Assessing an unknown engine

hot66 · Post by **hot66** » Sat Dec 07, 2024 10:06 pm

If you can , I’d stick with mfi as it’s a great system if all well with it and it’s quite interesting system to learn about too

RobFrost · Post by **RobFrost** » Sun Dec 08, 2024 3:20 am

hot66 wrote:If you can , I’d stick with mfi as it’s a great system if all well with it and it’s quite interesting system to learn about too

I'd like to if I can... but i have opted for 86mm high compression pistons and more aggressive cams than E. So getting the right space cams for the pump might be tricky.

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hot66 · Post by **hot66** » Sun Dec 08, 2024 7:23 am

I’m running high comp 10.5 with slightly different S cam… I didn’t need to change the space cam in the pump. The extra displacement isn’t massive .

Although I did take a bit of advice from Mark Jung. He rebuilt my pump and did some base setting changes to suit my engine spec. Just settings though, no mechanical changes or upgrades.

https://www.mfiwerks.com/about/

matteo68 · Post by **matteo68** » Sun Dec 08, 2024 9:20 am

I didn’t realise your engine wasn’t stock James?! No wonder you’re so quick on road trips!

RobFrost · Post by **RobFrost** » Sun Dec 08, 2024 11:02 am

Inspired by Graham's suggestion of some slip gauges, I thought I'd calibrate some steel bar i have for another job...

8 hundredths of a mm difference from one side to the other. Engineering is all new to me right now (although it's mostly common sense) but it just goes to show how careful you have to be.

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hot66 · Post by **hot66** » Sun Dec 08, 2024 11:04 am

Yep, only mild mods , but high comp twin plug with Neil Bainbridge light alloy pistons , lightened flywheel etc etc . Gives the motor loads of character

911hillclimber · Post by **911hillclimber** » Sun Dec 08, 2024 1:00 pm

Rob, as you say, mostly common sense, you just need to keep things simple and literally measured.
I would be surprised to see a difference in all six heights from seal face to barrel base.
I think there are 3 heights in these engines.

matteo68 · Post by **matteo68** » Sun Dec 08, 2024 1:18 pm

hot66 wrote:Yep, only mild mods , but high comp twin plug with Neil Bainbridge light alloy pistons , lightened flywheel etc etc . Gives the motor loads of character

210 bhp?

hot66 · Post by **hot66** » Sun Dec 08, 2024 4:31 pm

matteo68 wrote:
hot66 wrote:Yep, only mild mods , but high comp twin plug with Neil Bainbridge light alloy pistons , lightened flywheel etc etc . Gives the motor loads of character
210 bhp?

Straight off Neil Bainbridge’s engine dyno was 216bhp back when it was built , with the thought it might loosen up.

matteo68 · Post by **matteo68** » Sun Dec 08, 2024 4:52 pm

hot66 wrote:
matteo68 wrote:
hot66 wrote:Yep, only mild mods , but high comp twin plug with Neil Bainbridge light alloy pistons , lightened flywheel etc etc . Gives the motor loads of character
210 bhp?
Straight off Neil Bainbridge’s engine dyno was 216bhp back when it was built , with the thought it might loosen up.

Nice!

neilbardsley · Post by **neilbardsley** » Sun Dec 08, 2024 5:41 pm

Counter sunk screws surely?

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911hillclimber · Post by **911hillclimber** » Sun Dec 08, 2024 10:35 pm

They are Neil, just the head size is large.

Many fastener standards are now in place that were not in the 60's. Lots of people made their own fasteners in-house and unique to them then, not so much today.

I've found this on all the bikes I've restored over the last 10 years, English, Japanese and French.

RobFrost · Post by **RobFrost** » Mon Dec 09, 2024 3:04 pm

I had a chat with Ken Newman at Newman Cams. He said the cams are in great condition. Hoping to get them back to me this side of Christmas with a bit of a more modern grind and hotter than E. But I've not gone crazy as I'm using standard rods and springs... Maybe the next build if I ever do this again will be the high-revving beast.

RobFrost · Post by **RobFrost** » Tue Dec 10, 2024 10:14 pm

I was back at the machine shop in Hinckley again at the weekend. Sand blasted this.

I'm undecided whether to spray paint it or power coat.

And a bit of work making some tooling. I'm not sure I'll achieve the level of accuracy I need, but I'm learning as I go.

What I've learnt is that these jobs are 99% setup. The milling process is a fraction of the work. But i don't seem to have the shims and jigs I need for precision workholding. I'm usually pretty resourceful but it's challenging to say the least, not having a Pandora's box of engineering paraphernalia.

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911hillclimber · Post by **911hillclimber** » Wed Dec 11, 2024 8:59 am

Dead right. The way you go about things on any machine tool to keep accuracy is key to the outcome, but you don't need everything out of the catalogue, but you do need good essentials.

Doing machining is another world and why farming it out is expensive, lots of time spent!

IMHO, paint the air box rattle-can, Hammerite smooth black, really glossy without the thick coating of the powder. Keeps everything looking 'factory'.
UPOL etch primer is a very good base

DDK - Die Deutschen Klassiker