69 327 idle & backfiring
#1
69 327 idle & backfiring
ive taken on a project for a friend recently getting his drop top camaro running thats been in a barn for 30 years. its a 327 with a rochester 2 barrel. i changed all fluids and gave it a thorough carb cleaning. started it up today and it would rev good but not idle but it would also backfire out the carb when it killed.
im a motorcycle guy, not vintage car so im no expert. would this maybe need a timing adjustment of valve lash adjustment?
thanks -sam
im a motorcycle guy, not vintage car so im no expert. would this maybe need a timing adjustment of valve lash adjustment?
thanks -sam
#2
I would definitely rebuild the carb, since it's been sitting for so many years. It's probably gummed up, has sediment, and/or has dried out gaskets and a poor working needle and seat.
And assuming it has the original style distributor, replacing the points, condenser, cap, rotor, and wires just may do wonders for it (with an emphasis on the points).
Do the lifters make noise? If not, then I wouldn't be suspecting the valves or lifters just yet.
And assuming it has the original style distributor, replacing the points, condenser, cap, rotor, and wires just may do wonders for it (with an emphasis on the points).
Do the lifters make noise? If not, then I wouldn't be suspecting the valves or lifters just yet.
#3
30 years is a long time,no doubt that carb will need a rebuild and I'd be concerned with rust and crap in the gas tank so a couple inline filters might be a good idea to protect the newly rebuilt carb.
Any idea why it has been parked since so long ago or how many miles are on it or if the motor has been rebuilt at any time?
I mean even 30 years back it was far from a new car or even a late model,it could have a bad timing chain or who knows what that may have been why it was parked.
I wouldn't have started it without a good ****** of diesel throughout the whole engine to loosen up any rusted and stuck valves or rings or lifters etc.
Any idea why it has been parked since so long ago or how many miles are on it or if the motor has been rebuilt at any time?
I mean even 30 years back it was far from a new car or even a late model,it could have a bad timing chain or who knows what that may have been why it was parked.
I wouldn't have started it without a good ****** of diesel throughout the whole engine to loosen up any rusted and stuck valves or rings or lifters etc.
#5
alright. i did put a rebuild kit in, soda blasted and ultrasonic cleaned the carb.. so hopefully thats not an issue any more. the lifters werent making noise, and i attribute my false assumption that it was them to the vicadin im on from being hit by a truck last week haha. Ive siphoned out all the gas and flushed the lines, and it wasnt that rusty so im not concerned.
the car has been sittin in a barn for so long because my friends dad was injured and couldnt drive it, and he never brought it back out.
but now i have another issue. cuz in my vicadin stuper last night i decided to do a valve adjustment... but completely wrong so i have 2 more questions. how do you turn the engines over since theres no bolt on the crank that i could find, and how can you tell when each cyl is a tdc?
thanks for the replies -sam
the car has been sittin in a barn for so long because my friends dad was injured and couldnt drive it, and he never brought it back out.
but now i have another issue. cuz in my vicadin stuper last night i decided to do a valve adjustment... but completely wrong so i have 2 more questions. how do you turn the engines over since theres no bolt on the crank that i could find, and how can you tell when each cyl is a tdc?
thanks for the replies -sam
#6
Getting TDC "compression stroke" is pretty easy.
Get a friend to help if you can,pull out the spark plug and start bumping the starter one flick of the key at a time to turn it over while the other guy holds their thumb over the plug hole,when it come up on compression you'll know pretty quick.
If you pull all the plugs it should be easy enough to tug on the fan belt one way or the other to get the timing mark on the balancer at TDC if there's not a bolt inside the pulley on the balancer.
I've done this with a remote starter switch by myself by just having the sparkplug in the hole barely threaded enough to hold but loose enough to let air get by as it comes up on compression,pretty easy to hear it if you turn down the music.
You can also use the method of watching the valve lift as described here.
http://www.classiccarauto.com/impala...t_valves.shtml
Last edited by Y2K; 08-05-2010 at 10:20 AM.
#7
The 69 crank should have a bolt holding the harmonic dampener on. Look way inside the lower pulley.
If you have the spark plugs out, you can easily turn the lower pulley over by hand, without a ratchet.
And, you don't need to find TDC to adjust the valves the right way: http://www.chevyhiperformance.com/te...nfo/index.html
If you have the spark plugs out, you can easily turn the lower pulley over by hand, without a ratchet.
And, you don't need to find TDC to adjust the valves the right way: http://www.chevyhiperformance.com/te...nfo/index.html
#8
Last night I dropped 3 hits of acid and was tripping ***** when I decided to replace my intake. Woke up this morning only to find my lawnmower with a RPM intake manifold bolted on it, topped off with Holley 750. I must of been fried out of my brain, but that lawnmower really moves now! (having a little fun)
After your done playing with engine I would still drop the gas tank and really clean it out and replace the sending unit. As well, you can also use a piece of wire to check if the piston is at TDC. You'll have to do it a couple of time to know TDC, bump...check, bump...check.
Good Luck!
After your done playing with engine I would still drop the gas tank and really clean it out and replace the sending unit. As well, you can also use a piece of wire to check if the piston is at TDC. You'll have to do it a couple of time to know TDC, bump...check, bump...check.
Good Luck!
#9
at tdc on the compression stroke the dist should be pointing directly at #1 on the cap
adjust these valves
intake 1,2,5,7
exhaust 1,3,4,8
rotate engine 360 degrees and should be on #6 tdc
then adjust
intake 3,4,6,8
exhaust 2,5,6,7
works for me and unless you have a very radical cam!!
adjust these valves
intake 1,2,5,7
exhaust 1,3,4,8
rotate engine 360 degrees and should be on #6 tdc
then adjust
intake 3,4,6,8
exhaust 2,5,6,7
works for me and unless you have a very radical cam!!
#10
Last night I dropped 3 hits of acid and was tripping ***** when I decided to replace my intake. Woke up this morning only to find my lawnmower with a RPM intake manifold bolted on it, topped off with Holley 750. I must of been fried out of my brain, but that lawnmower really moves now! (having a little fun)
Last edited by Y2K; 08-05-2010 at 04:46 PM.