Jump to content

Bosch type pump fittings


Recommended Posts

I had a good run to Lincoln this morning, followed by an almost good run home, unfortunately my fuel pump decided to vaporise all my fuel when I was 1.5 miles from home. I remembered that I'd read about a bag of frozen peas being an effective workaround and duly called my wife out, the peas then got me home without further mishap.

 

I've now decided to go down the Bosch type pump route, I have been resisting this as I think the kits that are sold are overpriced, I can source a suitable pump, filter and bracket easily enough, I already have a suitable PRV, what I don't have are the necessary hoses.

 

Can anyone tell me what hoses I need to procure in order to move to a bosch type pump or am I just as well buying a kit?

 

Ian

Link to post
Share on other sites

Ian.

 

I have a bosch pump and experienced fuel vaporisation last week in 30+ degree heat and 6 hour drive in the sun (the only time it has ever happened to me). The car was moving again following a little rest. I’m not changing anything as a result, it’s the cars way of saying it needs a rest. The point is, don’t expect the Bosch pump to cure a vaporisation issue if the weather is extreme.

 

Cheers

 

Dave

Link to post
Share on other sites

Ian.

 

I have a bosch pump and experienced fuel vaporisation last week in 30+ degree heat and 6 hour drive in the sun (the only time it has ever happened to me). The car was moving again following a little rest. I’m not changing anything as a result, it’s the cars way of saying it needs a rest. The point is, don’t expect the Bosch pump to cure a vaporisation issue if the weather is extreme.

 

Cheers

 

Dave

Thanks for this Dave, I was wondering why the Bosch unit wouldn't suffer the same way. I'm extra paranoid as my car predates hazard warning lights, I must get round to fitting the kit, then I might be able to stop a little more safely!

 

Ian

Link to post
Share on other sites

The Bosch pump draws more current and with that dissipates nore energy in the fuel; this results in a quicker warm- up of the fuel, but there are other aspect like radiation from the hot exhaust warming up the fuel too.

As the fuel temperature increases, the risk of cavitation is increasing.

The warm weather inpacts this even more.

The pump design plays a role too: some pumps are better in this aspect than others; this is measured as the NPSH- req: the netto positive suction head that is required at the pump inlet. I do not know how the lucas and bosch pumps compare, but the higher flow rate certainly does not help the bosch pump.

Just some aspects that play a role, there are more.

Regarding the hoses:

I have bought Gates barricade hoses.

But I think the ptfe lined hoses in combination with the diaphagm prv is a good choise too.

The diapharm prv reduces/ eliminates vibrations, according to some specialists, which makes sense to me.

Regards,

Waldi

Edited by Waldi
Link to post
Share on other sites

The Bosch pump draws more current and with that dissipates nore energy in the fuel; this results in a quicker warm- up of the fuel, but there are other aspect like radiation from the hot exhaust warming up the fuel too.

As the fuel temperature increases, the risk of cavitation is increasing.

The warm weather inpacts this even more.

The pump design plays a role too: some pumps are better in this aspect than others; this is measured as the NPSH- req: the netto positive suction head that is required at the pump inlet. I do not know how the lucas and bosch pumps compare, but the higher flow rate certainly does not help the bosch pump.

Just some aspects that play a role, there are more.

Regarding the hoses:

I have bought Gates barricade hoses.

But I think the ptfe lined hoses in combination with the diaphagm prv is a good choise too.

The diapharm prv reduces/ eliminates vibrations, according to some specialists, which makes sense to me.

Regards,

Waldi

Thanks Waldi, another detailed response, I already have a diaphragm PRV, I bought one from Revingtons along with their SS shielded hose, I don't have any fuel smell in the boot now which is great. The rest of my system is freshly restored by Neil, the pump sounds strong but today it was a different sound, quite weak, I assume this was due to only vapour being present. The external pump temp was 48C, is there any point in fitting a cooling coil?

Link to post
Share on other sites

Last week my fuel pump was too hot to touch. The fuel tank was very hot to touch but slightly cooler than than the pump. I managed to cool the pump by pouring (gently) water onto it from a nearby stream (as luck would have it). Even so, I could only drive another 2 km before the fuel had cavitated again. I managed to solve by driving with the boot lid up the remaining 8km to my hotel.

