What material is this gear made of?

My 1958 544 Volvo had all metric fasteners. The 1986 Volvo station wagon also was all metric.
 
Ford did not limit the lunacy to the FE family of engines. The small block V8 suffered as well. My old mustang jumped timing at about 90,000 miles.
Luckily the Nylon chunks did not take out the oil pump.
 
Bi11Hudson said:
Theoretical meanderings by an old man, maybe or maybe not useful. I am officially an "old man", turning 70 this year.

First of all, a Volvo built in Sweden will most likely be metric. Being an automotive part specific to an engine, it might well be any thing. I would be disinclined to think "micarta" since, in electrical parts, micarta is usually a warm brown color. Bakelite is a very old process, one of the earliest incidents of plastic, if not the oldest. It is common as an electrical insulator, is very black, and is very brittle. Those two plastics aside, there are many plastics in use the last 30 odd years that I have no knowledge of.

Theorizing on the engine; if it is a clearance engine, in that the crankshaft can come to top dead center with a valve open, most any material could have been used. If it is a "zero clearance" engine, having the camshaft get out of time with the crankshaft could cause considerable damage.

In either case, using a molded (plastic) gear is a significant reduction to assembly costs and time. It can also possibly be used as a "weak link" to reduce other, more serious damage on failure. In any case, a replacement could be constructed of any material, most easily aluminium. The issues here are "non critical" being primarily increased weight, more affected by corrosive chemicals, and less likely to fail when failure would "save" another part.

The instructions, formulae, system, whatever, for determining metric vs imperial (Modulus V Diametrical Pitch) given above would be most useful. There are many other factors involved in making a gear. First and foremost is what the gear interfaces with. Another gear, timing chain, timing belt, short rope, whatever. If indeed another gear as it appears, perhaps research into that second gear will provide further insight into pitch, pressure angle, et al. Worst case, research and careful measurement would provide enough information to construct something that works. It may not work 100%, but well enough to refine the measurements closer so a second gear could be constructed that was 99.99% useful.

Last but not least, the gear appears to be a "taper" gear. Such is not easily reproduced in a hobby shop environment. It could be theoretically be printed, given enough time and a strong enough medium. My preference would be to find a similar machine in a junked condition to salvage the gear. Possibly having it built by a machine shop but the cost of that would be enormous. Again, this is mostly theoretical meanderings by an old man, maybe or maybe not useful. Just a little "out of the box" thinking to try to assist.

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I think the pictures maybe a bit misleading concerning the taper,it is not. I will speak to the client as soon as I can and ask if it runs on another gear,and I also think it does,and what it is made of and post that information too.
 
GM used a similar looking phenolic camshaft timing gear on a 2.5 litre 4 cylinder engine nicknamed the "iron duke" from 1978 to 1990. The stated purpose given at the time for using phenolic was to reduce engine noise caused by the normal backlash in the timing gears and the rapid loading/unloading of the camshaft caused by valce spring pressure. It was fairly common to replace a failed phenolic gear with an aftermarket aluminum one at the expense of more noise.
 

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I also have a Volvo and it’s all metric. Timing belt would most likely be a standard belt. I had recently looked at me me to check condition and from what I can remember it’s a straight tooth gear. I would also agree that getting a junker would make me sleep alittle better. You don’t want that timing off!
 
Fords V-6 (German sourced Mercury Capri) had a phenolic timing gear, I had to replace mine 3 different times, the third time was an aluminum gear, expensive, but never replaced it again, sold the car 60,000 later.
 
Most of the timing gears I have seen which were “plastics “ did appear to have a fabric reinforcement so I’d guess phenolic also. But, that’s just a guess. I have see nylon timing gears and yeah.... I too have seen that they degraded and snapped
 
RJSakowski said:
Measure the OD in mm and divide by the number of teeth plus 2. If the result is a nice number like 1.5, 2.0, etc. or close, then it is likely a metric gear and the answer will be the modulus. If not, the number of teeth plus 2 divided by the OD in inches would be the diametral pitch.

Bakelite with some sort of material added for strength was used in some automotive applications. McMaster Carr lists several types under the trade name Garolite.
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The gear has 42 teeth,the OD=148.50mm =5.846". So 148.5/44=3.37mm and 44/5.846=7.52. So I am still not sure if it is Module or DP. Would that M3.5 or DP7. Not sure about the presure angle also and another question is at how do you determine the angle of the teeth correctly although it looks like 45dgr. Could you perhaps assist me with this?
 
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