Mercury Cougar Owners banner

1 - 20 of 37 Posts

·
Registered
Joined
·
380 Posts
Discussion Starter #1
did a valve job on the 351W. vacuum is back up where it should be but there is an annoying miss and the compression check is suspicious - 75 to 95.

could be a bad valve job, or maybe the shop missed something putting it all back together. is there anything that needs to be done to set the correct valve lash initially, or do the hydraulic lifters take care of everything?
 

·
Registered
Joined
·
913 Posts
Pull plug, squirt some oil in that cylinder and see if comp. comes up, if it doesn't you have a valve problem. The valve adjustment on a 351W is just screw the rocker bolt down till it is tight (positive stop method).
 

·
Premium Member
Joined
·
413 Posts
If the valves are too tight, it can cause low compression.

I found the easiest to adjust my valves is with the engine running. I slowly loosen the rocker adjustment nut until the valve starts to click, then I tighten them up 3/4 of a turn. To keep the oil from getting everywhere, I took an old valve cover and cut out a couple of windows in it just big enough to access the adjustment nuts.

Here's a video: http://www.youtube.com/watch?v=8nFKom6SMd4
 

·
Registered
Joined
·
380 Posts
Discussion Starter #4
If the valves are too tight, it can cause low compression.

I found the easiest to adjust my valves is with the engine running. I slowly loosen the rocker adjustment nut until the valve starts to click, then I tighten them up 3/4 of a turn. To keep the oil from getting everywhere, I took an old valve cover and cut out a couple of windows in it just big enough to access the adjustment nuts.

Here's a video: http://www.youtube.com/watch?v=8nFKom6SMd4
nice video Adam. i'm assuming those are hydraulic valve lifters like on my 351W? how did you eliminate the oil in the video?
 

·
Registered
Joined
·
380 Posts
Discussion Starter #5
nice video Adam. i'm assuming those are hydraulic valve lifters like on my 351W? how did you eliminate the oil in the video?
sorry, i see it now. i was looking for little windows for the socket wrench, but basically you cut away the entire top of the valve cover so only the fender well wall side remained.
 

·
Registered
Joined
·
380 Posts
Discussion Starter #6
i should have titled this "hydraulic lifter valve adjustment", since mechanical tappets are different. anyway, the shop manual tells how to do it. it tells which valves to "adjust" (torque 18-20 ft lbs after nut contacts shoulder) when the crankshaft is in a particular position. position A is easy enough - TDC, 0 degrees on the timing mark. position B is 180 degrees from that, and position C is 270 degrees from position B.

the question is, how does one find and mark B and C as accurately as possible? seems like if you're gonna' do it, might as well be as accurate as position A is.
 

·
Registered
Joined
·
97 Posts
I had good luck taping a band of paper around the balancer, marked the right length, removed the strip & measured the length to figure the 1/4 - 1/2 & 3/4 points and then, by rewraping the paper around the balancer, was able to transfer those points to the balancer.
 

·
Registered
Joined
·
304 Posts
I thought 351 W were not adjustable unless you convert your valve train to adjustable like i did. You should just torque the rocker nuts and you are done.
 

·
Registered
Joined
·
380 Posts
Discussion Starter #9
I thought 351 W were not adjustable unless you convert your valve train to adjustable like i did. You should just torque the rocker nuts and you are done.
i thought the same thing. but that is not what the shop manual says. it says "the positive stop rocker arm stud eliminates the necessity of adjusting the valve clearance. However, to obtain the specified valve lash, it is important that all valve components be in a serviceable condition and installed and torqued properly". it then goes on to tell you which valves can be torqued when the crank is in position A, B and C. i don't know if it will make a difference, but i should have more than 95 psi compression after a valve job.

old man - cool idea with the paper on the balancer

billy
 

·
Registered
Joined
·
1,126 Posts
Here is how a Pro-Stock driver/engine builder taught me to adjust SOLIDS years ago.

* WHEN THE EXHAUST VALVE STARTS TO OPEN, ADJUST THE INTAKE FOR THAT CYLINDER.

* WHEN THE INTAKE STARTS TO CLOSE, ADJUST THE EXHAUST FOR THAT CYLINDER.

Works for me.

Dale in Indy
 

·
Registered
Joined
·
380 Posts
Discussion Starter #11
Here is how a Pro-Stock driver/engine builder taught me to adjust SOLIDS years ago.

* WHEN THE EXHAUST VALVE STARTS TO OPEN, ADJUST THE INTAKE FOR THAT CYLINDER.

* WHEN THE INTAKE STARTS TO CLOSE, ADJUST THE EXHAUST FOR THAT CYLINDER.

Works for me.

Dale in Indy
i'm guessing you get the same results torquing the valves when the crank is in position A, B and C? if so, it seems much more precise using these positions than just your eyeball to determine when the exhaust valve starts to open or the intake starts to close. another advantage would be getting all the valves done from just three positions of the crank. 'course, if anything else is off in the train, then A, B and C will be off as well. i would tend to go with the shop manual first. if that doesn't produce decent results, then i would try Dale's old school approach.
 

·
Registered
Joined
·
1,126 Posts
REMEMBER, I AM TALKING, SOLID LIFTER ADJUSTMENT.

