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amc49
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Post subject:
 Posted: Aug 30, 2009 - 03:57 AM
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| I just thought it quite curious to see the interest in things like intake changes in various heads when the limiting factor by far is the exhaust. Meaning the intake differences are pretty much moot, if you get my drift. |
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PerformanceWithEconomy
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Post subject:
Posted: Aug 30, 2009 - 07:21 AM
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Exhaust only needs to flow appr 75% - 80% of what the intake does in order to make a high level of hp per cubic inch. Granted, these heads are FAR from optimally designed, but i'm quite certain that there are far worse out there. If you doubt this, go back and look at one of the old original 351 Cleveland heads. Even with the horrible port contours in the exhaust, these motors were capable of making quite a bit of power and were responsible for quite a few wins in professional racing. That is, after the problems in the exhaust port were addressed  Sean
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92 White / Red 2.3 MTX 130K miles, 93 Cayman Green / Grey 2.3 MTX 140K miles, 94 White / Grey 2.3 MTX 196K miles, 94 Red / Grey 2.3 ATX 70K miles, SouthSide Chicago
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88ESCORTGT
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Post subject:
Posted: Aug 30, 2009 - 05:23 PM
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Blabbermouth
Joined: Jun 27, 2004
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| The 2.5L HSC head and the 2.3L HSO head have good flow in and out. |
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My Car Club Everyone Welcome Ford Or Mazda
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amc49
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Post subject:
Posted: Sep 06, 2009 - 04:56 AM
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| You're kidding right? That Tempo exhaust port flat sucks. I used to port heads for a living at our shop. Well aware of the 351C and M stuff, as well as the horrible but huge 429 Cobrajet too. Those ports flat sucked too. That's why you could mill off the last 1 inch of exhaust exit and bolt an aluminum plate on 351C that effectively raised the port exit. The easiest 100 horsepower you ever saw in pro stock class. We raced AMC, most people had no clue, the stock head flowed more than many smallblock Chevy later hi-perf heads. One stock head airflow comparison of the time rated the 351C and AMC about the same in dead stock form. SB Chevy nowhere close. AMC flowed like crap until exhaust port floor changed in 1970, then the whole thing came together. Had the flat chamber w/ low cc., optimum plug location, big valve, large intake port area without low velocity that Chevrolet worked toward for years with their performance heads. The exhaust port actually outflowed any other smallblock engine of the time. You could make 13/1 compression with a FLAT TOP piston and ZERO milling with right late model block. If more people had been aware of how well the engines ran, the story could have been quite different. As it was, we had no trouble beating the living stuffings out of the likes of 427 and 454 Chevy, 440 and 426 true Hemi Mopar. 460 Ford hand it up too. All from 395 to 408 inch AMC motors. It's all in the head, you can do what you want to everything else, but if the head does not flow well overall on BOTH sides, you'll still have a dog. |
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jtzins
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Post subject:
Posted: Sep 06, 2009 - 05:13 AM
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Blabbermouth
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88ESCORTGT
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Post subject:
Posted: Sep 06, 2009 - 06:06 AM
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Blabbermouth
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AMC I was telling you that all of the 2.3/2.5 heads the HSO 2.3 and the 2.5L flow he best I did not post they were race engines.
AMC made geat power i know i had a 3 AMC but they were too light in the rear end and that made them bad race cars. it took lots of work to make them hadle or stick .
but if you did make them stick it was a very powerfull car VIVA the AMC AMX the Gremlin and the Javelen the Javelin was one of the best looking car of its time. |
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PerformanceWithEconomy
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Post subject:
Posted: Sep 06, 2009 - 08:30 AM
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Old Ford "muscle car" heads always had deep breathing intakes with poor exhaust porting. I've mentioned that many times in various threads, even commenting on the "high port plates" that were welded onto Cleveland heads.
The original HSO head somewhat reminds me of the 70-71 351C head without the massive hump or dog leg in the exhaust port. I'm quite certain that it could be improved quite drastically though, and i'll be looking into this soon enough. I just spent about 6 hours trying to sort though the mess in my garage. After about another day or two of cleaning, sorting and organizing, i may actually be able to start getting serious.
