346 engine tick (next steps..)

[Bobby B]

The 3" check gauge is just a check.  The actual clearance required is 0.030 to 0.070.  Most likely you are fine.  To check the clearance you have to get the oil out of the lifter.

Brad, Hi...If we're talking about the same thing, the 3" distance is measured from the heel of the cam lobe to the valve stem tip, which can only be measured with the lifter blocks out, and only corrected with a Valve job or grinding of each individual valve stem tip, IF you were lucky enough that the clearance is less than 3'', which would be in your favor of stem tip grinding only.  Isn't the clearance that you're referring to the lifter's actual limits of travel? So if the 3" clearance is beyond those limits from the start, the lifter travel cannot compensate and that's possibly one issue that could cause some problems.  Am I missing something? I made sure that my 3" measurement was dead on, along with dis-assembling, cleaning, and checking every lifter. My Flathead sounds like a sewing machine. You can Barely hear it running......
                   Bobby

[Tom Beaver]

Bobby, the 3" clearance check is valid only if you have new cam follower and hydraulic lifter assemblies, if they are used (worn) or refurbished (reground) then setting the clearance to 3 inches may be in error.  The Cadillac service manual says to measure and set the lifter to valve stem clearance to the values that Brad provided. 

Tom Beaver

[Brad Ipsen CLC #737]

Not sure why Cadillac doesn't state that there is a tolerance on the 3" tool.  The tolerance is the range that the lifter is able to accommodate.  I'm sure the actual amount it can accommodate is actually more the what's stated also.  Good engineering would always allow for a little more.  This all is implied in the 1940 shop manual twice.  Once in paragraph 15 in the Engine section and again in 16.4.  The first reference states: "If Tool J-1055 is not available, it will be necessary to install valves, valve springs and lifters and check clearance between stems and lifters, which should be .030-.070 inch."  My reason for commenting is to make sure the original poster does not do any extra work that is not needed.  In fact he could have checked the clearance with the lifters in place although that may have been really difficult because of oil in the lifters.   

[Bobby B]

Bobby, the 3" clearance check is valid only if you have new cam follower and hydraulic lifter assemblies, if they are used (worn) or refurbished (reground) then setting the clearance to 3 inches may be in error.  The Cadillac service manual says to measure and set the lifter to valve stem clearance to the values that Brad provided. 

Tom,
Hi. I'm not following your theory on this. I checked my original Cam on "V" blocks which luckily turned out to be in great shape, so I opted to use the cam rather than a New China made one, have mine re-ground and/or sprayed, or paying big bucks to have one cut from a billet. Now....I had brand new guides, springs, oil seals, and Valves installed along with the valves seats cut. Now that that work was finished and the valves ready to be installed, I used the tried and true method of the 3" clearance (using a micrometer standard) between the Heel of the Cam Lobe and the Brand New Valve Stem Tip. Tedious yes, but worth it. With all that new work being done, wouldn't you agree that the 3" clearance is what you're shooting for if the lifters all check out after being dis-assembled, checked, and re-installed on their original lobes following the same wear pattern as before? My engine is as quiet as a Brand New Honda, so I must've done something right. Idling at 375 rpm you could put a glass of water on the air cleaner without a drop spilled.....
                                    Bobby

[79 Eldorado]

I don't know this particular engine but if it's impossible to adjust without removing the head and if there's a little too much clearance, and especially on only a single valve, couldn't you get an adjustable pushrod, determine the proper length to achieve the proper lifter pre-load, and then order a custom pushrod in the length to have the proper pre-load? On an adjustable set-up you would normally tighten down until you can tell the preload is proper by spinning the pushrod in your fingers. It seems like the same check could be done here with pushrod length change until it was correct. Everything posted seems to say that would work here as well.

Obviously you need to make certain the rocker tip maintains the proper geometry with the valve stem end but the tick is likely a matter of no more than 0.010 to 0.020" I suspect.

One other thing which I don't think anyone mentioned was a small exhaust leak can often sound like a valve train tick.

I did read through the entire thread but most of it was around a week ago so my apologies if I missed something by memory.

Scott

[The Tassie Devil(le)]

The 346 a Side Valve engine, so no pushrods.

Bruce.

[79 Eldorado]

The 346 a Side Valve engine, so no pushrods.

Bruce.

