Pontiac 400 / Keep this Cam (a bit wordy)
04-08-2007, 10:50 PM
#21
Le Mans Master
beware....the car you see in my vid is R.I.P. Detonation killed it at 600 miles. Only one I ever lost. Still yet to figure out what exactly caused the detonation though. I have built this combo several times with no issue. Only thing I did different was I used the XE series cam and aftermarket (Eagle) rods. And I blueprinted this one too. Top rod bearing on number 7 was beat to death when I pulled it for inspection. Mind you, I was only running 12 degrees initial and the cam was installed straight up. I have a vid somewhere of a ride in the car. Give me a few and I will post it.
Last edited by cerino2000; 04-08-2007 at 11:26 PM.
04-08-2007, 10:52 PM
#22
Le Mans Master
Ya, here it is. Mind you this is with 2.41 rear end so by the time it is shifting into 2nd, it's about 80 MPH!
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04-11-2007, 08:52 PM
#23
Racer
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Member Since: Jul 2006
Location: Woodstock Georgia
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That is sweet...but a shame to have had it die so soon.
I think that I've nipped my problem in the bud. The total timing was good at 36 with WOT - no pre-detonation. That put the initial at 16 with good lumpy idle and no hot start problems. However, part throttle under a load is where I was hearing it. I immediately replaced the vacuum advance unit (stock from a `77 Firebird) with my Crane adjustable. I set it so that it kicks in late. The AR10 that I pulled out kicks in at 3-5hg!....and maxes out at 11-13 for 18 degrees!!
I have no spark knock at all with this curve. I am also running 93 octance.
Here's my current curve which I am going to change:
RPM mech/no vacuum advance mech/ w vacuum advance
1000 20° 20°
1500 32° 32°
2000 34° 34°
2500 34° 50°
3000 36° 54°
I have the Moroso curve kit coming so that I can change those weak advance springs. I am also going to limit the vacuum advance to 10° instead of the 18.
I think that I've nipped my problem in the bud. The total timing was good at 36 with WOT - no pre-detonation. That put the initial at 16 with good lumpy idle and no hot start problems. However, part throttle under a load is where I was hearing it. I immediately replaced the vacuum advance unit (stock from a `77 Firebird) with my Crane adjustable. I set it so that it kicks in late. The AR10 that I pulled out kicks in at 3-5hg!....and maxes out at 11-13 for 18 degrees!!
I have no spark knock at all with this curve. I am also running 93 octance.
Here's my current curve which I am going to change:
RPM mech/no vacuum advance mech/ w vacuum advance
1000 20° 20°
1500 32° 32°
2000 34° 34°
2500 34° 50°
3000 36° 54°
I have the Moroso curve kit coming so that I can change those weak advance springs. I am also going to limit the vacuum advance to 10° instead of the 18.
