Discussion
After the cold winter months of building our new engine, the day came today when we finally fired her up and heard her sing...
It sounds awesome, once we'd got the timing sorted out... (although we've had to time it by "ear" Boosted LS1... could you drop me a line?)
Here she is...
slinky
587racing.com
It sounds awesome, once we'd got the timing sorted out... (although we've had to time it by "ear" Boosted LS1... could you drop me a line?)
Here she is...
slinky
587racing.com
Slinky, I don't know how helpful this is but the Chevy 350 that I built at school,(stock block & bottom end with after market performance heads, high torque cam and carb with small/long tube headers), was originally timed with 28° of advance. we found on the dyno that we got torque & hp improvements with up to 34° of advance but after that we started to lose torque and hp. It's amazing how much that "flower pot"/velocity stack helps by straightening the air flow into the carb.
Playing with your collector pipe length may find you some gains as well.
Glad you've got her running, she looks great and good luck to the team this season.
Playing with your collector pipe length may find you some gains as well.
Glad you've got her running, she looks great and good luck to the team this season.
Trooper... I'm really glad you've said that...
We were getting rather puzzled when she sounded really happy at 38 degree's!!!!
The idle is a bitch as well... it's not exactly what you might call a mild cam!
slinky
587racing.com
We were getting rather puzzled when she sounded really happy at 38 degree's!!!!
The idle is a bitch as well... it's not exactly what you might call a mild cam!
slinky
587racing.com
slinky said:
Troop... (or anyone else for that matter)
Static timing vs. Total Timing...
What's the difference?
slinky
>> Edited by slinky on Saturday 25th February 17:41
Static is also called initial advance iirc. Its the amount already dialled in when the engine is stationary, static advance 5 degrees btdc etc...
Total advance is the static plus whatever else it advances to when running say 14 degrees static plus 14 full advance(mechanical plus vac) =28 degrees total.....iirc.....
slinky said:
So 36 ish at idle.. aint quite right..
By ear it sounds perfect... by timing light... I don't think it is!
slinky
Have you got a locked distributor with no advance? Thatd explain the setting of 36 as it must then be set to 36 initially...??
Unless youve got a computer playing with the spark advance...or a duff advance mechanism?
Two degrees total advance is not sounding quite right to me.
Edited to add: Have you checked that the timing actually does advance when you wind the revs up? or is it "stuck" at 36 all the time with you having to adjust it manually?
>> Edited by deltafox on Saturday 25th February 20:00
How do Slinky, looks purposefull does that
Static timing wants to be say 8 degrees by advancing the distributor, or advance until it idles smooth but without starter kickback. Centrifugal advance is governed by how much the dizzy bob weights fly out. I'd suggest no more then 20 degrees and if you increase the static then decrease the centrifugal. Don't go past a total of 28 degrees until you know what's happening. On top of that you would then have vacuam advance but you won't use that
Also, are you referencing the dizzy above or below the throttle plates? You should reference below so as to get some vacuuam advance at idle. If your cams very lumpy your powervalve may be pulsing open. Check idle vacuam and look for a rich tail pipe. PM me if you want a chat.
Boosted.
Static timing wants to be say 8 degrees by advancing the distributor, or advance until it idles smooth but without starter kickback. Centrifugal advance is governed by how much the dizzy bob weights fly out. I'd suggest no more then 20 degrees and if you increase the static then decrease the centrifugal. Don't go past a total of 28 degrees until you know what's happening. On top of that you would then have vacuam advance but you won't use that
Also, are you referencing the dizzy above or below the throttle plates? You should reference below so as to get some vacuuam advance at idle. If your cams very lumpy your powervalve may be pulsing open. Check idle vacuam and look for a rich tail pipe. PM me if you want a chat.
Boosted.
Boosted Ls1 said:
One of my rovers loved nearly 20 degrees at idle but the starter would kick back!
The Omex system seems to take about an hour and a half of cranking before it starts sparking and fuelling (well maybe slight exageration, but there is a noticeable delay) and this was sold as an advantage because it meant the engine was up to speed before it fired which avoided kick-back.
- much improved on newer systems I have been told however.GreenV8S said:
One of my rovers loved nearly 20 degrees at idle but the starter would kick back!
The Omex system seems to take about an hour and a half of cranking before it starts sparking and fuelling (well maybe slight exageration, but there is a noticeable delay) and this was sold as an advantage because it meant the engine was up to speed before it fired which avoided kick-back.
I've only got the 150 for sparks and yes I've noticed this, I like to think it allows the oil to circulate a bit before running
. saying that if it doens't catch then I get a fair kick back 
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