valvetrain troubles

69mach351 · 04-13-2002, 07:14 PM

Hello, I have had trouble starting my engine. I did a compression test and cylinders 1,2, and 7 did not have any compression at all. I even put my hand on the plug holes of those cylinders and there was no sucking or blowing. The engine ran when I bought the car. After a few weeks a pushrod broke so I put new pushrods,lifters and roller rockers, and replaced the intake valve on cylinder 1 because the top of the valve was rounded. Perhaps this has something to do with this problem. ( Whatever caused the pushrod to break caused the piston or cam to break or vise versa??)I don't have experience with this kind of stuff. When I started the engine up it idled at 1500 RPM, which sounds way too high. Soon after this I could not start it again. I am about to check the head gaskets, and the head for cracks. I don't know if a brocken head gasket or cracked head would effect only three pistons ( one on driver side, two on passenger side of engine). I am positive that I did the valve clearance correct ( positive stop valves= tighten down 1 to 1.8 turn). All of the valves go up and down when I crank the engine over. There are no stuck valves. The problem is likely to be in the lifters since I am not sure how to put them in. I assumed that I just had to drop them in. If anyone knows otherwise please tell me. If I can't find anything in the valvetrain I will take out the pistons. However I did put oil on the piston before I did compression to see if it could be the rings. Again I got no compression. If this problem sounds familiar to anyone I would appreciate any help anyone can give. Thank you.

Gearhead999 · 04-14-2002, 03:44 PM

OK, I'll be the first to ask......how did you adjust the valves????

You should make sure the valve is closed and on the base. Then tighten the rocker till the pushrod won't turn and turn it in 1/2 turn. Then move on to the next valve.

When you changed the valve, did you grind the seat and all????? Or did you just throw a valve in the head????

Need alot more info to help...

69mach351 · 04-14-2002, 05:46 PM

To adjust the valves I made CERTAIN that every cylinder was at TDC of firing position, then I turned it 3/4 a turn after slack was taken up on pushrod. I am still convinced that the problem lies in the valve adjustment. I will try it with 1/2 a turn instead of 3/4 to see if that changed anything. In the last message I posted that I had positive stop valve train, I was wrong. I have the fully adjustable hydraulic valve train.
When I replaced the intake valve on #1 I just threw a new one in there. It is not only the #1 piston that has no compression though.
Thank you for your reply Dave, I do not have much experience with cars so I appreciate any help I can get.
I'll do the valves 1/2 turn and post the results.

Gearhead999 · 04-14-2002, 06:25 PM

You might want to try just stopping when there is zero clearance in the valve adjustment. Then readjust after you get it running.

69mach351 · 04-15-2002, 04:31 PM

I have not yet figured out this valve adjustment thing. I adjusted them all 1/2 turn when the rocker arm began touching the valve, then I got compression in all 8 cylinders. However when I took off the valve cover I noticed that the rocker arms would jiggle a little. I turned them so that there was enough friction so that they were not loose. I guess this means that I did not adjust them exactly at TDC of firing stroke. Again Dave thanks for the advice. When you say to adjust the rocker after I run the engine. Do I have to find TDC on firing stroke to do this? Or just tighten it a half turn or so?
I have had this 69 Mach 1 for a year and have barely drove it. I restored the interior and engine compartment, and put a lot of money into the car (over 5,000). Once I fix this problem I will be finished and ready to hammer down.

6t6stang · 04-16-2002, 03:53 PM

They may be adjusted properly already but you will not know until your lifters are pumped up.

Mine were a little loose until I started it up and got the lifters pumped up.

