| sundog126 | -- 08-04-2020 @ 11:03 AM |
|
on my 53 ford flathead with the head off, i made sure the piston was at tdc on compression stroke and noticed the timing mark was at about 2-4 degrees advanced on the pulley nd plate, the engine starts right up but the vacuum gauge jumps all over at idle, smooths out at increase of rpm's but pops a little the exhaust, could this be the cam being off a few degrees ?
|
|
| carcrazy | -- 08-04-2020 @ 11:28 AM |
|
This small difference shouldn't cause the symptoms you describe. I would look for sticking valves or retarded cam timing. I would put a degree wheel on the front of the crankshaft and measure the valve lift of #1 cylinder's intake and exhaust valves relative to crankshaft position. Install your degree wheel so that TDC is indicated at true TDC of the #1 piston as you have observed it. Place a Dial Indicator on the top of #1 intake valve and rotate the crankshaft in a clockwise direction to establish the opening and closing points of that valve. Then do the same for the #1 exhaust valve. This will tell you if the camshaft is timed correctly with the crankshaft. If you have recorded the data that has been generated, you will be able to also see the amount of overlap when the intake and exhaust valves are open at the same time.
|
|
| 40cpe | -- 08-04-2020 @ 3:57 PM |
|
The raised dimple on the crank pulley on an 8BA engine is 2 degrees advanced, not top dead center. There is no TDC mark, unless someone has put one on the pulley.
|
|
| sundog126 | -- 08-13-2020 @ 8:53 AM |
|
I found one exhaust valve sticking on number 2 cyl ,fixed that, put the head back on and started the engine ,vacuum gauge still vibrating between 5-13 ins at idle and poping out right exhaust pipe, I pulled number 1 plug wire and poping stopped, checked my rpm's pulling plug wires one by one and cyl 1 and 2 did not change rpm's, also viberating gets worse when engine gets hotter,like I said before the compression and cyl bleed down looks good, I did not do a true TDC because I had my heads back on by then ,but moving the dist. around and timing did not help.
|
|
| carcrazy | -- 08-13-2020 @ 10:54 AM |
|
With your vacuum gauge readings fluctuating between 5 and 13 inches, I would suspect late valve timing. Check the relationship between the camshaft and the crankshaft to be sure it is correct.
|
|
| TomO | -- 08-14-2020 @ 7:33 AM |
|
Compare your vacuum readings to the action in this chart: http://www.secondchancegarage.com/public/186.cfm It sounds like you may still have a stuck valve. Tom
|
|
| 37RAGTOPMAN | -- 08-15-2020 @ 5:50 AM |
|
HI sundog 126 when you took the compression test on the engine what was the reading, if not this is were you should have started, this should have been done first, before anything else. this is NUMBER 1 this is the ground floor in diagnosing what exactly is the problem. bad compression and it will never run smooth, I think you can see the top of piston when looking in the spark plug hoe to see top dead center, to see where are are at, take compression and see if the cylinders are all the same or close, did you check out all the valves when head was off, you might have broken valve springs or weak, or might have foreign made parts that are weak, if it is popping out the exhaust it telling me the exhaust valves are open, also make sure you plugs are clean, try a new set, hope this helps 37Ragtopman
|
|
| EFV-8 Club Forum : | https://www.earlyfordv8.org/forum |
| Topic: | https://www.earlyfordv8.org/forum/viewmessages.cfm?Forum=18&Topic=14043 |