small bore hemi minimum quench

[Truckedup]

This is a street engine, ....These old turds have so much crank flex that you car guys would have a meltdown.. Right now I measure .035 , and I'm thinking it will be ok..

that old article is interesting on single is interesting

[MadBill]

That Norton dome looks just like some early (a relative term, mid oughts in this case!) shapes used by a shop I frequent that specializes in Chrysler Hemis. With its huge stock chamber volumes, his next approach to minimize the domes required for 12:1+ CRs was to increase displacement instead. 572" is his current minimum and many are in the 636" -678" range.
More recently he has evolved to ~30 cc smaller sort of twin hemisphere chambers reminiscent of a Kasse design...

PS: Any thoughts on whether the crank flex is mostly gas loads vs. inertia-induced? Not much to be done re the former, short of larger main shafts and/or maybe squeezing in an additional externally mounted drive side bearing, but maybe some reciprocating weight could be whittled out re the latter.
I expect someone here has a spread sheet to quantify the numbers...

[Truckedup]

That Norton dome looks just like some early (a relative term, mid oughts in this case!) shapes used by a shop I frequent that specializes in Chrysler Hemis. With its huge stock chamber volumes, his next approach to minimize the domes required for 12:1+ CRs was to increase displacement instead. 572" is his current minimum and many are in the 636" -678" range.
More recently he has evolved to ~30 cc smaller sort of twin hemisphere chambers reminiscent of a Kasse design...

PS: Any thoughts on whether the crank flex is mostly gas loads vs. inertia-induced? Not much to be done re the former, short of larger main shafts and/or maybe squeezing in an additional externally mounted drive side bearing, but maybe some reciprocating weight could be whittled out re the latter.
I expect someone here has a spread sheet to quantify the numbers...

On the Triumph, the central mounted flywheel comes close to the cam lobes...Car guys need keep in mind these dry sump engines were built like aircraft engines,compact and light as practical even it it compromised durability. The minimum flywheel to lobe clearance with a engine making some HP is about .030, and it will kiss at anything less when the engine is at maximum power and RPM...The main bearings are ball bearing on one side and a roller on the drive side. The rods are pressure fed plain bearings..Ducatis use a similar arrangement with a far more robust crank, crankcase and outrigger bearings....There are $2000 billet cranks available, expensive after market cases and cylinders for the racer with a full wallet...
For guys like me running 60 year stock cases and cranks,the danger comes on at about 65 hp and 7500 rpm..My race engines are just shy of 65 HP and I spent some time getting competitive power at no more than 7000 rpm..No tach on the bikes, just shift right before it blows and hang on..

[RCJ]

How much timing do you run?

[Truckedup]

How much timing do you run?

37 degrees... Stock is 38, racers years ago ran 40-42 degrees...Some run dual plugs per cylinder and timing can be backed off to around 30 degrees...But for top end power and if detonation isn't a factor,it's debatable that dual plugs make more power ..