Torque converter maybe?
- Thread starter Jim B
- Start date
Jim B
Active Member
It will stop with moderate pressure but the engine sputters and dies.
Jim B
Active Member
Guess I should have left out the cold part, I let it warm up before I drive it. Don't know the cam specs but it goes "Bumpity, bumpity, bumpity............................................bumpity, bumpity, bumpity.........................................etc.
Not as much as Island Girls motor but does idle like a big cam.
Jim B
Active Member
Previous owner just had a blower shop install and adjust new blower carbs right before I got it. I have the receipt.
Can you take it back to them for adjustment?
old round fart
Well-Known Member
Try raising the idle just a bit and see if it makes a difference.
Jim B
Active Member
Nope, another state away. I just have you guys.
Jim B
Active Member
Ok. as soon as I get the new exhaust gaskets in and the new baffles put it, I will give it a try. And take note of the idle speed as Indycars suggested.
old round fart
Well-Known Member
Also blown motors act different after they warm up. If you rev them up cold they will backfire and sound like they blew up when the pop-off valve reseats! You’ll get use to it.
Did they drive it?
Jim B
Active Member
I was told that the blower shop people did drive it and bless it after the carb install.
Indycars
Well-Known Member
Could there be a big difference in elevation between the blower shop and your location ?
fletcherson
Well-Known Member
Exactly, or different temp/humidity due to season, etc... anything else, such as timing, been changed? How are the plugs? Lots of possibilities.
Jim B
Active Member
Idle speed bounces between 500 and zero at full stop with tranny in park. 1000 feet or less altitude change. Seems raising the idle is first on the list. Baffles are in and made it the perfect mix between deafening and hot rod sound. I can actually hear the blower now. Exhaust gaskets are in and no more leaks there.
Indycars
Well-Known Member
That's too low, even for a stock motor. I suspect your idle should be around 750-900 rpm when
it's in Park. Hard to know for sure without knowing specs or being able to hear it.
Can you make a video so we can hear it ? During the video start at 650 rpm, then adjust it up in steps
of 50 rpm until you get to 900 rpm. Be sure to call out each step so we know what we are listening to.
Then post the video on YouTube and post the link here so we can watch and listen.
fletcherson
Well-Known Member
Indy is correct about idle too low. Also, if you added baffles since it was tuned, changes likely occurred in the a/f mixture. After trying the idle speed increase, it may need a slight carb retune if problems persist. It’s hard to diagnose by description.
Hmmm. I have a blower motor. At first I used a big stock torque converter, but it took full brakes to hold it, so went with a B&M 2800 Holeshot and that fixed it.
Blower motors usually need lots of advance (because blower motors usually are low compression). I use 20 initial, 15 speed and 15 vacuum. And it should idle below the start of speed advance so it won't be surging in and out of advance. Mine idles at 900 and speed advance starts at 1000. And you want boost retard if you run much boost. That takes an ignition module. What does your ignition consist of?
Are the carbs true boost-referenced? Some big name makers cheat by replacing the power valve with a plug and call it a blower carb. Without boost-ref you have to run rich to keep from leaning out on acceleration. And your plugs foul.
If you want to get rid of carb issues, replace them with EFI. Self-tuning, clean plugs, touchscreen data and set idle, accel pump, etc. Many of them also handle ignition, so you can experiment with timing without fooling with springs and such. I love it.
Blower motors usually need lots of advance (because blower motors usually are low compression). I use 20 initial, 15 speed and 15 vacuum. And it should idle below the start of speed advance so it won't be surging in and out of advance. Mine idles at 900 and speed advance starts at 1000. And you want boost retard if you run much boost. That takes an ignition module. What does your ignition consist of?
Are the carbs true boost-referenced? Some big name makers cheat by replacing the power valve with a plug and call it a blower carb. Without boost-ref you have to run rich to keep from leaning out on acceleration. And your plugs foul.
If you want to get rid of carb issues, replace them with EFI. Self-tuning, clean plugs, touchscreen data and set idle, accel pump, etc. Many of them also handle ignition, so you can experiment with timing without fooling with springs and such. I love it.
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