Vintage Mustang Forums banner
  • Hey everyone! Enter your ride HERE to be a part MAY's Ride of the Month Challenge!

1 - 8 of 8 Posts

·
Registered
Joined
·
674 Posts
Discussion Starter · #1 ·
5.0 standard bore, B303 cam, roller rockers on Flo Tek aluminum heads-

I haven't got the valves adjusted correctly, here's how I did it;

1st start up of newly rebuilt 5.0 and a mechanic friend said it sounds like some valves are too tight and some too loose. This friend has been a mechanic for over 50 years. So I loosened all nuts til I could spin the pushrods by hand. Then turned motor over by hand until I saw one valve (intake or exhaust) raise to top of its travel then I got the valve next to it to zero lash- then I tightened that nut 1/2 turn. Then tightened the allen set screw and repeated the process 15 more times going to the next cylinder in firing order turning engine over by hand. Flo Tek told me to tighten the nut 1/2 turn beyond zero lash.

After done the engine won't even start.

Does it matter where you start in the process ? Should I have started at cylinder #1 with it at TDC ?

Saw a video in Youtube where they started on cylinder #1 with it at TDC- got both its valves to zero lash then tightened the nuts 1 full turn then tightened the allen set screw. Then they rotated the engine by hand 90 degrees and did same to next cylinder in firing order. Much quicker method doing both valves of each cylinder rather than 1 at a time as I did.

Somebody please clue me in. Thanks-
Aaron29
 

·
Registered
Joined
·
254 Posts
5.0 standard bore, B303 cam, roller rockers on Flo Tek aluminum heads-

I haven't got the valves adjusted correctly, here's how I did it;

1st start up of newly rebuilt 5.0 and a mechanic friend said it sounds like some valves are too tight and some too loose. This friend has been a mechanic for over 50 years. So I loosened all nuts til I could spin the pushrods by hand. Then turned motor over by hand until I saw one valve (intake or exhaust) raise to top of its travel then I got the valve next to it to zero lash- then I tightened that nut 1/2 turn. Then tightened the allen set screw and repeated the process 15 more times going to the next cylinder in firing order turning engine over by hand. Flo Tek told me to tighten the nut 1/2 turn beyond zero lash.

After done the engine won't even start.

Does it matter where you start in the process ? Should I have started at cylinder #1 with it at TDC ?

Saw a video in Youtube where they started on cylinder #1 with it at TDC- got both its valves to zero lash then tightened the nuts 1 full turn then tightened the allen set screw. Then they rotated the engine by hand 90 degrees and did same to next cylinder in firing order. Much quicker method doing both valves of each cylinder rather than 1 at a time as I did.

Somebody please clue me in. Thanks-
Aaron29
Your youtube method is how I do them. I also pull the plugs and verify with a screwdriver in the plug hold to confirm TDC. Start at number 1 and roll right through the firing order turning 90 degrees at a time.
 

·
Registered
Joined
·
1,113 Posts
Assuming your lifters are hydraulic, then the method is to go to TDC on a cylinder (top of compression stroke, both valves closed), tighten nuts to take up slack in push rod (not by spinning the rod but until the rod will not move up and down). Then 1/2 to 3/4 more turn. Then rotate 90 crank degrees and do the cylinders in firing order. Like the you tube was telling you more or less.
 

·
Registered
Joined
·
5,116 Posts
I am with Tallguy. If you crank them down until they do not spin, then you have them too tight. Just remove the up/down play then 1/2 to 3/4 turn.

BTW, for hydraulic lifters the term "pre-load" seems to be more accurate. "Lash" is for solid lifters.
 
  • Like
Reactions: aaron29

·
Registered
1967 Mustang Convertible
Joined
·
1,123 Posts
I assume you are setting the 5.0 firing order, 1-3-7-2-6-5-4-8, not your stock 302 from 65 firing order? And the Distributor goes counter clockwise. Just verifying, because that will cause it not to run also.
 

·
Registered
Joined
·
674 Posts
Discussion Starter · #6 ·
Update, yep I confirmed the firing order is correct for an HO motor. Adjusted valves again using the TDC method- it started and sounds like its close to being right but not quite. My mechanic friend said the valves sound noisy like some are loose now. He suggested I take the covers off and tighten each nut 1/4 turn then start it again.

I may just need to start completely over since I was tightening the nut until I couldn't spin the pushrod- wasn't checking its up-down movement at all.

Really appreciate all the replies/help.

