A dyno or rolling road that you think is running that far out is a sack of cack, and not worth using !

Where is the power loss - engine, gearbox, driveline, rollers, software, cooling system...  Bin it and find a proper one.  ALL dynos when set up properly should read within a BHP or two, so to lose 30% is plain unacceptable.

Having said that, the inline Sprite figures suggest it may be more accurate than you think.

The Janspeed road I use is calibrated regularly and matches the Slark one, which in turn has been shown to be within 2hp of the Swiftune dyno cell, so I'm pretty sure on my numbers.   Aaaaanyway.

12G295 head with slightly larger valves and light porting.  Not a fan of 1275 heads on a smallbore unless it's a small port SC 7-port head or has forced induction.  The MED RS cam is only 264° instead of the 276° Piper 270 I'd asked for.  May give a smidge more torque lower down, but ran out of puff at about 6200rpm.  The bottom end is built for 7500+rpm so it'd pull an SW10 or 285 cam but balls-out high rpm power isn't the total aim.  I'm hoping to get closer to 65 whp or 80-odd at the flywheel, though Janspeed don't usually do the wind-down transmission loss conversion so I may need to pop into Slarks for that.

Hi Alex!

Is yours a 3" stroke? 1275 head? I built this intending to have quite high compression and I succeeded! After this running tme, I got 210 PSI all around. I'm using the Elgin 103 cam, and am astounded at how low and smooth this idles, even with this Weber45! While not running on JP1, I am using the Sunoco Race fuel so far,  as I did not want to risk not being able to stop it using the clutch if it wanted to run on...

I would be thrilled to see your target power numbers.  But I think the dyno I know, the guys that Mini Mania have used during their "Open House" events reads lower figures, as nice 1380 cars were showing about 60HP at the wheels.  My 1380 produced 86 on that very hot 100 degree Plus (Fahrenheit!) day!  MM still use that dyno graph from my car in advertising...  On that scale, my target is 40-45 at the wheels.  The only small bore I've seen dyno'd was a beautiful Morris Minor with a fresh about .040" over 998 belonging to our friend Bruce Blair (Bruce's Morris Garage). I shouted out "22 HP" as they were setting it up, and after lots of messing about, they got 23!!

Speaking of power, my current race 1380, with MED crank, 6" rods and the Mini Spares alloy race head last dyno'd at 121HP at the (rear) wheels. My new engine going into a 66 Sprite is a multi web straight rod 1380 with MED 'Series 6' head to my specifications.  My target is 100HP per litre, so trying to get close to 138 at the wheels. Car being built now, should be on dyno in the coming weeks.

I think you started your 68mm engine just after I did.  The cam I fitted wasn't as lumpy as I'd thought (thanks MED) and I was missing 12° of duration so it's apart again at the moment for a refresh.

Target to aim for with just softer than a 266 cam is 60 hp and 60 ftlb at the wheels.

Ah, neighbors!  Only 3 or 4 within irritation range! Most are residents of a historic gold rush era cemetery, just outside of town, and those folks don't complain much!  Also for the locals, I try to start engines on days when gunfire from the Sportsmen's Club nearby provides a distraction!

Now, keep in mind this is only a tiny engine that I'm having some fun with, and I've given several hints about the "funny sound". 

My son "should" be in his 30s.... but I got a late start!  He's 4!  Hoping he'll do most of the actual work soon!

At first I thought you had dubbed in some jet engine start up sound track! Interesting. Oh and learning the dad part never stops. My kids are in their 30s and early 40s. It just never stops...

Oh yes, more details than you can stand as I 'designed' this engine and put it together in between my race engines and learning to be a dad! We've won several class championships with our #59 Bugeye based in Vancouver, BC, but I'm still learning the dad part!

Also been refining my YouTube channel and taking much more time to edit videos. I try to put projects in Play Lists like this one for the "Super Small Bore experimental engine".  I keep the videos short and show the good stuff... not much more than 4 minutes. I just can't take the 45 minute videos with excruciating, irrelevant details!

(I think this should be the play list.... MM seems to have done something here to prevent a hyperlink...)

Is that the CUstom Neighbor Hater exhaust?  Get'em Both Left and right?

Nice!

Nice build Jemal, care to share the specs?

I've been working on this one since I was at Mini Mania! Thanks Brendan and Tony for your patience helping me source all the odd bits!

Finally started it the other night.  The snow falling made it feel right at home, a nice cold start...