 

In short, I don’t think their is a cure as such. Keep the tank topped up and park under shade if possible whenever you stop in the kind of heat we currently have. In my case, I was in Spain and the last fill up used E10 98 Ron. I put it down to long drive (350km) with limited stops in 30+ heat, in a dark coloured car with e10 fuel. There are learning points there!

 

Good luck.

 

Dave

Link to post
Share on other sites

Hi Ian,

Revington (and others) provide good information about the Lucas system on their site.

Im not sure if a coil around the pump makes any sense. Is the coil cooling the pump or is the pump heating the coil (yes, it is the same????)?

To me, the coil is just a couple of meters of extra pipe in an uncooled area (the boot), I have never understood its working principle, but I guess I do not understand the full picture, since it was a design used by many. Maybe a more experienced fellow forum member know the facts.

Cheers,

Waldi

Link to post
Share on other sites

Perhaps some sort of cooler on the PRV return line might be worth considering to reduce the temperature of the fuel itself? The Lucas pump coil Waldi discusses above might be better located under the car where it could actually serve a useful purpose. It's on the low pressure side so wouldn't have to be too fancy - somethink like this perhaps?

 

post-14246-0-90593700-1530394433_thumb.jpg

Edited by KiwiTR6
Link to post
Share on other sites

I think cooling the pump is only part of the answer. If the fuel tank is hot (as in my case) then it doesn’t matter about the pump. I managed to cool the pump down (it felt cold to touch) yet upon restarting, I could only travel 2 km before the hot fuel from the tank raised the pump temperature to the point where cavitation occurred again. It was an extreme situation; hot temp, long drive, dark coloured car and e10 fuel and not a petrol station anywhere near.

Link to post
Share on other sites

Is the tank well vented? The NPSH at the pump inlet can be pulled down on a long run if fuel usage reduces the pressure in the tank due to poor venting.

 

Also check that the PRV return to the tank is well away from the suction line. Mine are on opposite sides of the tank, if they're too close you will get fuel short cycling between the supply and return lines.

Link to post
Share on other sites

Also

Make sure your pump, whichever it is has an adequate power supply and good earth.

Run a new wire battery to pump via a relay and use existing wiring to control the relay.

 

If your pumps not getting sufficient power it will have to work harder and therefore heat the fuel etc etc

 

Cheers

Guy

Link to post
Share on other sites

Also

Make sure your pump, whichever it is has an adequate power supply and good earth.

Run a new wire battery to pump via a relay and use existing wiring to control the relay.

If your pumps not getting sufficient power it will have to work harder and therefore heat the fuel etc etc

Cheers

Guy

It’s already powered via a relay Guy, but thanks for the suggestion.

Link to post
Share on other sites

Is the tank well vented? The NPSH at the pump inlet can be pulled down on a long run if fuel usage reduces the pressure in the tank due to poor venting.

 

Also check that the PRV return to the tank is well away from the suction line. Mine are on opposite sides of the tank, if they're too close you will get fuel short cycling between the supply and return lines.

I have an aftermarket locking cap Mike, I wouldn’t say that it seals that well, my previous cap was missing the vent so I know how that sounds when you open the cap, I don’t have that problem now.

Link to post
Share on other sites

Thanks Waldi, another detailed response, I already have a diaphragm PRV, I bought one from Revingtons along with their SS shielded hose, I don't have any fuel smell in the boot now which is great. The rest of my system is freshly restored by Neil, the pump sounds strong but today it was a different sound, quite weak, I assume this was due to only vapour being present. The external pump temp was 48C, is there any point in fitting a cooling coil?

If still using a Lucas pump along with the original CAV filter, you will always have trouble with cavitation in hot weather as the bore size of pipe is too small, from tank to pump. In the 1970's Lucas/CAV Dealers could obtain a larger filter head from CAV which enable you to use larger bore pipe of 3/8" and fittings instead of 1/4". this was not a 100% cure but pretty dam near. It raised the cavitation start point by at least 10C. Regarding Bosch pumps, in my view the best one was the Merc. diesel pump which only draws 5 amps, none of this 10 amps + business. My pump has been going for 35 years+ and was supplied by KMI who were the first to market Bosch replacement pumps and they are still in business.

Lastly keep your tank at least 1/2 full.

 

Bruce.

Link to post
Share on other sites

Put the pump assembly on the other side of the boot side panel - I.e. outside. TRGB do a reasonably priced kit with everything included. It's worked for me without issue - long drive, low fuel and spirited driving in 29C from Lincoln to Worcestershire and back yesterday.

 

Colin

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.