Date: Sun, 28 Feb 1999 00:18:35 -0000
From: "Dave Edge"
Subject: [imps] Oil Pressure
I installed an oil pressure gauge earlier because I have suspected for quite a while now that I have a slightly dodgy situation.
800 rpm 35 - 45psi
2000 rpm 55psi
4000 rpm 65psi
I didn't want to push the engine any higher than 4000 rpm off load. Are these figures reasonable - I suspect that the pump is fine but the oil pressure relief valve is a bit dodgy.
The oil pressure light does not extinguish until 1800 rpm when very hot with Magnatec thin oil, does anyone else find this.
From: Impmann@aol.com
Date: Sun, 28 Feb 1999 04:55:37 EST
Subject: [imps] Re: Oil Pressure
I've not a clue what the pressure readings are supposed to be... I've never had a pressure gauge that works:-)
However, I would strongly advise against using modern thin oils in an Imp engine (or 930), as it was not designed to work with them. Modern oils such as Magnatec & Mobil One are designed for use in modern engines which will have oil ways that are the right size for them, the Imp's oil ways were designed for old style thick 20w/50 oils.
I personally use Valvolene Racing 20w/50 in high performance Imp engines - it's not too expensive, it works very well, it has the correct viscosity and as a bonus smells lovely when the engine is warm:-) In high-mileage, standard engines, you will not prolong the life of the motor by using thinner oils, in fact far from it you will speed up wear. My advice in these situations is to use the cheaper oils such as the 'value' brands at motor factors, and change it slightly more frequently than normal. In a lot of these cases the engines burn a bit of oil or drop it on the floor anyway, so using an expensive oil is waste of money... the car changes it's own oil:-)
Final point, Castrol GTX used to be a 20w/50, and was my choice of oil for years, but overnight became a 15w/40 so that the GTi boys could use it. GTX is now too thin for the Imp (leads to oil leaks and heavy consumption - plus wear), and if I put it in the Husky it really notices...
Moral is... use a good old style 20w/50 (such as Penrite, Castrol Classic, Valvolene (Racing or Standard)) in a good high performance Imp engine. Use a standard 20w/50 in a standard Imp engine (such as Comma, Valvolene Standard) and cheap 20w/50 in a high mileage lump (such as Halfords Value, Impact, Le Mans etc).
And change your oil filter EVERY time you change the oil.
Date: Sun, 28 Feb 1999 10:30:22 +0000
From: Andrew W. MacFadyen
Subject: [imps] Re: Oil Pressure
A lot of owners would be pleased with oil pressures like that, I think from memory the switch should operate at about 7 PSi, they eventually stop operating at the correct pressure usually due to sludge and varnish build up within the switch. Different pressure switches were availble, I think 3, 7, 9 13 and 17. The switch for an A series Metro/Mini will fit but I think this a 3 psi switch (at least it was last time I checked in the seventies). The old switches can be devils to get especially if they are the type with small 7/16" AF hex.
Rather than risk breaking the switch in the block if it is really tight try mounting the switch at the other end of the main oil gallery where you will find a little plug with sunken hex head -- some late Imps had the switch fitted there as standard rather than adjacent to the distributer.
Date: Sun, 28 Feb 1999 11:05:33 +0000
From: Andrew W. MacFadyen
Subject: [imps] Re: Oil Pressure
Yes all the grades of Valvoline are very nice clean fresh smelling oils.
Interestingly launched in the 60s as a 20w/50 Castrol never marked the viscosity GTX in the late 70s and 80s, I suspect it was actually a 15w/40 or 20w/40 then as it gave lousy oil pressure when very hot. The main problem with modern oils in Imps in the oil thrower at the clutch end of the crankshaft might slightly leak more with very thin oils which is a pity because Mobile 1 is a very good oil, it gives terrific protection to he bearings and valve gear especially durring cold starts. Mobile 1 also virtually varnish and sludge free to strip an engine which has run on it from new is amazing.
As a winter grade oil would be Mobile 1 OK for imp engines but my choice for ultimate protection would be Castrol RS 10w/60 which is a lot thinner than 20w/50 at start up but thicker at high temperatures. The snag is the price £30 for 5 litres.
From: Gary and Carol Henderson
Date: Mon, 1 Mar 1999 00:11:42 +-1300
Subject: [imps] Re: Oil Pressure
5-7 psi was the standard Rootes oil-switch.
If the pressure readings you have are taken when hot, I'd say all is well with the lump & change the oil-switch.
I disagree with Tim to a limited extent - beware of developing too much oil-pressure , especially in winter. If you really think you need 20W50 oil, then p-lease keep the rpm down until the engine is properly warm.
If oil has been changed regularly, only the oil-pump end-plate will need levelling at overhaul time.
From: Jaap ten Hoeve
Date: Sun, 28 Feb 1999 13:49:50 +0100
Subject: [imps] re oil pressure
I have a bog standard '66 Chamois. Nearly two years ago I fitted a 'new' engine which I bought at the national weekend. I needed another engine because the pistons were (and still are) seized due to the car being 'stored' for over ten years.
From day one I used Brega Classic Motor Oil 20W60, which is marketed in Holland by Brezan a wholesaler for the motorbranche for approx. £12,50 for 5 litre. The label on the 5 litre can says: "Brega Classic 20W60 is a multigrade oil specialy designed for (petrol)engines for classis cars from the 50's, 60's and 70's. Specification: API SC/CB and US MIL-L-2104 A"
For the first few hundred kilometers the oilconsumption was rather high (1l.in 500 k), but now is about 1l. in 1500 kilometers, which fine as far as I'm concerned.
