74 350 Camaro

I just bought a 74 Camaro and it's back firing horible when it's idled
up. I've been told; "timing,s-plugs, wires, points, and it needs ahigh
rise intake since it has a new 650 edelbrock on it". I'm going through
the electrical side of things. It has new alternator, plug wires,
points, plugs, & distributor cap. I drove it back home from San Diago
CA to St. Louis, MO. I had to tweak the timing to make it through the
mountins in Vail/Denver. Any ideas?

First off a CA Camaro, Nice. Needs a high rise? High rise will improve
performance if it is needed. Will not do anything for driveability. Start
with the basics, plugs,points, cap, rotor & wires.Set your timing. Check
that both mechanical & vacuum advance are functioning properly. Backfire is
typically a timing issue. A miss on the otherhand could be an ignition
problem. If a basic tuneup doesn't solve the problem, pull the valve covers
and look at the valve train. Rocker arms, rocker studs, pushrods. Good Luck.
> wrote in message
oups.com...
> I just bought a 74 Camaro and it's back firing horible when it's idled
> up. I've been told; "timing,s-plugs, wires, points, and it needs ahigh
> rise intake since it has a new 650 edelbrock on it". I'm going through
> the electrical side of things. It has new alternator, plug wires,
> points, plugs, & distributor cap. I drove it back home from San Diago
> CA to St. Louis, MO. I had to tweak the timing to make it through the
> mountins in Vail/Denver. Any ideas?
>

wrote:
> I just bought a 74 Camaro and it's back firing horible when it's idled
> up. I've been told; "timing,s-plugs, wires, points, and it needs ahigh
> rise intake since it has a new 650 edelbrock on it". I'm going through
> the electrical side of things. It has new alternator, plug wires,
> points, plugs, & distributor cap. I drove it back home from San Diago
> CA to St. Louis, MO. I had to tweak the timing to make it through the
> mountins in Vail/Denver. Any ideas?
>

I have seen the hold down foot of the distributor get corroded so the
distributor loses it's ground which causes strange firing something like
you describe.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

did you check the compression on all cylinders? if all cylinders are
low its the timing chain.

On Jun 30, 12:39 pm, wrote:
> did you check the compression on all cylinders? if all cylinders are
> low its the timing chain.

Really?!?! Can't be the cam?!?! Can't be the valve adjustment?!?!
Can't be the lifters?!?! Can't be push rods?!?! Can't be the
rings?!?!? Can't be the rockers?!?! Can't be the rocker balls?!?!
Can't be the rocker studs?!?! (stock ones push out of the heads) Can't
be the bore?!?! Can't be...

On Jun 30, 7:25 pm, dahpater > wrote:
> On Jun 30, 12:39 pm, wrote:
>
> > did you check the compression on all cylinders? if all cylinders are
> > low its the timing chain.
>
> Really?!?! Can't be the cam?!?! Can't be the valve adjustment?!?!
> Can't be the lifters?!?! Can't be push rods?!?! Can't be the
> rings?!?!? Can't be the rockers?!?! Can't be the rocker balls?!?!
> Can't be the rocker studs?!?! (stock ones push out of the heads) Can't
> be the bore?!?! Can't be...

there are some clues there that the timing chain has jumped. its a
1974 so its old maybe by now the timing chain is stretched and it has
even jumped a cog. he had to adjust the timing to get through the
mountains. If the valves are not opening and closing in sync with with
the pistons going up and down it may or may not help to adjust the
timing. i think the confirming test is to check the compression. if
they are even and low the timing chain has jumped. if some are good
then its not the timing chain. It takes all day to replace the timing
chain (and of course you will also replace the gears)
so you want to make sure before you tear it apart.

If the engine backfires, the timing is off. If the spark timing is okay,
the valve timing is not. You've played with the spark timing, now it's
time to check the valves.

Might be good first to pull the chain cover and make sure it's lined up
nicely. I might want to do a compression test before anything else,
though. I _hope_ you did a compression test before buying, though.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

wrote in article
.com>...
> I just bought a 74 Camaro and it's back firing horible when it's idled
> up. I've been told; "timing,s-plugs, wires, points, and it needs ahigh
> rise intake since it has a new 650 edelbrock on it". I'm going through
> the electrical side of things. It has new alternator, plug wires,
> points, plugs, & distributor cap. I drove it back home from San Diago
> CA to St. Louis, MO. I had to tweak the timing to make it through the
> mountins in Vail/Denver. Any ideas?
>
>

First of all - to help narrow it down a bit - give us your definition of
"backfiring".

Is it backfiring through the exhaust or through the carb?

Also give us your definition of "idled up". Is it idling or off-idle?

Engine hot or cold?