proven engine combos, following a plan, and those deals...

grumpyvette

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Staff member
proven engine combos, following a plan, and those deals.

theres an old saying about
"theres more than one way to skin a cat" well building engines is a bit like that in that if your goal is to produce a reasonable level of horsepower,for an engines displacement theres usually several fairly well known, combination's that can be built that will allow you to arrive, at that power level.
the difference in each engines parts list and machine work is usually a compromise in the engines cost, durability, or power range, and while almost everyone works within some budget restraints,most of us want to build the engines in our cars for the lowest possible cost in the least possible time, and in an ideal world have an almost indestructible and extremely durable combo.
Ive built enough engines, for my self and for other people, and given advice on, and worked on enough engine projects that were completed by other people that it became obvious that although, theres thousands of ways to build an engine for your average street/strip muscle car, theres also many more ways to take what potentially could be an excellent engine,and change just enough of the components, the machine work or the drive train its mated too, to make the intended results fall below your expectations.
One of the recurring reasons is that almost invariably, the person building that engine is presented with a (DEAL) on parts that cost less or that don,t match the rest of the engines components intended air or fuel flow rates, heat range,or power band or rpm range or the parts sacrifice some durability.you look thru the parts catalog and see the trickflow, air flow research or brodix heads listed in the component list cost lets say $1450 and about ten minutes later when you tell your friend he points out that you can purchase vortec heads for about 1/2 that cost...and while thats true, if you go for the less expensive heads your power potential takes a huge hit. the same thing happens when you point out the component list indicates you need a hydraulic roller cam and lifters and you friend quickly points out that
"there is a cheaper generic version or even worse that a flat tappet cam with a similar duration should work just fine"
the same thing applied to intakes, pistons, rods, etc.
EXAMPLE
lets assume your goal is to build the very common 383 sbc and your goal is a reasonable 425 flywheel horsepower, you can rarely pick up a handful of the current, corvette, hot rod,Chevy, muscle-car or exotic car magazines , without finding an article telling you exactly how they exceeded that goal, so how hard can it be?
well, that depends on your skills and budget, and your machine shops attention to detail,and the parts you select
and I can tell you from experience that theres a great many cars out there that have spend a good deal of time and effort trying to reach that goal that have yet to reach it.
If you look over this site you'll find a great deal of info on selecting & matching components, and calculating the results, and a fair number of proven confirmations that did in fact reach or exceed that goal.
you'll also find links to engine calculators and software that can be used to detect trends, point out potential flaws or predict results with some accuracy.

HERES SOME EXAMPLE OF THOSE ARTICLES, AND SOME USEFUL RELATED INFO


http://www.airflowresearch.com/articles ... 5/A-P1.htm

http://www.airflowresearch.com/articles ... A19-P1.htm

http://www.hotrod.com/techarticles/383c ... index.html

viewtopic.php?f=69&t=519

viewtopic.php?f=69&t=2645

viewtopic.php?f=44&t=38

viewtopic.php?f=50&t=428

youll quickly find the combos are different as are the power produced, and it would seem that its just not all that difficult to build a decent 383 sbc, and while thats true to some extent, its also true that all those combos that produce a known and tested power level can be significantly reduced if you were to start swapping, a few key components.
drop the compression,ratio,go with a set of less expensive heads,use that old intake and carb of your current engine, use what you think is a similar cam, don,t use the rockers or headers or oil pan, and windage screen suggested in the original parts list and your results will frequently be lower than you might expect those changes to make.
and even if you do follow the component list exactly the machine shop you use and the care taken during the assembly and tuning can and will result in a different power curve.
but its the attention to details, care taken during the assembly process and following the know trends that allows you to build a decent engine.now Im not saying you can,t experiment or use a different component, but I am saying that any changes you make will have an effect on the results, that may or may not be to your benefit and the more changes you make to a well tested combo, the less likely that your get the result to match, the original planned results
 
