The Ford Barn

[email protected] · 10-31-2011, 12:01 PM

Is it possible for the camshaft to be 180 out of time and cause low compression on all cylinders (30 to 50 lbs) Dist and wireing is all right getting spark to all cylinders in the correct order at the top of the compression stroke, Getting gas but will not start, wont even pop or back fire

flatjack9 · 10-31-2011, 12:50 PM

Which engine are you asking about? Is the cam gear pressed on or bolted on?

George/Maine · 10-31-2011, 01:10 PM

Find TDC one way is pass side #1 is front and 2 and 3 pitons even from top.There is two top TDCs at different times with valves.# 1 TDC turning clockwise the crankshaft the intake will start to open.Turn one full turn thats spark time TDC 1/2 turn more and exhaust startes to open 1/2 turn more TDC again little more about 6 degs exhaust will close.
Or pull the timing cover check the dots.

[email protected] · 10-31-2011, 02:08 PM

It is pressed on 85 hp flathead

Walt Dupont--Me. · 10-31-2011, 08:07 PM

Quote:

Originally Posted by [email protected]

Is it possible for the camshaft to be 180 out of time and cause low compression on all cylinders (30 to 50 lbs) Dist and wireing is all right getting spark to all cylinders in the correct order at the top of the compression stroke, Getting gas but will not start, wont even pop or back fire

Yes, if the cam timing is off the compression will be low. because the valves will be open when the piston comes up on compression. Walt

38 coupe · 11-01-2011, 08:32 PM

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If the cam is 180 camshaft degrees out the compression will not be affected. If the camshaft is 180 crankshaft degrees out you will have low compression.

Tinker · 11-01-2011, 08:50 PM

What would be the chances the cam is off 180?

Wouldn't it fire anyway?

38 coupe · 11-01-2011, 09:06 PM

If the cam is 180 camshaft degrees out (installed upside down) then the spark plugs will fire at the top of the exhaust stroke, instead of at the top of the compression stroke. The quick solution for this would be to move your spark plug wires half way round on the distributor.

Is this a fresh rebuilt engine that won't fire off, or an old unknown engine you are trying to bring to life, or...
We need more information.

George/Maine · 11-02-2011, 03:34 PM

If this is a new cam, even a hot cam will have the exhaust close at TDC or few degs after.Pressing the gear on must be off mark.You can have ign timing correct.My guess the intake is half way down and not getting enought compresion and fuel.

Walt Dupont--Me. · 11-02-2011, 07:17 PM

i'm going to try to explain this to make it easy to understand. This is kind of hard with a press on cam gear and the engine in the car, but this has to happen. We will take any piston it don't matter witch one, but we will use no. 6 for an exsample. You've got to able to see the valves going up and down on this cyl. and tell when the piston is at TDC. We will make believe there is no timing marks on the timing gears. You will have to crank the engine, right hand rotation. Then watch the exh. valve on that cyl open and close, just before the exh. valves closes the int. valve will start to open. Now you came turn the engine back and forth and the 2 valve will rock back and forth. NOW, when they are both rocking (both valves off the seat) that piston should be on TDC. If the piston is not on TDC the the cam gear is off and the valve timing is off. That is called rocking the valve in relationship to piston TDC. NOW, that piston in on exh. stroke and the the conpanion cyl. (witch is no. 1) is on compression stroke. Every cyl. has a companion cyl. One is fireing and the other is exhausting, both pistons are at TDC. So you see, you could get the valve timing right if you didn't have any marks on the gears. Now, ain't that easy. Walt

F&J · 11-03-2011, 09:12 AM

If this is an engine that was not running for decades, it probably has stuck rings or has light surface rust on the valves and seats.

I am trying to start a 53 Olds motor in a 40 Ford right now with the same compression, and the same results...not even trying to fire on any cylinder. I've been doing stuff like this for 40+ years, and this is the only one I can't get to go. Most all that I have finally started, the heat/cool cycles will free up the rings and then it will start nice without oil smoke.

I will definately rebuild this motor, but right now, I just need the car to be yard drivable while I do the body work in my only work bay. A running car is better than pushing it out when I need the bay for another job.

I'll try more ideas today, and if it fails, I will tear it down.

