Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor
idle help
Kenth:
You will find measurements of the lobes, intake BHR233353 and exhaust BHR247360, here:
https://www.howardscams.com/sites/default/files/lobe%20list%20email%201-20-2014.pdf
HTH
tayto:
guess my post got cut short... both howards cams i've installed the advertised duration was at .006" HTH.
73ss:
Thanks for the replies, I think this cam would be better suited for a 454 with the stock heads. Any cam recomendations?
I took the head off with the leaky #5 valve and found that the valves have been floating, The intake valve kissed and took it out of round ever so slightly. Cant see it without a dial indicator. One of the spring shims got beat to hell as well. I installed the recommended howards springs that match this cam, Set them to the correct height, within a few thousands. I had 2 of the springs tested and they are about 20 ponds light on the seat pressure. I didn't realize I was getting into float, I've got a 6K rev limiter. It would start to break up just before 6K, I figured my rev limiter was off by a few hundred and it was valve float that was causing the breakup. Cam and springs are supposed to be good to 6400.
Looks like I'll be needing to replace all of the springs and a valve, Anybody have a trusted brand that they use?
Cliff Ruggles:
Common problem running into issues at high RPM's with HR lifter set-ups. Spring pressure may not be the answer and for sure that cam isn't making power past 6000rpm's in that application so really no need to rev it that high.
I've dyno'd plenty of big CID engines and a 230 @ .050" cam isn't making power in a 450-470cid engine must past 5500rpm's and some quit down around 5000-5200......
73ss:
I talked with a tech at Howards and apparently the cam that I have is more for blower & nitrous use for a 454 and not a stroker, which he said is contributing the low psi on a compression test. Also the springs they listed are the minimum requirement. Would be nice if that was made clear in their catalog.
Anyhow he recommended a 243/249 @ .050. 640/640 lift. 112 LSA 108 centerline.
Lunati also has a similar grind: 240/245 @ .050. 612/612 lift 112 LSA 110 centerline.
Thoughts on these please.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version