codylap
Mar 5th, 01, 09:31 PM
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Hello...I am now going to sum up my problem in one post since it will be easier to keep track of. The orginal problem was a backfiring sound coming from engine and resistance going above 80 km an hour. The backfiring noise has now gone away since I have adjusted the timing (knock on wood). The only problem I still have is that I can not go over 80 km an hour. The engine seems to hit a overdrive type thing but does not go faster, it is hard to explain but to get to 90 km an hour I have to be going down a hill. (Note*This may relate to this problem or not but when I am in drive and sitting still the oil light goes on). Any ideas or comments??? I am thinking it has to do with the distributor since with the vacuum hose off it does not stall when in drive and sitting still but with it on it does (I don't know **** so don't take my word for it). Thxs Cody L
P.S My car is an automatic 1981 camaro 267 from the california plant. I was looking in my good old haynes manual and it says that the 81 distributor does not have a vacuum canister to control spark advance well I say bull**** because my does.... or I really don't know **** all http://www.camaros.net/forum/smile.gif
travis
Mar 6th, 01, 12:19 AM
I'm just taking a stab here because your post was kinda hard to understand...
You say the car stalls in gear with the vaccuum advance connected, but doesnt with it disconnected? Sounds like you have way too much timing in there...what is your initial timing set out (with the vac. advance unplugged)? Does the engine start and idle normally?
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375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova
camcojb
Mar 6th, 01, 05:09 AM
You also should check your exhaust system. If you have a converter it sounds like it's plugged. A bad muffler or crushed exhaust pipe (some of them are double-walled and the outside will look fine while the inside is crushed by hitting a puddle of water when hot or ?...it happened to me!)will do the same thing. That's only like 60 mph or so. The Chevy dealer or cheaper yet a muffler shop can test the backpressure in the system. That's the only thing I can think of that would totally limit the speed at such a low mph.
Jody
codylap
Mar 6th, 01, 06:18 AM
Travis:Sorry, I know my post is hard to read since I wrote it down and then added some things. The car does stall in gear with the vacuum advance hooked up and it does not stall in gear with the vacuum advance unhooked and pluged. With the vacuum advance unhooked and plug it is set 10 degrees BTDC. The engine starts good and idles normally.
Camcojb: I know it is not exhust system since it was redone about a month ago.
Thxs Cody
travis
Mar 6th, 01, 12:44 PM
Heres something to check...take the cap and rotor off the distributor, and with your hand move the vaccuum advance plate to the full advanced position, then put your finger over the vaccuum pot port to seal it off...release the vaccuum plate and see if it releases...if it does then your vaccuum pot is blown and is causing a big vaccuum leak (assuming it is hooked to manifold or full time vaccuum like it should be)...I have never seen one cause the car to die in gear but your carb is calibrated pretty lean to begin with, so a vaccuum leak makes more of a difference. If the pot turns out ok, and you are sure it is connected to the right vaccuum port on the carb, then I can only think of one other thing...the timing chain is shot. Even with a ton of slack in the timing chain they will usually idle ok but will be real doggy when driving. With the vaccuum advance disconnected, watch your timing mark with a timing light and see if it moves around a lot. One last thing...you said that you had the exhuast system redone...was it stock replacement or headers and duals, or what? Are you still running the catalytic convertor? Hope this helps.
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375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova
codylap
Mar 6th, 01, 02:42 PM
Travis: The exhuast was redone orignal but without cat. I have noticed when I time my car that the mark seems to jump back and forth about 1 degree...Does this mean the chain is shot??
travis
Mar 7th, 01, 09:38 PM
The timing mark shouldnt move at all but 1 degree isnt enough to worry about. How many miles are on the engine? have you run a compression test on it? How much vaccuum are you pulling at idle (manifold vaccuum)? This is a strange problem you have...it could even be a vaccuum leak somewhere. DO a cranking compression test and check your vaccuum at idle and post what you get...this will help confirm whether the timing chain is ok or not.
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375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova
codylap
Mar 8th, 01, 02:12 PM
Thxs for the tips travis...I checked compression and it was low so I took it in (for free) and now I know I have a worn cam shaft http://www.camaros.net/forum/frown.gif Do you like I could tackle this myself or let someone do it???
travis
Mar 8th, 01, 09:47 PM
Personally, I would yank the 267 and drop in a fresh 350, but thats just me http://www.camaros.net/forum/biggrin.gif
I am curious to know how the shop determined that the cam is worn out...not that it is uncommon...just curious. As far as doing the work yourself, that depends...how confident are you in your mechanic abilitys? A cam/lifters/timing set swap is pretty involved and can be a real pain with the engine in the car...but if you can follow a haynes manual (or something similar) and have a few tools and a little mechanical apptitude then I would say go for it.
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375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova