Looking for help with a 74 cutlass 455 engine [Archive]

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1974Salon

07-20-2009, 06:16 PM

I have a 74 455 with has a hard start and rough idle. I have changed the cams, lifters, added shims to adjust for the preloads, new HEI distributor and new starter. Looking for any advice to make it start easier and idle smoother. Thanks

texxas8902

07-21-2009, 03:36 PM

I know it sounds simple but check your battery cable connections and your ground from the engine to the firewall for a start. I know you have probably already checked your timing when you swapped the distrib, right? Also your car only has one cam, not cams. :DGood luck.

mdkingsley

07-21-2009, 09:21 PM

May have a vac leak resulting in the rough idle, is it hard start after running or cold?

1974Salon

07-22-2009, 01:18 PM

It is idling rough after a cold start. The start is also hard. thanks

1974Salon

07-22-2009, 07:46 PM

The car is having an issue after a cold start.

ragz442

07-22-2009, 11:00 PM

If it runs rough cold only, I'd think it would be a choke/carb problem. First thing I would do is check the automatic choke operation, your choke pull off may be bad.

mdkingsley

07-23-2009, 01:40 PM

Hard start as in dragging or just spinning over not wanting to fire?

1974Salon

07-23-2009, 08:41 PM

It is dragging.

mdkingsley

07-23-2009, 10:16 PM

Sounds like new starter time, do you have another you can try? Or it could be the battery or cables. Check the ground strap also.

ahagey8879

07-24-2009, 12:38 AM

Probably way off, but I had a tiny fuel line leak that made my car hard to start and idle rough.

1974Salon

07-24-2009, 12:52 PM

thanks for the help.
changing the cables and changing the ground fixed the problem of the hard start and the rough idle, but now it is backfiring through the exhaust when speeding above idle. I am considering replacing the plugs. Any suggestions?

mdkingsley

07-25-2009, 12:14 PM

Did you put a timing chain that had the advanced or retard keyways in when you replaced the cam? I had one in a 455 and never did get it right on any setting. Finnally yanked and replaced it and it ran great after that.

1974Salon

07-28-2009, 06:14 PM

I used center keyway (O). I lined up the marks on the top gear with 0 and also the lower gear with 0. The distributor was pointing #1. TDC was used. I noticed besides backfiring through the exhaust. That not all the fuel was being used. I have used both a 600 and 700 cfm edelbrock carb. I tested the compression and the results was around 190-195.
Thanks for your help.