Rebuilt Flathead Problems.

A cam can appear to be 180 out - as it will ALWAYS be 180 degrees away from the crank dot at one point - as it turns at half speed. When the crank dot is UP, in one case the cam dot aligns, rotate the crank 360 degrees and the cam dot will be straight up at the top - 180 degrees out.

Hopefully I'm making sense.

B&S
 
GordonC said:
Guys I think I found it!! Here is a pic if I can get the darn thing to load.... interestingly enough the cam gear is almost exactly 180 degrees off from this dot. For some reason pictures are rotating 90 degrees on me when I upload them to this site. Doesn't do that on the HAMB?
Click to expand...

What do you mean by almost?

At that point , it should be exactly 180 out.
 
Hi Gordon,

Look at the gears in post #17. The cam turns 1/2 a revolution for a complete 360 degree revolution of the crank gear. In the picture above assume the crank gear is as shown. A full turn of the crank gear would yield the cam gear with dot 180 degrees out or on top in this picture. Is that what you are seeing?
 
Ok. I rotated the crank gear 360 degrees until the dot was at the 12 o'clock position again and the dot on the cam gear is now on the same location as the dot on the crank gear. It looks like it is set up correctly? If the gear is put on the cam correctly this thing should have fired?
 
Yes, alignment is correct.

Have you checked to make sure that your ignition wire to #1 and of course the rest in the right firing sequence, is on the compression stroke?
 
glennpm I need to put the timing cover back on once I am sure the cam gear is mounted properly and the timing is correct. Then I can go back to checking the distributor and the wiring. I am reasonably sure I had it correct.
 
There is some conflicting information out there. Be sure you know where the rotor is located inside the distributor when you are establishing No. 1 in the firing order. These two diagrams are 180 to each other.
 

Attachments

  • distr-sparkplugwiring_49-53v8.jpg
    distr-sparkplugwiring_49-53v8.jpg
    33.8 KB · Views: 119
  • Flathead_Sparkplugwiring-49-531.jpg
    Flathead_Sparkplugwiring-49-531.jpg
    16 KB · Views: 115
On my 8BA the rotor points to number 1 terminal on the cap when number 1 piston is a TDC and the timing marks line up.
 
Pic 17 shows how the marks are correct.
The keyway is TDC
What they are doing is retarding the TDC 2 1/2 teeth.
This is the start of the cam getting ready to open the intake.
If you have the dots lined up that's correct.
That's cam timing. now turn 180 and get #1 firing.
If the cap is marked#1 the rotor should be 6 o'clock +OR_
 
I would still look down no 1 plug hole and get valves rocking on the backstroke and see if your mark is exactly as you posted it post 20.

Then you can diss the cam timing and move on .

Rotate the crank 360 so that both marks are lined up.

This is TDC firing on #1.

Then check your plug wires are correct.

After you are sure you have cam and igntion timing correct, and a good spark at plugs, are you pouring a little gas down carby and then spinnng engine over with throttle wide open?
 
So from here-on, verifying the cam position is best done when the mark on the 8BA pulley is aligned with the pointer at TDC on the EXHAUST stroke where you can see the valves rocking like Mart described in post #8. Here's an excerpt from Walt Dupont from a long-ago post that walks you through it...

"With the intake off, turn the engine over (right hand rotation) watch the exh. valve on no. one piston (front piston on right side) watch the exh. valve open and close, just before it closes the intake will start to open, you can rock the crank back and forth and both valves rock back and forth, both valves will be off the seat, that's called valve overlap, no. one piston should be on TDC exh. stroke. If the timing cover is on the pointer should line up with the mark on the front pulley. If the mark is off quite aways, the timing gears are not lined up. Could be the dot on the gear is punched in the wrong place. Walt"

Lonnie
 
Ok.. so you have the cam that appears to be lined up but we still have to figure out why you are reading only 50lbs of cranking pressure. One question that scares me... if u say he s houldnt have been working on a flathead is did he do the valves correctly? 45 vs 30 degree valves... or grinding the valve seats parallel to the deck.... these are harder to fix.
 
Ok guys all good info now. I am going to have to pull the intake to be able to get a good look at what the valves are doing and when they are doing it in relation to where the cam and crank marks are. I will be doing that tomorrow and see what I get.

Pooch I initially used a shot of starting fluid until I could see gas squirting down the throat of the carburetor. I have 5 1/2 lbs pressure on the line feeding the carb and the fuel is recent as well. Not some junk that has been sitting in the tank for a while.
 
you may have washed the oil off the cylinders causing low comp.if your sure cam timing and ignition timing are correct pull the plugs makr sure they are dry.oil the cylinders and try pull starting it ive done it many times to get one going.
 
jake197000 said:
you may have washed the oil off the cylinders causing low comp.if your sure cam timing and ignition timing are correct pull the plugs makr sure they are dry.oil the cylinders and try pull starting it ive done it many times to get one going.
Click to expand...

I don't agree with this at all. I have done two fresh rebuilds in the last year and have had no problems getting them started. I set the timing with an ohmeter, filled the bowls through the vent, and both started almost immediately. In my experience, if you have trouble starting a fresh engine, there is a problem. Find and solve that problem rather than resorting to extreme methods. I found this out the hard way many years ago. Luckily, it didn't cost me a lot, because it was a snowmobile engine. I honed it and put in new rings, bolted the rest together and tried to start it. I almost tore my arm off and resorted to dumping gas in the carb and sprayed staring fluid until the cows came home. Finally it fired and ran. For 30 seconds. Then it self-destructed. It turned out to be improperly installed piston rings. A fresh engine should not be a problem to start. Your method is OK with "field cars" I guess, but I wouldn't do it with a fresh build.
 
I would take a look at the camgear...original bolts and the locking washer perhaps while you have it apart...and just to be sure check so the camgear is on right matching the holes in the camshaft.
 
Of the two diagrams in post number 29. As you stand on the passenger side viewing the distributor cap, number one should be on the bottom. Of course it can be made to work anywhere, as long as you have the rotor in sync with your chosen position. 1 at the bottom is stock.
 
You must log in or register to reply here.
Back
Top