[quote=“mitbes, post:1, topic:7233”]…At high RPM it’s going to choke…[/quote]Is the 4000 rpm the highest you plan to go with? If not, you may wish to take into account that this is a pushrod engine initially designed for high-torque stationary and agricultural use, possibly lacking the precision revolving mass balancing required for high speed operation. You may then need to replace the valve springs with stiffer ones and maybe have aluminium pushrods delivered [quote=“mitbes, post:18, topic:7233”]…The custom manifold was cheaper than a stock exhaust manifold from Kubota…[/quote]Is that to assume that Kubota never turbocharged this particular engine? If they indeed have, it would have been inferior to the one you have had cast, simply because yours will reduce turbo lag to a minimum which is otherwise an unneccessary feature for the applications it was designed for. So, if you have yours patended, Kubota must first request your permission for producing these types of conversions for automotive use
Hey mate, I will spin it up to whatever the governor lets me but don’t really plan on going much more than 4000. These engines have a very big performance following in the USA - google “Diesel garden tractor pulling” They mostly use the D1105 or D722, which are effectively the same as what I have, and spin them to 6000+rpm on standard internals and pushrods. With aftermarket gear they are getting 10,000rpm which is ridiculous for a little diesel. They drill the governor weights, to make them lighter, and increase the spring stiffness of the governor spring. They are also running 4x the fuel I am planning, with their pumps calibrated to do 100-120cc of diesel and turbos with 75+psi of air.
I have no doubt the internals will be fine for what I am trying to do, the unknown will be head gasket and cylinder head survival. Hopefully my huge electric water pump and excess air will keep it cool.
Diesels generally run cooler, because they burn fuel almost completely.
Here, a couple moral-boosting videos 
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Sorry if I have missed the detail but where did you get the manifold printed again?
Through craftcloud3d. Google for a 10% discount code. Other option is jlpcb, worth checking both as the pricing seems to fluctuate.
Kubota two-bangers were installed in French mini cars. In the second video, the owner tweaked his engine to do over twice as fast as original:
Brilliant road trip that was.
Now imagine that 2nd one with boost.
We could be on to something here:
Never knew about these - thanks for the pointer. Certainly helps with motivation.
I have actually made a bit of progress, flywheel is machined to suit the Daihatsu clutch and the intercooler is all plumbed in. Just waiting to get my workshop space back, end of October, then I will rip the EJ out and do engine mounts.
