FAQ |
Members List |
Social Groups |
Calendar |
Search |
Today's Posts |
#41
|
|||
|
|||
As your going to be driving this engine I would be concerned on what the shear plated would do to street manner.As its made it has great street manners.If you have them to be able to be put in a taken out with removing the carbs it might show you something.I DONT drive mine on solid linkage.Tom
|
#42
|
|||
|
|||
Quote:
|
The Following User Says Thank You to mgarblik For This Useful Post: | ||
#43
|
||||
|
||||
I ran a 255/260 Solid Flat Tappet for years on the street, Obvious Noticeable Idle but never had any hesitation with the vehicle on the street or the road.
IT WAS NOT A TAKE A TRIP camshaft though. Drove 150 miles from Kalamazoo Michigan to Grosse Pointe Michigan and almost ran out of gas. Oh! What fun, running along at 3000+ rpm with Wangers 4.33 rear gear under the car at 55-60 mph. The NASH TRANS (5 speed) and the proper Ford Gear in the 9" really helped that deal. So as you know Mike, drive-line match will be worth investigating if you take the car on trips. Have a great evening! Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#44
|
|||
|
|||
It has a 3.42:1 gear now and runs 2800 @ around 70 MPH Would like to change to a TKX 5-speed, will have to wait for some more $$$. Also would like to drive the Power Tour long haul route with it possibly next year. Confirmed next dyno session will be Thursday afternoon/evening.
|
The Following User Says Thank You to mgarblik For This Useful Post: | ||
#45
|
|||
|
|||
Unfortunately, no results to report. Had to cancel due to parts issues. The two strip kits I ordered from Summit that had the rich jets and metering rods in them had been opened. The exact metering rods I needed had been stolen from both kits and then the kits returned. The tamper resistant tape was missing from one and torn on the other. So someone took what they needed, and returned the kits to Summit. Shame on them for just re-boxing them and selling them again! No more kits available in the US. But I have the rods I want to try coming from Memphis. They were shipped today. Have the spacers installed. This thing is fighting me every step of the way. Sorry for the delay.
|
The Following User Says Thank You to mgarblik For This Useful Post: | ||
#46
|
|||
|
|||
I have some results to share concerning multiple dyno sessions I have had to squeeze in between classes and all kinds of other problems and distractions over the past couple weeks. Between parts getting lost by USPS for 2 weeks, endless problems with the dyno, printers specifically, and other distractions too numerous to list. I have been able to get 26 power pulls on the engine and get it tuned decently for now. I will consolidate the useful information, try to get it in a format I can post and put it up in the next week. These are my broad takeaways for what it's worth. 1. My overall engine package had too many compromises that were made necessary by not wanting to wait for years for the proper parts to be available. 2. This package needed more compression, round port exhaust and better exhaust manifolds/headers. 3. The bathtub intake wants lots and lots of fuel. 4. AFB carburetors are very, very sensitive to what is happening above the airhorn. Will flat out not run properly with an air hat on the top. I have seen this with some Q-jets as well. 5. Long branch, D-port, iron manifolds are crap on a serious performance engine with large displacement. They are just too small.
Now for some numbers: Best with exhaust manifolds, 464.6 Ft. Lbs @ 4700 rpm Peak HP 442.2 @ 5900 rpm. With borrowed 1 3/4 headers from a 74 GTO NHRA stocker: 18" long 3" collector, 481.6 ft. lbs torque @ 4800 rpm. 20-28 more ft. lbs. of torque everywhere. 448.4 HP @ 5800 rpm. Was not tuned to the headers, so 10-15 HP more on top could be expected. No reason to tune to headers because they are not going to be used. So I have presented the basic results. Since I have no ego to care about, it is what it is. Overall a frustrating, humbling experience. Sometimes, you just get a reality check when having to make so many compromises for the lousy pump gas, the fitment in the chassis, (exhaust manifiolds), and the super cool looks, bathtub intake and original looking AFB carbs with tiny air filters. On the plus side, excellent idle quality, starts quick and easy, snappy throttle response, seems like it will have excellent street manners. Anticipate using lots of gas. It runs best at 12.4-12.7 AFR everywhere. Starts to run lousy leaner than 13.2-13.4 AFR. It loves fuel. Going to put it in the car and drive it around through the fall here in Ohio. We have a chassis dyno at the school, so in the spring, I may try to do some tuning on the chassis dyno. That's more real world and the AFB carburetors can operate in their real world environment. That will be chapter 2. We will see how it runs on the street next. Last edited by mgarblik; 08-30-2022 at 10:24 AM. |
The Following User Says Thank You to mgarblik For This Useful Post: | ||
#47
|
||||
|
||||
Good info Mike, thanks for sharing. You might consider the Hooker headers that are are on super sale right now. As far as I know, they “should” fit a ‘62 full size as well as 1st generation Firebirds. At the price, it’s worth a shot. I have a nice set of original IA headers for my ‘63 that fit great.
Looking forward to hearing how it drives in the real world. https://www.holley.com/products/exha...arts/4107-1HKR
__________________
" Darksiders Rule "
|
#48
|
|||
|
|||
Quote:
|
#49
|
||||
|
||||
Early firebirds are rear steer, same as early full size. The long branch fit both cars so I don’t think the headers could be that far off. My headers are 2” with 3 1/2” collectors. Have not measured the length. I don’t want to clutter this thread with other info, just sharing header info. BTW, I committed to a 671 way before this intake was in the works so my intake is for a possible future build.
__________________
" Darksiders Rule "
|
The Following User Says Thank You to misterp266 For This Useful Post: | ||
#50
|
||||
|
||||
I don’t know if you folks have ever seen this guide chart for exh header tube size, but I have found it extremely accurate!
