Valve adjustment on 312

1930artdeco

1930artdeco

Well-known member
So I am going to do a compression check on my engine and thought I should make sure the valves are all correctly adjusted. After finding TDC I was following the books pattern. Got #1 done to .020 cold and moved to #5 exh. and found that I had to back the adj. nut way way off. Even then I could not get a feeler gauge under it and the valve spring would rotate a bit. I noticed that I could rotate #7 exh. a bit as well. Is that normal?

Also, Just curious as it has been awhile since I have been in the OHV world. But how far should I have to back the adj. nut off to get some movement in the rocker? I assume the nuts are supposed to be tight, I mean really tight.

Thanks,

Mike
 
You're able to easily rotate some of the valve springs? That doesn't sound right...
There should be 71-79 lbs of spring pressure holding the valves shut. ('57 shop manual pg 1-31)


Valve adjustment procedure.
Are you sure the TDC mark on the crank pulley hasn't slipped out of position?
Attached photo #1. On many Y-block pulleys the outer ring with the timing marks on it is rubber mounted and can move when the rubber layer begins to fail.

Here's a Tim McMaster valve adjustment video that's not dependent on finding TDC on the crank pulley.
As mentioned below by Crankster, with this version you can do the cylinders in numerical order, front to back, one side at a time. Not skipping back and forth from one side of the engine to the other and losing your place. CRS :o
https://www.youtube.com/watch?v=SqG-Q_kVI3s

Another of his videos, in case you prefer this method.
https://www.youtube.com/watch?v=PIB9m1Kp61o
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There's more than one way to skin a cat. It sort of sounds like you're not doing them in the correct order though, for some reason. I never really liked hop & skipping around to all the different valves/cylinders. You should be able to note whatever method you choose that whatever valve is "next in line" to be adjusted, the rocker will be slightly loose (lash); if it's under tension or has no clearance, then that particular valve is either way too tight, or it's the wrong valve being adjusted. The key takeaway when adjusting valve is that the lifter is on the base circle of that particular cam lobe.

What I do ordinarily is just bring the #1 piston to TDC on compression (both valves completely closed) and then adjust both intake and exhaust. Then 1/4 turn of the crankshaft, and do both valves on #5, and repeat this process continuing on in the Y block firing order.
 
Setting both valves at top dead center is not actually the most acurate method. Assuming you are at TDC of the power stroke, the exhaust lobe is starting to ramp up.

For the lifter to be on the very back side of the cam (base circle), crank the engine until the intake valve has just closed, at this point set the exhaust valve clearance. Crank the engine again until the exhaust valve has just begun to open and then set the intake clearance. With this method it doesn't matter what cylinder you start with or whether or not you follow the firing order
 
make sure you are adjusting the correct cyl. 1 through 4 is on the passenger side of the car, and 5 through 8 on the drivers side front to rear. alot of people get this wrong if not familiar with Fords. just trying to help, not trying to be a smart a.
 
The timing marks can slip? Is there a way to determine if it has-w/o taking the heads off? I l brought her up to TDC and then checked the #1 plug hole and saw the piston, so I am assuming she is still dead on.

The method i used was in the Ford Shop manual but now that I have watched Tim's video again, I will try his method. Since the engine is out of the car it is fairly easy. Thanks for confirming that the spring should not rotate at all. That was real head scratcher for me.

I think what I will do is back off all of the rockers so I can move the rockers by hand and then tighten them up. Do my comp. check and then pull the valves shaft off to check the bottom side for wear.

Mike
 
You can use a finger or small dowel to feel when the #1 piston stops moving at TDC, a partial turn after its intake valve closes, and the timing marks should line up.

If you can turn some of the valve springs by hand when the valves are closed the springs may have collapsed from sitting too long while compressed, or the valves may have receded into the heads. :confused:
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Lets say the timing marks have moved. Is there a way to fix the pully and move them back? Or do I just adjust for it when I time the engine.

