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Oil pressure problem....still!


Mike C

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I've still got an oil pressure issue on my 2.0vx HPC.

 

It's not dry sumped and originally i suspected the pressure relief valve but this seems OK. What's now baffling(hahaha) me is that despite the dipstick registering plenty of oil, it's still only registering 2 bar when cold.

 

Pressure initially increases when started but after a few seconds, slides back to 2 bar. It does increase on a loaded throttle, but as soon as revs plataux, pressure drops away again.

 

I suspected the sump baffle foam clogging the oil pick up, so went to drain the oil to start taking the sump off and.......only a trickle of oil came out!!!!

 

I topped up the oil with about a quarter pint and then fired up. All was well, with pressure back to 5 bar on idle when cold???????!!!!

 

Surely it can't just be lack of oil? I haven't driven the car yet, to fully test but still suspect the foam baffling has blocked a pipe. Any bright ideas on how to test for this?

 

Thanks!

Mike

 

Mike C

No longer K9 JPE

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Hello Mike,

I am not sure I can offer a cure for your probs, but my Vx HPC also suffers strange oil pressure readings when cold. It is a wet sump motor and after doing a session in April '07 round the Stig circuit, I suffered oil surge problems when it chucked out half a pint into the catch tank in 8 laps. It rattled like mad afterwards. I did the cam cover mod suggested by SBD, had the sump off and fitted new foam and also did a small pair of v shaped cuts in the end of the oil pick-up pipe. Cam followwers were also replaced. However, on start up pressure seems about 4 bar at idle but if I apply the brakes or go down hill the pressure falls to 2 bar even with some load on the engine. Once on the move again the pressure comes back to 4 bar and once the engine has warmed up the problem goes away and all seems to be normal. Redline did a mechanical test of the pressure and said it seems OK. So far it hasn't blown up, so I just put it down to one of those things you live with. I wonder if when cold, oil is staying at the top of the engine and not returning quickly enough to the sump. Why it should start doing this after 15 years I have no idea.

ps, why did you sell the JPE and get an HPC?

 

bradders

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Thanks Bradders, Gambo *thumbup*

 

I took the car out last night and after a couple of minutes of good oil pressure, it again fell back to about 2 bar. I noticed that it increased if I took a hard left corner.

 

Having got back to my garage, I decided to drain the oil, hardly any came out. 😳

 

The foam baffle in the sump is blocking the drain plug, so surely, this must be the problem. I'll drop the sump at the weekend and have a good look.

 

Ayone know where I can get some replacement foam?

 

Bradders, I sold the JPE to fund part of my E Type rebuild, but ended up missing a 7 too much 😬

 

 

 

Mike C

No longer K9 JPE

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Caterham supply the foam for not a lot. It has been changed in it's life when the hole in it where the oil collects was made larger. I changed mine last year just in time as it was like crispy seaweed but hadn't yet started to break up. Don't forget you'll need two gaskets *thumbup*

 

VX HPC - Loud and proud here

Watch out, whatever hits the fan will not be distributed evenly

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Don't forget you'll need two gaskets
And some sealing compound for the joins in the block around the oil pump and gearbox face. I got some from the local VX dealer.

Also helps if you can grow a couple of extra arms before trying to refit as I struggled to hold it all in position and get the sump bolts in place and tightened up. Solved the problem by getting the missus to "bench press" the sump into place whilst I inserted the bolts *smile* Thankfully she is a strong lass 😬

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Mike

 

Classic blocked foam symptoms. Do the tappets rattle as well?

 

If you're anywhere near Gomshall, Guildford, you're very welcome to come over and use my pit. Its dead easy when you can see what you're doing underneath.

 

Whilst the sump is off its worth doing the pick up pipe mod at the same time. The cam cover mod is a bit more of a fiddle, although easy to get at, as you have to remove all the sealant from around the casting which takes a bit of time to do thoroughly. You can usually reuse the cam cover gasket so long as its not nicked (damaged I mean, not stolen)

 

Paul

 

 

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Thanks paul *thumbup*

 

Yep, the tappets rattle as well. *wink*

 

What's the pick up mod? I'm in Billingshurst, so not far away so thanks for the offer but it's going to be in bits later this week hopefully 😬

 

Hope I have not done any damage!

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Ric

 

The pickup pipe can be sucked down onto the sump, almost closing off the end of the pipe. My sump had witness marks on it as a result.

 

The mod involves removing the pipe and cutting or filing four grooves crosswise on the sump end at 90deg, ie 12, 3, 6 and 9 o'clock about 4mm deep so that the oil can get through even if the pipe is in contact with the bottom of the sump. They don't want to be much deeper as it will suck air if the oil gets low in the sump. I used an 8mm round file so the slots were semi circular.

 

Paul

 

 

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So many problems I had with my wet sump and tappet rattle..........

 

The first thing to do is tie a piece string around the engine.

 

No.. seriously ! when you take the sump off you can hold it with the string and release it gently from above. That way it wont fall all over you and cover you in oil. Also you can use it to hold the shield plate and upper gasket to the bottom of the block whilst you postion and fix the the lower gasket and sump. it makes 'doing the sump' an easy two stage job rather than an impossible all at once job.

