M10 block, modified.

[kbmb02]

Bought some engines, half-engines and parts - sight unseen - from an old ex racer (no, not Toby ... he’s not old ... or an ex) at clearance prices.

There are some interesting bits to ponder and explore. -KB

[zinz]

Unusual way to knife-edge the crank, me thinks. 

 

 

[Hans]

Not to mention the main bearing caps.

[andyleonard]

Looks like a home-grown way to lighten the crank and foam the oil at high revs. Probably the alloy? saddle straps are to keep the 2 halves of the block together when it splits.

[TobyB]

Quote

he’s not old

feeling it, recently...

 

ha- they've bobbed the bob- weights.

Err, bobbed the counterweights.  I wonder if the bob- weights got left on the counter...

 

Lighter is lighter, and if you have a saw, as the old saw goes, everything looks like it could benefit from a bit of trimming...

I have always wondered if the energy 'gained' from lightening a crank was then absorbed by the extra vibration and flex in the engine...

 

As to oil foaming, that happens no matter what you do, and good return flow management seems to help the most,

if you can't dry- sump it.

 

I don't get the straps, either- they have to be pretty incompressible, or the bolt heads would sink, with the attendant loss of crankcase oil containment...

 

t

[kbmb02]

1 hour ago, TobyB said:

I have always wondered if the energy 'gained' from lightening a crank was then absorbed by the extra vibration and flex in the engine...

 

I don't get the straps, either- they have to be pretty incompressible, or the bolt heads would sink, with the attendant loss of crankcase oil containment...

 

In my view, lightened internals = quicker to spin-up, to get out of the corners quicker and, generally, more throttle control. Seems to be that lighter pistons on the other end helps balance what’s been removed from the crankshaft.

 

This racer ran M10’s in an open sprint car roundie-round series; there are some dry sump parts in the boxes, I don’t plan on using them.

 

Re, saddle straps - yeah, curious about those. I wonder if they did anything similar in the high HP F1 M10’s. -KB

[markmac]

Cool stuff Ken.

 

Regarding the BM F1 motor, you can sort of see for your self.  Negative pressure engine build room, parts, tools....must be nice.  You can see they spent a fair amount of time inside the block grinding and polishing.

 

https://www.youtube.com/watch?v=HWnWKLVUBcM

[Son of Marty]

It looks like BMW used stock based main caps on the F1 engine so I wonder what problem this guy was out to fix with the straps. The other thing that stands out about the F1 engine built video is the cylinder bores are polished with no sign of crosshatching that I could see  maybe they were running plain cast iron rings? not much for longevity but its only got to last 1 race.

[Simeon]

He must have read David Vizard’s BMC A series book. Knife edging and steel centre strap was common treatment there (for an engine with a long stroke crank and only 3 main bearings and, well, not a BMW M10). 

[71bmr02]

Re saddle straps maybe for storage, transport?  dont see what purpose they would serve.  note number 1 and 4 straps would appear to be struck by counterweight if crank rotated.

[Son of Marty]

That maybe the camera angle, they might be there to "wipe the oil vapor" from the counterweights in conjunction with a windage tray.

[kbmb02]

5 minutes ago, Son of Marty said:

That maybe the camera angle, they might be there to "wipe the oil vapor" from the counterweights in conjunction with a windage tray.

 

I haven’t pulled that blocks out of the shipping box yet; just flipped it over, spun the crank (very smooth) and snapped a photo. Looking forward to getting on an engine stand, will report.

[Pigpen]

Nice Kenny!

I just scored an original 1500 block in a junk yard, been sitting in the car for 25 years. Pulled it and now “seasoning” it to build a Race motor...

It will get its 15 minutes of fame!

[kbmb02]

49 minutes ago, Pigpen said:

Nice Kenny!

I just scored an original 1500 block in a junk yard, been sitting in the car for 25 years. Pulled it and now “seasoning” it to build a Race motor...

It will get its 15 minutes of fame!

 

I’ve got a few 1600’s, have not had my hands on a 1500; same crank, smaller bore?

[TobyB]

Quote

In my view, lightened internals = quicker to spin-up, to get out of the corners quicker and, generally, more throttle control.

...and far faster shifting, rev- matching, etc.  I certainly like DRIVING them better.  I have always wondered if there were attendant

lap- time reductions beyond 'the driver's happier', especially if you drive the unlightened engine correctly

(clutch dumps, etc, to recover the inertial energy, and so forth.)

Yes, (before everyone starts in) I get the theory.  Having driven both, I am not sure how much of it carries onto the timing sheets.

 

In for more pix!!!

 

t