All I can say is when the the rocker starts to move as my instructions state you have put the assembly in position to adjust, and when I questioned Steve on such, his answer was IT WORKS, AND SPEEDS UP THE ADJUSTMENT PROCESS. It is very fast.

I can't tell you how many times I have done it this way, it's MANY......

Dale in Indy
 

·
Registered
Joined
·
380 Posts
Discussion Starter #13
REMEMBER, I AM TALKING, SOLID LIFTER ADJUSTMENT.

All I can say is when the the rocker starts to move as my instructions state you have put the assembly in position to adjust, and when I questioned Steve on such, his answer was IT WORKS, AND SPEEDS UP THE ADJUSTMENT PROCESS. It is very fast.

I can't tell you how many times I have done it this way, it's MANY......

Dale in Indy
i guess i don't know all the lingo Dale. is a "solid lifter" a hydraulic lifter? or is a "solid lifter" a "mechanical lifter"? the procedures to set valve lash for each is different in the shop manual.

also, how do you rotate the crank such minute amounts to see the beginning of an opening or closing? do you use a remote starter to rotate the crank?
 

·
Registered
Joined
·
380 Posts
Discussion Starter #14
i guess i don't know all the lingo Dale. is a "solid lifter" a hydraulic lifter? or is a "solid lifter" a "mechanical lifter"? the procedures to set valve lash for each is different in the shop manual.

also, how do you rotate the crank such minute amounts to see the beginning of an opening or closing? do you use a remote starter to rotate the crank?
think i figured it out. solid cams and lifters are different from hydraulic cams and lifters. so, anyone out there know about adjusting the valve lash for hydraulic lifters?
 

·
Premium Member
Joined
·
413 Posts
Solid lifters and mechanical lifters are the same thing. You don't set the lash for hydraulic lifters, you set the preload (just more jargon).

Sorry if my post was confusing. The video wasn't mine. It was just something I found on you tube one day. That guy in the video was adjusting hydraulic lifters.

As for the valve cover I cut up, I took a one inch wide strip out of the top of an old valve cover to expose the adjustment nuts. When I get home, I'll take a picture for you. I'm currently away on "business".
 

·
Registered
Joined
·
380 Posts
Discussion Starter #16
Solid lifters and mechanical lifters are the same thing. You don't set the lash for hydraulic lifters, you set the preload (just more jargon).

Sorry if my post was confusing. The video wasn't mine. It was just something I found on you tube one day. That guy in the video was adjusting hydraulic lifters.

As for the valve cover I cut up, I took a one inch wide strip out of the top of an old valve cover to expose the adjustment nuts. When I get home, I'll take a picture for you. I'm currently away on "business".
thanks Adam. that is more jargon. the shop manual doesn't talk about "pre-load", but it does mention "valve lash" for hydraulic lifters. regardless of what you call it, has anyone done it per the shop manual? how important is it to "obtain the specified valve lash"?

the last engine i installed was a long block, so i don't know what the manufacturer did with the heads. but i'm pretty sure i didn't set the valve lash per the manual. could be wrong though - it was twenty years ago!

do you think what they guy is doing in the youtube video is basically the same as the shop manual procedure? i mean, do they both accomplish the same thing?
 

·
Premium Member
Joined
·
413 Posts
Yes, you accomplish the same thing with hydraulic lifters. Don't try to do it this way with solid lifters. If you do it by the shop manual, you have to worry about whether the lifters have been bled down. In my experience, you can get inconsistent results. It isn't so easy to find the point where you have exactly zero lash. Solid lifters don't have this problem. Also, if doing it with the engine running, it is also a lot faster.

I adjusted my valves per the shop manual instructions after I finished building my engine. When I went to start it up, it back fired through the carb. The valves were way too tight. I loosened them enough to get it running then I adjusted them as I described before. My Dad (hot rodder in his day) told me about this trick and it worked like a charm. I told my boss at the performance shop where I was working at the time. He did it on a Mustang that was giving him problems and worked right away.

You can buy clips to put on your rocker arms to deflect the oil if you don't have a valve cover to cut up. I don't know how well they work. I've never used them.
http://www.summitracing.com/search/Part-Type/Valvetrain-Oil-Deflectors/
 

·
Registered
Joined
·
913 Posts
Pull plug, squirt some oil in that cylinder and see if comp. comes up, if it doesn't you have a valve

problem. The valve adjustment on a 351W is just screw the rocker bolt down till it is tight (positive stop method).
You guys don't understand! The 289's and 302's have a different adjustment than the 351W. The 351W is a positive stop, which means, you screw the nut down till it reaches the stop, and torque to whatever is specified.
 

·
Premium Member
Joined
·
413 Posts
Towcat, you are absolutely correct. Unfortunately, positive stop only works well when everything is stock and new. If the heads or block have been decked, your valves could be too tight. You will need to find the correct length pushrods.

wbferran, do you know the engine history. Is everything that matters here original and stock?
 

·
Registered
Joined
·
5,279 Posts
You guys don't understand! The 289's and 302's have a different adjustment than the 351W. The 351W is a positive stop, which means, you screw the nut down till it reaches the stop, and torque to whatever is specified.
All Ford hyd. tappet engines had positive stop from 1969 on.
 
1 - 20 of 37 Posts
Top