Mike
 
1930artdeco said:
Lets say the timing marks have moved. Is there a way to fix the pully and move them back? Or do I just adjust for it when I time the engine.

Mike
Click to expand...
The crank pulleys can be rebuilt or replaced. If the ring comes off at speed it's very messy.
The quality of slightly less expensive (off shore) replacements can be questionable.
If there is a Made in the US source for new replacements it would be preferable.

For rebuilds....
https://damperdoctor.com/

https://www.damperdudes.net/harmonic-balancers/ford/
 
craig said:
Setting both valves at top dead center is not actually the most acurate method. Assuming you are at TDC of the power stroke, the exhaust lobe is starting to ramp up.
Click to expand...

I wondered about that, and while I was experimenting using different lash settings, and different methods of setting the lash, I kept that in mind.

If there is any difference in the resulting lash clearance adjusting both valves at TDC (versus "the book method", or the other EX/IN method) it is undetectable.

I like the "Walt Nuckels Y Block 1/4 turn method" for speed and ease of use. It is a lot more accurate than using a flat feeler gauge in most situations.

For accuracy and consistency though across all cylinders the P&G gapper tool is pretty slick. It makes for a noticeably smoother idle.
-----

To the OP - my Ford shop manual from '64 has a typo in the valve lash adjustment illustration, they made a mistake or transposed the cylinder order with the pic and the text iirc. Something like that.

Use a tool called a "piston stop" to precisely determine TDC. If the damper is original it is undoubtedly trashed by now.

But for valve lash adjustment, the base circle of the cam lobe is very wide, it isn't a matter of necessity to be within a gnat's *** +/- so long as you are at TDC it will be more than close enough.

I would not "loosen everything up" in your situation. You can, but it isn't necessary or helpful. If it's running now it is "close". Maybe remove the spark plugs (easier to turn engine over) and familiarize yourself with the routine.
 
I did not see this addressed previously ------ make sure you adjust the valves hot. I believe the Ford specs call for "hot" adjustment, not "cold".
 
Crankster is correct, in that several manuals have the firing order printed wrong. some have the FE firing order, not the Y-Block firing order. If the firing order is cast into the intake , use that.
 
Crankster said:
Use a tool called a "piston stop" to precisely determine TDC. If the damper is original it is undoubtedly trashed by now.
Click to expand...
Short of pulling the cylinder head and checking top-dead-center (TDC), a piston stop is the quickest and most accurate way to find TDC with an assembled engine. The problem is that piston stops, while cheap, are increasingly hard to find in-stock at a local parts store. Thankfully, piston stops are incredibly simple to make for just a few bucks.
Click to expand...
SOURCE - https://www.hotrod.com/articles/wrenchin-wednesday-build-diy-piston-stop/

And you also have to take into consideration timing chain set wear.
 
I think backing off all the valves is not the way to go. You want to see where the valves are (open or closed) so you can set them. I basically use Craig's method and it always works for me.
 
Since you say that the 5 and 7 exhaust valves were very tight and that there was very little tension on the springs, then I would say you have severely recessed valve seats. If this is what has happened then you have effectively lengthened the valve stems.
 
Was getting ready to do the valves on my '55 Vic. Craig's method appeals to me, so I'll try that approach.
 
It might not be a bad idea to mark each valve rocker with a grease pencil, indicating the lash has been adjusted on that one, if you're doing the hopping around to various valves method.

My ODC kicks in at the end, wondering if I somehow might have missed one. That's probably mainly why I do bofe cylinders at each jug and continue through firing order.
 
Well, followed Tim’s video instructions (decided I need some different feeler gauges). After I started adjusting some of the nuts they worked loose a bit. So they are all now gapped at .020.

For the comp check, I just need to get an adapter for my snap on gauge and hook up a battery. For this, I am thinking about bolting the solenoid to the block someplace, get all of the cables and a remote starter. I need to hook the battery to the block (-), (+) battery to the solenoid, cable from solenoid to starter and the remote starter to solenoid. Is this correct? Getting more excited….

Mike
 
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