Canal Rat Posted May 17, 2012 Report Share Posted May 17, 2012 Great post Richard. I wondered how the gears were selected without a drive plate clutch. Very informative. Cheers Link to comment Share on other sites More sharing options...
RLWP Posted May 17, 2012 Author Report Share Posted May 17, 2012 (edited) Thank you. Going back to this photo: Some of the PRM boxes are available in different ratios. This one is a nominal 2:1. It is the relative sizes of this big output gear and the small pinions that give the ratio (1:1, 1.459:1, 1.196:1, 2.94:1 for a 265 or 140) Richard Edited May 17, 2012 by RLWP Link to comment Share on other sites More sharing options...
blackrose Posted May 18, 2012 Report Share Posted May 18, 2012 I've talked to the PRM man with his cutaway 150 gearbox at Crick a couple of times, but your pictures and explanation are better Richard. Link to comment Share on other sites More sharing options...
RLWP Posted May 18, 2012 Author Report Share Posted May 18, 2012 I've talked to the PRM man with his cutaway 150 gearbox at Crick a couple of times, but your pictures and explanation are better Richard. Thanks Mike. In his defence, it is easier to explain something when you can hold someone's attention to a particular feature, so the photos of a dismantled box do help. Or perhaps I'm just good at explaining stuff Richard Link to comment Share on other sites More sharing options...
blackrose Posted May 18, 2012 Report Share Posted May 18, 2012 Yes, there'a a big difference in being an expert in something and being able to get that subject across to others. I've seen university professors who were obviously brilliant in their chosen field but didn't have a clue how to convey various aspects of it - perhaps because they couldn't see it from the perspective of a novice. Occasionally one comes across people who have combined a broader range of both technical and people skills. Link to comment Share on other sites More sharing options...
RLWP Posted May 18, 2012 Author Report Share Posted May 18, 2012 Link to comment Share on other sites More sharing options...
hillyardladybear Posted August 19, 2012 Report Share Posted August 19, 2012 Hi Richard, I'm new to the forum and not a canal boater. We have a 1956 Hillyard 12 tonner with a BMC commander with a PRM 160 gear box. I replaced the clutch on the primary shaft recently and changed all the piston rings and o rings while I had it stripped down and now I have limited drive in ahead but full in astern. Any ideas what it could be? Link to comment Share on other sites More sharing options...
dew Posted April 11, 2013 Report Share Posted April 11, 2013 I have heard that the prm 100/140 is the old version of the 160d and have read here that the difference between the 160 and the 260 is that 260 is metric and 160 is imperial. Is this all correct? Could I buy a prm 100/140 and fit it to a 1.8d 4000rpm and it be ok? If I can and the bolt holes for the bellhousing are the same I'll be very pleased. Link to comment Share on other sites More sharing options...
lexicon Posted April 11, 2013 Report Share Posted April 11, 2013 Be surprised if you can find a 100 as its a old box Link to comment Share on other sites More sharing options...
dew Posted April 11, 2013 Report Share Posted April 11, 2013 Yeah, there is one on ebay.. type in prm 100 and u'll see it. Do you think it would fit and be up to the job? Link to comment Share on other sites More sharing options...
Timleech Posted April 11, 2013 Report Share Posted April 11, 2013 Yeah, there is one on ebay.. type in prm 100 and u'll see it. Do you think it would fit and be up to the job? Some of the older PRM models use a different spline on the input shaft and you might have trouble getting a drive plate which fits. Tim Link to comment Share on other sites More sharing options...
