Oil Pressure Worries. (Ford Crossflow)
Discussion
Hi,
I have 1600 ford crossflow fitted in my TVR Vixen and have some concerns with my oil pressure.
When the engine is cold I have approx 55psi, when the engine is hot it drops to approx 12psi at idle and 20psi when held at 3000rpm. The engine has only about 15 miles on her since a total rebuild (all new bearings, seals, shells etc..)and the oil gauge is a capillary type directly off the block.
Is it normal for the pressure to run so low when hot or do I have a problem??
Any advice gratefully received.
Ren32 said:
Hi,
I have 1600 ford crossflow fitted in my TVR Vixen and have some concerns with my oil pressure.
When the engine is cold I have approx 55psi, when the engine is hot it drops to approx 12psi at idle and 20psi when held at 3000rpm. The engine has only about 15 miles on her since a total rebuild (all new bearings, seals, shells etc..)and the oil gauge is a capillary type directly off the block.
Is it normal for the pressure to run so low when hot or do I have a problem??
Any advice gratefully received.
My mate has one and I think it used to be similar until he ran valvoline and it went up a bit. Anyway, his vixen is for sale with spare engine if anyone is interested. It's a bit of a shed but he's an engineer and his work on it is a very high standard. Car is in SE Cornwall.
Does yours breath heavy? That seems to be the real snag with those engines
You have a problem, I would say the pressure is low. Use a good 20/50 such as Valvoline Racing.
When cold, 55psi at tickover is OK but does it go up when you rev it and by how much? If it is all new you could check the accuracy of the gauge. Is it a new pump and are all the seals and gaskets fitted OK and not leaking. Was the pressure like this from first start up after the rebuild?
When cold, 55psi at tickover is OK but does it go up when you rev it and by how much? If it is all new you could check the accuracy of the gauge. Is it a new pump and are all the seals and gaskets fitted OK and not leaking. Was the pressure like this from first start up after the rebuild?
falcemob said:
You have a problem, I would say the pressure is low. Use a good 20/50 such as Valvoline Racing.
When cold, 55psi at tickover is OK but does it go up when you rev it and by how much? If it is all new you could check the accuracy of the gauge. Is it a new pump and are all the seals and gaskets fitted OK and not leaking. Was the pressure like this from first start up after the rebuild?
When cold, 55psi at tickover is OK but does it go up when you rev it and by how much? If it is all new you could check the accuracy of the gauge. Is it a new pump and are all the seals and gaskets fitted OK and not leaking. Was the pressure like this from first start up after the rebuild?
Hi,
when the engine is cold, the pressure varies from 50-65psi with revs. The pressure was similar to this from first start up after the rebuild, 45 psi cold but when the engine was hot the pressure on the gauge dropped to about 10psi! My first thought was a blockage or air in the capillary tube, which I bled but to no avail. My second move was to fit a new high pressure pump (65psi) which has altered the pressure to as it is now.
There are no obvious leaks on the engine (apart from a very small oil seepage from the head gasket, but not enough to cause a drip yet! And it has been re-torqued!). I'm assuming that if the gauge works to 65psi when cold then that eliminates any mechanical problems with the gauge? I'll swap out the gauge in the next day or so to be sure. I cannot remember what grade oil I used when I first filled it, but was definitely nothing exotic, just cheap multigrade, as I was planning to change it after the first 100 miles, I could try changing it to 20/50?
Any further advice welcome because I'm at a loss with this.
Ren.
love machine said:
Does yours breath heavy? That seems to be the real snag with those engines
It doesn't appear to at the moment, but when I built the engine I ditched the PCV valve and the airbox return and fitted a catch tank. I didn't want those nasty oil fumes messing with my lovely mixture!
Who built the engine, you or someone else? Do you know what was done with the engine such as grinding and what bearings were fitted? A leaky head gasket will not affect oil pressure. Leaky seals on your pump or pick up pipes would do and as the oil gets hotter it will get worse.
If the engine was built to race specs with plenty of clearance on the bearings then the pressures you are getting may be OK.
Try putting a good quality 20/50 in and see if it makes any difference, I only use Valvoline racing oil in my racing engines.
BTW what pressures did you get before the rebuild?
If the engine was built to race specs with plenty of clearance on the bearings then the pressures you are getting may be OK.
Try putting a good quality 20/50 in and see if it makes any difference, I only use Valvoline racing oil in my racing engines.
BTW what pressures did you get before the rebuild?
jacko460c said:
There is either an internal plug missing or the bearing clearances are too big.
Are there any internal plugs in a cross flow? I can't rmember as it is a while since I rebuilt one and if there is one missing I would expect no oil pressure. I would go with the clearnaces too big.I built the engine myself, (my first effort and proud) and followed everything by the book (the crossflow rebuild manual.) The engine hadn't run beforehand as my car was a basket case project with a seized engine (luckily just rusty bores). The block was re-bored +60 thou, oversized pistons + rings to match. There was no line-boring done to the journals as these were deemed within spec by the firm that did the re-bore. New 'standard' big/small end bearings fitted.
