TR6 PI fuel pump/supply voltage

[Mk2 Chopper]

I've just fitted a relay to switch a new dedicated wire from battery to pump, all works well, but...I've noticed the ammeter now reads slightly to the positive side of the gauge, where it used to be pretty much in the center.

Is this normal as the wire is direct to the battery? 

Gareth

[FatJon]

Yes, because you are now taking the pump supply from the wrong side of the ammeter so the current going to the pump is current that the ammeter thinks is going to the battery to charge it rather than from the battery to discharge it.

I didn't give that much thought so I could be wrong but it seems logical to me from a cursory look at the wiring diagram.

 

 

[RobH]

Yes that is right. The ammeter will only indicate properly if all the loads are on the generator side of it.  It is only supposed to show current flowing into and out of the battery.

[Mk2 Chopper]

Thanks guys I get it now, so can I add the wire to somewhere else like the alternator or is this the best place for it? 

Gareth

[RobH]

Up to you really Gareth. It depends whether the ammeter offset bothers you.  If it does, then either the alternator output or the ammeter terminal will do the trick but are probably a bit more difficult to get to than the battery.

[Mk2 Chopper]

Thanks Rob, it didn't bother me, but it's good to have things working as they should, I'll see if there is somewhere on the alternator I could use and decide. 

Cheers

Gareth

[Xiberras]

Bonjour à tous et désolé de m'exprimer en français...c'est mieux qu'un Anglais déplorable... 

Je viens de remplacer le joint spi de ma pompe et il y quelques années j'avais récupéré les aimants permanents et les balais de mon moteur d'essuie-glace pour ma pompe en bien meilleur état. 

Les roulements laitons sont d'origines et on ne peut les trouver en Pièces détachés... J'ai d'ailleurs du mal à trouver une pompe en échange standard actuellement. 

En attendant, je vais moi aussi mettre un relais et un + plus gros pour la pompe et le câblage initial servira pour alimenter le relais.

La masse de la pompe est déjà prise directement dans le coffre. 

D'après vous faut il changer les 2 fils internes de la pompe qui alimentent les 2 balais ? Ils semblent aussi trop fin. 

Merci pour vos conseils 

Julien 

TR6 PI 1969 

[Iruka]

Hope this translation helps Julien!

Hello everyone and sorry to speak in French...it's better than a deplorable English... I have just replaced the oil seal of my pump and a few years ago I had recovered the permanent magnets and the brushes of my wiper motor for my pump in much better condition. The brass bearings are original and you can't find them in spare parts... I'm having trouble finding a standard exchange pump at the moment. In the meantime, I will also put a relay and a bigger + for the pump and the initial wiring will be used to power the relay. The mass of the pump is already taken directly from the trunk. Do you think it is necessary to change the 2 internal wires of the pump which supply the 2 brushes? They also seem too thin. thanks for your advices

[RobH]

If they are original it is not necessary to change the wires inside the pump motor.  The manufacturer will have sized those appropriately and they are so short that there will be no appreciable voltage drop.  Compare the cross-section of copper in the wires to the bare braid making the connection to the brushes.  

 

Edited August 6, 2022 by RobH

[Xiberras]

Merci Iruka pour votre traduction et merci Robh pour votre réponse. 

Je laisserai donc les fils d'origine de la pompe. 

Je pensais installer un petit ventilateur 12v type PC mais je ne sais pas trop où il serait le plus efficace... 

[RobH]

Si vous en adaptez un, il serait plus logique que le ventilateur refroidisse le corps du moteur, je pense. La pompe elle-même doit être refroidie par l'essence qui la traverse. Je ne suis pas sûr cependant qu'un petit ventilateur réalisera vraiment beaucoup à moins qu'il n'y ait un endroit pour que l'air chaud soit évacué.

