John L Posted April 21, 2018 Report Share Posted April 21, 2018 I think I would like to change the pipework for my Bosch pump 0580254996, its been running for some years now, but when the engine gets hot in the current weather, the pump is making a really strange noise, not really sure why, but when cold with normal running its fine. The regulator valve a new Bosch one from Kimi, pump and pipework at the rear are not hot to touch, when the pump is making the noise, but the pipe in the engine bay is very hot from the engine. Engine still running ok, but previous experience has shown that when the pump makes this much noise it could stop very soon. But will restart again once the bonnet is opened and cooled for half an hour. I still have the CAV filter in the boot, which feeds the pump that is mounted on the outside of the chassis behind the wheel. The flow from the pump flow then goes to the regulating valve on the inside of the chassis rail, the overflow from the regulating valve then goes back to the filter housing, and a pipe from the top of the CAV filter to the tank, which also has the return from the MU teed into it before going into the tank fitting, I think the std original system. I was thing of taking out the CAV filter and putting in a prefilter and a pressure filter after the pump, before the regulator valve, but making a new larger freer return to the tank with possibly a larger fitting into the tank, which would also incorporate the return from the MU. I did see a Lucas bulleting that did change some of the original pipework. I don't really want to go the expensive setup of the filter and pump together, but would what I'm proposing work if I can get the pipework to fit? Would be interested in knowing how others have their systems piped up, several people have said they are still using the cav filter setup with no problems, but how's it piped up perhaps differently to mine? John Quote Link to post Share on other sites
Mike C Posted April 21, 2018 Report Share Posted April 21, 2018 My return line from the original Lucas PRV goes directly back into the tank, to a nozzle on the opposite side (passenger side) to the fuel pick up. The fuel pick up is in a swirl pot under the tank on the drivers side. The PRV return line incorporates a loop of about 800mm of Gates Barricade to damp out resonances. This arrangement increases the cooling time of the fuel allowing it to dissipate more heat before returning to the pump. I run an original CAV filter alongside the spare wheel. The fitting on top of the filter is plugged close - I use it only when venting air after a filter change. Fuel from the filter goes to a small high suction (Carter) booster pump also mounted in the boot wheel well. The booster pump feeds fuel to a Bosch pump mounted on the wheel arch. My MU return line goes directly to a separate nozzle on the tank above the swirl pot. Provided I keep the tank more than about 25% full I can operate in stop / go traffic on a 40 degree day ( not that I make a habit of that). Quote Link to post Share on other sites
astontr6 Posted April 21, 2018 Report Share Posted April 21, 2018 I think I would like to change the pipework for my Bosch pump 0580254996, its been running for some years now, but when the engine gets hot in the current weather, the pump is making a really strange noise, not really sure why, but when cold with normal running its fine. The regulator valve a new Bosch one from Kimi, pump and pipework at the rear are not hot to touch, when the pump is making the noise, but the pipe in the engine bay is very hot from the engine. Engine still running ok, but previous experience has shown that when the pump makes this much noise it could stop very soon. But will restart again once the bonnet is opened and cooled for half an hour. I still have the CAV filter in the boot, which feeds the pump that is mounted on the outside of the chassis behind the wheel. The flow from the pump flow then goes to the regulating valve on the inside of the chassis rail, the overflow from the regulating valve then goes back to the filter housing, and a pipe from the top of the CAV filter to the tank, which also has the return from the MU teed into it before going into the tank fitting, I think the std original system. I was thing of taking out the CAV filter and putting in a prefilter and a pressure filter after the pump, before the regulator valve, but making a new larger freer return to the tank with possibly a larger fitting into the tank, which would also incorporate the return from the MU. I did see a Lucas bulleting that did change some of the original pipework. I don't really want to go the expensive setup of the filter and pump together, but would what I'm proposing work if I can get the pipework to fit? Would be interested in knowing how others have their systems piped up, several people have said they are still using the cav filter setup with no problems, but how's it piped up perhaps differently to mine? John Hi John! My suspicions are that you have the dreaded harmonic hammering which is usually due to the hose after the pump being too hard and not very flexible and too higher psi rating?. I had this problem years ago when I fitted a Bosch pump, I cured it at that time by using a flexible rubber hose rated 150 psi and never had a repeat. Now using a Gates hose again no problem. If you are using a PTFE smooth bore hose which some of the PI suppliers sell rated at 1000 psi you will not get rid of that noise using the Lucas PRV. I do not know if you do with the PRV diaphragm type? . The only PTFE type I have found that works is the convoluted hose type with loose S/S braid rated at 150 psi. Bruce. Quote Link to post Share on other sites
Waldi Posted April 21, 2018 Report Share Posted April 21, 2018 to add to all above: I think there are several different filters for the CAV, some have a higher pressure drop which increases the risk for cavitation which sounds like your pump is screaming Waldi Quote Link to post Share on other sites
John L Posted April 21, 2018 Author Report Share Posted April 21, 2018 Waldi That's a good point, at present I have a Moss filter, which I think may be a Unipart made, like the oil filters mention on here during the week. I thought that the diesel cav filter was not suitable for petrol or was that a long time ago, is there a good known one to use now? John Quote Link to post Share on other sites
Waldi Posted April 21, 2018 Report Share Posted April 21, 2018 Hi John, do not know which one (make, type) but it was mentioned on this forum some time ago. Cheers, Waldi Quote Link to post Share on other sites
Waldi Posted April 21, 2018 Report Share Posted April 21, 2018 An old post (2015) mentions Delphi HDF296 (7111-296), which is recommened by Neil Raven Smith, a PI Guru, also active on this forum. Waldi Quote Link to post Share on other sites
Rem18 Posted April 21, 2018 Report Share Posted April 21, 2018 (edited) I have just swapped out my 30 year old Bosch pump a 977 which was noisier last 10 years. Replaced with a 933. Its very quiete and cooler. I live in hot European climate, drive my car hard and am often in the alps too, even at 2650m with my 5. All on the standard cav plumbed to the Bosch on tubing just next to spare wheel. Rest bog standard Plumbed back to tank where I can head the trickle. Nothing funny at all. Maybe now slightly harder to start when standing in heat after an hour or so but nothing worrying and to be honest I believe that more due to a slight dribble on number one injector which needs to reprime after a sit. (Needs new oring) I have never ever had problems even though my tank is getting rather old. I do run an oil cooler and once after a layup forgot to check the radiator which to my horror after driving through town for 30m I found empty... Was sure I was going to find the head cooked but it was fine... I think the oil cooler must help an awful lot even with fuel too. So mines just a straight swap to the Lucas and besides left hand corners when fuel is low I have never had a problem and wonder if all these extra pumps and stuff are just more things to go wrong. I was thinking about a Bosch filter after the pump now as tank is old, but again 30 years and its never been a problem. Btw I have seen there are Marelli pumps that seem identical to the Bosch in look and spec and cost less than £30 if you want to try a cheap swap to test? Tony Edited April 21, 2018 by Rem18 Quote Link to post Share on other sites
Steves_TR6 Posted April 21, 2018 Report Share Posted April 21, 2018 I too have the racetorations style bosch pump in the nearside wheelarch arrangement. I use a standard disposable pre-filter mounted vertically in the spare wheel area, to provide a degree of stability to the fuel passing to the bosch, a 996. No post filter. Car runs grat right down to empty, even left hand bends on less than a quarter of a tank are ok eith the ‘sump’ of the pre filter. I did previously have a cav filter before the bosch, but replaced with the disposables when i wanted to tidy amd renew the plumbing, in abou 2013. Steve Quote Link to post Share on other sites
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