Combustion chamber size

[Lockwire]

Joe's ( JVB ) informatin is very very good, take a note of it, it will see you do well. Joe how are you ? I looked back its been 2 years since I talked to you. I'll drop you a note, hope you're well. Stuart.

[CREngines]

i would probably have to say i would favor the larger chamber. this goes back to Darins discussion on pressure recovery. that .250 past the valve seat on the short side chamber side is pretty important, and anything that could be done to maintain or increase that PR effect would be a benefit in my book. and on a way undervalved big small block with sky high velocity though the curtain area ill bet it is a better deal with the big chamber. All the chamber tricks in the world dont matter as much if it cant breathe. dont see to many Chrysler hemis with a dished piston. just my 2 cents.

[bigjoe1]

There sure are lots of ideas on this subject== I have made 748 Hp on 91 octane pump gas from a 427 Sb Chevy with a dart block and AFR heads, This was with 11.8 to one and a serious race camshaft and one big Dominator carb. I used flat top CP pistons with a low drag ring pack and vertical gas ports.I am going to build another one with a bigger bore ( 4.175 )and I am going to use the flat tops again and just mill the heads down to get the compression wher I want it,


JOE SHERMAN RACING ENGINES

[DrillDawg]

The problem with true hemi chambers are you have to be very careful when you close the ex valve and open the in valve or alot of that flow will go right out the exhaust port or reversion in the intake.
This style should work better.

[pdq67]

He, He!! "Twisted Hemi"....

Is that an old Ford 429 "shotgun" head?? Or a new D/C hemi-head?

pdq67

[Rizzle]

One of the biggest benefits of the 2v design nowadays, especially the ls, is the overall packaging. Look at size comparison between the ls and ford mod series engine. Smaller on the outside, bigger on the inside. Yeah, the hp/litre may not be the same, but the fuel ecomomy, production costs and low rpm power all seem to favour the ls series, even though its "old tech". Doesn't work for the 4 bangers though, size isn't an issue, where power is, and look at where those (2v 4-cyl) are. Gone.
If Gm goes the the viper style cam with the variable lobe center and cam timing, along with the DI it was said to get, the ls engine should be on top. I would think with that kind of tech, the 4.8 would replace the 6.0. The equinox with the 2.4 vvt di ecotec drive like a big v-6, with 110km/h cruising at around 2000 rpm. power is still there as well. I was quite surprised by the 4-cyl.

Anyways, back on topic, it would be interesting to find out which chamber style works out better in practice, seems there are some supposed benefits to either one, at least in theory. I would wonder if the tuning window would also be different between the two, maybe more so on a 2v where the plug location/quench pads would have more differences than a 4v head.

[DrillDawg]

He, He!! "Twisted Hemi"....

Is that an old Ford 429 "shotgun" head?? Or a new D/C hemi-head?

pdq67

It's Jon Kasse's Boss 429 head, he made around 950 HP with 10.5 cr and pump gas for his street mustang. Go to his web site to see the car and the build.

DD

[Ron E]

When the small block chevy of the DOHC injected engine shows up it will be all over for the pushrod.

Yes, that's what everyone said when all the competition went to DOHC 4V engines and GM came out with that antique LS design.

No, DOHC is not particularly new, having been around for 100 years now. Since then, most every clean-sheet racing engine has been DOHC 4V. However, racing has always had classes. Racing has always had cost concerns. Racing sometimes tries to link the race cars to production cars to get manufacturers involved. Racing in the US has favored pushrods 1,000,000 to 1. Sometimes, it's not about what's perfect. It's about what is at hand. Ford won Le Mans several times in the '60s with pushrod engines, running against fifty years of DOHC 4V development. Spend enough money polishing a turd and that will be one fast pushrod turd.