Unless you're running a quarter mile car and launching at very high rpm's, it's NOT about total flow. It's all about maintaining high flow velocities over the widest rpm range possible, good fuel atomization and minimal reversion. If you can accomplish those three things and maintain that high of a level in front of the motor ( intake system ) and behind it ( exhaust system ) and cam it accordingly, it really doesn't matter what brand the motor is. It will run circles around the competition. That is, IF you know how to drive and have the right gearing, tires and suspension
Just ordered some parts off of Ebay for the flow bench that i'll be building. Besides a manometer, i'll have a 0 - 10 Magnehelic gauge and a 0 - 100 Magnehilic gauge. The manometer will allow me to measure total airflow, either through an individual intake or exhaust port or through both ports and the combustion chamber. The Magnelic's will allow me to see high and low pressure areas, both in high or low levels of flow. Between manually porting the head and then extrude honing it, i don't think that the head will be the limiting factor in making power.
As far as AMC goes, i'm not all that familiar with their motors. I do know that they never had much money for R&D though, and used to use parts from other manufacturers in their cars. Autolite / Ford supplied them with carbs on some of their motors from what i can recall.
There was one thing that i saw on an AMC / JEEP motor that always amazed me. I always wondered what kind of a "brain surgeon" would design a motor where the oil filter was mounted up high and completely upside down. Not only did the oil have to take an extended trip to get to the filter, there had to be enough pressure to get it there and push it through. Once it did all of that, the oil would drain out of the filter when the car was shut off. This meant starting the motor on an empty filter that had to be pressurized every time. As much as i have complained about the "idiots" at FoMoCo and some of their designs, this one might take the cake!!! Sean
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92 White / Red 2.3 MTX 130K miles, 93 Cayman Green / Grey 2.3 MTX 140K miles, 94 White / Grey 2.3 MTX 196K miles, 94 Red / Grey 2.3 ATX 70K miles, SouthSide Chicago
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amc49
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Post subject:
Posted: Sep 07, 2009 - 08:11 AM
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Nah, the oiling system had no problems. Filter at a cockeyed angle but if you used the proper anti-backflow valved one worked great. One of the earlier filters that did that, now everybody does it. Long passage that carried oil to pump was relatively huge, the pumps always primed instantly and no trouble whatever to get 80 psi pressure. The bypass was in the timing cover, pull one nut off it and easy shim to bump pressure up without yanking pan. Autolite/Motorcraft 4300 series 4 barrel used, along with Carter AFB, Delco Chevy type distributor, along with Prestolite and later Motorcraft Duraspark type electronic. Ford starter, Mopar A727 Torqueflite and later GM Turbo 400 automatics, Borg Warner Super T-10 4 speeds. They used everything under the sun. You could put a Javelin 360 automatic down solid in the 14's 1/4 mile just by putting 800 Holley double pumper on it, that was a huge carb for a stock engine that size, those loved it. As far as making it stick, my brother and I used 68-70 AMX with the stock link over rear end to imitate the slightly later Chrysler leaf-linked super stockers. Meaning no traction device needed, the rear overhang along with the yank from those links meant with slicks you were trying to KILL bite, not get more. No trouble at all to make car wheelie, in fact would do it way too easy. I had one car with a lowly 304 from a station wagon, narrow bore meant 1.78 intake valve and 1.40 exhaust (stock package). 8.5/1 compression and hydraulic cam, 4 speed, ran 11.80s 1/4 mile. Biggest problem was too much bite, had to air up slicks and shocks enough to make a bit of slip so motor wouldn't bog at launch. With the bigger 395 inch everything one could do to make car go forward instead of flip upside down from wheelie. Look at any of the limited Hurst built SS/C AMX pics car leaving the line, there is daylight under them wheels Jack.
'Unless you're running a quarter mile car and launching at very high rpm's, it's NOT about total flow. It's all about maintaining high flow velocities over the widest rpm range possible, good fuel atomization and minimal reversion. If you can accomplish those three things and maintain that high of a level in front of the motor ( intake system ) and behind it ( exhaust system ) and cam it accordingly, it really doesn't matter what brand the motor is.'
How true indeed. I think about it somewhat differently maybe. I think that to get the total flow in most cases you must already have the several qualities mentioned in good quantity. The thing that drew Dad and later us boys to AMC engines was the large amount of torque the stock engines made. As everyone knows, torque is what really moves a car, you can turn that into horsepower but you cannot turn horsepower into torque (I can hear Pop preaching that now, God rest his soul). High torque is a sign of the overall efficiency of a motor. One can look at the stock engines of the times and see the torque, around 450 ft.lb. for the big hi-perf motors like Mopar and Chevy 450 inchers, the 390 AMC made 425 with a stupid single Carter AFB 500 cfm carb. Big carb, manifold and headers added a solid 100 horsepower and you hadn't even touched the crummy out to lunch at 4500 rpm cam and valvetrain yet.
