Mopar Muscle Association UK

Parcel from Hausers today!
New plugs gapped and ready to fit for the Nats.
New Felpro 0.3" rocker gaskets with steel insert, to sort out two major oil leaks

Gaskets look good quality Paul. Out of interest how much ?

£35 plus delivery. They're $35 in the U.S. so a pretty fair price from Hausers

Ta mate.
Good price. My covers drove me mad. Oil straight on the headers. Nice !!!
Resolved with Mopar performance covers and gaskets.

Can't beat a bit of cork though !

and they have a thin steel layer sandwiched in the middle so they can't belly-out, which my old ones were starting to do.

Some good tuning info using AFR-
http://www.dragzine.com/tech-stories/en ... rburetors/

Here's Holley's approach to tuning pvcr holes-
http://www.holley.com/data/Products/Tec ... 1-1rev.pdf

Some good info on pump cams & shooters-
http://www.crankshaftcoalition.com/wiki ... rator_pump

Interesting chat about pv's...
http://speedtalk.com/forum/viewtopic.php?f=1&t=3157

Out for a few hours today and achieved nothing

I lost the spot where I had vac of 7 at idle, it's back to 5 now @ 800. AFR is 14.5ish though. I've changed to 2.5pv.
Foot to the floor acceleration seems sluggish though AFR seems right at 12ish.
The BIG problem is under normal or gentle acceleration AFR goes to 18-20 vac is 20 so it's nothing to do with the pv as that won't be open.
I tried changing main jets from 64 - 68 (AFR at WOT never went over 13) I tried half a dozen different pump cams and 2.5, 4.5, 6.5 pv's just cos I couldn't think of anything else

UPDATE:
Just found leaks at the throttle shafts! Same as on the other carb, I should have bloody realised sooner
VERY ANNOYINGLY the rebuild kit I got for this carb doesn't have the little teflon strips.
Anyone got spares they can send me urgently?

Dave Carter spotted you

Bananarama! the little Teflon strips Pauly, get some simple Alraldite or equivalent and apply a thin layer to the shafts, let it set, apply a little more and it should cure most of the leak, enough to get a consistent tune

Thanks for tip mate- other Ade has spotted some on ebay uk for a fiver so i'll have 'em by tuesday-ish

charger01 wrote:Dave Carter spotted you

Can't get any bloody privacy

db wrote:

charger01 wrote:Dave Carter spotted you

Can't get any bloody privacy

Fake book freaks

Dave wrote:Make sure the power valve channel restriction is drilled out to around 50 thou. Just to be sure you get enough enrichment when the power valve does open.

I can just get a 1.4mm (.053") drill bit in, so they are about right.

have you done a timing advance curve? plot the timing against rpm every 500 rpm and draw a graph from there

for example

idle = 10 deg
1000 = 12
1500 = 18
2000 = 25
2500 = 30
3000 = 35
3500 = 38 (probably max advance around here)
4000 = 38
4500 = 38

that way you know the timing at any given rpm to relate it to what the fueling is doing. a lean mixture will burn slower.

also on light throttle it'll probably still be on the slow running circuit. on the GT40 to cure the leanness at light throttle i modified the carburettor by filing the slow running slots in the carb base slightly wider. i then restricted the air corrector so it had to draw more fuel for light throttle. on a holley the air corrector is a fixed orrifice so not tunable so to speak (iv'e seen on different make 4 barrel carbs removable jets for the air corrector). the above mod worked on the GT40 with a very worn throttle spindle.

i would say idle should be around 11 to 12 afr
light throttle should be around 14 to 15 afr
half throttle should be around 13 afr
full throttle should be around 12.5 afr


going back to the air corrector on the slow running circuit. what this does is compensate for engine rpm by introducing air to the emulsion devise slowing the amount of fuel drawn into the carb. if it wasn't there the higher the rpm the richer it'll get. so at very light throttle low rpm there is only a small draw on the slow running circuit. at high rpm very light throttle there is a heavier draw on the slow running circuit pulling a lot more fuel (this is to do with air speed and the venturi effect not vacuume in the inlet manifold). the air corrector affects higher rpm only where as changing jets will affect the whole range.

i hope what i wrote makes a little sence?

Thanks Boz, I'll have to read it a couple more times but yes, I think I'm getting it.
I've not done a timing curve.

I expected this carb (especially with the secondaries wired shut) to work pretty much the same as my vac sec but it's way different!
It'll be out of action for a few days til I've fitted the Teflon strips and my new clutch plate so I need to learn what to do before then

On a Mopar running on super unleaded the timing curve will be more like;

Idle - 20 degrees

2000rpm - 27 degrees

3000rpm - 34 degrees MAX

Measuring at 500rpm increments can be useful. At least it gives you a couple more points on the graph paper to join up with your pencil.