cant do burnouts

[Rsmach1 71]

Well with that cam I still believe you would benefit from a converter around 2000 stall. Try to at least determine what your initial timing is and post it. A 650-cfm carb will get you better throttle response for the street, if you stay with the 750 you'll most likely need to do some accelerator pump tuning as its probably dumping to much fuel.

[1969_Mach1 333]

Yeah, accelerator pump tuning is usually in order when the carb is too large.  But its most often because the slower air speed through large venturies delays start up of the main circuit.  This in turn causes a lean condition and response that is not as crisp as it could be.  In bad cases a bog and even popping through the carb occurs.  Sometimes the idle circuit is too rich on larger carbs for small blocks.  Then if smaller idle restrictors cannot be installed you have to increase size of the idle air bleeds. 

 

Fortunately in most cases increasing the squirter size, 31 is most common size to use, and installing a pink cam does the trick.  In really severe cases a 50cc pump is needed increase the duration of the accelerator pump.

[rwcstang 201]

build a stroker and you'll be in burn out heaven. lol

[barnett468 418]

im not a huge fan of power braking to do a burnout and that's half the reason why i wanted 3.80 gears when i did the swap...rolling burnouts. 

cam:Camshaft, Hydraulic Roller Tappet, Advertised Duration 270/276, Lift .513/.513, Ford, 351W, Each http://www.summitracing.com/parts/cca-35-421-8

Tires: 215/55r17

Carb: http://www.summitracing.com/parts/HLY-0-80508SA

 

Im curious with the trans/stall. with the AODE i can change the lockup at different points. not sure is this effects first gear or not. In my dad's fox and 95 mustang i would be able to do burnouts (not huge at all) with a stock trans so i would think* that with this motor it wouldnt be an issue. 

 

i dont have the compression info available right now. hopefully i can get it this weekend. 

 

i know the brakes are not dragging and they both wheels spin as i left two tracks in the dirt road. 

 

the motor doesn't seem to bog at all when i punch it and it feels pretty good off the line and through the rpms, but having never tuned in the carb, thats why i decided to get the AFR kit. 

 

.

to get an "impressive" burn out, you may need to install a stall converter even though you have 3.80 gears, because your tires are likely around 27" tall and 9" wide . . a 2000 to 2400 will work with the 2400 providing the most tire smoke for the buck.

 

post your exact tire size

 

Also, as was mentioned, compression is important . . if it is less than around 9.5, you would benefit from increasing it to around 10.0 - 10.25 . . if you live near sea level, and take a compression test witha GOOD gauge, and  the plugs out and the throttle open and it is less than around 150, you could benefit from more compression . . if you are at 160 or above you have enough..

 

a vacuum secondary 750 is not too big for your app although a 680 might work a little better . . if you had a mechanical secondary 750, it might cause a slight hesitation if you floor it from a stop.

 

 

you will NOT be able to do "rolling burnouts" with your set up.

 

you also have not posted the complete tire size i asked for, but as i mentioned, the tire size appears to be your main problem , especially if your compression is good . . if you put stock tires on it, you can roast em till the cows come home, however, with that much tire area contacting the street, your engine needs some help which is what the stall converter is for, therefore, either you can put stock tires on it, or put a stall converter in it, o put a bigger displacement engine in it.

 

if you want to do rolling burnouts with those gears, you will likeky need around a 3000 rpm stall.

 

.

[bryonbush 85]

I put the tire size in but the conversion is a 26" tall by 8.4" wide

[barnett468 418]

I put the tire size in but the conversion is a 26" tall by 8.4" wide

 

what is the number on the tire?

 

do you have a posi?

 

you still have around 2 1/2" per side wider tread than a stock tire that also has a flatter tread.

 

if it was running excessively lean, it would have a noticeable flat spot/hesitation when flooring it.

[bryonbush 85]

215/55r17 tires, limited slip unit

[barnett468 418]

215/55r17 tires, limited slip unit

 

that is actually 26.7 x 8.9 but they can vary slightly from mfg to mfg.

 

one of the most common tires for that car are 235 x 60 - 15 which is 26" tall and if you had 370 gears, the final ratio of this combo would be the same as you have now.

 

if you have flat top pistons, your compression is plenty high at around 10.3 unless your rings are leaking . . if they are dished pistons it will of course be less.

 

.

[sportsroof69 13]

We need a facepalm smiley.

[Max Power 74]

We need a facepalm smiley.

No kidding. Not a lot of careful reading going on here.

