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Issues with C4 and new Blueprint 306

nvrstuk

Contributor
Just a Bronco driver for over 50 yrs!
Joined
Jul 31, 2001
Messages
8,871
I am not running vacuum to the distributor. Both ports are plugged. BP recommends not .
Really? So who's distributor then?

If it's their ( BP) distr then I imagine they have set the wts and curve for no vacuum advance.

BUT-

If it's a distr that you bought or ran on another engine then there's a 95% chance that the 3rd point I made in my post above needs to be addressed because there's a good chance your old distributor (or whatever you have so long as it's not one BP provided) is only allowing base timing like appr 12 deg at 3300rpm plus when you should have appr 32deg timing therefore answering your concern about no power. Correct timing gives you power which you say you're lacking power .

One thing at a time. But this next part is important too.

Sounds like you mentioned an area under the valve cover is louder than the rest? Improper valve adjustment or a mechanical problem with lifter, pushrod, rocker, spring possibly. Better address this asap. Because it could cause catastrophic failure if you drop a valve.
 

Jaybr

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Oct 8, 2019
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536
My BP distributor that came with motor has vacuum advance
a234fd446096ae7a3abe50084cfa9b41.jpg



Sent from my iPhone using Tapatalk
 
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deltabronco

deltabronco

Bronco Guru
Joined
Dec 27, 2005
Messages
1,100
It’s a Petronix distributor (new) and does have a vacuum port, but BP says not to use vacuum advance. I dunno why but it’s in the tuning instructions. I’ll be taking off the valve covers this weekend and checking it out. Not gonna drive it until then.
 

m_m70

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Jun 14, 2001
Messages
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Pacifica, CA
It’s a Petronix distributor (new) and does have a vacuum port, but BP says not to use vacuum advance. I dunno why but it’s in the tuning instructions.
yeah, I don't know why blueprint wouldn't want you to have the vac advance hooked up with a distributor that's setup to use it. There's a LOT of people on here much smarter than I am though and looking forward to learning something new with this.......
 
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deltabronco

deltabronco

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Yeah, well blueprint also recommends a 50oz flex plate with a 157 tooth count. Which as you know won’t fit in the large bell housing. So my faith in there instructions isn’t exactly solid.
 
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deltabronco

deltabronco

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yeah, I don't know why blueprint wouldn't want you to have the vac advance hooked up with a distributor that's setup to use it. There's a LOT of people on here much smarter than I am though and looking forward to learning something new with this.......
I sent you an email with the instructions. Couldn’t paste here.
 
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deltabronco

deltabronco

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Dec 27, 2005
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1,100
I just read the entire thread.

-Check compression. This is important because if you had a carb that was allowing gas to pour through it then you washed your cylinders of oil before the rings seated and you have ruined it.

- is the gas 10% or 15% ethanol? How old is it? Was the entire fuel system flushed with fresh gas last summer or did the ethanol gas just get replaced when you suspected bad gas. This is also very important.

-then if your timing is appr.10-14 at idle and about 32 at full advance then you need to go back to the carb as I didn't read anything about a missfire- correct?

-Somebody around you has a carb(s) that works on their old rig and in 15 min it's swapped over to yours. Really is that easy. I have 2 loaned out right now to guys.
Then you could eliminate the carb part anyway and your timing, 3 things knocked out already.

-If the noise is a "light tick", SOLVE that potential unknown by driving to an exhaust shop and have the guy that listens to the joints he welds or bolts together as he does this every day and in literally 5 min can determine if there is a small exhaust leak or he can point it to a rocker or lifter possibly.

- You have to narrow this down and you do that with testing compression, distributor timing and then testing with a known carb. You will be really unhappy if you send that engine back and there is nothing wrong with it besides a slight tick which sounds like it could be exhaust. You would be paying shipping both directions and still have to fix the issue. Course if it worked great for them then you'd really have the problem isolated. :)

Important- -
Do ONE of these things each day or week depending on your schedule. Don't jump all around guessing and throwing $$ at it. Just do one at a time and you will figure it out.
I used non ethanol gas, gas was about 7 months old with stabilizer. Tank was drained to about 20% and new gas put in.
No misfires.
Good idea about carb. Unfortunately I don’t have an extra.
I’ll check compression this weekend as well as valve train.
Thanks for the help!
 

m_m70

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Sr. Member
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Jun 14, 2001
Messages
1,501
Loc.
Pacifica, CA
yeah all of their pictures of the sbf motors have vac advance distributors in them with a vacuum hose hooked up.

timing instructions bp engine.png

first line in instructions is to disconnect vac advance and plug the line.

not sure what they mean by this:
  • Start the engine and set base timing to 10-16°BTDC and verify that total timing is 32-34° degree at 3500rpm. (This is all just mechanical advance only. Do not have vacuum advance hose hooked up and please do not use vacuum advance unless you have the BP3023CTC)
What is the BP3023CTC??

Let me know what model motor you got and I can call them tomorrow if you want. Happen to have the day off and nothing to do.......
 
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deltabronco

deltabronco

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Dec 27, 2005
Messages
1,100
OK, to save money stop buying parts.:)

Pain to get it all to fit, sounds like maybe TC was not inserted, then turned, then inserted fully?

Did you have to use TC bolts to pull the bellhousing to the engine block?
TC seated 3 times. I used a curved bar to pull Tc forward.
 
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deltabronco

deltabronco

Bronco Guru
Joined
Dec 27, 2005
Messages
1,100
yeah all of their pictures of the sbf motors have vac advance distributors in them with a vacuum hose hooked up.

View attachment 919547

first line in instructions is to disconnect vac advance and plug the line.

not sure what they mean by this:
  • Start the engine and set base timing to 10-16°BTDC and verify that total timing is 32-34° degree at 3500rpm. (This is all just mechanical advance only. Do not have vacuum advance hose hooked up and please do not use vacuum advance unless you have the BP3023CTC)
What is the BP3023CTC??

Let me know what model motor you got and I can call them tomorrow if you want. Happen to have the day off and nothing to do.......
lol. I appreciate you going the extra mile when you don’t have to. It’s a BP306MAXCTF. I’ve called them about a dozen times about various things. Wish I would’ve just rebuilt the old block but I thought this was a better route.
 

Soylent

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May 4, 2016
Messages
342
Loc.
California
Strange about the vacuum. I have a 306 (BP3060CT) with a pertronix and my instructions state to connect the vacuum aftrr setting timing.

IMG_7811.jpeg
 
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