Aha! Thanks Bruce

[LaSalle5019]

As Brad mentions, the 3.00" dimension is a quick and dirty check on new parts and will get you pretty close.  It is best to set the valve length to the center of lifter travel, just like all the other hydraulic lifter engines. Just takes some time to measure dimensions with each lifter at full travel and fully collapsed. As long as you are somewhere in the travel zone you should be good unless you are right on the end, either way,

[Tom Beaver]

Bobby, my comment concerned the resurfacing of the cam followers or I think Cadillac refers to them as the valve lifter bodies.  I have had all of mine resurfaced, and in doing so, changed the overall valve lifter dimensions so that the 3 inch clearance check is no longer valid.

Tom Beaver

[Bobby B]

Bobby, my comment concerned the resurfacing of the cam followers or I think Cadillac refers to them as the valve lifter bodies.  I have had all of mine resurfaced, and in doing so, changed the overall valve lifter dimensions so that the 3 inch clearance check is no longer valid.

Tom,
Hi, If you resurfaced the lifter bases, it shouldn't change the travel limit of a lifter. By removing metal from your lifter bases, you just shifted your parameters of your lifter travel limit. If your valves were pocketed a bit from wear, you might get lucky, but I would think that the only way to compensate would be through the valves stems being longer, by X amount removed from the lifter base. I guess in your situation the 3" clearance really goes out the window, and you would need to check it in situ....
                                                                    Bobby

[Tom Beaver]

Bobby, what I did was use 38 - 40 lifter bodies which have a deeper recess for the valve plungers and then I used new or late model 41 - 47 lifter plungers which have a shorter upper section.  This makes sure that when the two are assembled there is plenty of clearance between the top of the valve plunger and the valve stem.  Then I place the assemblies in the lifter blocks and at each valve I measure the clearance between each lifter plunger and the valve stem and record the numbers.  I then machine a piece of shim stock (tubing) that has an OD the size of the upper part of the lifter plungers and an ID that is equal to the OD of the lower section of the lifter plungers minus enough for a press fit.  I then cut pieces off this tubing to shim the length of each lifter plunger.  The length of each shim is calculated from my clearance measurements to make the clearance between the lifter plunger and valve stem equal 0.050".  This places the lifter plunger in the middle of specified clearance range 0f 0.030" to 0.070".  I don't have to do any grinding of the valve seats nor of the valve stems to adjust the valves, you can do it with the heads on.  This may sound complicated but it's fairly simple, it just takes time to take the lifter blocks in and out, position the camshaft and make the clearance measurements.  It's certainly much easier with the engine out where you can work on it.

Tom Beaver

[wheikkila]

I'm going to ask a question here. I'm in the process of rebuilding my 1940 331. I have purchased a new cam, lifters, springs, valves. When I get the block back. I plan on measuring the 3 inch distance like the Manuel says. I'm I wrong?
Thanks Wayne   

[Brad Ipsen CLC #737]

No you are not wrong but the 3 inch dimension is based on the cam and lifters being dimensioned exactly like Cadillac  designed them in 1940.  If you understand where this dimension comes from then you can correct for any deviations in your new parts from Cadillac originals. Hydraulic lifters take up the slack in the valve train with a column of oil between a plunger and a cylinder.  In the case of the flathead the designed height of this column of oil is .030 to .070 inches.  Quite a narrow tolerance compare to later designs such as used in the 1949 331 OHV engine.  Assuming all original parts the 3 inch gap between the valve stem and the cam results in that height of oil.  I have not checked it but I would assume it puts it at .050 inches of oil (middle of the tolerance range) or with no oil in the plunger you would have .050 clearance.  So this gives you an alternate method to verify that the plunger will be within its range and able to maintain zero lash when running even if the cam and valve lifter deviate from the original dimensions.   

[wheikkila]

Hi Brad
So, If I have this correct. I need to put the lifters in dry. check with the cam lobe on the reverse side and check the clearance between the valve and lifter. Simple     

[Brad Ipsen CLC #737]

Simple, the only problem it is a pain to do because of the little spring on the plunger.  What I have done is take an old plunger and remove the spring.  You would want to compare it to your new plunger just to make sure that part is the same dimension.   

[wheikkila]

Hi Brad
I will check my old lifters to the new lifters. If I have any questions I will get back with you.
Thanks Wayne