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ET: Engine (Twin) ET48 Mag/ATD Pinion

Robert Watson

Well Known and Active Forum Website User
VOC Member
I have one of these brand new made of a black plastic feeling substance. It has a circle about 3/4 in dia with C T in the middle. I am guessing this is a Colin Taylor item and I was wondering if anyone can shed any light on the reliability (or not) of it. I do recall there was some talk of plastic ones that were not up to the task.
 

Michael Vane-Hunt

Well Known and Active Forum Website User
VOC Member
I have one of these brand new made of a black plastic feeling substance. It has a circle about 3/4 in dia with C T in the middle. I am guessing this is a Colin Taylor item and I was wondering if anyone can shed any light on the reliability (or not) of it. I do recall there was some talk of plastic ones that were not up to the task.
Like this?
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Michael Vane-Hunt

Well Known and Active Forum Website User
VOC Member
I was sold the one pictured above in 1993. It was touted as a superior product to the Tufnol pinion. It lasted about 4000 miles the it stripped the teeth. In the end it caused a holed piston and a complete engine rebuild. So I strongly suggest you not use it. Best to cut it in half so it can never be used. After my incident I found out that the black pinions were made from a hygroscopic plastic. I replaced it with a Tufnol gear and have had no problems with that yet.
 

royrobertson

Well Known and Active Forum Website User
VOC Member
Way back in late 1989 I had the misfortune to use a Nylon one in my racer. Practicing for Brands in 1990 engine seized solid on the bottom straight with shreds of the gear filling the oil feeds. The Damage was Huge. Nylon is hydroscopic and gets bigger. Use the tufnol one or machine a camwheel to fit if not using the atd.
Cheers Roy
 

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Bill Thomas

Well Known and Active Forum Website User
VOC Member
I was supplied a NON Tufnol type a few years ago,
I did say I was not keen , But was told that was the old ones ??,
And the new ones are OK ?.
Cheers Bill.
 

royrobertson

Well Known and Active Forum Website User
VOC Member
Yes. My two steady plates are made of Gauge Plate (a quality ground steel plate) the same thickness as the normal ally one. I worked on the theory that the Comet has a steel one and they have been fine. If I made them again I would use stainless. As you can see the access to the timing marks is great and a lot of work has been done to reduce the weight even to using titanium for the spacers and some of the nuts.
Cheers Roy
 

oexing

Well Known and Active Forum Website User
VOC Member
I have been meditating about choice of material of steady plates and went for alu 7075, why ? The engine is alu and with steel or worse titanium you deal with very different heat growth. So in a hot engine that does something to spindle distances which are not negligible at these sizes. So a no for me on a road engine.
i did not care about any timing marks if there had been any at all. My logic is to set two clocks on valve spring cups and turn the camshaft for equal lift. In this position I scribe one tooth on the camwheel with the Dremel and same on engine case close to each other for great alignment later. Do same job on second cam and set lines on wheel and engine. So later you just get the timing disc on crank end zeroed with piston stop in plug thread both directions used - on rear cylinder. Then turn crank with idler gear fitted to 4 degrees before TDC rear pot and look for a slot on crank end that fits the half time gear in exactly this position. Then turn the crank one turn plus 50 degrees minus 4 and see if the front camwheel can be engaged while the marks on wheel and case lign up . If not so you´d have to press out the gear and adjust for error. You can check these alignments all the time when turning the engine over as there is no hunting tooth problem in combination with old original marks on all gears. Hope I was clear enough or was I wrong for some BS in my description ?

Vic
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