Flow bench, eh? I always wanted to play with one of those. We almost got one for the shop a couple times, but it never happened.
As far as that Tempo exhaust, you're not gonna fix it. You can improve it, but the basic angle is cast in place. If one thing one should learn as far as heads for power, the STRAIGHTER the port the better the flow. Look at all high power engines, the ports go up not out. The exits are raised. See the 600 cc. pocket bikes with carb under tank now and downdraft carbs. That is main reason for the incredible power they make. Tempo port is a result of the basic tooling which produced the six cylinder heads and the over/under combo manifolds they used, works for a motor under 3500 rpm but not for higher flow speeds. Cross flow type frees up room to raise things on both sides. Tempo not cross flow, from what I know one of the main HSC design criteria said something about max torque in the 3000 range. They certainly did that, the stock motor has no free revability above that at all. It can be forced to rev there, but power is nil. Just as on most other engines though, that could be changed. Some respond better than others however. I've seen AMC sixes run in the elevens, and their exhaust design just as bad.
88ESCORTGT, we played there for awhile with a 401 Gremlin, THAT one fit your description, too short, no overhang weight to work with. Hard to hook it up. In a roll on with say a 440 boat anchor Mopar or 454 Chevelle on the street though and they could hang it up. We used to do PLENTY of street racing. |
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temptour
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Post subject:
Posted: Oct 07, 2009 - 05:44 AM
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Joined: Apr 15, 2004
Posts: 268
Location: Lebanon, PA
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Ok, just want to say that prior to the posting of this thread and the info it contains there was alot of rumor and confusion about the different castings and what they looked like. As can be seen there are at least a dozen different casting numbers along with differences in the combustion chamber and port shapes. This post has gone a long way towards demystifying what they are and eliminating the confusion. The conclusions that can now be drawn based on the info here weren't nearly as easily arrived upon or communicated as they are now. Hat's off to the original poster for assembling and sharing this info.
Moving on from that, lol, anyone familiar with the Classic Inlines aluminum six cyl. head? Ran across their website recently and was struck by the potential for the hsc. Since it was essentially a six with 2 cylinders cut off could this head be cut down to work? Can't see why not. Sure it would take some money and you'd have to fab an intake and exhaust but think about the potential. Check this thing out.
http://www.classicinlines.com/alumoverview.asp
http://www.classicinlines.com/Home.asp
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amc49
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Post subject:
Posted: Oct 08, 2009 - 03:33 AM
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Someone needs to reorganize some design criteria and marketing hype at that website.
'Contrary to popular belief, the primary goal in designing an efficient cylinder head, is to reduce the total ignition advance. Increasing the air flow, or cfm, is the secondary goal.'
Total crap. They then spend rest of page showing flow information, it must have been MUCH more important than they themselves seem to think. No mention of the improvement in lack of ignition advance, that one must have been tossed out the window, ergo, give it lip service then dump it. Some one should point out that when there is more flow, the mixture trapped inside engine is DENSER, which in and of itself requires less advance. When engine does not breathe well, it requires more spark lead. Statement given is horse leading the cart, backwards.
Appears to me that primary design idea was to use as many stock parts as possible and "by the way, make some flow improvements too".
'Even though a crossflow design would have resulted in significantly higher gains in air flow and overall performance, we felt the added cost of designing, developing, and producing the additional parts required, would have been prohibitive for most of our customers.'
There's your REAL design criteria. |
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temptour
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Post subject:
Posted: Oct 08, 2009 - 10:40 AM
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Well, ok, some of the marketing info may be misleading, but isn't that what happens when the sales department gives their viewpoint on anything? And trade offs may have been made in the design to make it more compatible with the stock parts but wouldn't that have been to make it appeal to a wider customer base and thereby make it economically feasible? In addition to making that head work, they've also got to it in a way that makes it attractive to enough people to make it relatively affordable as well as profitable. Might not be the ultimate design but it appears to be a substantial improvement over stock.