Maybe, it is horses for courses. For ultimate efficiency and ultimate performance, yes, DOHC with variable valve timing will always be superior. As far as cost per horsepower, packaging and maintenance, give me an LS any day. This from a guy who drives DOHC 4V turbo family cars, but builds antique pushrods. Don't own or build LS, but despite all the negatives from the weenie press, the past few years has shown GM made the correct decision to stay with 2V pushrods.

jack vines

Same can be said for the new Hemis. Tons of potential there.
Many advantages of multi valve engines diminish if maximum RPM isn't a primary (I.E. racing) goal. That will keep the much improved and less expensive 2V push rod V8's in good standing.

[Ron E]

He, He!! "Twisted Hemi"....

Is that an old Ford 429 "shotgun" head?? Or a new D/C hemi-head?

pdq67

It's Jon Kasse's Boss 429 head, he made around 950 HP with 10.5 cr and pump gas for his street mustang. Go to his web site to see the car and the build.

DD

If you're talking about the new hemis (5.7, 6.1, 6.4, etc.), they aren't twisted at all. Directly opposing valves and ports.

[pdq67]

Right,

Ford "Shotgun" chamber head.

OK, can any of you guy's that are way younger than me and have come out of BSME School with a degree create a head that will fit on our old beloved SBC block that is like the 6-banger, 6-lobe, SOHC Mail Truck engine JEEP head??

And I don't give a rat's as* about head-bolt spacing..........

Think Pete Ardema designed CHEAP conversion SOHC here except in a REAL cross-flow chamber like the Jeep head!!

pdq67

[af2]

SOHC here except in a REAL cross-flow chamber like the Jeep head!!

pdq67

The flippen Huricane head!!!!! OMG

[SchmidtMotorWorks]

OK, can any of you guy's that are way younger than me and have come out of BSME School with a degree create a head that will fit on our old beloved SBC block that is like the 6-banger, 6-lobe, SOHC Mail Truck engine JEEP head??

Sure send me a Jeep head and a check for $2K, done in 2 weeks.

[pdq67]

Jon,

I'd love to, but I don't have two 50 cent pieces to rub together unless I get into my meager retirement package. If I did that, I'd probably starve to death early so won't live long enough to be a thorn in our beloved GOV's as*...

I was just looking for the thread where one of the guys posted up some pic's of the Mail Jeep 6-banger SOHC head whose cam only has 6-lobes on it to import over into this thread but I can't find it??

You ever see one?? If you haven't but do get to at sometime, you will see why I would like to see it modernized so that it could be installed on our old SB's.

pdq67

[JBV-HEADS]

CR,

Don’t get lost in PR (Darin’s terminology, Bernoulli effect to me). It is a tool. If used in the hands of someone with the knowledge to improve flow, it is very useful. In most hands it just screws things up. The larger chambers in most SBC’s have the walls too far away to effectively use it. And the additional space the flame front must fill lessens the total pressure that can be built. In most 23 degree heads, it can only be used in a couple of locations and you must be able to predict the outcome. It is very easy to pull the flow away from the cylinder CL and lose performance. It works best in tight, shallow valve angles.

Stuart,

I don’t know if you know but a little over a year ago a ladder broke and I fell 15 ft. I didn’t make it. They revived me, air hammered a S/S needle into my chin to get medicine to my bone marrow. Life flight, 5 days in trauma ICU, then into the hospital, 3 broken vertebrae, broken ribs, perforated lung and bruised every organ. Enlarged heart that beats 10 beats a minute faster than it did before. Bad liver and kidney functions. But hey, I’m here still laughing and enjoying good people. And there is meaning to the saying, “better living through chemistry”. I still enjoy communicating ideas back and forth, but now I can’t stand those that make noise to impress themselves. No one has the right to harm someone else’s engine or education just to hear themselves talk. They have no business broadcasting when they should be tuned in. I’m pretty hardassed about it. Sorry on the down here but I hope everything is going good with you. I still like to work with others on projects so long as my labor is limited or I have time to finish it. I still love to compete but just on a different level now. Teaching someone to fish is more enjoyable than catching it and selling it to them. Good luck and thanks for asking about me.

Joe

[JoePorting]

Glad you're still around Joe. I've never been a big fan of going more then 10 feet on a ladder.