[themustangkid]

so let me preface this by saying that before i did any work to the engine, it started up in about one crank and ran beautifully with only the noise of some loose valve rockers.

so recently, i took off the valve covers and tightened them by rotating the motor until a push rod was on the bottom of the cam lobe then tightened it until the push rod didn't move anymore and just a skosh beyond until they were all tight. Then i gapped the spark plugs, i also replaced the water pump and painted the pulleys.

the first time i tried to start it, it flooded (bad float). now it just makes a weird whining noise that sounds like a starter, which works fine. the noise is metallic and has the same 'pulse' as the engine rotation. every now and again while cranking and pumping and holding the pedal in various positions, it will stumble for a few seconds but only until i let go of the key.

given this multitude of information, what do you gys think is up?
oh, and the firing order is infact correct.

 

[ieatdrt]

solid or hydraulic lifters? Sounds to me like the valves aren't shutting completely. I'll go out on a limb and say they're hydraulic. You may have one or more frozen lifters. What procedure did you use to adjust the lifters? I use the following: Rotate the engine until the exhaust valve just begins to open and adjust the intake valve. Then crank until the intake opens all the way and closes half way then adjust the exhuast valve. You can try to set them at "zero lash", instead of the 1/4 turn of preload. If it runs better at that point, it's probably one or more of the lifters giving you a hard time.

 

[themustangkid]

It does have hydraulic lifters. im not sure if you mean the same thing by adjusting lifters as you do by rockers. i just know i tightened the bolts on the top of each rocker once the cam lobe was on bottom circle for that particular valve. (if that makes sense)

also, i got it running today. it started up and i had to keep the gas at about half way just to keep it running for a while it was backfiring terribly out the carburetor, then that stopped, but it was still very rough. would you still point to the valves as the problem given this information?

Thanks so much,
-John

 

[Jonk67]

I don't have my shop manual with me to check valve lash procedure but it sounds like you may have the valves adjusted too tight. What is your timing set at once you get it running? Did you check it with a timing light? Backfiring points mostly to timing to me since you've verified correct plug wire placement.
Jon

 

[ieatdrt]

I'm sorry, you're correct I'm referring to setting the valve lash. I kept referring to adjusting the lifters. How are you verifying that you're on the base of the cam lobe? I'd almost guarantee that the lash is too tight. Your valves aren't closing all the way, that's where you're getting the backfire out the carb. Especially if you haven't done anything else, but adjust the lash.

 

[themustangkid]

my method was far from perfect. i got the push rod to a place where i thought it was on the bottom of the cam lobe then tightened it until the push rod just barely stopped moving. i went around the firing order like this several times until each rod was adjusted (or so i thought) properly. they are probably too tight. do you know of a more accurate method for making the adjustments?

 

[ieatdrt]

Loosen up the rocker arm nuts just enough so you can spin the pushrod with your fingers. Starting with the #1 cylinder rotate the engine until the exhaust valve just begins to open and adjust the intake valve, by tightening the nut until you can't spin the pushrod with your fingers anymore then 1/4 turn more. Then rotate then engine until the intake opens all the way and begins closing. Once it closes half way then adjust the exhaust valve the same way. Repeat that for all 8 cylinders and she'll be running like a top again. If you're not sure which is the intake and which is the exhaust. On the passenger side the intake is closest to the front of the car. On the drivers side the exhaust is closest to the front.

 

[themustangkid]

Thanks a bunch for all your help. ill do that today and let you know how it goes!

 

[themustangkid]

so, that didn't work out so well. it didn't start and it was farting out the rear a bunch. i found this technique around the interweb and was wondering if you or anyone else could verify it. thanks.

"The valve clearance minimum is 0.082 in (2.08mm). The maximum clearance is 0.152 in (3.86mm).Start with the #1 cylinder at top dead center, using feeler gauges, adjust to spec and then rotate the crank shaft till #2 cylinder is top dead center and adjust, repeat this process for every cylinder until you have them all adjusted. of course you need to loosen the rocker arm retaining nut to make these adjustments"

 

[Joe Bean]

Start over

That article is referring to setting valve lash clearances with a solid lifter camshaft. You don't use feeler gauges when adjusting hydraulic lifters. Hydraulic lifters run with "zero lash", plus some preloading, meaning there is never any clearance between the rocker tip and the valve tip.

If I were you I'd start all over again, but first I'd pull all your sparkplugs to make the rotation easier and begin by backing off all your valve adjustments until every rocker is loose and start over from "true TDC".

To verify true TDC, rotate your motor by hand until your timing pointer is on TDC. Since the motor rotates 360 degrees through it's firing order (4 strokes), it may either be on true TDC or "180 out". Now, go ahead and adjust both valves on No. 1, using the "finger spin and adjust" method to zero lash, then tighten them 1/2 turn (preloading) more and tighten the adjusting nuts. Next, go ahead and rotate the motor clockwise 180 degrees to where the timing pointer is at TDC again and re-check the No. 1 valve settings. If you were 180 out when you first adjusted them, they will be out of adjustment and you will know that you are now at true TDC and can now do final adjustment by loosening the adjustment nuts and readjusting both valves in that cylinder.

There are several methods of adjusting valves, but here is mine:

Now rotate the motor by hand, 1/4 turn, or 45 degrees clockwise, to the next cylinder in the firing order, which is No. 5. and go ahead and final adjust both valves.

Now go ahead thru the firing order (1-5-4-2-6-3-7-8) turning a 1/4 clockwise turn of the motor each time (I have a balancer that is marked every 45 degrees which makes that a lot easier). When you are finished going through the firing order you will be a full 360 degrees back to the No.1 starting point at true TDC for No. 1.

Here is Comp Cam's method (as ieatdirt also described):

"First turn the engine in the normal direction
of rotation. Start with cylinder number one (1). When the exhaust valve begins to move, adjust the
intake valve to zero lash plus an additional ½ turn more. Rotate the engine over again until the intake
valve reaches maximum lift and is almost all the way back down. Then set the exhaust valve to zero
lash plus ½ turn. Adjust the valves on each cylinder in this manner until all valves are adjusted."

I like my method better, as it involves less engine rotations, but with any method, your valves are now correctly adjusted. Put the plugs back in and cross your fingers. You may have bent a pushrod or damaged a lifter if they were too tight but you probably would have discovered that while going through this procedure.

Good luck!

 

[Joe Bean]

I just choked on my turkey sandwich

Hold everything Mustangkid! I just proofread my message while I was wolfing down a turkey sandwich and choked. I wasn't a math major and they didn't cover that in boot camp, so that will be my excuse, but I should have said:

" To verify true TDC, rotate your motor by hand until your timing pointer is on TDC. Since the motor rotates 720 degrees through it's cycle (4 strokes), it may either be on true TDC or "360 out". Now, go ahead and adjust both valves on No. 1, using the "finger spin and adjust" method to zero lash, then tighten them 1/2 turn (preloading) more and tighten the adjusting nuts. Next, go ahead and rotate the motor clockwise 360 degrees to where the timing pointer is at TDC again and re-check the No. 1 valve settings. If you were 360 out when you first adjusted them, they will be out of adjustment and you will know that you are now at true TDC and can now do final adjustment by loosening the adjustment nuts and readjusting both valves in that cylinder."

Also: "When you are finished going through the firing order you will be a full 720 degrees back to the No.1 starting point at true TDC for No. 1.

Now that you are totally confused, I'll get back to my sandwich.

 

[themustangkid]

so between ieatdrt's post and yours, i checked an article by crane cams that said basically the same thing as ieatdrt except for that half way intake thing, but they also added that you need to back the adjuster nuts way off and allow the lifters to return to neutral. so today my dad and i went through the firing order this way and lo and behold, when i backed te nuts out the pushrods went up about 3/8 inch before the lifters were neutral. In short, the valves were basically never closed. so im going to fire it up in the morning. if that doesnt work (god help me if i have to take it all apart again) ill do it your way.
Sorry you nearly choked because of me! :shigrin