Forum

[Alan R]

Good stuff, Stinkwheel...........Don't forget that EVERYTHING relating to the barrel
( and therefore head as well ) will now be 5mm different..eg The exhaust pipe and its' mountings will need re-aligning.....The carb will that much higher as will the inlet air trunking..and also your head steady bar....As 'er indoors said to me recently}----"You're doing a good job, keep it up" !!

[stinkwheel]

Well. Oil tank level sits higher than I'd expected according to this dipstick, which is the one it came with.

[stinkwheel]

Try those again:

[Wayne]

Stinkwheel - the design of these long stroke cranks have changed over the years and now the 5 mm spacers are no longer required, of course as with all tuned engines - these must have a dry build to check clearences etc and the previous comments made were made in good faith but I thought I had better mention before you built an engine with 8 : 1 compression !

[stinkwheel]

Thanks for that. I'm going to physically measure the compression ratio anyway. Got a burette on order. I'm quite looking forwards to doing some of the more enigmatic aspects of engineering like plastiguaging end float on cams and calculating compression ratios.

[Alan R]

Good stuff O wheel that doth stink !!.........At this rate you'll be up for an HNC (Mech.E).....Keep going, we are all behind you !!

[stinkwheel]

Just dropped the cases in with the engineers today.



As you'll know, the exhaust cam comes VERY close to the crank seal and the standard advice is to burr away the alloy until the cam fits.







That leaves almost nothing supporting one edge of the seal (picture from our hosts fitting instructions).







Local engineer loves doing stuff like this up and he says he can press out the cam spindle, measure up the cam rotating diameter then centre the crankcase on his boring bar over the cam spindle hole. He reckons he can then tool it with a longish cutter to undercut the seal seat to the exact diameter and depth required for clearance on the cam while leaving the seal seat unmolested. In much the same way as it is now, only deeper.



Glad I asked before diving in myself with the pneumatic burr.



He also questioned why they bothered knocking a recess out of the crankcase casting for the two topmost "blind" crankcase studs other than to as a vehicle for trapping dirt and corrosion when they could have run through the alloy all the way through. I said you stop asking questions like that after working on Enfields for a bit. It's what they do, there may once have been a good reason that's lost in the mists of time and now they just do it because that's what they do.

[Chris Tindal]

There must be more room on Indian casings than Redditch ones. A previous owner modded my 59 500 cases to take a timing side oil seal rather than just the bronze bush. In doing so he cut right through into the cam area so that the seal penetrates through and will therefore allow oil in behind it. Be aware there's very little alloy between the cam and the crankshaft.

[Alan R]

Hi matey !!-------- If I'm reading your chap's idea correctly he wants to machine a cavity below the seal housing without cutting down through the seal housing itself ??.........Is that the case ??...OK, if you do it that way how will you assemble the gearwheel/cam unit onto the shaft ??........You'll have to place the cam/gearwheel unit in position first ( ie ---with the cam inside the newly-formed cavity ) then push the shaft through the gearwheel and into the inner casing.....Then later on, how will you remove the camwheel ???

Personally I'd stick to our hosts method as the amount of "Almost unsupported" seal is very minimal........More important is the point raised by Chris Tindal}--- Be VERY CAREFUL not to break through behind the seal and thus effectively by-pass it...........I hope your man is a skilled machinist and can handle a vertical miller proficiently ??...........PS}--- has anyone tried actually reducing the cams' lift ( In order to make it fit more easily ) and relying more on the overlap for power increase ??

[stinkwheel]

The cam slides straight onto the shaft providing the lobe is pointing roughly away from the crank. There's a roughly 270 degree arc of rotation where the cam doesn't interfere with the casting at all.



To assemble it correctly timed, I can fit exhaust cam first, then the timing pinnion then the inlet cam.



Yes he's a very skilled machinist. The stated clearance is 0.02" round the highest point of the cam so that's exactly what I'll get. In a perfect circle. He'll be using the boring bar normally used for reboring cast iron liners to a WAY finer tolerance than that. It's a proper piece of 1950's british machinery he bought when tru grinds in Carlisle shut down. Also huge, they built the workshop extension around it. I should take some pictures of this guys workshop some time. He has over 20 lathes.