jonm1a1

1st off thanks for the help.
I have a 67 mustang coupe 1980 302. 2150 motorcraft 2bl carb.
Engine shakes in idle gets worse through acceleration on highway at 55 has a vibration still just not as bad. Also when I put it on the highway it overheats to 230 then I stop not sure if it will keep going up.
Idles at 700rpms
Smells rich

Things I replaced
Lower & upper radiator hose
Transmission mount.
Flushed the system
Thermostat
Water pump


Things I Checked
Engine mounts
Plugs
Timing

Gun Jam

When did it last run right?

If it shakes at idle its almost certainly a vac leak or a dead cylinder.

Use a temp gun to make sure all the headers are close to the same temp this is most easly checked at start up. The temps on each working header should be rapidly rising in temp.

Use b12 carb cleaner or similar carb cleaner and spray lightly around the carb base. Inspect and any vac systems for leaks like a vac booster to do this remove all vac lines from the carb and block them off at the carb with stoppers listen for engine rpm change after blocking off accessory ports and when using the carb cleaner.

jonm1a1

So I checked harmonic balancer and put new motor mounts in didn't fix the issue. pulled out the compression tester and here are my numbers

1=135
2=130
3=120
4=120
5=30
6=120
7=120
8=125

So with that said almost sure its the dead #5 causing the issue. I checked it 3 different times making sure the fitting was on right and all that. Is my next option to re-ring the engine?

Gun Jam

I would look into a short block if your heads are good...there are several options

barnett468

hello

number 5 cyl is dead, deceased, expired, it lives no more. this will cause at least some vibration.

it might be burnt valves or bad rings or both. you need to remove the heads to see if the valves are burnt.

if you can feel a ridge on the top inside of your cylinder, your engine needs rebore.

the other cyls should be within around 10 lbs of each other

Al Newman

What did #5 plug look like relative to the others? Not an absolute, but a good guideline to begin the diagnosis. If the plug is wet and oily, first place to look would be rings. If the plug is caked with baked ash, suspect valve guides. If the plug is whiter than the others, expect a head gasket leaking. or burned out. With the engine running, pull the #5 plug wire. If no change in the miss, expect a buned or stuck intake valve. If the miss becomes more pronounced, expect a burned or stuck exhaust valve. Pull valve cover and insure #5 valve train in intact, i.e. no broken springs, rockers, bent push rods, etc.
Best,
Al

jonm1a1

plug wasn't wet it was dark ashy if u will that's good advice I will look at it tomorrow and see

jonm1a1

Great advice I took the head off and it was a burnt valve(exhaust) and a bad head gasket really thought it was my rings. Thanks for all the help