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Sep 19, 2012 9:21 am
Sep 19, 2012 9:21 am
Subject: Re: Oil pumps
Hi Folks,
This is very interesting.
I agree with all of Julian's comments about the shortcomings of the 2 Litre oil pump and would like to remind readers that there are different variants of the basic design, as explained to me by the late Phil, Ridout. Basically the early pumps were smaller diameter and the later "speed model" ones were of larger diameter giving a greater swept volume. It may even be that supercharged cars had a yet larger version as well.
I have seen many of the problems Julian has mentioned, and have fitted a non-return valve in the line to avoid draining down. However, I would argue that because of the engine design, lack of oil pressure on start-up is not too serious a problem. This is because the speed model crank pin journals are hollow so would naturally accumulate oil in them. Also, it is good practice to wait for the oil pressure come up on starting. Nevertheless I very much like the idea of the improved pump to overcome this problem.
I have an additional issues that I would like reader's opinions on. When my car is warmed up, the oil pressure is pretty constant at just over 30 psi but if I am on an open road going quite fast, it can drop below 20 psi. I am not sure why, I think it could be that the oil gets hot and the viscosity drops. I have fitted a full-flow oil filter and generally uses a modern SF grade 10W-40 oil. On the other hand it might be that the relief valve comes open at high revs. Anyone got any ideas?
So Julian's improvements will give more flow and much more constant oil pressure, and I do like the idea of combining one of these pumps with his new crank whilst still looking just like the standard unit. Maybe some time I will try this out some time.
I must say I do like the 2 Litre speed model, and when combined with sensible mods, it becomes an even nicer car to use in modern conditions. so well done Julian.
Colin M34
Hi Folks,
This is very interesting.
I agree with all of Julian's comments about the shortcomings of the 2 Litre oil pump and would like to remind readers that there are different variants of the basic design, as explained to me by the late Phil, Ridout. Basically the early pumps were smaller diameter and the later "speed model" ones were of larger diameter giving a greater swept volume. It may even be that supercharged cars had a yet larger version as well.
I have seen many of the problems Julian has mentioned, and have fitted a non-return valve in the line to avoid draining down. However, I would argue that because of the engine design, lack of oil pressure on start-up is not too serious a problem. This is because the speed model crank pin journals are hollow so would naturally accumulate oil in them. Also, it is good practice to wait for the oil pressure come up on starting. Nevertheless I very much like the idea of the improved pump to overcome this problem.
I have an additional issues that I would like reader's opinions on. When my car is warmed up, the oil pressure is pretty constant at just over 30 psi but if I am on an open road going quite fast, it can drop below 20 psi. I am not sure why, I think it could be that the oil gets hot and the viscosity drops. I have fitted a full-flow oil filter and generally uses a modern SF grade 10W-40 oil. On the other hand it might be that the relief valve comes open at high revs. Anyone got any ideas?
So Julian's improvements will give more flow and much more constant oil pressure, and I do like the idea of combining one of these pumps with his new crank whilst still looking just like the standard unit. Maybe some time I will try this out some time.
I must say I do like the 2 Litre speed model, and when combined with sensible mods, it becomes an even nicer car to use in modern conditions. so well done Julian.
Colin M34