If you already tried this excuse me, I did not totally read thru

04-14-2002, 03:44 PM	#2
Gearhead999 Registered Member Join Date: Sep 1998 Location: Oviedo, FL Posts: 992	OK, I'll be the first to ask......how did you adjust the valves???? You should make sure the valve is closed and on the base. Then tighten the rocker till the pushrod won't turn and turn it in 1/2 turn. Then move on to the next valve. When you changed the valve, did you grind the seat and all????? Or did you just throw a valve in the head???? Need alot more info to help... __________________ "Support our Troops" Dave 1968 Cougar 2004 Thunderbird 2007 F150 Harley-Davidson, SuperCrew 1986 LTD 1997 Ranger 1992 Honda Civic

04-14-2002, 06:25 PM	#4
Gearhead999 Registered Member Join Date: Sep 1998 Location: Oviedo, FL Posts: 992	You might want to try just stopping when there is zero clearance in the valve adjustment. Then readjust after you get it running. __________________ "Support our Troops" Dave 1968 Cougar 2004 Thunderbird 2007 F150 Harley-Davidson, SuperCrew 1986 LTD 1997 Ranger 1992 Honda Civic

04-16-2002, 03:53 PM	#6
6t6stang Registered Member Join Date: Feb 2002 Location: Ct Posts: 8	Valve Adjustment They may be adjusted properly already but you will not know until your lifters are pumped up. Mine were a little loose until I started it up and got the lifters pumped up. If you already tried this excuse me, I did not totally read thru

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04-13-2002, 07:14 PM	#1
69mach351 Registered Member Join Date: Jan 2002 Location: California- Hollister Posts: 14	valvetrain troubles Hello, I have had trouble starting my engine. I did a compression test and cylinders 1,2, and 7 did not have any compression at all. I even put my hand on the plug holes of those cylinders and there was no sucking or blowing. The engine ran when I bought the car. After a few weeks a pushrod broke so I put new pushrods,lifters and roller rockers, and replaced the intake valve on cylinder 1 because the top of the valve was rounded. Perhaps this has something to do with this problem. ( Whatever caused the pushrod to break caused the piston or cam to break or vise versa??)I don't have experience with this kind of stuff. When I started the engine up it idled at 1500 RPM, which sounds way too high. Soon after this I could not start it again. I am about to check the head gaskets, and the head for cracks. I don't know if a brocken head gasket or cracked head would effect only three pistons ( one on driver side, two on passenger side of engine). I am positive that I did the valve clearance correct ( positive stop valves= tighten down 1 to 1.8 turn). All of the valves go up and down when I crank the engine over. There are no stuck valves. The problem is likely to be in the lifters since I am not sure how to put them in. I assumed that I just had to drop them in. If anyone knows otherwise please tell me. If I can't find anything in the valvetrain I will take out the pistons. However I did put oil on the piston before I did compression to see if it could be the rings. Again I got no compression. If this problem sounds familiar to anyone I would appreciate any help anyone can give. Thank you.

04-14-2002, 05:46 PM	#3
69mach351 Registered Member Join Date: Jan 2002 Location: California- Hollister Posts: 14	To adjust the valves I made CERTAIN that every cylinder was at TDC of firing position, then I turned it 3/4 a turn after slack was taken up on pushrod. I am still convinced that the problem lies in the valve adjustment. I will try it with 1/2 a turn instead of 3/4 to see if that changed anything. In the last message I posted that I had positive stop valve train, I was wrong. I have the fully adjustable hydraulic valve train. When I replaced the intake valve on #1 I just threw a new one in there. It is not only the #1 piston that has no compression though. Thank you for your reply Dave, I do not have much experience with cars so I appreciate any help I can get. I'll do the valves 1/2 turn and post the results.

04-15-2002, 04:31 PM	#5
69mach351 Registered Member Join Date: Jan 2002 Location: California- Hollister Posts: 14	I have not yet figured out this valve adjustment thing. I adjusted them all 1/2 turn when the rocker arm began touching the valve, then I got compression in all 8 cylinders. However when I took off the valve cover I noticed that the rocker arms would jiggle a little. I turned them so that there was enough friction so that they were not loose. I guess this means that I did not adjust them exactly at TDC of firing stroke. Again Dave thanks for the advice. When you say to adjust the rocker after I run the engine. Do I have to find TDC on firing stroke to do this? Or just tighten it a half turn or so? I have had this 69 Mach 1 for a year and have barely drove it. I restored the interior and engine compartment, and put a lot of money into the car (over 5,000). Once I fix this problem I will be finished and ready to hammer down.