How to find TDC?

[18Fiatsandcounting]

Pete, I should know this, but where do you get "the little tool"? And does this work by turning the camshaft until the lobe fully opens the valve, inserting this tool to hold the valve open, rotating the cam lobe 180 degrees, and thus providing clearance to remove the shim? Or ???

I vaguely recall doing something like this in the past, but I didn't have the right tool. I made sure the notch in the valve bucket faced out, turned the cam to open the valve, found something in my toolbox to keep the bucket depressed, rotated the cam back, and used a dental pick through that notch to lift up the shim.

But I kinda agree with Steiny: Unless the valve clearances are obviously far off, I tend to leave them alone. But, I do have a full shim set (five of each shim thickness, plus many spares), so maybe I need to tinker with this someday.

-Bryan

[ORFORD2004]

If you have the shim, do it it's very easy. The tool is to pry the shim bucket when the lobe is up. That way you are able to remove the shim.

https://autoricambi.us/valve-adjusting-tool/

[18Fiatsandcounting]

Great, thank you Orford!

-Bryan

[SteinOnkel]

Yeah, that dumb tool goes for $65 - $130. Absolutely not. From what I've read, it's a pretty hit and miss approach.

Somebody built something similar with zip ties and e-tape. It just needs to hold the valve open.

[18Fiatsandcounting]

I hear you Steiny. I'm really trying to remember what I did back in the late 1970s when I was first working on my '69 spider, but I do recall changing shims with the camshafts in the car. I *think* this is what I did, but my memory is really fuzzy:

Turn the engine so that the pistons are in the middle of their stroke (avoids valves hitting pistons). Remove timing belt. Remove camshaft covers. Measure valve clearances (cold engine of course). For each valve that needed adjusting, rotate the camshaft by hand so that the lobe is depressing the valve all the way. Insert a large open end wrench (this is where my memory fades) that is large enough to clear the shim diameter but small enough to push on the edges of the bucket. Maybe I used a large screwdriver or pry bar or some angle iron or the like? Rotate the camshaft so that the lobe is facing away from the bucket and with luck, the valve remains depressed as the "tool" is between the shaft of the cam and the bucket. Remove the shim with a dental pick, using one of the two notches in the bucket lip. Measure shim and find a new one to get you to the clearance you want. Oil parts generously, and insert new shim. Repeat with other valves as necessary. Set cam, auxiliary shaft, and ignition timing and replace belt. Fire that bad boy up. Quaff a beer. Ahhhhh....!!!

One issue is that my '69 has the narrow cam lobes, so this method may not work with engines that have the wider lobes. Not sure when that change was made.

-Bryan

[RRoller123]

CH0-012, $43.99 from AR and worth every penny, makes this job almost trivially easy. Not at all hit and miss, works great, except possibly at E4. You can use it there backwards, i.e oriented from the inside instead of like the other 7 positions, but I chose to do a small bit of filing so it would be used consistently across the board in all 8 positions. Works great.

[18Fiatsandcounting]

Thanks, Roller, I'll take a look. Even at the risk of Steiny never speaking to me again*, I may remove my cheapskate attitude and break down and buy one. But just this once!

*Perhaps I'll start a post on how points are better than electronic ignition systems, or cross-threading SAE bolts into metric nuts can work if you're careful, just to be sure...

-Bryan

[geospider]

I have one. they work great. very easy if we all have enough shims, can get it done quickly. if not, need to order the shims.
either way, we can share the tool

Geo

[18Fiatsandcounting]

Thanks, Geo, and I went ahead and ordered one. $43.99 with free shipping from AR, once I got above $99 total, which I did by ordering some weatherstripping that I need.

I can hear Steiny getting spun up already, but hey, with this tool, and a full set of shims, I shall rule ze world! Bwah, ha, ha, ha!!

Errr, Ahem....

If you ever needs shims, just let me know.

-Bryan

[geospider]

too bad. but a well used tool as you will find.
After doing new gaskets for my cam boxes: ALL of the shims needed replacing.

one hint. if you need to order a shim (first, check with me)
put the old one back in when checking all the rest. don't want the cam lob rolling just on the bucket. (you're smarter than that anyway).
The grinding you need to get #4 out is very little; don't get crazy/

Geo

[18Fiatsandcounting]

We should go into business in the Bay Area, Geo! Attention all Fiat owners: Valve clearances adjusted, only $5 per valve, order today! Order 7 and get the 8th one free! (gaskets not included, not available in all areas, beer compensation extra, delivery charges may apply)
-Bryan

[RRoller123]

I have read in multiple locations never to reuse old shims. I am not sure why , but I suspect that they rotate in the cups, and take on a slightly cupped shape in the identity of the particular camshaft lobe that they have been working with, and that measuring the thickness in a particular spot and assuming them to be uniform, then putting them under a different lobe would cause trouble. Or maybe if they are put in the new location opposite side down from before, they won't sit quite right. Purely a guess on my part. Maybe someone knows why, and I am pretty sure that it is NOT so the suppliers can sell more shims. Could it be as simple as people assuming that the marked thickness is still the same, and thus causing error if it is worn and then then used elsewhere?

[18Fiatsandcounting]

I have read in multiple locations never to reuse old shims.

I haven't heard this about Fiat spider shims, but I have heard you shouldn't mix lifters, pushrods, or rocker arms from different cylinders (of pushrod engines). The reason was the same, i.e., the parts develop a "set" for each other based on very subtle differences in shapes and contours, and mixing and matching parts from different cylinders would result in premature wear.

I don't have any real data to say whether this is true or not, but maybe it's kinda like the advice not to reuse a cylinder head gasket (or gaskets in general). I mean, if you put a cylinder head back on and torque it down, and then remember you left your screwdriver in the #2 bore, all (most?) of us would use a new head gasket when we removed that screwdriver and put it back together, right? But is this really necessary? I really don't know, actually, but I myself would use a new gasket.

-Bryan

[tima01864]

Interesting question, We measure under the lobes but what of wear on the lobes? Guess it doesn't matter so much?

[SteinOnkel]

Thanks, Roller, I'll take a look. Even at the risk of Steiny never speaking to me again*, I may remove my cheapskate attitude and break down and buy one. But just this once!

*Perhaps I'll start a post on how points are better than electronic ignition systems, or cross-threading SAE bolts into metric nuts can work if you're careful, just to be sure...

-Bryan

Lmao it sounds like you have my number