dbehunin

Hello, I need help with a 351 C, been trying to time the engine, but the balancer marks don't match. When the #1 cylinder is at the top, the distributor is firing on #4. The engine runs OK but lacks power, has lots of vacume and idles smooth. When the balancer marks line up, the distributor is firing on #4 turn it 180, and it fires on or #8. Any suggestion appreciated. Thank's dbehunin.

ghettoct

check your firing order to make sure you have the 351 cleveland firing order (1 3 7 2 6 5 4 8). and that the wires are in sequence to the rotation of the distributor.

if this is correct, then you may have the distributor out of sync on the camshaft, then try a timing light to see where you fall on the degrees. if all else fails put the engine in TDC and see where the distributor rotor lines up, should be on the #1.

you dont mention the hows to how you got to where you are? rebuild, distributor replacement etc?

james
73 mach1 351C, 2010GT premium,

dbehunin

Thanks for the reply....I did put the TDC mark on the pointer, but the dist lined up on #4, not #1...thats how it likes to run. I used a TDC finder through the #1 spark plug hole, but the timing marks were'nt even close. I have checked the firing order over and over, it's correct. I pulled the old dist to replace it with an MSD ready to run dist. But when I lined up the balancer on it's TDC mark, and stabbed the dist where the rotor was on #1, it would'nt run, just to experiment I kept re-stabbing it on different teeth, I got a few back fire's one through carb, but it started running, and pretty good to, but it's not right, and impossible to time. Any advice is welcome. Thank's dbehunin

ghettoct

hey no probs, its the distributor and its timing on the cam shaft. your off and thats causing the problem, i would not run the engine as you have it, in fact have you noticed any of your exhaust manifolds/headers turning red? i saw a guy who put a distributor in off and his #4 exhaust was turning the header red hot. not a good thing esp since your getting the backfires through the carb.

remember that TDC occurs every other revolution, one just after exhausting the gases in cylinder and one just prior to combustion.

if i was you i would start from step one, keep it as you have it and do this:

put dist cap on new dist. cap should identify the #1 on it. put a marker on the side of dist so you will know when cap is removed that this is the #1 position. remove cap to watch the rotation of rotor.

chalk car and put emergency break on and put in park.

remove #1 spark plug, and coil wire to distributor and coil (prevents engine from starting, place index finger OVER spark plug hole NOT in IT. bump the motor over and feel for compression, may take a few revolutions to get the hang of it. (harmonic balancer should also concur that your in the general area of TDC)

(NOTE: the piston travels up twice, one will get no back pressure, since the exhaust valve is open, the other will have back pressure for the intake and exhaust are closed thus this is the TDC you want)

since you have stabbed the dist several times i would then remove the dist and rotate the rotor on dist until it lines up with the mark you put on the side of it, GENTLY put in the hole and "feel" for the meshing of the teeth on the gears, you want to make sure that the rotor of dist is in the area of the mark, you may have to pull it out and rotate the rotor clockwise or counter clockwise to get the right position with your mark.

once you are satisfied, bolt down and put plug/ coil wires on, button dist and secure the dist.

start car, you may have to loosen the dist bolt slightly so you can rotate the whole dist to get car to run. once its running good apply a timing light, disconnect your vacuum line to dist and time the motor to specification. tighten the dist and reconnect your vacuum line.

should work out for you.

good luck,
james


351C dist rotates counter clockwise.

dbehunin

Thank's for the info,
I used a top dead center indicator through the #1 spark plug hole, I made sure it was on the compression stroke, I got it very close to the top of the stroke, and the rotor was pointing at #1 in the dist, but the mark's on the balancer were not where they were suppose to be, the TDC mark's were back at least 2 cylinder's. Could the balancer be off? Do they ever move out of sync? Thank's for the help. It has helped alot. dbehunin

ghettoct

hey no probs.

hmmmmmmmm...to answer the question on the harmonic balancer (where the timing marks are engraved), they do not move unless you shear off the "wedge key" which is highly unlikely...BUT you can have a timing chain stretch and even worse jump a few teeth on the sprocket which is attached to the cam shaft which is conected to the distributor...and cause the timing to be off.

BUT that is in motors that have age. i dunno if you have a fresh 351 or one with over 150K miles on it. without opening a fresh can or worms....take the mds one out and put the old one back in the same way i mentioned for the new one and start it up and see how it runs. that is an easy way to see if your mds is the bad part.

if the motor is old you may want to consider replacing the timing chain but you have to remove the front h2o pump, timing chain cover etc to get to it. about a day job. BUT if you do that you will know what the status of your timing chain/timing is.

iam pretty sure that the TDC mark should line up with the marker on the balancer and the dist rotor should be in the area of #1, if the motor is at TDC of the compression stroke.

one other way to possibly look at the timing chain is to remove the mechanical fuel pump which rides off the ecentric on the cam shaft and you can look at the tc and probe with a small screwdriver to see how tight loose it is.


how did the motor run b4 you put the new dist. in ?? i dunno also if you have manuals but i highly recommend you pick this one up: at local autozone or advance auto etc. lots of good info and step by steps to go by. iamnot sure your level of mechanics and such but i always reference them from time to time.

http://www.haynes.com/products/produ...tm_medium=feed


hope this helps out, curious to figure this out too.

james

ghettoct

iam guessing the new mds is that an electronic one or points??

dbehunin

Hello....and again, thank's for the help. I never ran the car with the old dist in it, so I dont know how it ran if at all. And yes, the MSD dist is electronic, no point's. If the timing chain jumped a notch or two, would it still run? If so, would it damage the motor? Also, does the oil pan on a cleveland need to be removed to get to the timing chain? Thank's again for all the advice.Dbehunin