julians Posted January 6, 2001 Share Posted January 6, 2001 I have noticed (on my tuned zetec powered 7) that if I keep the revs high for a while the oil pressure starts to drop, I presume this is because as the oil gets hotter (than it should maybe?) it becomes less viscous therefore less pressure. Firstly ,should this bother me? It idles at 2 bar, when at nominal revs its just under 4bar, and when its been held at high revs for a while its back down to 2 bar. Secondly, I use mobil 1 at the moment (0w -40w) , would using mobil 1 motorsport ease my problem or would I start to suffer from sticking valves. Thirdly, I guess fitting an oil cooler would help, are they easy/expensive to fit yourself. Does anyone have any recommendation for a grade of oil to use? The car does spend a lot of its life in the upper echelons of the rev range. Cheers for you advice Julian Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted January 6, 2001 Share Posted January 6, 2001 Don't know a lot about Zetecs, but I was told recently NOT to use 0-40 oil but 10-40/50. The reasoning was that it never really gets that cold in Britain (yeah, I know it can feel like it) and that the 'watery stuff' (0-40W) just won't do a good enough job when the eng is really warm. The suggestion was to really get the eng OIL warm (not just up to water temp) before 'giving it some'; five or six miles+ It seemed good enough advice to me; unless of course (you lot) know better! Link to comment Share on other sites More sharing options...
StewartG Posted January 6, 2001 Share Posted January 6, 2001 I've had a similar problem with my Vx and I don't think it's anything to do with overheating the oil. Having said that I would agree that 0w40 Mobil 1 is too thin for Caterham use. Try the 15w50 Mobil 1 or any 10w40.I figured with my engine as, like your's, the oil pressure was good at idle when hot there was nothing radically wrong with the engine. The answer was cureing an oil leak on the pressure sender, changeing the oil pressure relief valve spring and polishing the piston in case it was sticking and tightening the electrical connection on the sender unit. One of these has solved the problem. I also wasted money on a baffled sump because I thought I had an oil surge problem. Link to comment Share on other sites More sharing options...
Marius Posted January 7, 2001 Share Posted January 7, 2001 I recently fitted an oil-cooler to my 16V VX and found that it never reached operating temperature, so I closed the oil-cooler again. Obviously the external oil-tank reduced temperatues already significantly. This was in November though, let´s see what the summer will show. I use 0W-40 in my everyday-car which is mainly used on short distances, fine for that but stick with 10W-something for the Caterham. This bloody 0W is like water, some engines also leak the OW-oil ´cause it´s so bloody thin. Had this on a motor-bike, put in a different oil and away was the oil-leakage. Give your 7 some CastrolRS for christmas! It´s worth the money ans smells fantastic.... Link to comment Share on other sites More sharing options...
julians Posted January 7, 2001 Author Share Posted January 7, 2001 Castrol RS, that looks interesting (10w-60), do halfords sell it, or do I have to go to a specialist outlet to buy some. And can it just be added to the existing oil, or do I have to drain out the mobil one. The oil pressure relief spring also sounds like a good point to investigate, this went on my TVR once, and caused (albeit a more severe reaction) zero pressure at high revs but it was fine at idle etc, does anyone know where this is on a zetec and how easy/quick it is to change. Julian Link to comment Share on other sites More sharing options...
Swiss_Tony Posted January 7, 2001 Share Posted January 7, 2001 Julian Ford recommend 5w30 for the zetec engine. If the oil is a lot thicker they tend to have problems with the hydraulic tappets etc holding the valves open. Mobil 1 0w40 would about right. Good luck James Link to comment Share on other sites More sharing options...
Pierre Gillet Posted January 7, 2001 Share Posted January 7, 2001 Does Castrol RS smells like castor oil? Pierre Link to comment Share on other sites More sharing options...
Fast Westie Posted January 8, 2001 Share Posted January 8, 2001 Pierre Unfortunately Castrol RS doesn't smell like castor oil smile.gif On another note I used Castrol RS twice in my Cosworth and twice I blew the cam cover gasket. On the subject of Zetec, they prefer 5W30 otherwise they can 'jack up' the tappets Link to comment Share on other sites More sharing options...
murph7355 Posted January 8, 2001 Share Posted January 8, 2001 An alternative to a typical cooler is an oil/water heat exchanger. This gets the oil up to temperature quicker (as it feeds off the water temp rise) and keeps it "cool" (in operating band). They can also be fitted pretty much anywhere rather than blocking off rad' area. I've now scanned the images of my install so once I get a suitable repository a shot of one of these is included. They're about 85 quid +VAT...I think they're easy to fit but had mine done with the rest. Unless you're somewhere really hot I don't think trad. oil coolers are really necessary. C7 AJM Link to comment Share on other sites More sharing options...
CommaGirl Posted January 8, 2001 Share Posted January 8, 2001 Comma SynerG synthetic 5w40 is the best oil for small tuned 4 cyl engines. I can't tell youi how similar it is to Mobil 1 5/40 that was discontinued a few years ago, but its probably closer than the fit of my lycra catsuit. Its good for wrestling in too.... Bye Bye Boys wink.gif CommaGirl wink.gif Good in the wet bits...... Link to comment Share on other sites More sharing options...
