how much total timing are you running on your na motors?
#31
Re: how much total timing are you running on your na motors?
Originally Posted by Nordicflame
So what rpm do you carb guys run at idle in and out of gear "without" timing assistance such as the TBV has.
We are having a slight problem on a new 564ci motor dying when going into gear (at 850-900rpm). I have the Crane ignition installed on it and have the 14-34 curve in it. It does have a new 24-34 curve and am wondering if this will help it. I think I still need to richen up the idle mixture as well but was wondering on the idle timing. Cam is mild 238/248 114LSA.
I'm a spoiled laptop efi guy so any input here would be appreciated
Thanks,
Dave
We are having a slight problem on a new 564ci motor dying when going into gear (at 850-900rpm). I have the Crane ignition installed on it and have the 14-34 curve in it. It does have a new 24-34 curve and am wondering if this will help it. I think I still need to richen up the idle mixture as well but was wondering on the idle timing. Cam is mild 238/248 114LSA.
I'm a spoiled laptop efi guy so any input here would be appreciated
Thanks,
Dave
Try locking it out,The richer idle does help also
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#32
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Re: how much total timing are you running on your na motors?
I'm a believer that total timing on a NA engine should be at (or max 2 degrees less) where the motor wants it. Fuel octane should be changed to one that the motor does not detonate on.
Many stock BBC rect port heads on performance applications like 38-40 total timing. If ported with better chamber work this # may reduce.
Many aftmkt heads have much more effecient chambers and will run best with 35-36 degrees timing.
One engine is not another engine - there is more too timing requirements than just parts bolted on.
Many stock BBC rect port heads on performance applications like 38-40 total timing. If ported with better chamber work this # may reduce.
Many aftmkt heads have much more effecient chambers and will run best with 35-36 degrees timing.
One engine is not another engine - there is more too timing requirements than just parts bolted on.
#33
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Re: how much total timing are you running on your na motors?
nordicflame, I dont think its your cam you probably need a good carb tuner. My motors idle@1000, in gear600. I run alot more cam than most.269-276 @50 .693-709 lift on110+2. Ialso run msd ignition with the advance free weighted. A single 1050 carb with alot of bleed work.
#34
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Re: how much total timing are you running on your na motors?
Thanks for the reply guys.
I will richen it up and switch the curve for him and see how she does.
The carb was just rebuilt and tuned by Mesa. I think the idle would be hard to hit off of a bench because we are at 5000 feet elevation
Thanks,
Dave
I will richen it up and switch the curve for him and see how she does.
The carb was just rebuilt and tuned by Mesa. I think the idle would be hard to hit off of a bench because we are at 5000 feet elevation
Thanks,
Dave
#35
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Re: how much total timing are you running on your na motors?
Nordicflame - don't forget to use the secondaries idle speed screw to your advantage . Many idle issues can be cleared up with adding some more air thru them during idle. You'll then be able to lower primaries a touch and have more sensitivity on the idle mixture screws while still getting enough air past throttle blades.
If you don't lock out your timing, I'm going to guess you'll need somewhere around 18-20° at idle.
If you don't lock out your timing, I'm going to guess you'll need somewhere around 18-20° at idle.
#37
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Re: how much total timing are you running on your na motors?
Dont Y Want To Know Timing On A Blower Motor, Ratman???????????????????????????????????????????? ??????????????
Mine 540 Na
34deg
Always Premium
702hp Really 660-680
Dart Heads
Jesel Rollers Stud Guides
Mine 540 Na
34deg
Always Premium
702hp Really 660-680
Dart Heads
Jesel Rollers Stud Guides
#38
Registered
Re: how much total timing are you running on your na motors?
Hey guys,
I dont mean to hijack this thread but I have the same question about timing.My motors on dyno pulled most HP at 28 degrees total.So this is where Im running them right now.I really think I should be around 34 to 36 according to what you guys are posting.I have MSD distrib. set with 9 degrees advance,so Im at 19 initial and 28 total.Boat runs well but it dont seem to have the rpms Im looking for.I wonder if this is what is causing it.How can I tell for sure if I am detonating or not when I move the timing?
502 mag
Edelbrock aluminum heads
9.8 ratio
631 hp on dyno w/o accesories and dry exhaust,about 575hp in boat
crane 651 cam
revolution marine exhaust
Thanks in advance
I dont mean to hijack this thread but I have the same question about timing.My motors on dyno pulled most HP at 28 degrees total.So this is where Im running them right now.I really think I should be around 34 to 36 according to what you guys are posting.I have MSD distrib. set with 9 degrees advance,so Im at 19 initial and 28 total.Boat runs well but it dont seem to have the rpms Im looking for.I wonder if this is what is causing it.How can I tell for sure if I am detonating or not when I move the timing?
502 mag
Edelbrock aluminum heads
9.8 ratio
631 hp on dyno w/o accesories and dry exhaust,about 575hp in boat
crane 651 cam
revolution marine exhaust
Thanks in advance
#39
Re: how much total timing are you running on your na motors?
Nordic
NA 502's seem to like 34-36 degrees....turn it up to 34 and see if you can pull more rpm....you will not come close to hurting anything there. Mercury puts 36 degrees in their iron headed 500EFI's directly from the factory and they tell you to run 87....and speaking from experience they run better on 87.
NA 502's seem to like 34-36 degrees....turn it up to 34 and see if you can pull more rpm....you will not come close to hurting anything there. Mercury puts 36 degrees in their iron headed 500EFI's directly from the factory and they tell you to run 87....and speaking from experience they run better on 87.
#40
Registered
Re: how much total timing are you running on your na motors?
Originally Posted by jdnca1
Nordic
NA 502's seem to like 34-36 degrees....turn it up to 34 and see if you can pull more rpm....you will not come close to hurting anything there. Mercury puts 36 degrees in their iron headed 500EFI's directly from the factory and they tell you to run 87....and speaking from experience they run better on 87.
NA 502's seem to like 34-36 degrees....turn it up to 34 and see if you can pull more rpm....you will not come close to hurting anything there. Mercury puts 36 degrees in their iron headed 500EFI's directly from the factory and they tell you to run 87....and speaking from experience they run better on 87.