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http://web.camaross.com/forums/showt...threadid=99143

Rich starts the oval honda discussion about half way thru this thread.

 

Still really don't think that the Ford Mod motor is worth much, much rather have a SN95 with a 5.0L in it and 2000+ body work on it. Hell I want a 5.0L with a 408 W swap in it for my next toy car. (Yes I know even OldSStroker thinks that's scary!)

Bret [/B][/QUOTE]

The last MM I raced with made slightly over 1600HP,with a BIG hair dryer and runs in the 7-000's.Not to shabby for 284CID.Well its really a 301 after mod's.The engine before the monster had over 300 pases on it with a Vortec and ran 8.9-9.0 all day long in a 3200lb car.Accufab has a very good machine shop and a lot of pieces were made in house,main girdle and stuff.

Not TO shabby.

 

when you guys said oval i didn't know you meant OVAL, i thought you meant oblong
http://www.survivalskills.clara.net/nrpiston.jpg
http://www.auto-innovations.com/site...iston-oval.jpg
they seem to be using 2 rods to. do you think that with modern tech, they could get it to 1?

 

VE is more closely associated with TQ/CID than HP/CID.

HP/CID is usuall how short your stroke is and how good your heads are for that bore.

 

I don't think I'd describe that thing as an oval "O"

More like a short loaf of bread.

That's gotta be one heavy chunk of aluminum at max speed.

-Mindgame

 

Thanks for bringing that up.

I agree on Tq/CID when comparing dis-similar engines like a F1 and a Cup engine, or even an LS6 and a Honda S2000. This especially true if you compare the Tq/CID at the power peak rpm.

HP/CID, as you said, is a function of rpm. For engines that turn about the same rpm for HP peak, looking at max HP/CID and max TQ/CID may give a good comparison and tell you where they tried to maximize the VE. 5.4 SOHC Ford and 5.3 GM truck engines are a pretty good example.

 

To me the best thing about a pushrod motor is the light weight compared to displacement. For instance, a Mazda Miata motor (1.8l) weights only like 50 lbs less than a LS1 and you get to gain almost 4l of displacement and a hell of a lot more power potential. Plus, with horsepower basically being a rpm based, you can rev a LS1 or a SBC to at least 7000 if built right, which is high enough for me on the street.

 

To answer earlier questions about the 4.3 I built.... it has the V6 version of Vortec heads on it. Had to convert over from the stock metric rocker studs they use on the V6 heads to "traditional" SBC V8 7/16" studs. Also machined down the guides to get adequate lift clearance, and of course, installed some killer-diller valve springs. Ports and chambers were untouched stock as-cast. Spending money on port work didn't seem like a good idea since we found out we had been outlawed before I even got the heads finished. At that point it just became a for-fun project and we were already tight on the budget.

The REAL interesting part is the intake. NOBODY makes a single-plane carb intake for V6 Vortec heads. So I started with a lowly Edelbrock Performer dual plane. With an even firing order V6 like the 4.3 there's no over-and-under with the runners. Just a divider down the middle of what is basically a low-rise single plane intake. So I machined the divider out completely, opened up the plenum area as far as I dared, did a little home-porting and clean-up on the runners and bolted it on.

In short, it's definitely restricted as far as breathing goes. Even so, it should put out a REAL 330-340HP at the flywheel. If we put on the beautiful GMPP aluminum NASCAR race heads and matching high-rise intake my brother bought on e-bay that number could be close to 400 with no problem. Unfortuately, those heads require shaft-mount rockers which just weren't in the budget. Again, the money issue.

 

I think one thing most people forget about on OHC engines is that the majority lose rpm capability because they still run a lifter. The DSM 4g63 and the sohc and dohc 4.6 Ford use lifters. Seems kind of pointless to me, and limits rpm. That's why hondas run to 9000+ rpms with relative ease. Stock dohc B series engines turn 8200 - 8600 stock, and with better valvetrain, 9 and 10K are common. Directly actuating the vavle is the way to go. Im unaware of how the LT5 worked. Anyone know if if had lifters? I will say one thing on fords modulars - they LOVE boost.

 

The "lifter" on a SOHC 4.6 is probably more correctly called a "lash adjuster". It doesn't "lift' or reciprocate at all so it doesn't add to the valvetrain mass. It just supports one end of the rocker arm.

http://www.musclemustangfastfords.co...MMFF_MixMatch/

(Clock on the 7th pic from the bottom)


The rocker can be relatively light and you don't need a bucket or big lash cap on the valve, so the total valvetrain mass which is moving isn't much different from a direct acting solid. You can get lifter pump-up, but even the 1966 Pontiac OHC inline 6 which probably pioneered hydraulic lash adjusters on OEM engines would rev to near 7000 with minimal valve springs. If the head could have flowed some air, another thou was probably available with good springs.

My $.02

 

Yeah, I was searching my memory for the "lash adjuster" term, but couldn't remember it. I guess my question is, why use them at all? Is there that much of an issue with lash on the followers? I think Honda has a recommended maintenance schedule of every 15K or so. Its a cake job too. It just looks like an rpm limiting issue, that could have been handled better. I think some of the 03/04 cobras have seen 30+ with solid "lash adjusters".

FWIW, in the article you reference, they call them lifters . Also, if you convert to solid, is it still a lash adjuster?

 

 

Hey Jon: could you elaborate a little? I think I get it, but am not sure.


Rich Krause

 

Good thought on the (2114) intake. It looks like it might like an open spacer for more plenum. Did you see the Hot Rod (I think) story on modding a 4.3? The stock head flow was terrible. Even with porting they didn't get much flow. Too bad the Vortec 4.3s don't flow like the Vorted V8 heads!

Yeah, 450 flywheel hp is available with the NASCAR heads, etc. Unless you must run a 6 and are limited to 4.3 L, why bother?

I do like your idea of challenging the import guys with the 4.3, however.

Keep up the good work.

 

Ford 5.4 SOHC: 350 lb-ft @2500, 260 hp @ 4500
GM 5.3 L59: 330 lb-ft @ 4000, 295 hp @ 5200

Intake length and cam timing on the 5.4 seem to be biased for lots of lowend torque, which means they are getting pretty good VE there. This is further shown by the hp peak at 4500 where it still has 303 lb-ft. They are down 35 hp at peak to the 5.3, so VE is down there. Again length and timing. That's 13% down on hp with only about 6% more peak torque.

The Vortec 5.3 has 330 lb ft (and 251 hp) at 4000 and still has 298 lb-ft at 5200. IMO, the VE was biased toward the mid-upper range (4000-5200). The 5.3 actually has more hp(and torque) @ 4500 than the 5.4! Unfortunately I don't have a torque/hp curve for both engines handy. My recollection is both engines have fairly flat torque curves with probably 80++% (Vortec) and 90% (5.4 Ford) of peak torque at converter stall. Yep, the 5.4 should get a trailer in motion easier. However, there is a good chance the 5.4 pulls less rear gear in a similar application due to its lower rpm range.

Looking at torque/L at hp peak, the 5.4 is 56.19lb-ft/L and the 5.3 is 56.22 lb-ft/L! My conclusion is that the two engines are about equal in airflow potential so they could be configured for virtually identical torque/power curves.

My take is that most 5.3s spend very little time towing heavy trailers. Maybe 5.4s tow more trailers, but I'd be surprised. I also wouldn't be surprised to see a 5.4 model with torque and hp peaks similar to the Vortec 5.3 for some models. Hey, I'm not on Ford (or GM's) short list for product advice, so I could be all wet.

My $.02