Anybody care to comment on the cam specs?

 

Already have. Dunno. Lotsa lift as the Comp Cams unit I put in the '82 Explorer gave .500ish at the valve. But beyond that I don't know.

 

Typical roller cam, higher lift without having to go overboard on duration. Certainly not too much for street use. Might be a bit shy on "take-off" power with a stock converter and 31" tires, since the advertised RPM range is 1600 and up, but it should come on pretty strong shortly thereafter.
Will it make the HP that was claimed? No clue. Getting the carb and timing (both initial & advance) tuned will certainly make a big difference towards reaching the max power output.
I'm guessing it was degreed in as per the spec sheet.

 

OK, so today I ,made it out to Gary's in order to mess with the carb issues. Gary measured and wrote down the specs on both my carb (Edelbrock 1406) and my buddy James carb (Edelbrock 1405). They were almost identical in some areas,but,extremely different in others. Gary has the notes and will post them in a bit. He was worn down from working on carbs all day(mine,james & his also) so he may wait until the morning.


I made a severe exhaust leak in the header on the passenger side test driving it. It scared the crap out of me because I thought I had destroyed the motor. Luckily I am pretty sure it is the exhaust and not bent valve.

 

Here's the info. I have it in a spreadsheet (what else? ) but don't have an easy way to print to a jpg on this Mac. Will do tomorrow and edit this post, but I think you can see what the variables are.

We pulled Bruno's carb completely apart and cleaned and blew out all passages and orifices. We found the float level high so dropped it to spec, but that made matters worse as it started running out of gas in 1st this time, not just 2nd. So we planned to put the float level back up as well as swap seats and secondary venturii between Bruno's and James' carbs. But, when we pulled the passenger-side seat off Bruno's we found lint that looked like it was from a red shop towel on the screen below the seat. Ah ha! We thought we'd found the problem as it could easily have been blocking a significant portion of the screeen, thereby preventing gas from getting in.

So, we just put the float level back up, reassembled James' carb, and Bruno headed home. Apparently we didn't find the problem, so I'm guessing another round is in store and this time we'll probably go ahead and swap the parts we'd planned before. The seats are just slightly smaller on Bruno's carb and it wouldn't seem like that could make much difference but it is worth a try. And, the air bleeds on Bruno's secondary venturii are much larger than on James', so the secondary A/F ratio is probably a lot leaner.

All in all I completely disassembled 3 Edelbrock carbs today, and one of them more than once. Unfortunately only the work on Rusty's carb was successful, although we now know several things that aren't the problem on Bruno's.

 

Gary, email me the spreadsheet, either excel or for a Mac. I can open either.
.092" = .00665 square inches
.094" = .00694 square inches
Difference = .00029 square inches or 4.2% of the larger, 4.4% of the smaller, so a .094 inlet is 104.4% of a .092 inlet.

Interesting.

 

Bill - Didn't find your "in the open" email address, although I may have it, and the FTE email thingee doesn't allow attachments. But, there's a pdf attached here of the file's output.

My book on Carter/Edelbrock carbs doesn't give any info on the secondaries. But, that may not be the problem at all since it just seems to go flat as if it is running out of gas. However, it doesn't buck nor spit back, it just slows or stops the acceleration. And, apparently with James' carb it just keeps climbing. So, would a lean condition in the secondaries cause it to act like it is running out of gas?

And, by the way, there is a fuel pressure gauge on the regulator, but Bruno isn't willing to drive with the hood up nor ride in the engine compartment with the hood down. So, we don't know what the fuel pressure is doing. However, keep in mind that apparently with just a change of carbs it runs like a banshee.

 

In my experience, lean secondaries will cause an almost immediate bog when you hit them, running out of gas will cause what you describe. BTW, don't think that just because the air bleeds are bigger it will run leaner. The design of the emulsion tube has a lot to do with it.

That said, from Weber's "Technical Introduction to the Master Catalog":
The main jets effect the total mixture, the air bleeds effect the top end mixture, emulsion tubes have a varying effect.

If it were caused by too large an air bleed, I would expect a more gradual drop off sort of the feeling you got when you reached the max airflow, just won't go any faster. I would see if you can get a set of the .094 or larger inlets for Bruno's carb and try that.

 

Very good input. The engine doesn't bog when the secondaries open, it just runs out of steam far earlier than it should. And, from what I'm told, far earlier with the 1406 than it does with the 1405.

And, it is a gradual drop off of power, so that seems to fit the too-large air bleed symptom. So, it sounds like swapping the needles & seats as well as the secondaries would be the next step. At that point the secondary side will be exactly the same as the 1405 since the jets are the same.

Oh, wait a minute - we haven't compared the weights on the air valve. Maybe we should swap those as well, or at least make it that the next step if the other doesn't do it.

 

Should I bring my grain scales next time to compare the weight?

I am going to scour craigslist to look for a used 1405. If I find one that is reasonable I may just put the electric choke set up off of mine onto it and either keep my carb for Kris's truck or sell it.

 

I just found a guy on craigslist that has 3 of the 1405 carbs and will sell any one of them for $75. Does this sound like a winner?

 

Pretty decent price for a carb. Too bad I'm low on funds right now.

 

FWIW, I found great results by installing these needle/seats: Edelbrock 1465 - Edelbrock Carburetor Needle and Seats - Overview - SummitRacing.com

Got the kit thru o'reilly's.

I'm interested in trying one of these: http://www.summitracing.com/parts/SUM-M08600VS/

 

Bruno's text to me says he's gonna pick up one of the 1405's. Should be a good solution to the problem, and less expensive than buying parts to fix his - assuming that it'll take both seats and secondaries.

 

Had so much fun with the three Carterbrocks yesterday that I pulled Rusty's down today to document the parts in it. Then I redid the table and included the area calcs we did yesterday.

Note that Bruno's 1406 has non-stock metering rods and springs. Mine is stock, although I don't know what difference the secondaries boosters make.

It'll be interesting to see what his "new" 1405 has in it, assuming he buys it.