 

Check your dipstick level marks. The dipstick is shortened for the wet sump application and you could be filling to the wrong mark, this would drastically underfill the engine and could explain the lack of oil on draining. Look for the handscraped marks on the back of the dipstick not the manufacturers one. (mine is actually missing the low level manufacturers mark after being shortened.)

 

The foam baffle has a hole cut in it where the end of the pickup pipe sits, make sure its aligned properly.

 

Use a piece of blue-tack and push the sump up into position to check the gap between the bottom of the pickup pipe and the base of the sump pan. About 1/4 to 1/3 of an inch is about right.

 

If you cut holes or rooves or slats in the end of the pickup pipe you increase the chance of cavitation during hard cornering as you have effectively increased the gap to the floor of the sump.

 

When filling with oil keep pouring it in gently to just below the correct full mark. Run the engine and see if the tappet rattle stops after a moment or two. If not gently pour in another 1/2 cup. keep going until the engine runs smoothly.

 

On my engine filling to the full mark = terrible tappet rattle

- and adding 1/2 a cup = smooth running bliss

- adding another 1/2 cup for luck = lumpy bogged down stalling nastiness.

 

It really is that sensitive.

 

I get 2 bar at idle and about 4 when running on Mobil 1 15w 50. I've run several track days and on the road and the engine has yet to blow up on me.

 

have fun

 

Regards

Rowland

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Thanks Roland, Paul *thumbup*

 

I removed the sump tonight. Good news is that the foam is in one piece and not deteriorating, although I will renew.

 

Not so good news is that I can't find any obvious problems. Amount of oil eventually seemed about right, or maybe a little low, so I'll replace by a known quantity and take note of your advice Roland.

 

The oil pick up pipe has only a very small down turn return on it, where it lines up with the hole in the foam baffle. Is that right?

 

mike

 

Mike C

No longer K9 JPE

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I run a wet sump V X and had many problems

Tried different oils and oil levels and also an Apollo Tank and remote filter

Evntualy traced to oil aireation caused by crank whipping oil

Removed sump and reduced foam baffle to allow faster return of oil to oil pick up then cut a slot between the two center exterior fins and welded a plate to the bottom at the same exterior profile to form a chanel in the bottom of the sump and with an extended pick up pipe dropped the oil level by 20 mm to the normal V X levels

Now the crank does not whip the oil and the preassure remains good even after extended high speed runs and fast cornering (Tested out last year on the Swiss trip)

 

John

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Are you sure it is the oil pressure? My Vx has had a dodgy oil pressure reading for a while but the 35psi minimum oil warning light does not come on (it would at 2bar oil pressure) unless I near stall the engine and then it's on in a flash. That's why I suspected the oil pressure sender first.

 

Many have bought new senders. Before doing that I tried earthing mine - cleaned the body with a file and soldered on an earth wire that I attached to a ring contact under a suitable earthed bolt. You could simlpy put a suitable sized hose clip around it and clamp the earthing wire under that if you prefer.

I also soldered the sender wire directly onto the tag - the push on contact was a bit oily and probably never makes a good contact - we are taking small signal voltages there after all.

Anyway problem solved in one! Constant 4bar where you'd expect it dropping to 2 bar at tickover.

 

Your's could be a oil pressure valve problem - you can buy nylon ones or remove the existing one and clean off any burrs as they can get a little sticky.

 

I also had problems when running a wet sump. It would chuck oil into the catch tank on track - perhaps a bit overfilled for comfort.

If you have not already done so, you need to do the camcover oil channel mod to stop this.

See

here

 

and the photo's after it - I might even have the SBD diagram stored I could send you i you can't find it on the SBD website anymore.

 

Edited by - stevefoster on 9 May 2008 08:46:45

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All good advice above, the only comment being that,in my experience, the tappets can take a long time to pump up if they've been starved of enough oil, ten to fifteen minutes not being unusual.

 

The foam can look alright and still be blocked. A friend's had exactly the same symptoms as yours and changing the foam cured the problem instantly.

 

Rowland's point about the dipstick is a good one to look at. The original Vauxhall stick was recalibrated by Caterham and the face at the bottom end is ground to remove the MAX mark. On my old stick a new max filling mark has been made at 285mm below the lower large face of the rubber bung and is 25mm above the original Vauxhall mark. I have read of other calibration levels so it my be worth checking with Caterham to see if they can tell you the recommended level.

 

Can you see any witness mark on the bottom of the sump? Look for a small shiny mark where the pickup pipe would touch the casting. If the pipe's original and unmodified the end will look clean and plated. If its been modified or shortened you'll almost certainly see evidence of a hacksaw or file.

 

The subject of Vx oil has been hotly debated here for years. I think the winner was Mobil 1 sport. Try the archives.

 

Keep us posted.

 

Paul

 

 

 

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Wowww.. it's nice to know I've not been alone with wet sump problems.

