db's 66 Belvedere ***FOR SALE***

sidewaysjas · Post by **sidewaysjas** » Thu Feb 28, 13 10:33 pm

At least you can take it for a spin even if its not perfect, thats progress!
Jas

db · Post by db » Sat Mar 02, 13 9:59 pm

You know what Jas, it's such a buzz driving it now with all it's flaws. i can't imagine what it's gonna be like when it runs right!

30 mile round trip today.
Still has the vibration so correcting the uj angles did nowt

Though I nailed it straight up to ton and it barely shook, til I slowed down thru 90-80 then it was terrible!
Obviously I've ignored Pete's excellent advice and just took it out and nailed it

I did take some notes tho...

At idle (800-ish rpm) afr = 14-15, vac = 5
At steady 2000 rpm afr = 13-14, vac = 15
At steady 3000 rpm afr = 16ish, vac = 15
At full throttle afr = 16.5, vac = 0

That mean anything to anyone? To me it looks bigger mains-ish?

mopar_mark · Post by **mopar_mark** » Sat Mar 02, 13 10:06 pm

db wrote:
At idle (800-ish rpm) afr = 14-15, vac = 5
At steady 2000 rpm afr = 13-14, vac = 15
At steady 3000 rpm afr = 16ish, vac = 15
At full throttle afr = 16.5, vac = 0

That mean anything to anyone? To me it looks bigger mains-ish?

Yes, getting very lean @ full throttle, it needs more fuel

As for what it means, 16:1 = 16 bits of air , mixed with one bit of fuel

I personally prefer to run richer on full throttle, lean will make more power, but easier to do damage, also depends on pistons, ring gap, etc, etc

db · Post by db » Sat Mar 02, 13 10:49 pm

Bigger mains for starters then...
Currently has 072 primary, 086 secondary.
What would be a good starting point?
Any recommendations for jet suppliers?

Adrian Worman · Post by **Adrian Worman** » Sat Mar 02, 13 11:11 pm

Marks spot on Pauly, the reasons could be many tho

Checked fuel pressure? What size fuel line?
I take it you got a vac sec Holley then?
5.5-6lbs pressure max is what you want, any more will push past the seats.
When you jet up try to keep the difference between the fr and r the same, too much of a size difference will cause hesitation.
I know its very boring but make sure you got your timing perfect and your idle circuit tuned for max vac before you start, if you don't baseline the lot before you start it will be next to impossible to get it nailed quickly

And maybe try isolating the primaries and getting them dialed in first, along with the pv, then tune the secondaries for power?

db · Post by db » Sun Mar 03, 13 3:55 pm

Ade- fuel system is plumbed as per Barry Grant diagram below so -8 to reg, -6 to carb.
Carb is a vac-sec 750 Holley.

Fuel pressure from pump is 17, at reg was 6.5, I've dropped it to about 5.5 (though it's fluctuating between 5-6)

Vac at idle -=5
Timing at idle 800rpm = 17*
Timing at steady 3000rpm = 35*
Timing at 4000-ish rpm = 40*

I'm guessing I need one of Turnips advance-limiter jobbies?

I had a 'mare getting the thing to idle at all so I'm very reluctant to mess with the mix or idle screws again. I spent ages carefully balancing the primaries and secondaries. It's not set by the book, but as Dave said 'if that's what it likes, leave it at that'. If they're not right like that I'm screwed!

So would a change of PV be 1st?
I've tried it with 6.5 and it had big bog coming off idle.
Currently on a 2.5, ok off idle, slight bog everywhere else.

db · Post by db » Sun Mar 03, 13 5:29 pm

Top end is sounding a bit tappy.
What should my clearances be anyone?
Solid lifters, roller rockers, ally heads, in a high-revvin 360.

Jon Connolly · Post by **Jon Connolly** » Sun Mar 03, 13 6:00 pm

That looks like loads of total timing Paul ??

Pete · Post by **Pete** » Sun Mar 03, 13 6:04 pm

Too much all in timing - that is probably an adjustable distributor.
Pop the cap off an dlook down the slots for som torq screws 180 desgrees apart.......

Pete · Post by **Pete** » Sun Mar 03, 13 6:14 pm

Needs more pump shot......

db · Post by db » Sun Mar 03, 13 6:21 pm

Thanks Pete.
Can you expand on the pump shot? Adjustment/ change of cam/ change of diaphragm?

Pete · Post by **Pete** » Sun Mar 03, 13 6:43 pm

Check that the primary (only

) pump is adjusted correctly, and try a cam that gives a bigger / longer discharge of fuel off idle.

Trial and error.........

db · Post by db » Sun Mar 03, 13 7:57 pm

I've been reading since my last message and I remember it all now.
15 thou clearance at full throttle, etc. I'm sure it's adjusted right but i'll re-check.
Real Steel do a set of cams so I'll get them and ask them about main jets too.

This was helpful - http://www.junkyardgenius.com/holley/tune01.html

This too - http://www.crankshaftcoalition.com/wiki ... rator_pump

db · Post by db » Sun Mar 03, 13 10:01 pm

Can't see any adjustment in the dissy, it wouldn't be under the plate surely?

Adrian Worman · Post by **Adrian Worman** » Sun Mar 03, 13 10:19 pm

It would be on the yoke that has the advance weights and springs attached

Mopar Muscle Association UK

db's 66 Belvedere FOR SALE

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