View single post by Esprit2
 Posted: 05-05-2016 03:29 pm
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Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 330

Jensen-Healy 'assembled' eccentric tensioner
Industry Standard ball bearings, such as ...

INA 6005-2RS
ID .............. 0.9843" (25mm)
OD ............. 1.8504" (47 mm)
Thickness: ... 0.4724" (12 mm)

Two of the 6005 ball bearings are assembled inside a proprietary outer steel ring/ roller, and with an eccentric hub pressed through the bores. The hex head for adjusting the eccentric is between the tensioner and the block, so access isn't as easy as it should be.

All "Lotus" tensioners (eccentric and spring-loaded) used a dual row/ double width, integral bearing/ roller. The bearing IS the tensioner roller.
ID ........... 1.214" (30.8356 mm) ... did the math and
OD .......... 2.478" (62.9412 mm) .... kept the decimals
Thickness: 1.179" (29.9466 mm)

SKF .......... 414871A ... Excellent quality, my favorite
SKF .......... VKM 14300 (??) In general, SKF is a quality brand.
Flennor ..... FS03299 ... Now sold by JAE
Ford ......... 1500004 ... 1977-1986 Ford Transit Van
INA .......... 531 0098 20 (??) In general, INA is a quality brand.
Timken ..... TKR 9841 (??) Timken production is in China.

Early Lotus Eccentric Hub ... P/N A907E0684FB
Later Lotus Eccentric Hub ... P/N A912E2176F
Either Lotus hub will work with the above bearings. I believe the significant difference was the size of the adjuster hex. The Lotus eccentric has the adjuster hex head on the front side. No special, thin, bent wrench required.

NOTE: There are minor dimensional differences between the JH and Lotus versions of the front seal housing. Due to those differences, the Lotus eccentric is not a direct plug-n-play upgrade for the JH 907. However, if you also swap in the Lotus front seal cover, then the Lotus tensioner will fit your JH engine. "OR"... Joe Van Ruth, 'qwerty' on this forum, has made up a Lotus-style eccentric that accepts the integral bearing/ roller, and fits the JH front seal housing. He sells them as a group buy on JHPS and the Jensen Healey Facebook page.

DO NOT buy bearings by price. There's some cheap crap out there. If the bearing fails, it will take out the timing belt, and then the pistons wipe out the valves. "Cheap" can be really, really expensive.

Some new bearings feel rough out of the box. Hand try it before you buy it. Buttery smooth is what you want. Some of the Chinese bearings, in particular, have no business being anywhere close to a J-H/ Lotus timing belt.

Last edited on 07-10-2017 08:51 pm by Esprit2