Hello All,

I've owned a slew of bricks but have never checked my valve clearance in hundreds of thousands of miles. I guess the consensus is that valve adjustment is rarely necessary on these engines. However, I recently purchased a depressor tool and checked and even played with removing shims with a couple of picks and a magnetic probe.

Here's what I found starting from the front (#1) for all eight.

.011 .017 .010 .011 .013 .013 .013 .013

I know what the Bentley indicates: that if checking .012 to .016 is OK, if adjusting .014 to .016 is what to adjust to. I have two questions about this. First, especially for the master mechanics, should I bother adjusting the valve clearance given the numbers above?

Secondly when removing shims for the first two cylinders, I found that the valve clearance of .017 was created by a shim without a designation (unlike the ones stamped 4-10 or 4-15 on #2) and when measured was .190 inches which most closely corresponds with the 4.80mm shim, which seems to be the largest size available. Think I should leave that alone or go looking for the 4.85 shim wherever that may be? Lastly, since the other shims were 4.10 and 4.15 doesn't having a 4.80 seemed a little odd? Anyone have any take on that?

But again, as in the past, my lack of experience breeds a lack of confidence which is why I turn to the BB. Thanking you all for your thoughtfulness this year in answering my call for help and likely for next year as well.

Marty Wolfson

Proud member of the 300K club

Hi Marty,

I have a dealer set of the Fiat shims that Dave mentions. I'll see if there are any in the 4.15 or thicker range. Some aren't marked, but if you can give me the decimal dimensions you need, I can pick thru them and maybe get lucky.

IMO, you can disregard the oil thickness between bucket and shim.


--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Hi Bruce,

Thanks for thinking of me. For that oddball valve serving #1, the shim in place most closely measured 4.80mm (actual measurement was .190" = 4.826mm) although there was no designation on the shim. 4.80mm is the largest size that FCP shows on their website which leaves me scratching my head.

The clearance measured was .017" which is just out of range (.014 to .016"), so I suppose either a 4.85 or 4.90 would do the trick. The other ones which were out of spec were too tight and used either a 4.10 or 4.15 shim which would call for a 4.00 shim.

With three of these 240's, I suppose it's time for me to start my collection of shims along with an array of valve cover gaskets. But if you can dig up a 4.85 or 4.90 that would be great.

Thanks again,

Marty Wolfson

"For that oddball valve serving #1, the shim in place most closely measured 4.80mm (actual measurement was .190" = 4.826mm)..."

Hi Marty,

That Fiat box stops at 4.7mm, so I couldn't come up with anything single shim thick enough. But taking Randy's shim stock tip, I matched up a new .170+" shim with an unused brake caliper shim (better than brass stock here, IMO) for a total thickness of .012", which shows as just under .193" on my old Harbor Freight vernier caliper. I didn't try cutting a circle out of the .012" shim, but believe it can't be too hard, if you want to go that route.

As for the .010" and .011" clearances, if you can give me the actual shim measurements, I can probably find some a little thinner.


--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Others have already suggested adjusting those with the smallest clearance--I'd agree with that but the reason I'm posting is to let it be known--Fiats (at least the 128 SOHC based models--probably the 124 twin cam too) use the same diameter shims but the range of thickness extends beyond those Volvo uses. If yours is way out machine work is probably in order but for those that are just a little beyond spec size shims the Fiat shims may buy some time. -- Dave

For what it' worth, as long as I was there, I'd bring them all into running spec, 0.014 to 0.016 and call it a day for 50,000 or so miles. Take your time and make sure any new shims are seated before checking clearance. Your engine will thank you. At a minimum the 0.010 and 0.011 need to be adjusted.

Mike

Thanks for the help Mike,

Since only #1 and #2 valves were off, I only removed those shims and don't know what's in place on #3 and #4 because the clearance was OK. Your recommendation to take care of the other .013 clearance valves is something I prob should have done but didn't consider since I was only "checking"

One question comes to mind, however. When I removed the shims, you could feel the adhesion of the shim to the follower (I think that's what it's called) from the oil between the two parts. The two parts are actually hard to separate until you break that "seal". I wonder how much thickness that oil occupies in the contact area between the follower and shim? and might that oil have diff thicknesses depending on type of oil and temperature?

Anyway, just thinking about this til the shims and valve cover gaskets get here.

Marty

I never like the clearance to be on the tight side; as a mechanic friend says, "I would rather hear them and not smell them"- meaning of course that too tight flirts with burning a valve.

Having said that you have to ask how tight is too tight? I don't know, but if I owned the tool I would probably go after those that are .010 and .011 and bring them into tolerance (I don't own the tool, but I do any adjusting on new arrivals when I change the cam belt by simply removing the cam).

I always wondered about what I might do if I came across one that was too loose and a shim was not available to correct it. I thought I would simply cut a piece of brass shim stock that coupled with an existing shim would provide the correct clearance. I ask my friend about that plan and he said he approved :-)
I would cut the shim stock to almost the same diameter as the shim and place it in the cam follower- under the shim.

Good luck,
Randy

Thanks Randy,

Thanks for the info. The too-tight clearance seems to call for new shims.

The .017, I will leave be. I like the idea, however, of cutting an additional shim to place under the 4.80mm one. I suppose in that way, by cutting the proper thickness shim, you could even use the "standard" shims of 4.10 or 4.15 that seem to be prevalent.

From what I've read, the clearance diminishes over time, so maybe my .017 will come into spec in the coming years. The car has only 190K.

Thanks again,

Marty Wolfson