[bryonbush 85]

Well, today i went to the bank and the road was smoother than others. after a slow pull out of the bank, semi straightened the wheels and punched it. Got the tires to kick the car straight. Didnt change anything with the carb so maybe the road conditions were in my favor. It did rev.. hesitate, then took off though. 

 

to follow up on the torque converter: i read a post someone made showing a photo from the ford manual showing that the factory stall speed for 4r trans was in the mid to high 2K. 

[barnett468 418]

Well, today i went to the bank and the road was smoother than others. after a slow pull out of the bank, semi straightened the wheels and punched it. Got the tires to kick the car straight. Didnt change anything with the carb so maybe the road conditions were in my favor. It did rev.. hesitate, then took off though. 

 

to follow up on the torque converter: i read a post someone made showing a photo from the ford manual showing that the factory stall speed for 4r trans was in the mid to high 2K. 

 

 

your torque converter is likely not in the high 2's . . point your car in a straight line then mash the pedal to the floor and look at your tack . . the highest point your engine immediately revs to if the tires dont spin is the stall.

 

also, the hesitation is reducing the burn out capability so it needs tuning.

.

[1969_Mach1 333]

The accelerator pump needs tuning.  I have never seen a 750 vacuum secondary Holley on a 351W work without tuning the accelerator pump.  The hesitation is the motor gets a gulp of air and not enough fuel when quickly opening the throttle.  Try a #31 accelerator pump nozzle, a pink cam (if it doesn't already have one) and make certain the accelerator pump linkage is adjusted correctly.  No play in the accelerator pump linkage at idle and do not bottom out the accelerator pump diaphragm at WOT.  Also make certain the primary throttle plates are positioned correctly at idle.  You cannot turn the idle speed adjustment screw without considering the throttle plates to transfer slots relationship.  There should be roughly 0.020" to 0.040" of the transfer slots exposed below the throttle plates at idle.  With too much transfer slot exposed at idle stumbles can occur during mild acceleration, and also the idle mixture screws at idle will not function.  If you have to adjust the idle so that too much of the transfer slot is exposed, the first thing to do is open the secondaries a little more to let more air in through them at idle.  There is a small set screw at the right side of the base plate and accessed from the bottom for the secondaries.  

[bryonbush 85]

1969mach: you live in the Dallas area by chance? I'd probably mess something up trying to dial this thing in. I'll look into a new cam and some jets today as I'll probably need them. Here's where I saw the stall speed on a stock 4r trans.http://www.allfordmustangs.com/forums/4-6l-tech/54585-4r70w-torque-converter-stall-rpm.html#/forumsite/20799/topics/54585?page=1

[Rsmach1 71]

Pick up a holley Trick kit for your carb, it will come with an assortment of pump cams, squirters, and pretty much everything you need to dial it in except jets. Probably a good idea to pick up a book on tuning Holley carbs. Once you install your A/F gauge that we'll make tuning easier.

 

Edit, Although I haven't read it personally, this is supposed to be a good book. http://m.summitracing.com/parts/sad-sa216

Not my pic.

[1969_Mach1 333]

1969mach: you live in the Dallas area by chance? I'd probably mess something up trying to dial this thing in. I'll look into a new cam and some jets today as I'll probably need them. Here's where I saw the stall speed on a stock 4r trans.http://www.allfordmustangs.com/forums/4-6l-tech/54585-4r70w-torque-converter-stall-rpm.html#/forumsite/20799/topics/54585?page=1

+1 with Rsmach1.  Here is a pretty good reference book, http://www.summitracing.com/parts/sad-sa216/overview/

 

Various accelerator pump cams, pick your brand they're probably all from the same mfg. http://www.summitracing.com/search/part-type/carburetor-accelerator-pump-cams?SortBy=Default&SortOrder=Ascending

 

The last Holley Trick Kit my neighbor bought when I rebuilt his carb didn't have accelerator pump cams or discharge nozzles.  I know they use to have some of those in the kit.  Anyway, here are some links to individual parts.

 

Accelerator pump nozzles.  Again pick your brand they are all probably from the same mfg.  Your carb does not use the rectangle looking anti-pullover style.  Some people prefer the old style with tubes.  The argument is the tubes help direct the fuel toward the center of the venture but I don't know how true that is.  http://www.summitracing.com/search/pump-discharge-nozzle-size-in/0-031-in?SortBy=Default&SortOrder=Ascending

 

I am in Northern CA.  Get the book, after some reading you'll realize Holley carbs are not that complicated.  These changes are not complicated or difficult to do.  The only caution is don't go crazy tightening the screw on the accel pump nozzle and strip the threads.  I've been there and a thread repair kit for that screw size is available but hard to find.  Get a feel for how hard it was to loosen it when removing it. 

