I'm getting close to starting up the 3.4 after 18 months restoration work (yay!).

Managed to solve most of the usual leaks - oil, transmission, diff, cooling system, brake hydraulics.

I imagine this has been discussed before, but the front SU is weeping fuel from the junction of the enrichment device (choke?) to the float bowl. New gaskets & tightening the Bejesus out of it does not seem to have cured the leak.

It's not bad enough to cause the fuel pump to tick over, just annoying enough to cause the dreaded smell of fuel.

Any ideas guys?

Peter

 

I have been into Datsun 240Z's for decades and thus know SU's. The Jag's use the same exact carburetors and this is NOT something DIY should deal with as you will NEVER get them to run as good in my opinion. Don't waste your time just send them to S.U. Carburetors, Rebuild Kits, Gaskets, Components, Datsun Z Car, su, ZCar, 240z, Roadster, SU Videos
and have them rebuild them and they will be like new. To me it is cool many Jag owner try to do a lot themselves but I really feel SU's when they are old should be professionally rebuilt and Ztherapy is the best and go to shop that many Z car specialist use.

 

Hi Primaz,

Check that you don't have any foreign matter (dirt / grit) on the gasket surface.

Smear some Loctite thread sealant (567) on each side of the offending gasket, re assemble and see if the weeping stops.

I've used this stuff in Australia and can vouch for it stopping the odd fuel weep or seven.

Cheers,

Nigel

 

Whoops,

i meant to address redtriangle

Sorry

nigel

 

Make sure and lubricate the threads on the aluminum/banjo bolt with grease _ the steel and aluminum like to gall.
When I assembled mine I used copper and bit of grease there too.
I'm not sure if the spare parts kits are now using those fibre washers, but I don't think they're quite as reliable as copper.
And there has to be one on each side of the banjo fitting of course _ just in case you forgot.

 

Try Hylomar. It always stops fuel leaks.

 

Thanks guys for all those suggestions. I might remove the carbies (yet again) and try those tips, then bench test them using a spare SU pump, fuel can & a battery.

Amazing how all these niggling problems arise the closer you get for that long awaited test drive!

 

Again unless your SU's are new or were professionally rebuilt I still recommend sending them to Z Therapy as all they do is just rebuild SU's and they do it to a level not found any where. Also say you have modified your motor with a performance cam or porting work on the head, Z Therapy can rebuild them specifically to enhance a custom engine. You might get them to stop leaking but if you really want them to run well consider going the extra step to rebuild them and not by some general Jag or other mechanic. Z Therapy is not a repair job but rather only a SU carburetor rebuilding shop and most of the top Datsun performance shops send SU's there.

 

Thanks Primaz for your advice. Unfortunately, shipping costs from Oz to the US would make it an expensive proposition. But it may come to that if there's no success otherwise.

 

Red,


Unfortunately I do not know the Australia Datsun scene but you might ask this person as they build decent Datsun engines from what I hear.


Les Collins Racing

8 Olympic Street
Warragul, VIC 3820
Australia
Tel. 613 5623 3108
Fax 613 5623 3064
The reason is that I have found that Datsun high performance shops really know the SU carburetors better than Jaguar mechanics. I think that is because the Datsun racers build in line 6 engines with the Datsun's that just dominated every other engines with way more horsepower than Jaguars have ever been able to do.

 

From my experience, if the system has been left dry for a while the washers need to moisten up a bit. Thats if its just looks a bit moist rather than running in fuel.
barry