RFguy Posted July 8, 2022 Posted July 8, 2022 How do people hang their 912s ? I have chain hanging from the purlins, I have loads of D shackles, chain blocks, slings of zillion sizes etc straps, cant put a sling under each side of the cylinders- there are pushrod tubs there I have seen people hang etc off the intake manifolds, seems a little crude, I dont think Goring had that in mind ! but I guess well think the tension rating of those head screws I want to keep the mount screws locations free. thin sling under gearbox and another under rear just in front of the water kit ?
BrendAn Posted July 8, 2022 Posted July 8, 2022 Nothing wrong with hanging off the manifold . That's how small and big block V8s are lifted. The adaptor bolts to the carby threads. 1
Blueadventures Posted July 8, 2022 Posted July 8, 2022 This may help, can not verify correct, The factory approves lifting the engine using flexible straps looped around the intake manifolds. Another way is to loop a flexible strap under the crankshaft/prop hub in the front and behind/under the accessory case in the back (be careful not to tweak any wires back there). Two or three friends work well too! The ROTAX is very easy (a one-man job) to mount on the RV-12. 2
IBob Posted July 8, 2022 Posted July 8, 2022 (edited) There are a couple of threaded holes in the top of the engine, approx 150mm back from the gearbox. A fellow builder lent me bolts with the bracket he made to go on there. The lift here is on that bracket on the shackles you can see. The strop is on there just in case, and under no load. You can see one of the holes in the second pic. Edited July 8, 2022 by IBob 4 1
IBob Posted July 8, 2022 Posted July 8, 2022 Suggestion: Before installing engine, remove rear engine cover and check ignition coil and trigger gaps are set correctly. This is best done with non-ferrous feeler gauges (some sets include a selection of brass gauges) as the rotor magnets will stick to steel gauges, causing the gap to feel snug even when it is not. In the absence of non-ferrous gauges, ensure the next size up is no-go. This is generally easier to check with the engine out. These coils provide both the power and the trigger for the ignition, and correct setting is critical to good starting. We have seen one instance of incorrect large gaps on an older engine causing poor starting, with resultant expensive clutch damage. 1
RFguy Posted July 9, 2022 Author Posted July 9, 2022 (edited) Thanks Bob. I will do that, that's an easy one. and thanks everyone for their input. Engine is now hung, currently front and rear. I have a ring mount, seems there are many variations of ring mounts... mine isnt 'original rotax' but something else, but well made. So what's the story with getting the lower left (from the rear) around the water bits at the bottom. ? I have read that juggling is required, and it depends on how the mount was welded up- is adjusting/removing the water outlets required in some cases, or should I persist ? glen Edited July 9, 2022 by RFguy
IBob Posted July 9, 2022 Posted July 9, 2022 (edited) Hi Glen, I can only speak from the experience of my own build: 1. The engine was much easier to fit to the ringmount supplied, by first removing the coolant pump cover with it's coolant outlets. 2. After fitting the engine to the mount, the pump cover was easily refitted, but the position of two of the coolant outlets had to be adjusted to allow the hoses to pass through the ringmount. 3. This was done by holding the cover gently in vice softjaws, gently heating the required outlet and rotating it by pushing on a piece of dowel inserted in the outlet. I made these adjustments several times before getting them right, and was concerned that I may have leakage as a result, but there has been no problem. The pump outlets are a soft alloy with a fine thread secured with Loctite 243, which requires a moderate amount of heat. (The coolant inlets at the cylinder heads are a similar fitting with the same fine thread, but a higher temperature Loctite is used there, requiring considerable heat for removal. I have replaced one cylinder head port, it was a difficult job which took me three attempts to achieve a leak-proof installation.) Edited July 9, 2022 by IBob 1
RFguy Posted July 9, 2022 Author Posted July 9, 2022 thanks Bob. Just read through the Rotax maintenance- overhaul chapter on that. probably should get a gasket for the refit.
danny_galaga Posted July 9, 2022 Posted July 9, 2022 At the weight were taking about, you could also talk a couple of tall, stout mates to hold it for you 😃
RFguy Posted July 9, 2022 Author Posted July 9, 2022 Yeah. I managed to pick it up and put it on the bench my myself but that wouldnt stretch to holding with one arm and thigh and putting the mount together.
Marty_d Posted July 9, 2022 Posted July 9, 2022 Do get a gasket - they're only $12 or so and it's very likely you'll rip it when removing the water pump (which you have to do unfortunately!)
Marty_d Posted July 9, 2022 Posted July 9, 2022 Whoops, too late. Didn't see your photo before I posted.
RFguy Posted July 9, 2022 Author Posted July 9, 2022 (edited) Will need the oxy on the mount struts . pump gasket is just a pain because need to clean the flanges. lower mount holes are not in perfect alignment. However they DID get the width perfect, slightly interference fit on width on top and bottom. anyway, something to look at carefully in the week with lots of light. Edited July 9, 2022 by RFguy
onetrack Posted July 10, 2022 Posted July 10, 2022 Just remember - the engine doesn't know, if the mounting holes are out of alignment! When I find things like that, I start to wonder about what else that hole-driller installed to perfection!
RFguy Posted July 10, 2022 Author Posted July 10, 2022 the engine is drilled/milled correctly. the mount is not. *groan*. nothing an oxy cant fix. will need some deformation of the support struts of that corner. not much. needless to say, I'll be keeping an eye out for mount cracks. next thing 17mm ID hose....
BrendAn Posted July 10, 2022 Posted July 10, 2022 4 hours ago, RFguy said: the engine is drilled/milled correctly. the mount is not. *groan*. nothing an oxy cant fix. will need some deformation of the support struts of that corner. not much. needless to say, I'll be keeping an eye out for mount cracks. next thing 17mm ID hose.... What sort of 17mm hose. Water. I had to replace 2 800mm lengths of 17mm heater hose on one of my trucks. Isuzu wanted $700 for the 2 pieces. I bought a 50 mt roll for $160. I have 48mt left If you want any. 4
RFguy Posted July 10, 2022 Author Posted July 10, 2022 Thanks Brendan. So there is someother mfr using 17mm. (not 16 or 19 the two popular sizes) I'll probably use the silicone reinforced 17mm hose I can buy, since its around the exhaust system... but I might contact you you about the top half (cooler) . cheers. glen 1
BrendAn Posted July 10, 2022 Posted July 10, 2022 1 hour ago, RFguy said: Thanks Brendan. So there is someother mfr using 17mm. (not 16 or 19 the two popular sizes) I'll probably use the silicone reinforced 17mm hose I can buy, since its around the exhaust system... but I might contact you you about the top half (cooler) . cheers. glen no worries.
facthunter Posted July 11, 2022 Posted July 11, 2022 White is a great surface for fabricated engine mounts for sighting cracks best.. Don't have the paint very thick. I've used a thin coat of white etch satisfactorily. Nev 2
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