 

The basic problem is easily explained if you have a look at the normal installation in a Vauxhall Astra GTE or Callibra. The Vauxhall pressed steel sump has a deep well (A good 4 inches) and the original pick up pipe curves over and carries on for a good couple of inches vertically downwards and ends in a 'top hat' type end fitting with an integral mesh filter.

 

Now then, Caterham had to use a flat bottomed sump to get any reasonable ground clearance (even so, just look at how much the sump pokes down below the bottom of the chassis!) and therefore the pick up pipe has to be sawn off just as it bends downwards and so you miss out on the original designed depth of the oil as well as the stabilising effect of the top hat/filter assembly on the flow. Making it in aluminium and providing the necessary cooling and strengthening fins along the bottom means its a 20 mm thicker than a pressed steel one which further reduces the available depth of oil.

 

The end result is an installation insanely sensitive to the depth of the oil. A little too little and you get air pick up and tappet rattle, a little too much and the crank whips up a frothing frenzy causing lumpy engine syndrome and tappet rattle if severe.

 

Now then... to go dry sump is the obvious solution (give or take the odd £Thousand)but if you go Pace, you need to sacrifice the extended passenger footwell for the oil de-aeration tank, a mod too far for me. If you go Caterham dry sump (oil well integral to the gearbox bell housing) you have to convert to a hydraulic clutch as the cable actuation lever would need a hole stright through the bellhousing oil tank).

 

It's just 'bellhousing' marvellous isn't it ?!?? *mad* *mad*

 

I like the mod to deepen the well by modding the bottom of the sump, but you are dealing with Aluminium and that can be tricky, also one kiss with a brick and the whole sump could split wide open (yes ! it happened to me - long painfull £500 pound repair bill story)

 

I have seriously considered the anti-cavitation kit and would like to hear how you got on with that.

 

And finally... I well remember oil blowing merrily out the breather on my first track day. The rocker cover baffle mod is a must, and Swindon Racing can sell you a couple of pipes that you put into the head that converts the engine to internal breathing and you can get rid of the external riser pipe integral with the oil dipstick assembly that feeds into the rocker cover by the dizzy takeoff. These helped the oil surge problems I had to dissapear.

 

Such fun !!!

 

Regards

Rowland

 

 

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I went Pace dry sump with the SBD sump a few years ago and its been great. All of the track related oil pressure problems vanished. The only problem was where to locate the oil tank which, in my case, is in front of the engine. Pictures here. But it is a real squeeze and a sod to change oil, cam belts etc. But at least my passengers can stretch out their legs. If you look at the photos you can see how Pace extended the bottom of the tank by welding in a gusset to increase the capacity, whilst retaining the cylindrical top for effective separation.

 

Although the Caterham bell tank solution has its detractors, the principal benefit, apart from not having to locate the oil tank, is that it retains the original integral oil pump and filter arrangement. If the belt comes off the scavange pump (2-stage Triton) you can detect it and cut the engine/dump the clutch before loss of oil pressure and any damage is done. A new belt and you're away again. If the belt comes off the Pace 3-stage pump you've almost certainly lost oil pressure for long enough to have a bearing pick up, at least. If you don't strip the engine and check the bearing shells and crank, you'll quite likely have a blown engine with rods out of the side. Ask Gambo!

 

The disadvantage of the CC system is the hydraulic clutch slave cylinder which is part of the bell tank casting and a devil to repair. There were also concerns expressed about the tank's effectiveness at air/oil separation as the top is rectangular rather than cylindrical. But it does make for a very neat installation.

 

If you're regularly tracking your car you should seriously consider dry sump. If you're using it mainly on the road, the CC wet sump can be made to work by frequently checking the oil level and changing the foam at least once every 6000 miles. Frankly if I was still running a wet sump I'd change mine every 3000 miles as rumour has it that modern synthetic oils attack the foam causing it to clog and break up. After 2 years and 6 thousand miles mine looked like one of those hard foam things that florists use to put flowers in.

 

Paul

 

 

 

Edited by - Paul Deslandes on 9 May 2008 15:46:18

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Going a bit of topic - i have always wondered if you would notice the oil level raising in the engine should a 2 stage pump belt come off...

How would it feel - loss of power as windage increases and you would back off and shut down or straight to hydraulic lock and snapped conrod?

I considered fitting a belt off warning light but common sense got the better of me *smile*

 

My 2002/2003 racing pics

here

General pics (mostly of 7's and cars).

here

 

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Thanks for the brilliant advice all!! The problem is resolved 😬

 

Having dropped the sump, I was glad to see the foam in one piece. I reassembled with new foam and also modified the end of the pick up pipe. Yes there were witness marks in the sump *thumbup*

 

Lots of cursing and swearing later, i eventually managed to get the gaskets and ally bolt rings back in place and filled up with 4 litres of oil.

 

Hey presto, all seems fine again! *biggrin* *rolleyes*

 

I'm pretty sure it was a blocked foam baffle and also the pick up pipe might well have had something to do with the problem too!

 

Thanks again, an invaluable resource of help *thumbup*

 

 

Mike C

No longer K9 JPE

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