| Author | Message | ||
| Jim Shepherd (Rv_safetyman)
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Sonnie Gray (Catskinner) and I are going to present a seminar on engine conversions at Bussin’ 2006. I am excited to work with Sonnie on this seminar. As some of you know, he has a very unique conversion. Both of us have Eagles and have tended to focus on these buses. I would like to hear from others that have done engine conversions – especially in MCIs and Prevosts. We will concentrate on four stroke conversions, but we want to hear about any conversion. The more unique, the better. If you have an engine conversion, please call me, toll free, at the number below, drop me an email at: jim ** at ** rvsafetysystems ** dot ** com, or post a reply here. Thanks!! Jim Shepherd Evergreen, CO ’85 Eagle 10 1.888.349.0704 | ||
| Jim Shepherd (Rv_safetyman)
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I have had some great email responses. However, I am still looking for some input from MCI and Prevost folks. One person mentioned putting a Series 50 in an MCI. I would assume that can be done by raising the bed area. How about an M11/ISM. Will that fit in the various MCI models without raising the engine compartment and also fit in the length? Sonnie and I met yesterday to go over the presentation and we think we made it pretty generic. However, we would love to add some specific information about all buses Thanks, Jim | ||
| Marc Bourget Rating: N/A |
Jim, With the various engine/tranny/axle combinations possible the answer is "it depends". I venture that, from a lay person's perspective, the crux criteria is drive shaft length and installation. There's lots more important issues to engineers, but they tend towards longevity and serviceability, not whether it will suddenly "break". The issue is Angular Velocity. Angular velocity loads are probably the most important but least understood. A lay person can get an "idea" of angular velocity from their socket set. Get two 3/4 U-joints, 2 6" and 1 24" extensions. put them together with the 24" in the middle. Offset the 6" extensions so each end is parallel and at 45 deg with the center. Now rotate one end while keeping the short extensions parallel to each other. The force required for rotation gets harder and easier at points in each revolution. The change in rotation force is the angular velocity load(ing) For most u-joints the maximum angle is about 15 degrees. So what? you say??? Well thinkaboutit! Pulling Rocky Top at 60 MPH in your overweight, overpowered (compared to original drive train) and hitting a bump that puts the bus on the jounce bumpers. Think all that force, multiplied by the factor of angular velocity will rest easy with the u-joint? The second major point is installation. You have to consider full suspension deflection (usually 8-12") and also add in chassis deflection, motor mount compression and still have 2" clearance over the tag (if installed) Since shaft angularity will cause a change in distance between tranny output and pinion as the suspension pieces move up and down relative to the power supply, a slip joint is typically required, that shortens the "effective" length of the drive shaft and exacerbates the shaft angularity situation. So, if you can fit your engine/tranny/axle into the compartment, cycle the suspension to it's limits and keep the u-joint angles below 15 degrees, you have a good start on a re-power. After this it gets much more technical, but I've digressed. . . in answer to your question, M-11 in a MCI is a yes! | ||
| JR
Rating: N/A |
FWIW, a DD50 Series will go just under the bed in an MC9. Don't know about any others. A 60 Series requires extensive reworking of the bed area. Even though a 50 and 60 are similar sans two cylinders, for some design reason a 50 is a few inches shorter from crank center to the top of the valve cover. A closeup of an MC12/S50 would show how it's done. If ya'll do the presentation on engine conversion in MCIs, I'd pay for a video of the program...wouldn't matter about the brand engine. Others may also. I'm not yet convinced that an MC9 would be worth repowering...but?? JR | ||
| Jim Shepherd (Rv_safetyman)
Rating: N/A |
Marc, just to make sure we are on the same page, a correctly aligned drive shaft will not have significant velocity fluctuation or angle velocity. A correctly setup drive shaft is one whose cardon joints are correctly phased, and whose input and output shafts are parallel. The error most folks make is to tilt one of the shafts towards the rear end and thus the input and output shafts are no longer parallel. In this case, there can be considerable velocity fluctuations and premature U-joint failure. If the input and output shafts are parallel and remain so over the operating range of the rear end, then the joints can handle a reasonable angle at the extremes of the travel. The second point you make is very important. The length of the drive shaft must be set so that the slip yolk can accommodate the length change that occurs as the rear end travels through its operating range. I hope we agree. Thanks for confirming that the M-11 can be installed in at least some of the MCI versions. Jim | ||
| Marc Bourget Rating: N/A |
We do agree. Assuming proper selection of the u-joint, (not a parts counterman's expertise!) the angular velocity loads will be fine if the included angle remains under 15 degrees The drive shaft should not be installed to be straight. A minimum of 1 degree included angle must be built into the installation to insure sufficient movement of the u-joint's roller bearings to prevent premature wear and failure. As to my second point, any binding or interference runs the loads to Valhalla (infinite). A stupid installation on my father's Prevost conferred upon him the privilege of making the evening news. He tied up the 91 fwy on New Years eve. Nothing like having 5 news copters circuling your coach as you sit, stalled the the middle lane of a 4-5 lane freeway in the middle of a holiday weekend rush hour. Karma does return to those who deserve!! Wish I had the opportunity to present my "All you ever wanted to know about cooling and more" lecture in conjunction with your seminar at this years Bussin' event. I'll make it next year, God willing and the Storm surge don't rise! | ||
| Tom Caffrey (Pvcces)
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Marc, I thought that there was a much larger desired minimum angle for u-joints to avoid premature failure. The theory that I am recalling is that the movement needs to be great enough to walk the grease into the pressure areas. Do you know anything about this? Tom Caffrey PD4106-2576 Suncatcher | ||
| Marc Bourget Rating: N/A |
Yo, Tom! What I was really trying to communicate is that the shaft shouldn't remain straight for any sustained periods. Your "theory" is an actual design criteria. I was told at least 1 degree, but a few more ought to be better. I wonder, given the greater size of these ujoints, 1 deg. may provide enough movement to insure adequate lubrication. | ||
| RJ Long (Rjlong)
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"Karma does return to those who deserve!!" Nice "inside joke", Marc.  RJ | ||
| Jim Shepherd (Rv_safetyman)
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We now have had two folks who suggested a video of the seminar (one via email). We don’t have any plans to do that. If someone attending wants to make a video and make it available to others, we have no objection. We want to be really clear about the seminar. This is not a how-to-do seminar. It has some of those elements, and we will probably cover more during the question and answer period, but a couple of hours would not even begin to cover all of the options/detail. We are doing the presenting part of the seminar in PowerPoint. If there is enough interest, I will try to find a way to mail CDs of what we have prepared. The file is currently 22 meg, so it is too big to email. We are trying to include several pictures, and that jacks up the size of the file. We are trying to put a reasonable amount of detail in the slides, so it should be reasonably self-standing. If you are like me, you have looked at a ton of conversions and perhaps talked to the owners. The problem is that the conversion is a lot like an iceberg. Most of the work and detail is hidden in the depths of the engine compartment. We have several slides that show some of the detail that is often hidden. We are currently in Arcadia at Jack’s. I talked to him today and I believe he is planning the conversion seminar for 2:30 Sat, That is the last seminar, and will give us a ton of time to answer questions and brainstorm the group for other input (we are not the experts, we are a couple of guys crazy enough to tackle a project to this magnitude). We will also visit Sonnie’s bus and perhaps others. I only wish we had the whole day! This is really sounding fun! Jim |