![Very Happy :D](./images/smilies/icon_e_biggrin.gif)
*all of the kits in Sticky's book were just assembled with no attempt @ port matching/optimising which suggests to me that there is scope for further gain.
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Warkton Tornado No.1 wrote:That makes sense to a great extent. The only flaw that particularly applies to the very conservative port timings of the RT is that with the extra 4 mm stroke I would advise that the durations are raised to @ least pro rata. It can be done with care & the correct tooling as I have done to plated bores. The image herewith depicts porting WIP.
dickie wrote:Warkton Tornado No.1 wrote:That makes sense to a great extent. The only flaw that particularly applies to the very conservative port timings of the RT is that with the extra 4 mm stroke I would advise that the durations are raised to @ least pro rata. It can be done with care & the correct tooling as I have done to plated bores. The image herewith depicts porting WIP.
Yes Mark, it's not going to be completely straightforward with a 62 stroke crank, but who wants straightforward anyway? I might take the exhaust up to around 180 as I was surprised how easy my 175 was with 178 exhaust duration. It'll probably depend on what mood I'm in at the time. I've never worked on nicasil bore before but I guess you just use hard stones instead of diamond burrs? And take your time of course.
Anyway that's probably not going to.happen until winter.
Fast n Furious wrote:Stick the crank in an ultrsonic cleaner containing some very warm neat oven cleaner for 30 mins. Wash it clean and then check it.
Storkfoot wrote:Is it possible to properly measure the piston to bore clearance with feeler gauges?
dickie wrote:Well, it seems nobody knows what that gasket is from or they're not interested![]()
Anyway, the top end came off without any drama and isn't very worn at all, but is at the top end of acceptable wear. 0.5mm ring gap and 0.006" bore clearance (inaccurate as I only measured using feeler gauges).
There's quite a bit of blow-by and lots of carbon build up in the bottom end.
Also, the crank and big end seem to be in decent nick although obviously need carbon cleaning off.
So I'm wondering if I could just renew the piston rings and put it all back together after a good clean. Of course I could, but is it advisable? How much difference does it really make?
The thing is that I'm trying to replace as little as is reasonable. For example, the big end feels like there is no play and is smooth, but can I really tell without getting it rebuilt?
Advice please?
dickie wrote:Which way do these go?
I think the protruding tube goes inwards to make contact with the cones in the frame, but I'm not sure and the ones I took out seemed to be the same both ends; due to wear I'd guess.
And what should the distance between them be? Having (nearly) always fitted later large type before it's not something I've had to think about.
Anyone know for sure?
Warkton Tornado No.1 wrote:Brand new, unfitted, such pre-stressed moulded bushes would usually be symmetrical. Inevitably, rubber creeps during use, but the bush depicted will pull back to shape. I'd fit the protruding part LH side outboard just to make fitting engine to frame easier as well as that may be the softer bush of the two you have there.
dickie wrote:Warkton Tornado No.1 wrote:Brand new, unfitted, such pre-stressed moulded bushes would usually be symmetrical. Inevitably, rubber creeps during use, but the bush depicted will pull back to shape. I'd fit the protruding part LH side outboard just to make fitting engine to frame easier as well as that may be the softer bush of the two you have there.
I get what you're saying Mark, but I'd already decided to fit them both with the protrusion against the cones. My reasoning is that I don't want the outer bush making contact with the frame or cones and restricting engine rotation.
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