Yet another timing issue!!
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John Swift (05-19-2018)
07-28-2018, 01:57 PM
#22
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First, again, thank-you all for your comments!
I have been doing some digging and finally was able to find the information on the engine! I pressed the seller until they sent me the info.
It is a Jegs Blueprint Dress Engine BP3834CTC1
SBC 383ci 420HP/450TQ w/Aluminum Heads
I’ll give the link below if you would like to see it.
First, I understand that back in the day when emissions came into play, manufactures cared more about emission control rather that hp, so advancing timing was beneficial to the engine.
But HERE I have a manufacture that wants the best HP, and TQ for their engine!
(I would assume)
Is it safe to assume the timing recommended for this setup is what I should use, even with that cam???
Timing (Initial/Total Advance): Initial timing - 10-16° and Total timing 32-34°
As of right now, I have it set to 15° initial and 34° total
It seems to be running well.
I don’t know the RPM that the mechanical fully engaged because I did this myself, but I revved the engine until it advanced no more
The distributor seems to be a LARGE CAP standalone MSD ..HEI with the coil in the cap, although it doesn’t say MSD on the cap.(The weights, springs etc are up on top for easy access, and apparently a curve kit was shipped with the engine).
It also has an adjustable vacuum advance, so I was thinking getting a inside the car vacuum gauge so I can adjust THAT as well.( I realize that will take adjusting, driving, adjusting, and driving over time.
I have also connected the vacuum advance to the manifold rather than ported off the carb.
I DO understand now, that I CAN advance further than recommended and the reasons!
At this time I am going to leave everything as is until at which time I can find a chassis dyno shop and get it done properly as DUB has highly suggested to me….
Thank - you DUB for taking time to help this old fart out!~
For the record, I am using 91 Octane NON ethanol.
Does anyone else have this setup, and what is YOUR timing??
https://www.jegs.com/i/Blueprint-Eng...SABEgJ-5vD_BwE
I have been doing some digging and finally was able to find the information on the engine! I pressed the seller until they sent me the info.
It is a Jegs Blueprint Dress Engine BP3834CTC1
SBC 383ci 420HP/450TQ w/Aluminum Heads
I’ll give the link below if you would like to see it.
First, I understand that back in the day when emissions came into play, manufactures cared more about emission control rather that hp, so advancing timing was beneficial to the engine.
But HERE I have a manufacture that wants the best HP, and TQ for their engine!
(I would assume)
Is it safe to assume the timing recommended for this setup is what I should use, even with that cam???
Timing (Initial/Total Advance): Initial timing - 10-16° and Total timing 32-34°
As of right now, I have it set to 15° initial and 34° total
It seems to be running well.
I don’t know the RPM that the mechanical fully engaged because I did this myself, but I revved the engine until it advanced no more
The distributor seems to be a LARGE CAP standalone MSD ..HEI with the coil in the cap, although it doesn’t say MSD on the cap.(The weights, springs etc are up on top for easy access, and apparently a curve kit was shipped with the engine).
It also has an adjustable vacuum advance, so I was thinking getting a inside the car vacuum gauge so I can adjust THAT as well.( I realize that will take adjusting, driving, adjusting, and driving over time.
I have also connected the vacuum advance to the manifold rather than ported off the carb.
I DO understand now, that I CAN advance further than recommended and the reasons!
At this time I am going to leave everything as is until at which time I can find a chassis dyno shop and get it done properly as DUB has highly suggested to me….
Thank - you DUB for taking time to help this old fart out!~
For the record, I am using 91 Octane NON ethanol.
Does anyone else have this setup, and what is YOUR timing??
https://www.jegs.com/i/Blueprint-Eng...SABEgJ-5vD_BwE
You'll need to set the idle speed in DRIVE to achieve at least 9-10" so this VAC remains "locked" at full advance at idle.
Duke
07-29-2018, 01:41 PM
#23
Advanced
Thread Starter
You need to check manifold vacuum at idle speed in DRIVE!!! Measure and report vacuum @ actual idle speed (the numbers). You need a vacuum advance connected to a full time manifold vacuum source. If the installed dist. will accept HEI VACs the one you want was used on late seventies L-82s, start at 4" and 10 (crank) @ 8". The number should be in Lars VAC listing.
You'll need to set the idle speed in DRIVE to achieve at least 9-10" so this VAC remains "locked" at full advance at idle.
Duke
You'll need to set the idle speed in DRIVE to achieve at least 9-10" so this VAC remains "locked" at full advance at idle.
Duke
I have a HEI distributor with adjustable vacuum advance.
I also have a full sweep vacuum gauge mounted inside.
At operating temp it is 1000 rpm idle @ 15"
In gear it is 650 rmp and fluctuates between 9", and 10 ".
Operating temp idle is at 1000 rpm and 15" vacuum. In gear
Pardon my ignorance but I don't know what you mean start at 4" and 10 (crank) @ 8".
and how is this achieved? I assume your speaking of adjusting vac advance?
Thanks
John
Last edited by John Swift; 07-29-2018 at 07:08 PM.