Lack of Free Reving beyond 2500RPM 1972 V8 3500S Manual.
- Thread starter Lovel
- Start date
if it give you a clue i'm on KP currently. This is a HS6 needle. You get slight pinking where the sheet says it's weak.
I'd go for BFC as a gentle step up given my experience thusfar. Experience though does seem to suggest these graphs are pretty accurate so straight for BCA may be a step better again.
I'd suggest that you'll be able to advance your dizzy a bit too.
This is educated guesswork - i obviously cant guarantee this is dead on right but it'll be much closer than the standard bak needles.
I'd go for BFC as a gentle step up given my experience thusfar. Experience though does seem to suggest these graphs are pretty accurate so straight for BCA may be a step better again.
I'd suggest that you'll be able to advance your dizzy a bit too.
This is educated guesswork - i obviously cant guarantee this is dead on right but it'll be much closer than the standard bak needles.
http://www.mintylamb.co.uk/suneedle/ allows you to compare different needles graphically if that's any help.
MJP6B
Member
Lovel
[/quote] At least we can confirm that AUD 521 carbs are fitted to the 3500S. Could you confirm the needles that you had fitted or are using now?
[/quote]
Sorry for not responding sooner had to be away from PC. According to my data HIF carbs fitted to 3500 & 3500S cars had AUD 521 L & R fitted to all suffix A, B & C vehicles excepting the detoxed engines which had AUD 408 L & R.
From suffix D onwards AUD 623 L & R were fitted.
I fitted new needles and jets to my HIF`s in 1997 replacing the originals with exactly the same codes but I cannot lay my hands on any paperwork which confirms any numbers, I would have to dismantle a dashpot on my car in order to tell you which in ordinary circumstances I would be more than willing to do, but at the moment its raining stair-rods out there !
[/quote] At least we can confirm that AUD 521 carbs are fitted to the 3500S. Could you confirm the needles that you had fitted or are using now?
[/quote]
Sorry for not responding sooner had to be away from PC. According to my data HIF carbs fitted to 3500 & 3500S cars had AUD 521 L & R fitted to all suffix A, B & C vehicles excepting the detoxed engines which had AUD 408 L & R.
From suffix D onwards AUD 623 L & R were fitted.
I fitted new needles and jets to my HIF`s in 1997 replacing the originals with exactly the same codes but I cannot lay my hands on any paperwork which confirms any numbers, I would have to dismantle a dashpot on my car in order to tell you which in ordinary circumstances I would be more than willing to do, but at the moment its raining stair-rods out there !
Lovel
Member
Just an update from tonight. I fitted BCF needles, left the timing at 6deg BTDC, and she certainly revs cleanly and with urgency all the way to the red line 
Haven't had any time to deal with the idle and mixture screw atm, The idle is a bit lumpy/eratic. One other thing I noted though was that when I release the throttle there is a bit of popping/banging from the exhaust. Could this indicate too rich a needle? I might try a bit more advance possibly to 10deg BTDC and see how it goes from there.
I'm also thinking it may be worth trying BAK's too ?
Haven't had any time to deal with the idle and mixture screw atm, The idle is a bit lumpy/eratic. One other thing I noted though was that when I release the throttle there is a bit of popping/banging from the exhaust. Could this indicate too rich a needle? I might try a bit more advance possibly to 10deg BTDC and see how it goes from there.
I'm also thinking it may be worth trying BAK's too ?
Lovel
Member
I have settled on BCF needles for now. Set ignition timing to 8deg BTDC and adjusted the idle mixture a tad. Getting more consistent smoother running now so will see how it goes over next few weeks. Spark plugs are slightly darker now compared to when I had the weaker BBG needles fitted they were almost white then.