Crankcase Alignment

[timer]

I’ve just reassembled a 40+ (FP) model. On other engines there have been 2 short tubes to help with alignment of the crankcase halves when fitting the bolts. There were none on this. Is this normal?

[Collector Inspector]

Yep....normal.

Just make sure that the join is flush and square across the block base.

Have fun with yr engine.

BnC

[timer]

Thank you for that. The flatness is not brilliant so I have taken it apart to redo. Do you think it will be a good idea to fit the block at the same time so that the joint will be pulled flat? I’m using high temp rtv silicone in all the joints ( as well as gaskets in the block). I’ve taken the block and head off and cleaned the waterways. Thank you for your advice

[Charles uk]

Stick the paper 10 thou. cylinder/crankcase gasket only to the cylinder with RTV & replace, leave overnight, remove cylinder, remove all the RTV snots with a scalpel, oil the face of the paper gasket & replace cylinder & fasten finally.

[timer]

So Charles are you suggesting I assemble the crankcase and cylinder base at the same time to ensure that the crankcase mating surfaces are flat?
It’s a lot easier with the locating tubes!

[Charles uk]

No that's not necessary, just tighten up the crankcase while it's resting, less piston on the cylinder base, you can give it a couple of light taps with a "rubber" hammer just to be sure, sorry.

[timer]

Hi Charles I get it now. Many thanks that makes sense. I may leave the piston on as the head is not back on yet. I have a spare decent crankcase with the locating tubes but the magneto baseplate screw is absolutely tight and I think it will need a load of heat to get it out so will stick with my existing case.

[Charles uk]

You can always weld a long 8mm bolt to the end of the baseplate screw, that should be enough heat & you've got something to put a spanner on!

Plus there is less chance of heat damaging the ignition & it will only cost 1 baseplate screw.

£1.24 inc Vat, I think.

[timer]

That sounds like a good plan! I’m nervous since I dropped a previous engine after cleaning the waterways and rebuilding and it blew bubbles from the crankcase so I had to strip it again and rebuild for a second time! It also sheared a tank bolt! Not that I’m planning to let this one fall over. I think I’ll continue with the crankcase and ensure that the surface is flat. Incidentally with your experience do you think there is any diffence in speed between the hydrofan 40+ clutchless or the weedless 40+ clutch?

[Charles uk]

Props are a difficult, a lot depends on the load your asking it to push & the conditions, the Hydrofans are horrible looking props that seem to work way better than they look.

If you've got a digital rev counter & a GPS, try both out & let us know which works best in your situation, I'd wager £0.10 P that the Hydrofan wins!

But no more!

[timer]

I did some trials years ago on my Wayfarer dinghy with a gps. I actually got the 5 blade century prop machined to fit the 40+ clutch!!! But I always reckon the hydrofan direct drive is slightly faster.

Exerpt from my post on Wayfarer forum

"For anybody who happens to be interested I did trial on flat lake, no mast, no cruising gear and got around 4 knots (SOG gps) with Seagull forty + with clutch and weedless prop (12:30 gearbox) and also forty + direct drive and hydrofan prop (10:35 gearbox). Both at around half throttle engine not straining – extra revs did not give much extra speed

Tried hydrofan prop and also 5 blade century prop on clutch model and it didn’t have enough power

Also tried seagull century and got around an extra 0.5 knot but it wasn’t running very well (I borrowed the engine and it was longshaft)

So I’m sticking with forty + and clutch. I had a very interesting afternoon on my local pond!

This may be of interest to impecunious cruisers"

[timer]

The crankcase is now lined up nicely after I fastened the cylinder to it during assembly as suggested. One more query. The pin that holds the collar inside the propellor isn’t a roll pin but just a tight fitting rod made from brass. Should I get a roll pin or will this be ok?

[Nudge]

All of mine are plain brass, i think most are like this..... not sure if that is how they came or not.

[Hugz]

I've had a problem of the brass pin splitting a collar. The brass pin seems to work ok and I havent seen one work adrift. A rolled non ferous pin seems like a worthy replacement even if not original.