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I've gotten a buddy who's been playing the lean burn game since the early 70s I think and swears that as long as you aren't measuring measuring stuff like NOx you can get pretty good mileage out of it. The new tech seems to claim they've fixed the emissions.....but I'm not really sure I personally care about that too much.

As I may well be the buddy that Markie mentioned, I'll chime in.

I run a '68 OHC-6 'Sprint' with a sort'a homegrown EFI, 13 to 1 CR, 45+ deg advance and 19.5 to 1 AFR (two gages in two headers) from off idle to WOT, regular gas--no detonation and moderately good performance--4-speed with TCC gives me 40's MPG. BTW, haven't used a cooling fan in decades.

My thoughts on how/why it works? Lots of CR, lots of SA, nice wedge chambers with good plug placement and .025 quench clearance (yep, no slap) and clean living.

How far can lean op go? Last Fall, the Lift Pump (drags fuel from the 50 year old tank to a 'swirl pot' that gravity feeds the high pressure pump) blew its fuse and the one I replaced it with--50 miles from home. But it ran! Backfired at WOT but accelerated, albeit slowly. Fuel pressure gage failed (I accidentally pulled the sense lead scrambling to replace the pump fuse) but fuel pressure had to be miniscule with the high pressure pump somehow getting fuel from the rear of the car, through the dead lift pump, into the swirl pot and to the injectors! Both AFR gages were 20+ (their limit). Got me home just fast enough that an underwear change seemed unnecessary...

Now, if I am not the bud Markie mentioned, ignore all the foregoing.

Paul S

Paul, were you working with Cooper Superior on their lean burn engines back in the late 80's?

I remember a guy named Paul who was trying to sort out the torch ignition on these injected engines (medium speed Mitsubishi's being converted to gas from diesel). I recall it was a PITA to get them mapped.

No, cribbj, I'm a mere hobbyist, aerospace engineer and dabbler in the fine arts of software at the behest and encouragement of Mr. E.

I started out in the early 70's putting leaner and leaner jets in the Quadrajet of my SPRINT, then moding the distributor for more advance to quell the misses and get something like real gas mileage, then building engines (OHC6's, cause I love them so) with greater CR and reduced quench clearance (mixture turbulence, burn rate and detonation suppression). Then along came EFI...

BTW, used water injection before I could use EFI (haven't used Premium fuel in 40 years). Now don't bother with that at 6000' where I live and the very lean WOT.

Paul S

Yup , I meant you Paul

I'm honestly amazed that thing runs good at 13:1 on regular!....do you ever actually open the throttle?

.025" squish is tight too...I thought I was being aggressive at .035"

In other news I was in the shop for almost an hour last night. I cut a bunch of bolts to a more useful length and started bolting the seal plates to the 1st head before being called back up stairs

Soon.....

Very exciting stuff....cut bolts and plates bolted to the head! It's forward motion at least. I spent a couple hours tonight getting that done and cleaning up the head. I still need to make something to bolt to the coolant exit port but I'm almost ready to test it.....progress at least right?

I still read FC and a 19yr old kid asked" Daddy will buy me a car for college and ALL those old hacks steered him away. tp porch,,,,same deal for me in 72,250 SWB.$12000 for FCA Winner.GTO were $35,,,,bump

The vibe on FC and to be honest a lot of forums is a bit harsh......not here though!

....unless you say something I don't like

Sorry its been so slow.....life has just been all consuming. I gave notice at my day job yesterday and will be off to a new job the end of the month and I'm sure that will be crazy for a bit, but for the next couple weeks I'm not really responsible for anything other than finishing anything and everything Lana can think up (its the mulch I thought I'd dodged at the moment).....I'm really really going ot try to get the frikin heads fixed.....I still don't have the valves....time to email again.

I see the engine and imagine that during the days you are the team technical boss for one of the F1 teams, then I worry that maybe you're an accountant, hospice nurse or patent clerk or something. What DO you do during the days?

Whatever your endeavor, here's to wishing you all the best on the next chapter of The Big Adventure.

No F1 team for me....I design medical devices at the moment. I used to be a prototype machinist while I went to engineering school at night, then a manufacturing Eng, then designed fuel cell systems, then designing medical devices, now more managing the design of medical devices.....next up will be building an engineering group to design 3D printers for medical prosthetic devices and perhaps 3D imaging to allow the patent to see how they will look with the prosthetic....so the new job uses all the skills from my past jobs plus the ECU programming experience, quite a challenge on its way.

The big question of course is.....what kind or ferrari parts can be #D printed????

I was talking to another engineer a few months back about the frankenFerrari and he wanted to know why, just WHY? The answer really is because all day I worry about pennies on cost and features that will appeal to most people and what the complaints/million units will be and what the regulatory compliance path with be ,and what is the value proposition to the physician and all kinds of stuff that has NOTHING to do with anything I want....i build stuff like the frankenferrari simply because I can and I like it and I'm the only one who has to like it, it doesn't need a purpose or an economic case.....it just needs to make me smile thinking about it