It's no shit... Richard Hammond, and James May, will be joining for a 30-minute special. They’ll be joined by former hosts Rory Reid and Matt LeBlanc, plus special guests David Coulthard, Susie and Toto Wolff, and Jess Hawkins.
Yeah, I'm glad to see it, and am looking forward to it. Seems like one of the few reasons why they'd all get together amicably.
Looks like a former NASCAR crew chief and multiple championship winning engine builder is going to do the machine work on my Sea-doo engines. Not because I expect him to make it any more powerful or anything, but because he works closely with my brother-in-law on builds like this LS going in an old C10 pickup along with a 6-speed out of a GTO. It was a fun weekend working on this project. BIL almost has me convinced to LS swap my old 2500 chevrolet.
Well, this isn't a big-block Mopar (more on that in the coming days), but right now I've got a 5.7 Hemi in a Ram that had some lifters fuck up, eating the cam-lobes along with them. Did you know that you need to remove the cylinder heads on Gen 3 Hemis to access the lifters? Because you do. Not one of Mopar's better designs... So today I replaced all the valve seals, and got the heads cleaned up for reinstallation: Spoiler Spoiler This little fucker tried to ruin the party: Spoiler FUN FACT: New Hemis LOVE to break exhaust manifold bolts. Really, every one I see with 80K+ miles has at least a couple of broken bolts.
The new ('02- up) Hemis have always been two-plug per cylinder. It's for emissions, not performance. This was a 2013 Ram, for the record.
I knew that Chrysler had copywrite on "Hemi" and that the new Hemi Heads were not actually Hemispherical. However I did not know that they were that non hemisperhical.
When I got the new (then) Grand Cherokee with the 5.7 hemi it had the multi-displacement shit in it, and I understood that is what required the twin plug setup. That way when it was coasting/whatever, it was running half the volume which had one set of plugs, and then when you were giving it it was using the other volume as well, which had its own plugs. I have no idea if that's complete BS or not, but that's what the Jeep mechanic told me when I asked how it worked.
Of course, in my race cars, we just had twin plugs because we wanted to burn ALL the gas... and without twin plugs, at that compression, you'd never burn it all, never mind as fast as you wanted.
Rotaries utilize twin plugs too, one leading, one trailing. The theory being that the combustion chamber is so huge, one plug can't ignite the mixture in a timely manner.
AND you need 16 of them! Yup, it's BS. The large chambers of the Hemi heads don't burn as efficiently as something with more quench area, like an LS head, so the engineers compensated by adding spark plugs. It could still run just fine with only one plug. The criminally underutilized Ford 6.2L V8 has a hemi chamber, and also uses two plugs. I've heard about some aircraft and industrial engines with more than two plugs per cylinder.
Dad was a mechanic on big old radial engines (Beavers, etc)... some had 4 plugs, staggered, so that you'd start the burn before TDC and then really kick it off at/after TDC so that you'd maximize power. There was just so much volume and the detonation had such a long life span that it made a huge difference to the performance. They'd also want the improved symmetry from dual plugs for such a high pressure explosion.
My brother's 1987 Nissan pickup had two plugs per cylinder. I wonder how they fire those mult plugs on the older stuff. There wasn't adjustable timing until computers became prevalent. A distributor for each plug?
I can only speak for early RX7's, they used a single distributor and twin coils. A short primer on rotary ignitions from the experts at Racing Beat. Awesome, weird, finicky, little engines that are amazing when running right and frustrating as hell when something's wrong.
My old 911 race car had a special twin-plug single mechanical distributor. And HOLY FUCK I should have hung onto the 2 distributors I had with that engine! They're pushing $3k each now!
I can't find a pic of the engine close up, but this is the best I can do... but you can see a normal plugged, street gas engine beside the twin plug. (I also shared the carbs between the engines).