Look at the dyno results. They appear to be organized in a comprehensive fashion indicating there may be significant gains available. http://www.classicinlines.com/dynoroom.asp
And unless I'm mistaken the head itself has everything in the right places in terms of cylinder spacing, pushrod locations, head bolt holes, etc. to make it possible to adapt to the 4 cylinder. Haven't researched that to be sure, so if that's a misassumption somebody please say so. The water outlet's on the wrong end but that could be dealt with. Otherwise this thing has a lot of potential.
Now if I only had a bunch of money.... |
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PerformanceWithEconomy
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Post subject:
Posted: Oct 08, 2009 - 01:43 PM
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If you look at the chamber shape on this aluminum 6 head, it resembles the 2.5 / later 2.3 HSO chamber more than the standard 2.3 HSC design. This is the chamber shape that i said was most desirable of the 2.3 / 2.5 heads outside of the original 85 & 87 HSO chambers. The more pronounced the "dip" or "heart shape", as it is on standard 2.3 HSC castings, the poorer the flow, the poorer the fuel distribution and the less flame travel you'll have. There's simply too much shrouding taking place for anything but extremely low rpm use.
There is one thing that I find "funny" after seeing their test results on the factory FoMoCo 6 cylinder heads. While the OZ head flows measurably better on intake than the USA version, the exhausts are identical. I don't know why, but Ford has ALWAYS had a hang-up in this area. From the "muscle car" days of the 60's all the way till today, they've always tried to get the intake to flow while completely neglecting the exhaust. As we all know, you can't cram more intake into the motor if you're not fully scavenging the spent fumes efficiently. As both AMC49 and i have mentioned, prime examples of this "backwards" approach would be the Cleveland, Boss 302 and 429 Cobra Jet / Super Cobra Jet designs. Intakes that have phenomenal potential with exhausts that are absolutely HORRIBLE!!! Some of the "high performance" castings for the 427 FE motor i.e. the "high rise", tunnel port and SOHC heads are the same way!!! With the HSC's being similar in approach, one has to wonder if the same engineers from 30 - 40 years aren't still working there!!!
I would also add that while GREAT flow at higher lifts can make more peak power, improving the flow at lower levels of lift are what count on the street for day to day driving. This pumps up torque and low to midrange pulling power, as you can start to flow more air sooner and fill the cylinder slightly quicker. Using a head that has better lift at lower rpm's is equivalent to running a cam with a much faster ramp on it. In effect, cylinder fill occurs more quickly than if one concentrated on achieving max peak flow at higher rpm's and higher lift figures.
This is why it is important to select parts that compliment the intended purposes of the motor i.e. using a race motor on the street for a daily driver would work about as well as using the motor from a "grocery getter" in a race car. Two completely different priorities and designs.
There's info in this thread that needs to be edited and stuck into the Tech section. Mlburgoon's initial work here needs to be preserved in a manner that makes it easy to reference. Sean
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92 White / Red 2.3 MTX 130K miles, 93 Cayman Green / Grey 2.3 MTX 140K miles, 94 White / Grey 2.3 MTX 196K miles, 94 Red / Grey 2.3 ATX 70K miles, SouthSide Chicago
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amc49
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Post subject:
Posted: Oct 09, 2009 - 06:21 AM
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| The primary reason to go to the trouble of designing a crossflow head would be to get the exhaust ports as high as the intakes. Next reason would be to be able to make all ports same, so flow is same. When you cram one set in with the other, room becomes issue, leading commonly to two different patterns, at least one will be screwed up with more than one port design in the set. Of course, Ford even messed that up, witness the 2.3 OHC, which had crossflow head and 4 totally different intake ports. A nightmare. |
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Dagr8tim
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Post subject:
Posted: Apr 28, 2010 - 04:00 AM
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Blabbermouth
Joined: Jul 03, 2002
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| Not to drag up an old thread, but somebody asked me about HSO cylinder heads and I went looking for some info on them. Anyone got any info on the 88-91 HSO heads. I know the casting numbers on both of my 89 HSO's were either E8 or E9. |
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temptour
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Post subject:
Posted: Apr 28, 2010 - 04:49 AM
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| They'd be the E83E head. All '89's would have gotten that head. The cfi hso's were the only ones that got a head that didn't have a heart shaped chamber. All the later 2.3 heads were heart shaped and essentially all the same. |
Last edited by temptour on Apr 28, 2010 - 05:15 AM; edited 1 time in total
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