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Carb Guru question. Updated with after action report.

Re: Carb Guru question.

That's the article that led me to get the Summit carb. All the jets, valves, etc are holley.

Sluggo, if you find that leak, and follow the rest of Pat's advice, you'll get that vac up and you'll forgive her for the cam episode
 
Re: Carb Guru question.

"apollard" said:
That's the article that led me to get the Summit carb. All the jets, valves, etc are holley.

Sluggo, if you find that leak, and follow the rest of Pat's advice, you'll get that vac up and you'll forgive her for the cam episode
Click to expand...

I've already forgiven her. She runs like a scalded arse ape other than the loading up and the melted :ep thing.

I can't imagine how insane it would be with a 3:70 out back
 
Re: Carb Guru question.

IIRC, idle vacuum readings were generally in the 12-14 range in gear. IMO, that's a good number to shoot for, but don't worry if it's anything over 10. I don't know the rest of your combo but it's probably low compression so overlap reversion and the relevant vacuum signaling is always an issue at idle. I'm assuming, if it were close to 'stock', we wouldn't be having this conversation LOL...

Good luck!
 
Re: Carb Guru question.

"camachinist" said:
IIRC, idle vacuum readings were generally in the 12-14 range in gear. IMO, that's a good number to shoot for, but don't worry if it's anything over 10. I don't know the rest of your combo but it's probably low compression so overlap reversion and the relevant vacuum signaling is always an issue at idle. I'm assuming, if it were close to 'stock', we wouldn't be having this conversation LOL...

Good luck!
Click to expand...

Here's some info:
351w stroked to 427 10:1 compression, cast iron heads, performer intake, summitt carb, Lunati bracket master II camshaft part 00061 using 289 firing order, manual transmission.

If I can get a steady 10 I'd be thrilled. Oddly enough the power brakes work pretty decent.
 
Re: Carb Guru question.

With those cubes, that cam and 10:1, that thing should idle like stock. That's a little cam for a big engine. I mean that in a good way. This idle issue should be easily resolvable. If not done already, do the vacuum leak tests that I and others suggested, first.

Also, as a baseline, borrow a known-good carburetor for comparison. If this issue has been around since installation, there might be something wrong with the carb.

I offered the same advice to Tom (Sac69) at Knotts when he was complaining of a miss in the mid-throttle cruise range. Baseline it, then work the problem.

Maybe I should start a business as a fly-in engine consultant. I'm sure Aunt Toni would love that :lol
 
Re: Carb Guru question.

You should do that.

The carb is known good. It functioned properly prior to the new camshaft install.

I'm still at work. Heading to Dallas tomorrow then Oklahoma City. Got a wedding rehearsal Friday and wedding Saturday.

If I don't get too hammered Saturday night I might get a chance to mess with the car Sunday :sad

Thanks for all the tips.
 
Re: Carb Guru question.

If you rule out a vacuum leak, you could also pull the valve covers and make sure all the valves are adjusted properly. I'm not sure what iron heads you are using but if the nut is too tight the valve won't fully seal and will cause what acts like a vacuum leak and a rough idle. I'd tackle the vac leak test first though :ecit
 
Re: Carb Guru question.

I adjusted them per Lunati's instructions. Zero lash then half turn.

Definitely on my list if no vacuum leaks are found.
 
Had about 30 minutes to spare today.

Idle speed 950
Idle screws out 1 1/4 turn
Initial timing 12 degrees BTDC
Total Timing 35 degrees
22 inches of vacuum at idle and steady
No test drive because it's rainy outside
Still a little stinky but way better.

Thanks for all the pointers! :ecit
 
22 inches of vacuum? :ep You got a vacuum canister on that bad boy? :lol So what all did you do, or did you do anything??
 
Yes it has a canister. It's a factory A/C car.

I reset the timing, set the idle to 1200 then adjusted the idle screws.

I also used a different vacuum gauge.
 
Well,

I took a little (little being the key word) test drive and got a bout 3 miles before the dizzy gear failed. WTF?

This car is killin' me.

Steel dizzy gear with flat tappet cam is correct, no?

Callin' Lunati Monday to see what they say.

So, got wreckered to the shop and there it will sit for at least a week while I determine which gear to get, getting it in hand and having the machine shop press it to the proper depth.
:rp
 
Steel dizzy gear with flat tappet cam is correct, no?
Click to expand...

Yes, a standard distributor gear should work fine. Do you have a HV oil pump on the engine? Double check the oil pump drive for adequate clearance and free function. When everything is installed, it should be movable, slightly, by hand, up and down. Check before and after insertion of distributor to compare.

I don't know what's going on with parts these days....
 
Damn man, you are having the worst run of bad karma, I hope it turns around for ya Boss.
 
"Sluggo" said:
Well,

Steel dizzy gear with flat tappet cam is correct, no?
Click to expand...

Negative! Cast gear with flat tappet. Steel gear with a roller cam. You probably just destroyed your new cam.
 
"johnpro" said:
Negative! Cast gear with flat tappet. Steel gear with a roller cam. You probably just destroyed your new cam.
Click to expand...
Been there done that...got the t-shirt. Make sure that you use the correct dizzy gear or it will get wiped out and probably take out the cam gear.
 
OP, did your distributor come with a standard drive gear? If so, IME, that's the 'standard' cast gear. Or, did you order it with a specific gear type? We always used bronze gears with steel roller cams, since steel against steel (similar frictional/metalurgical qualities) was contra-indicated. I guess that's changed. The Ford SVO catalog lists three different gears that can be used with a 0.467-inch distributor shaft. Its newest is a steel gear compatible with the factory steel roller cam and aftermarket cams (PN M-12390-B), while a larger 0.531-inch-shaft-diameter steel gear for 302 EFI roller-cam motors and all 351W engines is also offered (PN M-12390-F). An SVO bronze gear (PN M-12390-E) is also available.

Could you post a picture of the distributor gear?

As an example, here's the steel gear Ford sells:

fms-m-12390-b.jpg
 
"camachinist" said:
We always used bronze gears with steel roller cams, since steel against steel (similar frictional/metalurgical qualities) was contra-indicated.
Click to expand...

I have read/heard that you can use steel/steel or bronze/steel, but the bronze was considered sacrificial and eventually needs to be replaced. I'm running steel/steel in my 408 (roller cam) and cast/cast in my '66 (flat tappet).
 
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