davidwheeler
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« on: 21 March, 2023, 04:08:04 PM » |
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I have Boot's engine apart to address various problems, one of which is slop in the vertical shaft. I have found a spare upper shaft which eliminates the play in the junction with the lower (I have only carried these bits around for some 57 years - they will come in use sometime). Next problem is the bearings. There are two sorts, 102406 and 102408. They both have the same dimensions. In my car, 102406 are standard ball bearings and 102408 are unidirectional thrust bearings. I cannot find bidirectional bearings to replace them and am wondering about the thrust abilities of deep groove ball bearings. Moreover, I am not sure which way up they should be if unidirectional. There has been vertical play in the lower shaft though not in the upper since I fitted a new sleeve with unworn holes for the pin. The other curiosity is 11170 which I have never seen in either car and I do not know what it is (described as ball race bush on top vertical shaft) What are others doing about these please?
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David Wheeler. Lambdas, Aprilia, Fulvia Sport.(formerly Appia and Thema as well).
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davidwheeler
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Posts: 1479
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« Reply #1 on: 28 March, 2023, 08:02:27 AM » |
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I am disappointed that so many people have read this and yet nobody has responded. Should the thrust bearings be next to the skew gears or at the other (inner) ends of the shafts? It would semm perhaps that there should be standard bearings next to the drive gears? In which direction are the thrusts? When the cotter pin broke the upper shaft rose up and disengaged from the camshaft gear and from the lower shaft, suggesting that I had things the wrong way round - I had the thrust bearing at the upper end of the shaft set to counter downward thrust. Surely you do not all send your engines to your mechanic???!
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David Wheeler. Lambdas, Aprilia, Fulvia Sport.(formerly Appia and Thema as well).
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Dikappa
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Posts: 556
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« Reply #2 on: 28 March, 2023, 09:52:00 AM » |
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David, i'm sure I read something about this. I'll try to remember where....suppose it was not on the forum as then you would know I'm sure... I did not put my engine together so no hands on experience I'm afraid...
Now for sure modern deep groove ball bearings can take a lot more axial thrust then the original ones.
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Dikappa
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« Reply #3 on: 28 March, 2023, 09:56:47 AM » |
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davidwheeler
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« Reply #4 on: 28 March, 2023, 01:05:03 PM » |
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Goodness, I had completely forgotten! I shall transfer the information to the technical information thread. Thank you for reminding me! To save folk looking:-
"After correspondance with Mike Benwell and study of the Spares Catalogue, we have discerned the correct configuration of the bearings, to whit:-
In the head, the top bearing is a thrust bearing and the bottom one a plain ball bearing. In the block, the same.
Thus, the thrust is directed downwards on both shafts, being pushed down on the top shaft and pulled down on the bottom one.
I found I needed about 1mm. of packing washers on both shafts to eliminate all play and ensure a trace of preload. I even fitted the upper gear on the lower shaft (if you see what I mean) without the key and then pulled up the nut to check that it did not skid round on the shaft and also that it required a little tap to free it from the taper. I made up an extractor to remove the gear and found that the threaded holes in the original gear are Whitworth but in the Consortium gear metric. Fortunately, if you are removing an original gear, metric bolts will fit well enough!"
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« Last Edit: 28 March, 2023, 01:25:28 PM by davidwheeler »
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David Wheeler. Lambdas, Aprilia, Fulvia Sport.(formerly Appia and Thema as well).
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Dikappa
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Posts: 556
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« Reply #5 on: 29 March, 2023, 10:16:48 AM » |
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David, I asked a friend in OZ how they go about it, so maybe more knowledge to share in a couple of days....
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davidwheeler
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Posts: 1479
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« Reply #6 on: 02 April, 2023, 09:43:23 AM » |
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"Angular contact bearings are fitted. They are standard metric bearing 7305. When fitted you need to set the bearings by giving a good whack with a copper hammer on the end of the vertical shaft. Once set, measure the end float with feeler gauges or better: Dial indicator. Take up end float and apply .001” to .002” Preload by adding shims between the sleeve that is fitted (by taper pin) to the lower section of the shaft and the lower bearing." from Koen's friend which I think is definitive! Aluminium heads of course expand a little more than steel shafts and are a bit more delicate so perhaps a gentle whack with a hammer and even try the bearings with the head heated? The important thing I think is that the angular contact bearings (not cheap!) take thrust downwards and are fitted at the top of their shafts corresponding to 102408 in the diagrams.
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David Wheeler. Lambdas, Aprilia, Fulvia Sport.(formerly Appia and Thema as well).
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