Fuel pressure, 'internal seepage' and the T-piece mystery

[Andy McGhee]

I'm sure a lot of R4 owners will be familiar with this diagram - it appears in quite a few manuals (most of the text is translated in the Haynes manual). I've seen a lot of posts that say something along the lines of 'One of the T-pieces has a restrictor in it', but I think this is a misunderstanding caused by the diagram - the section of the text that deals with the parts required (with the blue dots) clearly states that 2 identical T-pieces are needed: in other words, both T-pieces have a restrictor in them.
It's interesting that Renault addressed this issue in September 1976 - R4 owners of a certain age will remember that summer!

 

[JdeW]

I've seen the same modification schematic in a Dutch R4 service manual.
It concerns the problem of difficulty in restarting the engine caused by a rise in temperature under the bonnet, I think most R4 drivers are familiar with that issue.
Normaly the fuelpump has 2 connections but mine GTL has 3 connections with that calibrated return.


GTL 3 lead fuel pump.

 

[Andy McGhee]

Yes, the Dutch text appears to be a translation of the one on page 252 of the later Haynes manual - a reader of either might infer that only one of the T-pieces has a calibrated opening. I just thought that it was interesting that the Renault engineers' solution has two calibrated T-pieces.
I also imagine that most of the R4 owners who experienced vapour lock/'percolation'/heat soak/internal seepage/increased fuel pressure issues had cars with Billancourt engines - the problems were addressed by Renault in Sept 76, so only a few R4s would have had Cléon engines then.
The 3-pipe pump solution is a great idea - but I'm not sure if there's a similar pump available for RHD R4s. Ours have the 'upside-down' pump first found, I think, on R5s - this doesn't foul the steering column.

 

[JdeW]

Indeed a few models had the Cleon engines, in 1975 the R4 models R2370 and R2430 and according to PR1104 there was a 3 lead fuel pump for UK RHD R4's for GTL's and the later Savane and Clan

 

[Simon Knight]

Hi all, i was wondering if anybody had fitted a cooling fan behind the carb and if this helped?

Cheers Simon.

 

[angel]

The Renault 5GT had a factory fitted cooling fan and duct arrangement for the carburettor but it wasn't a good idea, it had the tendency to catch fire when fuel vapors or eventual carburettor overflow passed through the fan motor. Removing it was a must for most owners.

 

[Simon Knight]

HI Angel, thanks for the reply. I must admit i hadn`t considered the fan catching on fire. I thought a fan would duct from outside and blow across the carb, not suck and extract? Anyway it was just a thought.

on a separate note, the door pocket clips have arrived, thank you. Enjoy the rest of your holiday.

Cheers Simon.

 

[blakeyboy]

A modern 12v cooling fan is brushless, so the fire risk would be minimal.

I always found on quick Minis when I hammered them in the summer that it was the pipe insulation and routing
that was the problem, and the solution...

 

[Simon Knight]

Hi Blakeyboy, thanks for the advice, it's much appreciated. I will look at rerouting the fuel supply.

Cheers Simon.