baxsom

Did I just wipe a cam lobe.

I got the car back from the shop today. When i picked it up it was running great. Throttle response was dead on. no backfiring, no issues at all.

now i can barely get the car to idle. i can get it cranked but it idles all over the place and puffs air out of the carb with every revolution.




very very rough idle. needle on a vacuum gauge bounces 5 or so inches up and down. if i turn the curb idle screw to faster nothing happens.

white puffs of air will come out of the carb.

i took off the valve covers and all 16 rockers seem to be moving up and down.

i dont understand the night and day difference since there was no work done on it from running well to almost not at all.

TimAT

Any noise when it's running? A wiped cam will cause a whole bunch of extra clearance and that rocker will rattle. tick-tick-tick all the time. When you had the covers off did you look at the pushrods and springs? A broken spring could be the culprit too.

baxsom

springs are brand new triples from comp cams.

no noise like a loose valve. the best way to describe how its running is that it is only firing on 5 cylinders. with it in gear and my foot on the brake the whole car just shakes.

i replaced the wires, HEI control unit, and have played with the timing all over the place.

next is new plugs. after that gasoline and a match.

calwldlife

how old is the timing gear set?

TimAT

Mix up some dish soap and water, put that in a spray bottle and wet the plug wires down while it's running. A bad plug wire will show like magic. The soap keeps the waer from evaporating so fast. Quick and dirty plug wire check. Works on the cap and coil too. I've even seen plugs arc across the insulator.

gingerbreadman1977

check your timing first. dizzy clamp prob not as tight as it should be.

Budman68

I agree, sounds like the dizzy moved.

DRIVESHAFT

By triples I hope you really mean double springs with a damper.
Actual triple spring are only needed with big solid rollers and would probably collapse a hydraulic lifter.

baxsom

sorry yeah
double spring with dampner insert

distributer is tight
plug wires are brand new
plugs are brand new

all of the old plugs were filthy black.
new plugs and wires and it runs and idles now but still rougher than it should be.

i think that the shop set the valves too tight because i backed off of one of them 1 full turn and still didnt get any clatter with the engine running.

its too noisy to tell for sure but when i loosened the valves the rpms would go way up by a few rpms. after i loosened each valve with the engine running i had to reset the curb idle because it was up so high.

the needle on my vacuum gauge still jumps 10" back and forth rapidly while idling.

i am going to repull each plug now and set the valves with the engine off so i know for sure it is on like it is supposed to be.

i think its got a vacuum leak somewhere,
revved it up and the rpms stay up for a second before climbing back down.

if i could figure out why the carb is puffing air out of it i could hear the valves easier.

DRIVESHAFT

If your valve adjustment is way too tight, it could be responsible for your puffing carb.
I would set the valves first and then work on other things if there is a still a problem.

HamadUP

It seems that your lifters were adjusted way too tight, re-adjust them to a half turn after zero lash and see what will happen.

A friend of mine with a 454 got exactly the same symptoms, and he was ready to tear it down thinking it's a wiped cam, when a friend suggested re-adjusting the lifters and it's running just fine ever since.

LFZ

what are some details on the motor? cam specs? please tell me your not running Keith Black pistons.