Ian Macquarie Posted January 8, 2001 Share Posted January 8, 2001 Where do you get an Oil/water heat exchanger for £85? What do they look like and how much heat can they transfer? Ian Link to comment Share on other sites More sharing options...
murph7355 Posted January 8, 2001 Share Posted January 8, 2001 The exchanger unit itself was 82.55 +VAT from Ratrace. It may be slightly more usually as I did spend quite a bit with them, but I believe this is the cost. I don't think all the plumbing gear was with it though. So after adding VAT and pipes etc. you're probably not looking at much change out of 105-120. It looks like an alloy cylinder about 10" long with square sections running its length top and bottom. I guess total height is about 4" and depth 3"-4". Either end has a fitting for a hose as do the square sections top and bottom in the middle. I think the former are for water and the latter for oil if memory serves but I could have this the wrong way round! It then has Mocal written on the side in nice letters. I'll get the images I have put up somewhere tonight and will post where they are... As for how much heat they transfer, couldn't tell you as I don't have figures. Sadly I also never tested how quickly my old engine got up to speed with oil temp etc. Perhaps if anyone else with an 1800k has timings to a set temp we could do some sort of comparison? C7 AJM Link to comment Share on other sites More sharing options...
Paul D Jones Posted January 8, 2001 Share Posted January 8, 2001 For more advice on the type of oil and all other things technical regarding zetecs contact Paul Dunnell Engines 01449 677726 he has also cured the heating/cooling problems and is one of the top men on zetecs paul Link to comment Share on other sites More sharing options...
Alex Wong1697456877 Posted January 9, 2001 Share Posted January 9, 2001 Castrol RS is now 0w 40 or something close. It's pretty much as thin as Mobil 1 but cheaper. I use the thicker Mobil 1 M'sport cos it has a racing car on it. Seriously, though, if you're going to use a thicker oil, make sure the it's hot before you start driving normally. Alex Link to comment Share on other sites More sharing options...
StewartG Posted January 9, 2001 Share Posted January 9, 2001 For Mocal parts try Think Automotive they advertise in CCC. By the way from experience I can tell you the problem is not the oil or its temperature. I tried loads of diferent oils with no improvement and this time of year it's hard to get oil up to working temp let alone overheat it. Link to comment Share on other sites More sharing options...
Pierre Gillet Posted January 9, 2001 Share Posted January 9, 2001 Agree. It's hard to get the oil higher than 60°C! Pierre Link to comment Share on other sites More sharing options...
murph7355 Posted January 10, 2001 Share Posted January 10, 2001 I've had a quick look round the web but can't find what the "ideal" operating temperature is for synthetic oils... However with my set up the temperature is pretty much stable at about 75degC, occasionally getting up a bit higher (highest I've seen so far has been 84degC). I'll keep hunting for operating temperature info, but if anyone else has it I'd be interested. I agree fully that a bigger problem in 7's may well be the oil being too cool in many circumstances, especially in this country in winter! C7 AJM Link to comment Share on other sites More sharing options...
StewartG Posted January 10, 2001 Share Posted January 10, 2001 I seem to remember in a previous oil thread someone quoted modern synthetics as being good for over 100 degrees or something like that. I'll repeat Julians the problem is not caused by hot oil. Link to comment Share on other sites More sharing options...
julians Posted January 10, 2001 Author Share Posted January 10, 2001 That seems to be the general concensus throughout everyone I've spoken to. Paul Dunnell blames the raceline sump. Dave Andrews thinks it could be the bleed valve in the pump is clogged with crap. A few poeple have said the standard caterham guages are not very reliable. I'll take the sump off tonight and see if I can see anything obvious. Julian Link to comment Share on other sites More sharing options...
StewartG Posted January 10, 2001 Share Posted January 10, 2001 Julians, I spent £200 on a QED baffled race sump which made no difference to the drop in oil pressure what-so-ever give me a ring if you like 07974367206 and I'll give you the benefit of my dubious experience with this problem. Link to comment Share on other sites More sharing options...
julians Posted January 10, 2001 Author Share Posted January 10, 2001 I have just spoken to raceline who have suggested a few places to look. - Check the guage is working correctly (also suggested bya few people here) - There is a small filter at the front of the raceline sump, which could become blocked and stem the flow of oil, remove this filter and clean it. (sounds hopefull) - Take the sump off and remove the bleed valve and clean it (as Dave Andrews Suggested) I will be giving all these a look tonight, apart from the guage, as I dont have a proper mechanical guage to try. Link to comment Share on other sites More sharing options...
old captain slow Posted January 10, 2001 Share Posted January 10, 2001 I don't think temperature is the problem. See the thread "Oil Temp" - last posting 20 August. Link to comment Share on other sites More sharing options...
Mike Biddle Posted January 11, 2001 Share Posted January 11, 2001 I had this problem on my VX car, and fitting an oil cooler did not help. A dry sump cured it. 75 to 80C should be fine, I heard that Honda spent megabucks to get their race engines to run at this temp. Link to comment Share on other sites More sharing options...
StewartG Posted January 14, 2001 Share Posted January 14, 2001 Julians, have you solved your problem yet? Whilst a dry sump will almost certainly effect a cure it could be an expensive hammer to crack a nut. Link to comment Share on other sites More sharing options...
julians Posted January 14, 2001 Author Share Posted January 14, 2001 No, not yet. The engine did have the wrong filter on (too small), so I though that may be the problem, but its not. I've been trying to locate the oil pressure relief spring, so I can check its not sticking. The haynes manual says it should be near the crank pulley by the oil filter, but I cant find the bloody thing on my engine. So can anyone describe in exact detail where on a zetec the oil pressure relief spring is? If I cant get it sorted over the next couple of days, I'll give the car to a pro to sort out, its needs a couple of other things anyway (rolling road tune, bolt check etc), but it would be nice to sort it myself. Julian Link to comment Share on other sites More sharing options...
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