(désolé si la traduction automatique est incorrecte)

 

Edited August 6, 2022 by RobH

[Xiberras]

J'ai fais quelques mesures avec un thermometre infrarouge à chaud par temps chaud dans le coffre:

Le corps du moteur atteint 148 degrés F° (70C°)

La partie pompe 104 degrés F°(40C°)

Le coffre est à 104 degrés F°

Je me suis posé la même question car brasser de l'air tiede n'aura pas ne pourra pas beaucoup diminuer la température du moteur. 

Pour créer un flux d'air frais, il faut une entrée d'air frais dans l'intérieur de l'aile mais il faut j'imagine aussi une sortie à l'arrière du coffre... 

(Écrivez-moi en Anglais ça me fait beaucoup progresser) 

 

[RobH]

 

70°C is a bit warm for the motor but not excessively so for electrical parts. Most have insulation capable of withstanding 120°C or more but the grease in the bearings will be the weak link.  

 I seem to recall that some people have used liquid  cooling by wrapping a coil of thin copper pipe around the body and plumbing it into the low-pressure fuel return line from the Pressure Relief valve to the tank - though of course all that does is warm up the fuel in the tank over time. 

I found these interesting old threads on the subject - one person talks of air ducting  which is probably the best answer though it does mean making holes :

 

 

Edited August 7, 2022 by RobH

[Tom B]

On 6/20/2020 at 3:32 PM, Phil Read said:

Any chance of a wiring diagram? Since fitting a new pump to mine it will not start straight away if left overnight, it was ok before the new pump. Once started it is ok. The company who sold me the pump said check starting voltage at the pump but not sure how to do this.

 

 

Phil,

Wiring diagram above (I previously posted this). The original (white) inertia switch is probably not up to the job of carrying the larger currents - I fitted a modern one and put it in the line from the ignition to the relay. (As mentioned in another post) - That way it is only seeing 140mA (in this case) and there is no voltage drop associated with that feature. I ran mine off the legacy TR5 connector block which is on the bulkhead - this does a fine job and saves connecting to the battery. A fused relay makes things a bit tidier as well.

All the best

Tom

 

 

[super6al]

Hi 

I fitted a heat pipe connected to a heat sink mounted in the wheel arch. I managed to reduce the temperature by about 10 deg C at both the motor & pump.

Motor was 62 deg & pump 51 deg. After the installation this dropped to 52 & 42 deg C.

I found my original post with pictures but don't know how to copy/paste into this post.

Alan

[stuart]

14 hours ago, super6al said:

Hi 

I fitted a heat pipe connected to a heat sink mounted in the wheel arch. I managed to reduce the temperature by about 10 deg C at both the motor & pump.

Motor was 62 deg & pump 51 deg. After the installation this dropped to 52 & 42 deg C.

I found my original post with pictures but don't know how to copy/paste into this post.

Alan

https://www.tr-register.co.uk/forums/index.php?/topic/77845-hit-by-cavitation-last-sunday/page/2/&tab=comments#comment-734381

Here you go

Stuart.

[Jonny TR6]

My silencer will be due for renewal at some point. I'll probably get PECO who are local to me, to make one up and will get them to weld some tangs on so that I can attach a heat shield. There must be quite a heat soak from the silencer to the boot floor.

Anyone else done this ?

Edited August 8, 2022 by Jonny TR6

[super6al]

Thank you Stuart! 

Its not the neatest of installations but its done the job. A year on & still no issues.

Alan

[michaelfinnis]

1 hour ago, Jonny TR6 said:

My silencer will be due for renewal at some point. I'll probably get PECO who are local to me, to make one up and will get them to weld some tangs on so that I can attach a heat shield. There must be quite a heat soak from the silencer to the boot floor.

Anyone else done this ?

I put some heatshield insulating material on the boot floor. I haven't taken any temperature readings to quantify what difference it makes, but as you say I would expect that there must be heat soak from the exhaust, especially when stationary and there is no airflow, so can only help.

Mike.

[Xiberras]

Intéressant montage sur une 2500pi trouvé sur le net,  des ouvertures dans le coffre s'imposant à ce montage de canalisation de l'air sur la pompe !