RLWP Posted April 11, 2013 Author Report Share Posted April 11, 2013 ASAP have manuals and installation drawings for both: http://www.asap-supplies.com/marine/spares-and-accessories-for-prm-100-gearboxes http://www.asap-supplies.com/marine/spares-and-accessories-for-prm-260-gearboxes Both are free downloads, you can now check the shafts and mounting bolts Richard Link to comment Share on other sites More sharing options...
dew Posted April 12, 2013 Report Share Posted April 12, 2013 Thanks for that.... I have discovered that the splines and bolt holes are the same on the prm 100, 101, 140, 160, 260 which I am not sure now if it's good news or bad news. I know some parts aren't available for the older models but prm seem to be the most versatile with them being able to run both directions as forward.. lh or rh props. OH! and I have discovered that prm box input shafts need shortening by 30mm when used with a Ford xld or linx / endura block using the bellhousing from Lancing Marine. My first instinct is to chop the end off with a grinder but have a strange feeling that isn't the right way to do it Link to comment Share on other sites More sharing options...
Timleech Posted April 12, 2013 Report Share Posted April 12, 2013 Thanks for that.... I have discovered that the splines and bolt holes are the same on the prm 100, 101, 140, 160, 260 which I am not sure now if it's good news or bad news. I know some parts aren't available for the older models but prm seem to be the most versatile with them being able to run both directions as forward.. lh or rh props. OH! and I have discovered that prm box input shafts need shortening by 30mm when used with a Ford xld or linx / endura block using the bellhousing from Lancing Marine. My first instinct is to chop the end off with a grinder but have a strange feeling that isn't the right way to do it Sounds like good news to me. I know it's not true on some of the bigger models. Yes, chop it with a grinder, why not. Don't get it too hot (use a 1mm cutting disc). Put some tape around the oil seal where the shaft enters, to keep out grinding grit. Carefully chamfer the end and remove all burrs, otherwise you'll have the devil's own job entering the shaft into the drive plate. Clean the splines thoroughly to remove all grit when you finish. Tim Link to comment Share on other sites More sharing options...
Bee Posted April 12, 2013 Report Share Posted April 12, 2013 That is an excellent posting, thanks, that's actually an impressive bit of engineering, I took a technodrive box apart years ago, brand new and it seized, removed a couple of shims from the end of a shaft to give it a bit of clearance and it worked ok but I was not impressed. There`s a micrometer in one of the pics, did you put it there for effect? Sorry, pressed wrong button, should have continued with...... `cos that's what I`d have done or can you actually read the things? 1 Link to comment Share on other sites More sharing options...
RLWP Posted April 12, 2013 Author Report Share Posted April 12, 2013 That is an excellent posting, thanks, that's actually an impressive bit of engineering, I took a technodrive box apart years ago, brand new and it seized, removed a couple of shims from the end of a shaft to give it a bit of clearance and it worked ok but I was not impressed. There`s a micrometer in one of the pics, did you put it there for effect? Sorry, pressed wrong button, should have continued with...... `cos that's what I`d have done or can you actually read the things? Cheeky bugger! Yes, I used the mike to check the thickness of the shims to get the right endfloat If I had been placing a tool for effect, it would usually be a hammer Richard Link to comment Share on other sites More sharing options...
dew Posted April 12, 2013 Report Share Posted April 12, 2013 Sounds like good news to me. I know it's not true on some of the bigger models. Yes, chop it with a grinder, why not. Don't get it too hot (use a 1mm cutting disc). Put some tape around the oil seal where the shaft enters, to keep out grinding grit. Carefully chamfer the end and remove all burrs, otherwise you'll have the devil's own job entering the shaft into the drive plate. Clean the splines thoroughly to remove all grit when you finish. Tim Thanks Tim. I'll do it myself. Thanks for the advice. Link to comment Share on other sites More sharing options...
Timleech Posted April 12, 2013 Report Share Posted April 12, 2013 Thanks Tim. I'll do it myself. Thanks for the advice. Another bit of advice. Make sure you cut it in the right place. Tim Link to comment Share on other sites More sharing options...
dew Posted April 13, 2013 Report Share Posted April 13, 2013 Another bit of advice. Make sure you cut it in the right place. Tim From what I understand, its 30mm from the end but to measure, ill put grease on the shaft and try to install, the pushed aside grease should give me a depth of the stop on the shaft itself, then when at the stop, ill measure the gap between the plate and the box and that should be a bit less than 30mm. If 30 doesn't look like it will work then ill go half way between the difference in the measurements? Link to comment Share on other sites More sharing options...
