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1968 Hydro Valve lifter problems

Joined
Jan 7, 2008
Messages
15
Location
Ardrossan South Australia
G'day all,

My 68 J code has just started to make a ticking noise, (intermitant), I am sure it is a crook lifter, what is the best fix, Mecahnic told me to replace lifters and camshaft, sounds a bit drastic to me as its only done about 200 miles since it started, what do you think.

Jar
 

rvrtrash

Well-known member
Joined
Apr 25, 2003
Messages
3,649
Once the lifter goes bad, you have to replace everything. If you put a new lifter on the old lobe, it'll flatten the lobe and you'll have a dead cylinder. It may last a month or a year, but it will go bad. I have heard of people putting new parts in the old lifter shell, but it's probably just a matter of time before they all start failing. Now would be a good time to think of a roller cam conversion.

Steve
 

robert campbell

Well-known member
Joined
Apr 10, 2007
Messages
4,321
Jar,
Steve is right on if you have a bad lifter or cam lobe.

Have you tried to adjust the lifters? I assume this is a 302. Does it have adjustable valve train? I quick look is do you have 5/16 diameter studs for the rocker arm adjustment or are they 3/8 diameter. If they are 5/16 diameter it is almost always a non-adjustable valve train. You can get .030 and .060 longer push rods and it may cure the valve "click". Another check is do you have "rail" type rocker arms that keep the rocker arm on top of the valve tip by a "rail" system on the end of the rocker arm? Most all of those are non-adjustable.

Answer these questions. Before you throw the baby (dollars) out with the bath!!

Rob
 

mechanicalguy48

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Joined
Dec 8, 2008
Messages
77
Location
Poulsbo Washington
Ford used an adjustable valve train up into 1969 when it went to a positive stop type rocker. In 1966 Ford went to rail rockers but still used an adjustable system although with press in studs. So if your using the stock heads and lifter types you can adjust the preload on your lifters which should be about one half to one turn. I agree its taking a chance but I have replaced bad lifters in the past and used a break in moly lube to do so. You do run the chance of flattening a lobe but its better then just replacing the entire cam and lifter set. If you go to a roller cam the block must be machined to accept the lifter hold down, and a smaller base circle cam used on the early blocks. The higher spring pressure will necessitate screw in studs and other head changes. The later model blocks are already machined for roller cams.
 

robert campbell

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Apr 10, 2007
Messages
4,321
Jar,
Mechanical guy is correct on being able to replace just one lifter. But you first need to check your adjustment. If your heads are stock and unmodified they should be the 5/16 diameter “posi lock” system with rail rockers. But many heads are modified with screw in studs and guide plates. The posi lock system is non-adjustable by turning the nut. But if you can isolate the offending rocker arm you can try the .030 longer push rod. A very cheap try. Unless the cam was poorly broken in, with 200 miles on it, it should be ok.

If you decide to go roller, a couple companies offer a “short” hydraulic roller lifter eliminating the need for drilling and tapping lock bolts for the spider to hold the lifters in place. They have interlocking “bars” between the pairs to keep the roller oriented on the cam. And allow the use of stock hydraulic rollers that are not the reduced base circle style. This opens up a huge array of choices in the hydraulic roller world for old blocks with the shorter lifter bores. Below is a link to these lifters. You will have to remove the heads to drop them in the lifter bores.

http://www.cranecams.com/?show=browseParts&lvl=3&prt=117&action=partSpec&partNumber=36532-16

Rob
 

@Holmes

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Joined
Dec 22, 2006
Messages
238
Location
McAllen, Texas
All good - but have you checked the head? You mention 200 miles so if you mean a rebuild then: remove valve covers and check the torque on the head bolts, then check lash on each rocker following the proper sequence. I say this because if the lash is lose/tight on one side you can correct the problem.
 

mechanicalguy48

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Joined
Dec 8, 2008
Messages
77
Location
Poulsbo Washington
Actually as I said the positive stop studs were not used until very late 68 and became stock on 69 and later. So if it is stock it will likely have an adjustable stud. No posi locks were ever used(stock), I believe you meant the positive stop stud. You should be able to adjust the valve train by turning the nut. If it does have positive stop studs then you wont be able to turn the nut and you can only adjust as Robert says with longer pushrods. You can look at the stud and see the difference, on positive stop studs there is a shoulder below the threads whereas the non positive stop studs the thread is larger then the diameter of the stud.
 

mechanicalguy48

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Joined
Dec 8, 2008
Messages
77
Location
Poulsbo Washington
To check your lifter preload: when using Non-Adjustable Rocker Arms
Pick a cylinder that you are going to check. Hand rotate the engine in its normal direction of rotation until both valves are closed. You are on the compression cycle for that cylinder. (At this position the valve springs are at their least amount of tension making the job a little easier to do.)

Wait a few minutes, allowing the lifters to bleed down. Now, lay a rigid straightedge across the cylinder head, supporting it on the surface of the head where the valve cover gasket would go. Using a metal scribe and the straightedge, carefully scribe a line on both pushrods. Now carefully remove the torque from all valve train bolts, removing any pressure from the pushrods. Wait a few minutes for the pushrod seat in the hydraulic lifter to move back to the neutral position. Carefully scribe a new line on both pushrods.

