700 double pumper on a road car

GJUK · Post by **GJUK** » Thu Aug 07, 14 9:07 pm

Thank you

GJUK · Post by **GJUK** » Fri Aug 08, 14 9:51 am

Just to confirm (from reading other forums)

A big block crank turns clockwise and dizzy turns anticlockwise.

Is this correct?

Thanks

Dave-R · Post by **Dave-R** » Fri Aug 08, 14 9:57 am

GJUK · Post by **GJUK** » Fri Aug 08, 14 10:01 am

Thanks,
That looks like a cool paperweight

GJUK · Post by **GJUK** » Sat Aug 09, 14 3:15 pm

Update,

So I got my wife involved today, after trying to kill me by driving the car at me, she worked out how to get everything in Park and we were away...

Found TDC
Marked the damper with tipex so I can see and got the car running about 800-1000 rpm (I couldnt see the tach) but wife confirmed with wild hand movements and nodding of her head.

Timing was about 12 degrees advanced on idle (though you had to kind of feed it throttle to keep it there)

Car revved really strong, up to 5k or so, perfect.

Idle was sh!te. It just died off.

Kept playing for a while then I noticed the front (near to the car front) two barrels getting full of fuel... Then I noticed fuel 'waterfalling' out of the area between the spacer and the carb....

Nipped everything up. Treid again

Same situation.

The floats must be stuck? It must be pouring in fuel for some reason on idle...

Anyway, carbs off now, ready to be rebuilt. Timing seems okay but the fueling seems to be the problem here (I think!)

Thoughts on a postcard experts please!!!

Jon

Blue · Post by **Blue** » Sat Aug 09, 14 5:40 pm

Looks like the float level is way too high, should only just trickle out of the level plug. Probably need more initial timing yet, 17 to 20 degrees at a guess, will all make a big difference once you sort it.

GJUK · Post by **GJUK** » Sat Aug 09, 14 6:51 pm

Blue wrote:Looks like the float level is way too high, should only just trickle out of the level plug. Probably need more initial timing yet, 17 to 20 degrees at a guess, will all make a big difference once you sort it.

Thanks.

It just would not run well with any more advance.

So rebuild of the carb now - I have someone that's done a couple before helping me on Monday evening. Then bolt back on and see how it all goes. I guess I might need a new gasket for the spacer > carb. Though mine was drenched in fuel it looked okay (and is only 200 miles old)

J

Mick · Post by **Mick** » Sat Aug 09, 14 9:11 pm

I agree with John, if your float levels too high or sticking that will cause the problems you're having. If your friend let's you down Jon, let me know and i will rebuild it and set it up for you but it will have to be tuesday onwards because i'm busy sunday and monday, i can also bring my timing light and check the timing if you wish. I trust you've got a rebuild kit.
Mick

db · Post by db » Sat Aug 09, 14 9:13 pm

Needle valve seats are a favourite for leaking too

Mick · Post by **Mick** » Sat Aug 09, 14 9:22 pm

Here you go Jon.
If you take the needle and seat out make sure you change the O ring on the needle.

http://www.google.co.uk/url?sa=t&rct=j& ... WU&cad=rja

GJUK · Post by **GJUK** » Sat Aug 09, 14 10:09 pm

Thanks guys and thanks Mick.

I have a full rebuild kit from RealSteel, my friend has built these before though if I get stuck I will certainly be heading your way!!!

Cheers for the offer of setting her up also.

Thanks

GJUK · Post by **GJUK** » Sun Aug 10, 14 10:03 am

Update #2:

Bot the floats are brass and are water tight, no bubbles when you hole them under water at all for 2-3 minutes. They sound empty also so it might be float height settings maybe?

I did notice the jets though. The circuit which was 'flooding' in fuel has a pair of 99 jets (largest you can get?!) and the other a pair of 86 jets.

Could these jets be WAY over the top?

GJUK · Post by **GJUK** » Sun Aug 10, 14 10:05 am

Taken from here:

http://www.allcarbs.com/tech.php?art=21

4778 700cfm

Primary main jets 66, Secondary main jets 71, Power valve 6.5, Primary Nozzle 25, Secondary Nozzle 32

4778-1,2 700cfm

Primary main jets 66, Secondary main jets 76, Power valve 6.5 Primary Nozzle 28, Secondary Nozzle 31

4778-3,4,5,6,7 700cfm

Primary main jets 69, Secondary main jets 78, Power valve 6.5, Primary Nozzle 28, Secondary Nozzle 31

All DP spec holleys all with a max of 78 size jets... 99 must be the problem?!

Might explain the miles per gallon I've been getting as well

Blue · Post by **Blue** » Sun Aug 10, 14 10:15 am

A 700 should have 69 primary and 78 secondary from the factory, power valve would be a 6.5. I always start with factory jetting when setting up, you know the car will run and optimum jetting should be within a few sizes up or down. Power valve size you arrive at with a vacuum gauge and a little experimentation.

GJUK · Post by **GJUK** » Sun Aug 10, 14 10:19 am

Thanks Blue.

So the jet size appears way overkill for the application?

My friend has a jet set which he said I could borrow when we rebuild the carb. May just slap the sizes you suggest in there...

Mopar Muscle Association UK

700 double pumper on a road car

Update

Think the jets are wrong!