The only tempering I add to this is if I need more exh flow then the port is providing in order to get the exh to intake ratio better . Any exh port I have ever worked with of any make on my flow bench ( and even long ones like Pontiacs ) will pick up 3 to 5 percent more cfm above .350” lift if the header tube that bolts to the exh flange is 1/8” larger in it’s perimeter. This why especially with a race motor that the exh side is flow tested with at least a 6” long tube in place.
__________________
I do stuff for reasons. |
The Following User Says Thank You to 25stevem For This Useful Post: | ||
#51
|
|||
|
|||
Quote:
I made final pulls last night with manifolds in place again. No changes in set-up. Started pull at 180 degrees and the engine repeated within 1% of best previous pull last week. Don't remember the exact numbers but torque approx. 468 ft Lbs +- @ 4800 rpm and HP 446 @ 5900 rpm. Pulling it off in a few days and getting it ready to install. Once I can get the files off the computer or actually get a printer to work, I will post more details for anyone interested. The ancient computer that runs the dyno has a broken CD drive and no working USB for a flash drive. It's always something. Last edited by mgarblik; 08-31-2022 at 09:23 AM. |
#52
|
|||
|
|||
I hope you don't mind me jumping in here with what I think are questions related to the subject being discussed. I do not have a bathtub intake, but I am building a pair of SD clone carbs from a pair of 2840S AFB's ('59 Buick 401). My biggest concern is regarding the weight of the secondary air flapper valves. Seems to me that with half the volume of air passing through each carb at any given RPM (compared to a single carb), it's going to require considerably more RPM (twice?) to fully open the air valves.
Any thoughts on how to go about scientifically and methodically fine-tuning the air valves? Is the shape of them all the same and the only changes are to the counter-weights? Perhaps you do indeed want to delay the secondary air valve opening somewhat in a dual carb setup to avoid low velocities and poor atomization? The jetting can be worked out in a straight-forward conventional manner, but the transition of the primary circuit enrichment for decent street manners is another matter. I think getting the spring just right is going to be hard. I'd appreciate any and all thoughts and comments.
__________________
Hoping to finish a project while I'm still able to push the clutch in.... 1963 Tempest Convertible (195-1bbl, 3-speed transaxle. 428 RAIV, 5-speed, IRS planned) Pictures |
#53
|
||||
|
||||
FYI as you may know I've done a number of those carbs for people over the years, over ?? eighty sets at this point. For 389 through 535 cubic inch engines using the 2840 carbs you have as well as '59 Buick 2982s as well as 3221 and 3012 Chevy 348 carbs and one set using 2955 Crusader marine carbs. On the vast majority of these sets I installed the secondary air valves that originally came with the carbs back in both carbs. On a few sets I installed a lighter (in weight) valve in the front carb, under the theory that it would observe a weaker signal when it began to open than did the primary carb which opened up first. Most of the 3221 and 3012 (and the 2955s) had the same valves as do the 3010, 3266, and 3433 and 3435 SD carbs which by the way have the same weight valves in both carbs. I have NEVER gotten a comment from any customer re problems with valves opening up as they stabbed the gas pedals. Most of the sets I've done are on show or cruise in cars but at least four sets are on Nostalgia Super Stock cars and no comments from them either. More than one of the 389 engine owners I did the above sets for told me they could get rubber in third gear with their new dual quad setup and they were never able to do this with the tripower set they had before they installed the dual quads. My recommendation to you would thus be to put the original secondary valves back in both carbs and see what happens. If you see a bog, not a hesitation but a kind of ?? dull momentary pause where the engine seems to dag on at one rpm before going on up higher, then take the front valve out and drill a hole at the front edge of both weights and try again and see what happens.
|
#54
|
||||
|
||||
Quote:
While I don't know how well that formula works. He does state there is a range for FD of from 80 to 90. The Graph uses 80 which produces a larger pipe size than 90 will. We can see at 160 cfm the difference is a little over 0.09" in diameter ► cfm=160 ► ((cfm*1.27)/80)^.5 1.59374 ► ((cfm*1.27)/90)^.5 1.50259 Stan
__________________
Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#55
|
|||
|
|||
Quote:
__________________
Hoping to finish a project while I'm still able to push the clutch in.... 1963 Tempest Convertible (195-1bbl, 3-speed transaxle. 428 RAIV, 5-speed, IRS planned) Pictures |
#56
|
|||
|
|||
Quote:
|
#57
|
|||
|
|||
Quote:
BTW, the spring I was referring to is the one under the metering rod piston that determines the vacuum level required to transition from the richer to leaner primary mixture.
__________________
Hoping to finish a project while I'm still able to push the clutch in.... 1963 Tempest Convertible (195-1bbl, 3-speed transaxle. 428 RAIV, 5-speed, IRS planned) Pictures |
#58
|
|||
|
|||
Quote:
|
#59
|
|||
|
|||
Quote:
__________________
Hoping to finish a project while I'm still able to push the clutch in.... 1963 Tempest Convertible (195-1bbl, 3-speed transaxle. 428 RAIV, 5-speed, IRS planned) Pictures |
#60
|
|||
|
|||
The jets in my carbs do not follow the standard naming convention with the last 2 digits being the opening size. Does anyone know where to find a chart showing the size of these jets?
#120-166 Primary #120-222 Secondary The metering rods are #16-82X and measure .060 and .067, although there is some variation in them. Thank you!
__________________
Hoping to finish a project while I'm still able to push the clutch in.... 1963 Tempest Convertible (195-1bbl, 3-speed transaxle. 428 RAIV, 5-speed, IRS planned) Pictures |
Reply |
|
|