-Ryan22
 

·
Registered
Joined
·
36,567 Posts
… So I loosened all nuts til I could spin the pushrods by hand. Then turned motor over by hand until I saw one valve (intake or exhaust) raise to top of its travel then I got the valve next to it to zero lash- then I tightened that nut 1/2 turn. Then tightened the allen set screw and repeated the process 15 more times going to the next cylinder in firing order turning engine over by hand. Flo Tek told me to tighten the nut 1/2 turn beyond zero lash.

After done the engine won't even start.

Does it matter where you start in the process ? Should I have started at cylinder #1 with it at TDC ?
The 1/2 turn should be based on the recommendation of the cam manufacturer (Ford and most makers recommend 3/4) but the 1/2 should work.

Depends on how you determined zero lash. If you did it by spinning the pushrods, that's likely the problem. It doesn't matter where you start, I start with #1 because I'm easily confused.

<style> <!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:3 0 0 0 1 0;} @font-face {font-family:Cambria; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-536870145 1073743103 0 0 415 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; mso-bidi-font-size:10.0pt; font-family:"Cambria",serif; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Cambria; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt; font-family:"Cambria",serif; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Cambria; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} @Page WordSection1 {size:8.5in 11.0in; margin:1.0in 1.25in 1.0in 1.25in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.WordSection1 {page:WordSection1;} --> </style> Adjust hydraulic valves with the engine cold.

Do this, and it will run smoothly, and likely with more power:


Disconnect the coil + wire.

Attach a bump switch to the solenoid, or just use a screwdriver.

Turn the engine so the #1 intake valve is fully opened. Loosen the exhaust valve until you can move the #1 exhaust valve pushrod up and down (NOT spinning).
Tighten this valve until no up and down movement can be felt, then tighten an additional 3/4 turn.


Note: Spinning the pushrod can cause a false adjustment, as a slowly collapsing lifter can allow the pushrod to spin freely, thus throwing off the base line of your adjustment.

Turn the engine so the #1 exhaust valve is fully opened. Loosen the intake valve until you can move the #1 intake valve pushrod up and down (again, NOT spinning).
Tighten this valve until no up and down movement can be felt, then tighten an additional 3/4 turn.

Repeat for the other 7 cylinders.

I did this on a friend’s engine that had been adjusted when built, then driven for several years. It was running OK, but not great, you could hear some valve noise. After doing the above, it did not seem to be much better immediately after adjustment, mostly because the lifters had been varnished into position by years of driving. Coupla miles around the block, though, and it was a whole 'nother engine.


Adjusting mechanical valves.

I drove a 289HP daily for 20 years, and every 6000 miles I adjusted the valves, which took less than an hour.

Adjusted properly, they aren't noisy, either, just a high-pitched singing sound.

Factory spec for the 289HP C3OZ-6250-C cam is .022" cold, .018" hot.

The procedure in the Manual is a bit complicated, and involves marking the balancer at 90° points, and then you follow some weird pattern, like I1, E4, I6, E2, or some complex crap. Takes an hour just to figure out what they want you to do.

Do this instead-

Run the engine until it is a full operating temperature <style> <!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:3 0 0 0 1 0;} @font-face {font-family:Cambria; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-536870145 1073743103 0 0 415 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0in; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; mso-bidi-font-size:10.0pt; font-family:"Cambria",serif; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Cambria; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt; font-family:"Cambria",serif; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:Cambria; mso-fareast-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} @Page WordSection1 {size:8.5in 11.0in; margin:1.0in 1.0in 1.0in 1.0in; mso-header-margin:.5in; mso-footer-margin:.5in; mso-paper-source:0;} div.WordSection1 {page:WordSection1;} --> </style> , and remove one valve cover. Disconnect the coil + wire.

Attach a bump switch to the solenoid, or just use a screwdriver.

Bump the starter until the second valve on the #1 cylinder is all the way open. This means the one closest to the radiator is closed, on the base circle of the cam lobe. Adjust the valve to .018".

Bump the starter until that valve is fully open, and adjust the second valve.

Continue to adjust the valves in pairs until the RH head is adjusted, and install the valve cover.

Repeat the process on the LH side of the engine. I like to start and run the engine to be sure it is still fully warmed up.

Remove the LH valve cover, and adjust the LH valves to .018".

Very quick, and very accurate.

If the engine has just been assembled, do the procedure cold, at .022”. Then warm up the engine and do it hot.
 
  • Like
Reactions: aaron29
1 - 8 of 8 Posts
Top