter on the end of it.
I measured the volume of oil, the sump is standard, sump plug definitely in!
I've never had this engine running because when I bought it I knew it needed a rebuild.
I actually found there was a problem a couple of months ago, tried various things to solve it and had no luck, so the engine is out of the car and in
bits at the moment. What bothers me is the fact that I can't find anything wrong with it!
The post by MikeRJ about how you can hear an engine slow down when the pressure builds worries me. When my engine seemed to slow down or tighten up I
stopped what I was doing because I wasn't sure if the pressure was building, if I was damaging the engine or if the battery needed a charge. I
found that if I left it for a bit and then tried again it was back to turning over very easily - perhaps if I had just kept it spinning over on the
starter I would have got pressure and it would have been ok. It didn't feel right though.
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