The only bearings not replaced were for the 3 for camshaft but these were checked for play when assembling. But other than that, all seals, gaskets and bearings replaced. Oil galleries maticulously checked and blown out. Oil pick-up pipe re-sealed with a drop of loctite. Everything was as snug-as-a-bug after assembly and primed with oil during assembly. She was also cranked with plugs out to prime oil system before first start up (55psi approx).
I'll try the oil change and try rigging a pressure switch/ warning light for reference in case of a duff gauge.
Don't remember any internal plugs?? Eeek!
Appreciate the advice.
At least if you did it your self then you know what you have done. I would go with an oil change and see what happens. I can't remember the layout on these but did you renew the seals on the pressure relief valve and or the relief valve itself?
Also is it a new pump or recon, did you clean all the galleries, you could have a bit of crap in the relief valve but if an oil change makes no difference check the pump.
Also is it a new pump or recon, did you clean all the galleries, you could have a bit of crap in the relief valve but if an oil change makes no difference check the pump.
Edited by falcemob on Sunday 10th December 20:49
falcemob said:
At least if you did it your self then you know what you have done. I would go with an oil change and see what happens. I can't remember the layout on these but did you renew the seals on the pressure relief valve and or the relief valve itself?
There is a plunger-type pressure relief valve incorporated in the oil pump itself on these. So should be okay as the pump is new.
(Just double checked, luckily there aren't any internal plugs on these blocks. Phew!)
Two things that you have mentioned could be causing the problem that you have.
When you say that the cam bearings were checked for play on assembly, just how was this done to ensure that they were OK? I have come across bearings that look fine visually but were badly worn and causing loss of pressure when hot. The other thing that could potentially be at fault is the oil pick up pipe in the sump. Any hairline crack in this will open up as the engine gets hot and cause air to be sucked into the oil system which will result in lower pressure. Favourite place is around where the bracket is welded to the pipe.
Another potential is a badly worn rocker shaft. Was this stripped during the rebuild and checked?
Your low hot pressure could be any or even all of the above, or excessive crank bearing tolerances as suggested.
When you say that the cam bearings were checked for play on assembly, just how was this done to ensure that they were OK? I have come across bearings that look fine visually but were badly worn and causing loss of pressure when hot. The other thing that could potentially be at fault is the oil pick up pipe in the sump. Any hairline crack in this will open up as the engine gets hot and cause air to be sucked into the oil system which will result in lower pressure. Favourite place is around where the bracket is welded to the pipe.
Another potential is a badly worn rocker shaft. Was this stripped during the rebuild and checked?
Your low hot pressure could be any or even all of the above, or excessive crank bearing tolerances as suggested.
530dTPhil said:
Two things that you have mentioned could be causing the problem that you have.
When you say that the cam bearings were checked for play on assembly, just how was this done to ensure that they were OK? I have come across bearings that look fine visually but were badly worn and causing loss of pressure when hot. The other thing that could potentially be at fault is the oil pick up pipe in the sump. Any hairline crack in this will open up as the engine gets hot and cause air to be sucked into the oil system which will result in lower pressure. Favourite place is around where the bracket is welded to the pipe.
Another potential is a badly worn rocker shaft. Was this stripped during the rebuild and checked?
Your low hot pressure could be any or even all of the above, or excessive crank bearing tolerances as suggested.
When you say that the cam bearings were checked for play on assembly, just how was this done to ensure that they were OK? I have come across bearings that look fine visually but were badly worn and causing loss of pressure when hot. The other thing that could potentially be at fault is the oil pick up pipe in the sump. Any hairline crack in this will open up as the engine gets hot and cause air to be sucked into the oil system which will result in lower pressure. Favourite place is around where the bracket is welded to the pipe.
Another potential is a badly worn rocker shaft. Was this stripped during the rebuild and checked?
Your low hot pressure could be any or even all of the above, or excessive crank bearing tolerances as suggested.
Hi,
In the rebuild manual, it stated that the camshaft bushes "seldon wear" and "if they look alright and not scored it's not usually necessary to change them" (perhaps I was being naive?). They looked fine, so I initially fitted the camshaft dry and felt for sideplay then fitted with a light smear of thin oil and rotated it by hand to check it didn't spin loosely. Which seemed ok, but I must admit that was about all I did. But if you've known these to cause problems, I'll bear that in mind if the engine needs to come apart!
Again with the pick up pipe, This was just left soaking in petrol and cleaned up before fitting and I didn't actually notice any cracks but in the same respect wasn't looking for any either so that will be something else to check if it comes to taking it apart again.
Rocker shaft got the strip/clean and re-assemble treatment, again on re-assembly the rockers were just hand felt for free play as they were assembled on the shaft and there was not any questionable play noticed but again will re-check if it comes to a stripdown. My only comment here is that the valve gear doesn't appear to be noisy when running and when the head was re-torqued tappet clearances were still good.
Thanks for the tips, looks like I have plenty to check,
Appreciate the advice.
falcemob said:
As you are in Kent, which company did the checking and machining?
It was done a couple of years ago by Bailey & Liddles in Faversham (it's taken me this long to get the rest of the car done so I could start the engine!). They came recommended and are were pretty helpful people. They did the cleanup, rebore and checks and also the head-work (valve seats/refacing etc).
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