George/Maine · 11-03-2011, 09:40 AM

I had a Olds 49 303 and I couldn,t get it going.Put a 12 volt coil,still wouldn,t go.Afther weeks of trying remembed the condenser maybe no good.Where up the street and friend had a Studebaker got the condenser out of it and put in Olds,started to fire afther little turn dist she fired and run.I did lap the valves so I new they were good.Years afther it sat and tryed to start it again and found the valves had rusted and stuck.I took a crow bar and under the push rods I lifted and broke all the valves free sock with oil and k1.Run good again.Those old GM car would start when cold but had hard time when hot.Good Luck with the Olds.

F&J · 11-03-2011, 01:10 PM

Thank You, George

I read what you said about turning the dist and that made me start thinking again.

I had this set static timed to the notch which is maybe 6 or 8 advanced. So I retarded it, and also pulled out every-other plug in the firing order after I oiled the cylinder walls. That got it to fire a few pops, so I then pulled those 4 plugs out and did the same to the other 4.

I kept checking comp, but it was lower than yesterday, so I kept oiling with heavier oil, heated all the plugs on the wood stove, set the choke tight closed, a little gas down the carb, and it fired! I can't believe it went from no pops yesterday, to a silky sweet hot idle.

The oil deal I learned from a young guy on hamb with a 56 Buick V8. He had to oil the cylinders every time he tried to get fire. He claimed the oil would burn off, then lose comp, then quit running. That made no sense to me, and his video made it sound like the carb was not giving enough fuel mix, so that is why I shut the choke on mine just now...and it worked. Feels like Christmas..dang..

I ran it as much as I dared with no water, hoping the heat-then-cool, might free some of the rings. We will see later today when it cools off.

10-31-2011, 12:50 PM	#2
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,527	Re: 38 Ford Low Compression Which engine are you asking about? Is the cam gear pressed on or bolted on?

10-31-2011, 01:10 PM	#3
George/Maine Senior Member Join Date: May 2010 Location: Mid coast Maine Posts: 1,878	Re: 38 Ford Low Compression Find TDC one way is pass side #1 is front and 2 and 3 pitons even from top.There is two top TDCs at different times with valves.# 1 TDC turning clockwise the crankshaft the intake will start to open.Turn one full turn thats spark time TDC 1/2 turn more and exhaust startes to open 1/2 turn more TDC again little more about 6 degs exhaust will close. Or pull the timing cover check the dots.

10-31-2011, 02:08 PM	#4
[email protected] Junior Member Join Date: Sep 2011 Location: Sacramento, ca Posts: 8	Re: 38 Ford Low Compression It is pressed on 85 hp flathead

11-01-2011, 08:32 PM	#6
38 coupe Senior Member Join Date: May 2010 Location: South Texas Posts: 1,631	Re: 38 Ford Low Compression Sponsored Links (Register now to hide all advertisements) If the cam is 180 camshaft degrees out the compression will not be affected. If the camshaft is 180 crankshaft degrees out you will have low compression.

11-01-2011, 08:50 PM	#7
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: 38 Ford Low Compression What would be the chances the cam is off 180? Wouldn't it fire anyway?

10-31-2011, 12:01 PM	#1
[email protected] Junior Member Join Date: Sep 2011 Location: Sacramento, ca Posts: 8	38 Ford Low Compression Is it possible for the camshaft to be 180 out of time and cause low compression on all cylinders (30 to 50 lbs) Dist and wireing is all right getting spark to all cylinders in the correct order at the top of the compression stroke, Getting gas but will not start, wont even pop or back fire Last edited by [email protected]; 10-31-2011 at 12:24 PM.

11-01-2011, 09:06 PM	#8
38 coupe Senior Member Join Date: May 2010 Location: South Texas Posts: 1,631	Re: 38 Ford Low Compression If the cam is 180 camshaft degrees out (installed upside down) then the spark plugs will fire at the top of the exhaust stroke, instead of at the top of the compression stroke. The quick solution for this would be to move your spark plug wires half way round on the distributor. Is this a fresh rebuilt engine that won't fire off, or an old unknown engine you are trying to bring to life, or... We need more information.

