The Stovebolt Site Forums The Shop Area Engine Shop popping over 30mph (long story)

Okay heres what happened one day I was driving my truck and decided to take the muffler off and run a straihgt pipe just to see if I like it. Come to find out I did so I left it off. Since I can here it know going down the road I heard it popping/missing and thouhgt it could be the points so I replaced the points and condenser and it stills does it. So I wind up taking it to my "mechanic" and he says it is a burned valve and blown head gasket......know I take it to my "other mechanic" he says that it's not a burnt vavle and head gasket because if it was the head gasket it would smoke which it doesnt. He said I need to adjust the valves so I did and quess what ,IT STILL DOES!!!! so what do yall think it is?

If you want to see for yourself if it is a burnt valve or head gasket, one quick way is to do a compression test on the engine. If the results are within specs., then you might look at other areas.

Another thing to do would be to hook a vacuum gauge up to the engine and then drive around. If it is stock you should get a constant reading of about 17-21 in. Hg. This gauge will also indicate bad valves by dropping significantly rhythmically at idle.

Good Luck
Adam

Just guessing, but I might check the timing also.

how exacly do you set the timing. I have always just loosened the distributor and turned it till it sounded right.

If the poping sound is readly herd by quickly opening the throttle while running at idle ,it may be a flat cam (kinda sounds like popping corn) I took valve cover off after performing above threads and found flat cam shaft lobe

I have to lean towards a burnt valve myself, then a flat lobe second.

popcorn The Truth is Out There (Keep us posted always like to hear problems solved) Pops

you have alot of ideas on this,,,hard to hit on the problem thru a computer,,,so lets go,,install a vacum gauge should be steady,,check intake mounting bolts,,if missing at idle find cyl at fault,,check plugs,wires,dist cap,dist bushings for wear,,run a compression check if ok,,if miss is constant look under valve cover for broken spring,,check to see if all rockers move full travel(bad cam lobe) check push rods(bent),,I don,t know what it acts like,,if not missing at idle I,d do the 1 intake 2 ing 3 vacum leak 4com ck 5 under VC 6 carb 7 install muffler...doc