Measure the distance between the two scribe marks, it represents the amount of lifter preload. If the lines are .020? to .060? apart you have proper lifter preload. If the lines are the same or less than .020? apart you have no or insufficient preload. If the lines are further apart than 060? you have excessive lifter preload.
 

mechanicalguy48

Well-known member
Joined
Dec 8, 2008
Messages
77
Location
Poulsbo Washington
Here is a pic I just happen to have a 68 302 4V head, these were only made that one year so kind of rare, although they arent much different. Just the casting "4V' which you can see in the pic. Notice these heads still have the standard, non stop, press in stud. There is no large shoulder at the end of the threads and you can notice since this head has been used that only about half the thread was actually used.
heads68003.jpg
 

robert campbell

Well-known member
Joined
Apr 10, 2007
Messages
4,321
Jar,
And all those other people that are snowed in and want to adjust there lifters!!

The first thing to do is to ensure your lifters (rocker arms) are properly adjusted. You have many suggestions in this thread as how to do that if they are stock 1968 4V castings( I also have a pair) with 3/8 diameter studs that are not “posi stop” (my bad on the posi lock reference) of design. Posi stop usually is in reference to a positive lock nut for rocker arms. The easiest way to tell is by the stud diameter. This way you do not need to disassemble the rocker arms. So many things happen during production that always makes me never speak in exact dates or absolutes for running changes in design.

There are many noises that can simulate a “clicking” lifter. Fuel pumps are one area. I have an “auto” stethoscope that I use. There is always the screwdriver to the ear trick. If it is a lifter, even telling it from on bank or another is a challenge. If they are not posi stop in nature, then the best thing to do is a total readjust before you do anything.

We will assume that they are not posi stop in nature and can be adjusted by the nut in the center of the rocker arm. This is how I would do it. First open the hood and locate your top dead center (TDC) mark on the vibration damper used for timing the engine. Mark it with a nice line of white chalk. Then to the best of your ability, and it does not need to be highly accurate, put a mark directly opposite of the TDC on the damper and one half way between the bottom mark and the TDC. Sort of divide the damper up into four 15 minute marks of a clock, or every 90 degrees. Get the engine up to full operating temperature. I recommend a short drive and not just sitting in the garage. Then remove the valve covers. Get a 15/16 inch ½ drive socket and short extension to roll the motor by the vibration damper bolt in the center of the lower pulley. I personally like to remove the distributor cap, spark plug wires, and spark plugs. Makes rolling the motor very easily. Of note , notice which spark plug wire that comes from the most forward spark plug on the passenger side of the engine. This is number 1. Use the ratchet and socket to roll the motor, in a clockwise direction, as you are looking over the radiator. That is the direction the engine runs. Watch the rotor and use the distributor cap to estimate when the rotor is pointing at the number one wire on the cap. As you roll and it gets close to this location on the distributor cap look down at the damper. You will see the top dead center mark come into view and line it up with the pointer. You now have the number one piston at TDC and both its rocker arms completely lose and ready to check adjustment. The above is the only way to ensure that the rocker arms are in the full relaxed position. Do not just roll the engine and watch valves close to determine this. Many a set of lifters is misadjusted that way.

Since we think they are correct in adjustment I would be careful as I un-adjust them to check. Most hydraulic lifters are set between ¼ turn to one turn of the rocker arm nut past a term called zero lash. Before you do anything I would first grasp the end of the number one rocker arms at the valve side and see if you can gently lift them or feel play between the rocker tip and the valve stems. You can also move it side to side on the valve stem (not very much on a rail style rocker) and it should feel like it is tight to the valve stem. So if they feel tight, in a counter clockwise direction loosen both rocker arm nuts ¼ of a turn. Then repeat the above. If they were correctly adjusted somewhere between ¼ and 1 turn you should start to get play between the rocker arm tip and the valve stem. Now that they are loose, you can adjust them. The push rods should rotate very freely if you grasp them and spin them in your fingers. Now start in to discover zero lash for each rocker arm. I like to just nudge the rocker arms say a 1/16 of a turn clockwise in. Then spin the push rod. If it still fells loose you have play. Nudge the rocker arm again and when the pushrod starts to spin much harder, you have it very close to zero. Back off and go in a couple times and get the feel. After a couple times you will find this point of zero lash easily. For stock hydraulic lifters I then slowly turn the rocker arm ½ turn in to load them. ¼ turn for anti-pump up higher performance lifters. This has worked well for me over the years.

Ok, now number one is done! Grab the ratchet and roll the motor 90 degrees to the next chalk mark on the damper. Number 5 is now at top dead center. The spark plugs are 1 to 4 starting at the front of the passenger side and 5 to 8 from front to back on the driver side. So go to the front two rocker arms on the driver’s side and repeat above. The firing order is 15426378. When you are done, you will have rolled the engine two times and the TDC mark will come up if you roll 90 degrees more after you adjust the number 8 rocker arms. The rotor should be pointing at the number one wire on the distributor gap. Do not follow some of those “motors” manuals procedures that talk about adjusting multiple rocker arms at various positions on the crank. It assumes a stock camshaft and the above method is fool proof. There is an engine running procedure with a valve cover with the top cut out. It can be very messy, and if you are not careful you can hurt parts by turning tightening the rocker arm nut to quickly.

Put the valve covers back on and reinstall the cap, wires and spark plugs. Do this before you spend any money.

If you do have posi stop rocker arms, you can roll the engine through the firing order as above and see if any feel lose. If you find one, a longer push rod may fix your clicking.

Rob
 
OP
OP
A
Joined
Jan 7, 2008
Messages
15
Location
Ardrossan South Australia
Thanks Rob,

Ill give it a try in the next few days when it cools down a bit, we are in the middle of a heat wave here in south OZ past 5 days have been over 44 C (110 to 120 F)
will advise when done

Jar
 
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