Even with a hot engine the oilpressure hardly drops while idling. Has anyone any experience with 20W60 oil?
From: Impmann@aol.com
Date: Sun, 28 Feb 1999 12:49:40 EST
Subject: [imps] Re: Oil Pressure
>I disagree with Tim to a limited extent - beware of developing too much oil-pressure , especially in winter. If you really think you need 20W50 oil, then keep the rpm down until the engine is properly warm.
The reason I use a 20w/50 is because that is what is recommended by Rootes....
I haven't ever had problems with oil seals leaking or excessive consumption (not on a good engine), so I don't think that 20w/50 is producing too much pressure, after all it shouldn't do the engine is designed for that grade:-)
Also, don't ever over-rev a cold engine....quick fire way to a head gasket leak!:-)
Date: Sun, 28 Feb 1999 11:55:48 -0600
From: ABryson@sperry-sun.com
Subject: [imps] Re: Oil Pressure
Pressure looks excellent if this is when hot. You may have a high pressure oil switch as used in some competition cars. Mine is set at 45psi.
From: Kristian Jonsson
Date: Thu, 4 Mar 1999 13:18:26 +0100
Subject: [imps] Re: oil
Oil pressure on my Imp:
The oil pressure light is always glowing when the engine is hot and under 1000 revs. In the beginning it did make me nervous, but then
I did attach an VDO mecanical oil pressure gauge to make an checkup. To my relief there was no oil pressure problem. Its just the electrical sender that was 'pessimistic'. To have an mecanical oil ressure gauge in the car would be right, but the 'hose' have to be so long. But are there any problem with a long oil pressure pipeline? I canīt see any.
From: Impmann@aol.com
Date: Thu, 4 Mar 1999 07:36:54 EST
Subject: [imps] Re: oil
There is no problem with having a long pipe going to the dashboard of the car.
In fact the late Imp Sports had an oil pressure gauge built in to the dashboard in the black space above the oil pressure light (semi-circular) and can be retro-fitted (I may even have a Sport dashboard kicking around at my mum's garage).
The oil pressure light switches can be a pain, however, I managed to buy an Imp with a 'faulty oil pump' from a chap, whose car displayed the same problem as yours. I changed the switch and hey preso, the oil pump was fixed:-) I ran the car for ages, and was one of the best Ģ50's I've ever spent!
Date: Mon, 01 Mar 1999 18:07:23 +1000
From: Darcy Maddock
Subject: [imps] Re: Oil Pressure
both Russ and I use Castrol R synthetic in both our 930s. No problems and 65lb on start up and constantly the same while running while dropping to about 50lb on idle hot. No leaks other than a drop hanging on the sump plug. A new seal would fix that. It is expensive but worth every cent (penny).
Date: Thu, 4 Mar 1999 12:47:36 -0800 (PST)
From: paul waites
Subject: [imps] Re: oil
No problem, my sport has a mechanical oil gauge as standard. I picked-up a smiths electrical gauge at an autojumble for my Stiletto and it works fine but is a bit slow responding.... So reckon that if I had a sudden loss of oil then the damage would be done before I realised!!! So personally I would go with a mechanical gauge.
Date: Thu, 04 Mar 1999 13:22:43 +0000
From: Andrew W. MacFadyen
Subject: [imps] Re: Oil Pressure
It is actually possible to build a high capcity oil pump for an Imp by fitting the internals from a Hunter or Avenger pump but it requires machine shop facilities to machine an alloy spacer plate to fit between the housing and end plate to accomodate the longer rotor. Really not worth the effort.
From: Impmann@aol.com
Date: Thu, 4 Mar 1999 09:33:43 EST
Subject: [imps] Re: Oil Pressure
Castrol Special R? The gorgeous smelling racing oil? Hmmmm yummy...
Problem is that it is illegal for road use in the UK... god knows why.
From: D.K. Pitts
Date: Thu, 04 Mar 1999 15:09:38 GMT
Subject: [imps] Re: Oil Pressure
So the Hunter etc. rotor is the same except for length?
Date: Thu, 04 Mar 1999 16:07:37 +0000
From: Andrew W. MacFadyen
Subject: [imps] Re: Oil Pressure
Yes both the Avenger and Hunter pumps are the same diametre but longer I am not sure if the Hunter is exactly the same length as the Avenger but either could be used. I also know the relife from the Hunter is the same fitting at least on later cars not sure about the blow off pressure but I suspect it will be the same. Either way it is easy to make adjustable.
From: Jaap ten Hoeve
Date: Thu, 4 Mar 1999 22:58:32 +0100
Subject: [imps] re oil pressure
I have a standard '66 Chamois. Nearly two years ago I fitted a 'new' engine which I bought at the National Weekend. I needed another engine because the pistons were (and still are) seized due to the car being stored for over ten years.
From day one I usedBrega Classic Motor Oil 20W60, which is marketed in Holland by Brezan, a wholesaler for the automotive branche, for approx. £12,50 for 5 litres.
The label on the can says: "Brega Classic 20W60 is a multigrade oil specialy develloped for (petrol) engines from the 50's, 60's and 70's. Specification: API SC/CB and MILL-L-2104 A"
Even with a hot engine the oilpressure hardly drops while idling.
Has anyone any experience with 20W60 oil?
Date: Thu, 04 Mar 1999 17:38:29 -0800
From: frank hoeffner
Subject: [imps] Re: oil
My light goes on at low idle speed also.
I have a electronic oil pressure gauge in the car and a mechanical in the engine compartment so I can see what's going on when I'm working back there.
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