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Thread: Orion, What do you know about redrives?

  1. #16
    Registered User StRaNgEdAyS's Avatar
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    Many thanks.. off to look
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  2. #17
    Registered User StRaNgEdAyS's Avatar
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    Here's one that does what I want, it's not too costly and it comes made for an application that I can use (Holden V6 and Leyland V8).
    http://www.northwest-aero.com/produc...ex-psrus.shtml
    Either engine is a contender for me at the moment.
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  3. #18
    Super Moderator orion's Avatar
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    I met the owner of Northwest Aero Products a couple of years ago and have been though his shop. At the time he was producing engine kits along with the redrive - I wonder what happenend to that part of his business. I haven't talked to him in about two years.

    He is a very good machinist and has quite a bit of capability in-house. I was tempted to select his product for the project I was working on at the time but although the overall design of the drive looked just fine, there were a couple of things that as an engineer I did not like. The first was the fact that his upper pulley is cantilevered off the output housing and front plate. I know his shafts are generous and this is probably not an issue, but to my way of looking at something like this, I certainly would prefer to see a bearing on both sides of the pulley.

    The second thing that struck me a bit ackward was the mechanism for adjusting tension. To adjust the belt you loosen all the bolts holding the output housing to the plate, then swivel the housing, sort of like adjusting a typical alternator, and then retighten the bolts. Yes it's simple (and is probably the reason the pulley is cantilevered out) but to my way of looking at it, it just seems like there's too much chance for the thing to loosen eventually and the mechanism has no way of adjusting the tension as the belt heats up and loosens. He did not think this was a problem since if you tighten the system cold, the resulting slack when it warms up should be minimal and is supposedly within the belt's capabilities - personally I would have prefered a rigid mount and then tightened the belt with a self-adjusting spring loaded viscous idler cam or arm.

    Overall I'm not recommending against this drive, it's just that it did not meet some specifics that I would like to see in such a critical system.

    On another note, yesterday I started a discussion with Ray Fiset, the new individual responsible for the Marcotte redrive. So far it sounds promising - we'll see.

  4. #19
    Registered User StRaNgEdAyS's Avatar
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    Thanks for the encouraging reply.
    I was wondering about the upper pulley and belt tension, but since I'm not putting 300hp onto it, it might just do.
    I'm glad you managed to get hold of the Marcotte folks, I'd be interested to hear what they have to offer these days. Apart from that 3rd party link I've not found any other info for them online.
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  5. #20
    Super Moderator orion's Avatar
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    I'm finally in front of my office computer so here's a couple more links for potential redrive suppliers. The first one is for a company that sounds quite knowlegable about auto conversions and applications. I don't know them persoanlly but if I was to base an opinion solely on the contents of their web site, I'd say this company is a very good candidate for anyone considering auto conversion:

    http://www.epi-eng.com/index.html

    The second is an airboat redrive manufacturer. The unit is based on a 5" wide belt and seems beefy enough for just about any application. In the pictures it looks to be possibly heavy but I don't remember if they post a weight for it. If the housing is aluminum maybe it's not too bad but if its steel or cast iron, no thanks. The link is:

    http://www.airboatdriveunits.com/ch3.htm

    The prettiest airboat based units are from Classic Airboats and if they perform anywhere near as well as their design looks to be done, these should be a good solution for just about anyone looking to use a GM based powerplant. Their products can be found at:

    http://www.classicairboats.com/pages/reduc.html

    And finally, here's a page of all sorts of engine related links. This will keep you clicking for days:

    http://www.aviator.cc/engines.html

    And one other note - for those interested, I did finally get a hold of the folks who are now supposedly producing the Marcotte reduction drive. The unit is for Mazdas and Subarus and based on specs that I got a hold of several years ago, it is the drive I would design if I was to do another one.

    Apparently, the original owner's partner was a tad less than honest so many people's deposits got pocketed (including mine). According to the email I got back, the company is under new ownership and is supposedly working on getting the drives to full production.

    But here's a potential problem - I've followed up our initial email conversation on at least three occassions with additional questions - and got no answer. I asked about their products and the engines they were specifically producing for now, a price list, and also if they had a web site for further details. Given the lack of resopnse, I'd say that my enthusiasm got squashed pretty quickly. Oh well, next!

  6. #21
    Registered User StRaNgEdAyS's Avatar
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    While the EPI units look great and their weights are fairly good (58lb for their new Mark 15 versus their earlier 78lb Mark 9)I think I recall from somewhere that they were rather pricey. I haven't been able to find any hard data on pricing, maybe an email is in order.
    The units on offer from Airboat Drive Units are fairly hefty, the CH3 (the big one) comes in at a whopping 127lb! I can't see the lighter duty (apparantly not in size) CH2 being much lighter. In either case, that's just a tad too much to hang on to the front of my little bird.
    Now the Rotator redrives featured on the Classic Airboat site are a little more weight friendly, at 64lb and it certainly is one of the more affordable units but I don't know if that pretty housing (How easy would that nice cast alloy be to break?) comes in a model to fit my engine candidates.
    The Northwest Aero products (I wonder if they're related to Southwest ) units I know will fit my application, and are probably the lightest of the lot. (but once again the hard data escapes me, I guess all I can do is ask) Unfortunately this one is close to the top end of the price range as well, at US$3200, (that will put it at about AUD$4500 incl. freight!)
    I've yet to find any locally built item.
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  7. #22
    Super Moderator Midniteoyl's Avatar
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    EPI PSRU

    Careful with EPI. They designed for the now-defunked EngineAir. John Barrett of Carbinge fame has a little tidbit on his site. There's no real details given, however, and up till 2002 the PSRU did seem promising. Not really sure what happened. Just look into it before plunking down cash.

    http://www.carbinge.com/epi_psru.htm


    note: it says 'EPS' in the text, but its the EPI PSRU. Click the top links for older news.
    Last edited by Midniteoyl; August 25th, 2005 at 09:41 PM.
    Jim

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