351C Will Not Fire

quote:

Using starting fluid, it is firing

no fuel ... if you push the accelerator .. is there gas squirting in the carb if you look down there ?

On the opposite side of the fuel tank ...tank a spark plug boot off and see if you have spark ?

Ron

Yes to both. Fuel is sprayed by the accelator pump. Definitely spark at cylinders 1 and 4. Thanks.

The harmonic balancer outer ring (where the timing marks are located) may have slipped. Pull the #1 spark plug, rotate the engine until the piston is at the top of the compression stroke. This will get you very close to TDC. Check the timing pointer and the marks on the balancer. If it is off by quite a bit, then the balancer ring has slipped. To find exact TDC, you will need a probe (a dial indicator works best) that touches the top of the #1 piston. Slowly rotate the crankshaft by hand until the upward movement of the piston stops. Try to find the exact point where the piston stops its upward movement. Next, put a mark on the balancer in line with the timing pointer. Continue to slowly rotate the crankshaft by hand until the piston just starts its downward movement. Fine tune this point just as you did with the upward stroke. Mark the balancer. Half way between these two marks is TDC. If your balancer outer ring timing marks are off, then the ring has slipped. You can mark off your 4* for initial timing, retime the distributor, and start the engine.

John

John,

What you are saying makes a lot of sense to me. As I originally wrote, it seems like the timing is significantly off even though the timing is set within reason according to the marks.

Is it OK to use oil in a clear tube that is fitted snugly into the spark plug hole for finding TDC?

Also, if the balancer has slipped, should it replaced, or is it OK to continue to use with corrected timing marks?

Thanks, Steve

Steve,

Definitely replace the balancer. If you don't, the outer ring will separate from the hub. I had mine come off the hub. Fortunately, I was at home when it happened.

You should be OK to fire the engine for a test, but replace the balancer soon (assuming the balancer is the problem).

I will send you a PM.

John

Steve,

quote:

Is it OK to use oil in a clear tube that is fitted snugly into the spark plug hole for finding TDC?

Oil will leak out of the combustion area through the ring end gaps, but you can probably make it work.

If you make the check with oil, after you are done, pull all of the spark plugs and rotate the engine by Hand through several revolutions. Then crank the engine with the starter for 20 or 30 revolutions in order to get as much oil out of the cylinder as possible. Upon engine start up, be prepared for a big cloud of smoke. Better alert the neighbors that your garage is not on fire!!

You can just do a quick check of the timing marks by bring the #1 piston up on the compression stroke. Shine a flash light into the #1 spark plug hole and watch the piston as is comes up (as you rotate the crankshaft by hand). You can get very close with this visual check, close enough to see if the timing marks are off by a significant amount. If they are, then you will know that the balancer ring has slipped. You should be able to approximate TDC and set your initial timing for a start up.

John

The outer ring on the balancer has slipped.

It is off by about 120 degrees.

John, this was a very good diagnosis. I did not know that balancers might behave as such.

I will recreate the timing the timing marks as a temporary measure and start looking for a new balancer.

Thanks for your help with this.

Regards, Steve

Steve,

If the ring has slipped that far, be careful as it is probably about ready to come off the hub.

Balancer/ring separation is a common problem, as the ring and hub are "connected" to each other with a piece of rubber-like material.

Let us know how it works out. I'll be watching the seismometer for earth tremors. LOL

John

quote:

The outer ring on the balancer has slipped. It is off by about 120 degrees.

Be sure to replace it with a SFI approved balancer.

I ordered the Scat Powerforce Plus 9000 SFI approved damper (D-90006 - has holes for either 3-bolt or 4-bolt pully) for only $185:
http://www.flatlanderracing.com/scat-dampers.html

Same as this one (D-90006) for A LOT LESS money:
http://www.flatlanderracing.co...erforce-dampers.html

Romac and Ford Motorsport are also highly recommended, but cost about $100 more.

Success !!!

After adjusting the timing for the slipped balancer ring, a few cylinders would fire but the engine still would not start. I then added a MSD box and it started up right away.

I ran the engine at 2000 - 2500 RPM's to break in the cam and lifters. I eventually had to shut it down because the coolant bottle overflow hose came loose. I need to hook up the second bottle in series and finish the cam break in.

The good news is that my low tech engine stand did not collapse or catch on fire. The parts of the stand near the exhaust are wrapped in header tape which seems to have worked well.

The project is back on track. John, thanks again for the diagnosis.

Steve,

You're quite welcome. I'm glad to hear that it worked out.

When will you have it back in the car?

John

I will be smoothing and refinishing the engine bay next. This includes hiding the AC lines and wiring harness, along with welding sheet metal over the unused holes in the compartment. This task will probably take a month or so.