Timing curve

[CamaroAdam73]

I thought i had this figured out but i didn't. Comp cams is telling me i should be using the LIGHTEST set of springs supplied with my curve kit, but i can only use the heaviest set. If i use even the medium my engine is into it's advance at idle. Is what comp cams is saying just not going to work for my setup, or is there something wrong i'm not seeing?



Oldsmobile 403

Idle speed: 1000-1100RPM

Cam
Comp cams thumpr, dick miller recommended me this cam profile
http://www.compcams.com/Company/CC/cam- ... =1463&sb=0

Lift : 491 / 476
Duration: 278 / 296
Range 2000-5800

Ignition
Stock dizzy recurved, DUI DYNA MOD ignition module/ coil.
Moroso adjustable vacc advance
Moroso Pickup

Car
88 Monte, now setup with a 2.41 rear gear, Th350 / 2100RPM stall converter

 

[pontiacgp]

Did you put on the weights that came with the springs and when your setting the timing with the medium weight springs you have the vacuum plugged? Also it sound like the idle is too high which may cause the mechanical timing to advance

 

[CamaroAdam73]

GP, yeah i'm using the weights the kit came with. I've always trusted moroso for good parts, i checked to make sure nothing was sticking as well.
Yes vac advance is unplugged/ line plugged while i'm tuning. About the idle speed, again comp cams recommends to keep it idling between 1000-1100 RPM, so what should i do?

I was going to try dropping idle speed to 900, setting initial timing with heaviest springs, then switching to the medium set to see if i would still be into my advance at 900 RPM.

 

[pontiacgp]

does comp cams give you any hints on what springs to run in the distributor?

 

[CamaroAdam73]

Gp, i just told them what curve kit i bought and they said "run the lightest". It would be nice if these springs came labeled at specific resistance/ weight haha.

 

[CamaroAdam73]

http://www.summitracing.com/parts/mor-7 ... oldsmobile here;s the kit i used. I think i see my problem, this kit has the springs listed as "Quick, super quick, Ultra quick".

 

[autonaut]

My MSD SF HEI has different sized weights than the ones found in stock GM HEI's.. They are bigger.
It's a guess, but maybe there is something wrong here. You springs could be for a different sized weights than what your dizzy is actually running.

 

[pontiacgp]

in the instructions for the spring kit the ultra quick springs don't kick in till 1500 rpm

 

[CamaroAdam73]

in the instructions for the spring kit the ultra quick springs don't kick in till 1500 rpm

Yeah, i don't know why mines coming in so soon..Is there something i could've done wrong to force the centrifugal advance to come in sooner?

Autonaut, i'm using the weights supplied with the springs so i don't think its possible for them to be mismatched, right?

I don't want to rule anything out here, kind've stumped.

 

[pontiacgp]

when you put the springs on are they slightly under tension in neutral positon or is there a little play?