RLWP Posted April 13, 2013 Author Report Share Posted April 13, 2013 You should be able to work it out with some kind of straight edge across the flywheel housing, a rule, a bit of paper and a pencil Richard Link to comment Share on other sites More sharing options...
dew Posted April 13, 2013 Report Share Posted April 13, 2013 Oh, BTW. Am I right in thinking PRM are the most versatile and long lasting boxes? Also, I am in two minds whether to get a 2:1 or a 1.5:1 box for a shaft drive. On my gland at the minute, there are no leaks while travelling at 1500 rpm and the gland is stone cold. At 2000 I would be happy the gland would still be cold and not too stressed at a maximum of 2600 ish. It would seem so much more sensible to be able to keep a smaller prop and go a bit faster with it. I understand the prm 150. You should be able to work it out with some kind of straight edge across the flywheel housing, a rule, a bit of paper and a pencil Richard oh yeah lol.. trust me to think of the hard way.. a stick poked down the hole and a bit of straight paper across plate. Thanks Link to comment Share on other sites More sharing options...
Svdrummer Posted April 21, 2016 Report Share Posted April 21, 2016 I have a pr160. On a routine test run (between pylons) I started the engine, a few mins later i put the gear into forward. The prop turned for a few seconds, then reved high with shaft no longer turning. I got the manual out which states that if the shaft will not turn forwards or backwards, then this is the oil pump. Remove oil hose to cooler and check for oil. No oil comes out. I removed the oil pump and by hand turning the spindle, i can see oil is moving what residual oil is in the pump. I started the engine with the oil pump off (few seconds) the bar with a slot in it, which connects to the oil pump didnt turn. This would explain why the oil pump is not giving pressure to clutches. I am not a mechanic. Does anyone know what the next thing to check may be? I am in Brisbane, Australia with no access to a mechanic this will come to a boat. Any advice is apreciated. Link to comment Share on other sites More sharing options...
RLWP Posted April 21, 2016 Author Report Share Posted April 21, 2016 I would check that the driveplate is OK. If the 'bar with a slot' isn't going around, I doubt anything inside the gearbox is Richard 1 Link to comment Share on other sites More sharing options...
Svdrummer Posted April 21, 2016 Report Share Posted April 21, 2016 (edited) Thanks Richard. I have been looking on line and, even though a prm160 manual was on this 30 year old yacht (i live on this) i noticed my gearbox has an oil filter built in. By looking at the newage website, this would mean i really have a prm140. I also have the forward and reverse lever on top, not on the side. Excuse my ignorance, but, i looked in the manual, and cant see anything marked as a drive plate...i did see another manual say an input drive plate, but no picture to show where it is. I was only testing the boat so i could get an overdue antifoul. Now, i am not going anywhere. Is the drive plate the bit that attaches to the engine? By the looks of mine, to remove my gear box, i will have to take the bell housing off the engine and chock it up at the bell housing has the engine mounts on it. I did get a pdf off the newage web site under the "old gearbox" section. The fault flowchart says oil pump or input drive plate, but none of the exploded views indi ate a drive plate. Is the drive plate a common fault, could it mean i have something bound up inside causing plate to snap. Apreciate your time. Terry Edited April 21, 2016 by Svdrummer Link to comment Share on other sites More sharing options...
WotEver Posted April 21, 2016 Report Share Posted April 21, 2016 Is the drive plate the bit that attaches to the engine? Yep. It's the plate which takes the engine output and 'drives' the gearbox. They usually have some kind of shock-absorbers built in and they can break up. However, Richard is the guru on these matters so I'll shut up now and allow him to give a fuller reply. Tony 2 Link to comment Share on other sites More sharing options...
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