[Rsmach1 71]

Holley pt# 37-933 has all you need, pump cams, nozzles, extra gaskets, secondary springs. Just no jets.

http://m.summitracing.com/parts/hly-37-933?seid=srese1&gclid=CMWn58aFtsgCFYlhfgodZT8GkQ

 

Edit The only thing else I'd recommend are these idle mixture screw seals from Quick fuel, as the Holley cork seals tend to leak over time. http://www.quickfueltechnology.com/metering-blocks-and-parts/red-nylon-idle-mixture-screw-seal.html

[barnett468 418]

1969mach: you live in the Dallas area by chance? I'd probably mess something up trying to dial this thing in. I'll look into a new cam and some jets today as I'll probably need them. Here's where I saw the stall speed on a stock 4r trans.http://www.allfordmustangs.com/forums/4-6l-tech/54585-4r70w-torque-converter-stall-rpm.html#/forumsite/20799/topics/54585?page=1

 

for some reason, i cant connect to that link so you can just copy the text and paste it here if you want.

 

i mentioned how to see what the converter you have stalls at . . stall numbers on paper are not 100% relevant, because even if they are accurate, they are only accurate for that app . . for example, a 2000 stall converter will NOT stall at 2000 rpm on every engine because they are torque dependent.

 

 

.

[barnett468 418]

.

as far as changing the cams on your carb, i would try messing with the ignition timing first . . insufficient timing can definitely cause a hesitation.

 

to see how much timing you need i would first plug the vacuum advance unit . . then loosen the distributor bolt around 1/8 turn . . then with the engine warm, and idling normally, advance the timing around 3 - 4 degrees and listen for an increase in rpm . . if you hear the rpm increase and the engine still runs good, it likes that setting better.

 

to see if it needs more advance at higher rpms then you previously had you can set the timing back to the previous level then hold the throttle open amost half way and then increase the timing by 3-4 degrees again and listen for an increase in rpm.

 

if it likes more advance, try test driving it and see if it pings . . if it doesn't, you can leve the timing at that setting for now and leave the vacuum advance plugged until you fix the hesitation.

[Rsmach1 71]

Barnett468, in that post there were a few thoughts on stall for that trans in Stock form, the ranges were from 1200 to 2500. I've driven a stock stang with that trans and can say for sure it's no where near 2500 lol, probably closer to the 1200-1500 range.

[barnett468 418]

Barnett468, in that post there were a few thoughts on stall for that trans in Stock form, the ranges were from 1200 to 2500. I've driven a stock stang with that trans and can say for sure it's no where near 2500 lol, probably closer to the 1200-1500 range.

 

 

ok thanks for the info . . i actually have done a lot with stock converters because a guy near me rebuilds them and and i have sent him several to increase the stall on when i use slightly larger than stock cams because it only cost me $120.00 and i asked him what the stall was on the ford converters and he said he has never known one to be more than around 1500 which is obviously why a stock car will take off if hard if you put it in gear and rev it to 1500 rpm.

 

heck, if they were a 2500 stall, i woul buy every used one i could for $20.00 then paint them red and sell em for $150.00 on ebay, lol.

[Rsmach1 71]

Where is your converter guy located, I need an FMX converter done. Thx

[barnett468 418]

Where is your converter guy located, I need an FMX converter done. Thx

 

 

hes in the corona/norco area of so calif . . i dont remember how far he can bump up a stocker but i had him set them to around an 1800 stall with the initial grab at around 800 or 900 so it would not drop the idle much if at all if you put it in gear at idle . . this worked well with cams like the comp xe262h in 289's and 302s but it was just marginal for an xe2698h cam in those engines.

[Rsmach1 71]

That might be a viable option for me, and I'm not all that far from corona/norco.

[barnett468 418]

That might be a viable option for me, and I'm not all that far from corona/norco.

 

ok, xlnt . . i haven't sent him anything in a while so im not sure if he's stil there but i will dig his number up for you . . it may take me a day or so because i just moved and i have to find my phone book but i will try to look for the number tomorrow.

 

the one guy that said the stall is 2300 - 2700 said that was for a 4.6 engine and he may be right but i know nothing about those so i can't say, however, i know the stalls on the overdrives for the v8 engines was around 1500 max or possibly even 1800 but that would be on a very good day.