11-02-2011, 03:34 PM	#9
George/Maine Senior Member Join Date: May 2010 Location: Mid coast Maine Posts: 1,878	Re: 38 Ford Low Compression If this is a new cam, even a hot cam will have the exhaust close at TDC or few degs after.Pressing the gear on must be off mark.You can have ign timing correct.My guess the intake is half way down and not getting enought compresion and fuel.

11-02-2011, 07:17 PM	#10
Walt Dupont--Me. Senior Member Join Date: May 2010 Location: Gardiner Me. Posts: 4,200	Re: 38 Ford Low Compression i'm going to try to explain this to make it easy to understand. This is kind of hard with a press on cam gear and the engine in the car, but this has to happen. We will take any piston it don't matter witch one, but we will use no. 6 for an exsample. You've got to able to see the valves going up and down on this cyl. and tell when the piston is at TDC. We will make believe there is no timing marks on the timing gears. You will have to crank the engine, right hand rotation. Then watch the exh. valve on that cyl open and close, just before the exh. valves closes the int. valve will start to open. Now you came turn the engine back and forth and the 2 valve will rock back and forth. NOW, when they are both rocking (both valves off the seat) that piston should be on TDC. If the piston is not on TDC the the cam gear is off and the valve timing is off. That is called rocking the valve in relationship to piston TDC. NOW, that piston in on exh. stroke and the the conpanion cyl. (witch is no. 1) is on compression stroke. Every cyl. has a companion cyl. One is fireing and the other is exhausting, both pistons are at TDC. So you see, you could get the valve timing right if you didn't have any marks on the gears. Now, ain't that easy. Walt

11-03-2011, 09:12 AM	#11
F&J Junior Member Join Date: May 2010 Location: Eastern Connecticut Posts: 20	Re: 38 Ford Low Compression If this is an engine that was not running for decades, it probably has stuck rings or has light surface rust on the valves and seats. I am trying to start a 53 Olds motor in a 40 Ford right now with the same compression, and the same results...not even trying to fire on any cylinder. I've been doing stuff like this for 40+ years, and this is the only one I can't get to go. Most all that I have finally started, the heat/cool cycles will free up the rings and then it will start nice without oil smoke. I will definately rebuild this motor, but right now, I just need the car to be yard drivable while I do the body work in my only work bay. A running car is better than pushing it out when I need the bay for another job. I'll try more ideas today, and if it fails, I will tear it down.

11-03-2011, 09:40 AM	#12
George/Maine Senior Member Join Date: May 2010 Location: Mid coast Maine Posts: 1,878	Re: 38 Ford Low Compression I had a Olds 49 303 and I couldn,t get it going.Put a 12 volt coil,still wouldn,t go.Afther weeks of trying remembed the condenser maybe no good.Where up the street and friend had a Studebaker got the condenser out of it and put in Olds,started to fire afther little turn dist she fired and run.I did lap the valves so I new they were good.Years afther it sat and tryed to start it again and found the valves had rusted and stuck.I took a crow bar and under the push rods I lifted and broke all the valves free sock with oil and k1.Run good again.Those old GM car would start when cold but had hard time when hot.Good Luck with the Olds.

11-03-2011, 01:10 PM	#13
F&J Junior Member Join Date: May 2010 Location: Eastern Connecticut Posts: 20	Re: 38 Ford Low Compression Thank You, George I read what you said about turning the dist and that made me start thinking again. I had this set static timed to the notch which is maybe 6 or 8 advanced. So I retarded it, and also pulled out every-other plug in the firing order after I oiled the cylinder walls. That got it to fire a few pops, so I then pulled those 4 plugs out and did the same to the other 4. I kept checking comp, but it was lower than yesterday, so I kept oiling with heavier oil, heated all the plugs on the wood stove, set the choke tight closed, a little gas down the carb, and it fired! I can't believe it went from no pops yesterday, to a silky sweet hot idle. The oil deal I learned from a young guy on hamb with a 56 Buick V8. He had to oil the cylinders every time he tried to get fire. He claimed the oil would burn off, then lose comp, then quit running. That made no sense to me, and his video made it sound like the carb was not giving enough fuel mix, so that is why I shut the choke on mine just now...and it worked. Feels like Christmas..dang.. I ran it as much as I dared with no water, hoping the heat-then-cool, might free some of the rings. We will see later today when it cools off.