LD32 Engine build

[MCBladeRun]

I have no idea about fluid dynamics (or whatever it's called) but if a circular cross section tube is squashed into an oblong would it still flow the same? The cross section won't have changed, just the shape.

A circle has the most optimal cross sectional area (given the circumference). When it is squashed slightly, it would be a smaller cross section, but the same circumference. You're talking only a slight difference between the two.

I would have thought overall, it would be likened to adding an unnecessary bend, slowing the flow rate down?

 

[Bazzateer]

Sounds about right. When it comes to this stuff I'm like Manuel, "I know notheeeng"

 

[jonbills]

I found another thing that needed adjusting.
A friend pointed out that the fan belt was not running true, and my alternator was maybe 5mm forward of the right line.
So I cut 5mm or so off the front of the cast alternator bracket and moved it to the back. Sorted.


The engine went well at Santa Pod yesterday although I didn't equal the 12.97 the L29 managed on carbs a couple of years ago.
Next up, retard the cam timing to where it was on the old engine. More revs, more powah.
And the car is booked in at BTB exhausts to gave the exhaust modified to miss the the gearbox mount.
And then a rolling road session somewhere.

 

[peter_s]

Following with great interest!

 

[jonbills]

Last week I dropped the car off at BTB Exhausts to get my exhaust better aligned and stop it rattling on various bits of the underneath (gearbox mount and diff, mainly).
I picked it up today and the irritations are fixed, and I've already pushed the rev limit up to 7700. The old engine used to love to rev to 8k and beyond, but this new one wasn't so keen past 7k, and I was thinking I'd got something not quite right in the build, but it's a joy to rev today, so I'm very glad I took it there.

The main work was to build this new Y pipe to compensate for the lower and different angle of the engine.



And I think a number of tweaks along the rest of it, as well as re-hanging it better.

 

[Rob Gaskin]

Just a thought, if you go to a 90mm stroke do you have issue with the conrods hitting the block? I'm not following all this in any detail but just checking that a long stroke isn't a problem in that respect?

 

[jonbills]

Just a thought, if you go to a 90mm stroke do you have issue with the conrods hitting the block? I'm not following all this in any detail but just checking that a long stroke isn't a problem in that respect?

Yes, even with a 83mm stroke you have to notch a petrol block. The LD block has notches built in, but I'm sure you'd have to do more for a 90mm stroke.
Are you thinking of building one Rob?

 

[jonbills]

There was some discussion back in March on the block notches:
https://zclub.net/community/index.php?threads/ld32-engine-build.26902/page-7#post-323769