WHEN I started building engines many years ago, an older engine/machine shop owner and a Pontiac dealer mechanic took the time to answer many of my question, I remember the engine shop owner saying one day that building an engine correctly is a bit like baking and decorating a wedding cake, you use a component list on an engine build similar to a recipe, youll use to bake a cake and that recipe will list ingredients like flour,sugar , eggs, milk, baking powder,vanilla extract ,which ingredients get added at what stage,the amount of the ingredients used, the temperature you must bake it at, the pan size,etc
and an engine combo will in a similar way list the intake, carb,rotation assembly, compression ratio, etc.
now lets say your well into baking that wedding cake and the recipe, calls for 6 cups of white sugar, but youve only got 5 1/2 cups in your pantry,your on a strict budget , so looking around you notice that SALT LOOKS THE SAME, and the only other choice you have is dark brown sugar, which looks totally different,, because the salt looks like its a far more similar component you select the salt,and when you add it to the batter,to make up the difference, it BLENDS IN JUST FINE, and the cake looks identical once its baked, so whos going to now the difference?
I think you can grasp the significance, a small change will ruin the expected results, just like swapping some component in the proven engine package will also at times ruin the results, and if you had selected the brown sugar,when baking the cake, which appeared to be a total mismatch, you might have also ruined the cake but you might have improved the taste.
the same thing applies to engine building, some changes can improve the combo, but experience has a huge effect on making rational choices

There are places money can be saved and places it can't be some parts really make the combo what it should be. There are reasons why guys fall short on their goals of what an engine should be putting out. It usually has to do with a variation or compromise in the proven formula.

yeah! thats one extremely common reason why guys fail to build a decent engine,
I can,t begin to list the number of times I've had some guy ask me to build him an engine ,that will make 500,or 600 hp, for his muscle car, and when I explain whats involved in time and money to do it correctly,
and propose a very detailed list of the required machine work and draw up a parts list,of a well tested , known combo, I've built, before
without any doubt the first thing out of their mouths is the fact they want to substitute 1/2 of the parts for less expensive components,
and skip 3/4's of the machine work and then use a few parts they already own
they invariably are convinced that cheaper similar parts will work out fine and cost less!

When I explain that we can follow their version but it won,t make anywhere near the same power,
they generally can,t or won,t believe me.... at first!

I generally say, look this is a bit like backing a cake, if the recipe, calls for 2 cups of cane sugar and that sugar costs $4, and you go to the local store and find you can buy SALT that looks identical, for 79 cents, you could use that and save almost 80% on the cost!
both items are white granular substances, they look almost identical,, both are commonly used and there,s not a damn thing wrong with either product,
but I can assure you the resulting "
cake"or ENGINE, built using the less expensive substitute product will result in a much different finished result.
then I point out that THEY will be buying the parts and paying the local machine shop bills for the things I don,t have the required , tools to complete, and I'm probably not going to make over $5 an hour for the week or mores time that the project will require.
THEY WILL BE MAKING ALL THE DECISIONS, THEY WILL BE BUYING ALL THE PARTS,AND THEY WILL BE LEARNING A GOOD DEAL IN THE PROCESS ABOUT HOW AND WHY THINGS WORK THE WAY THEY DO!
they have a choice, they can go to almost any local machine shop or buy a crate engine and in either case spend less money, but they are also not going to get the same end result.
you can take your time, take advantage of decades of experience, and learn how and why things get done a certain way ,and measure and carefully clearance and fit components and do things correctly
or
you can buy and assemble any random list of parts, or buy a crate engine, in either case your car will probably be up and running in a few weeks,
if you want things done correctly you,ll spend a good deal more time and probably 60%-to 200% more money , but I will not be making squat on the deal,but I will get a good deal of satisfaction from the end result.
yes I enjoy the builds and enjoy teaching, and yes I love watching guys, who correctly built their engines, blow the doors off the guys who go the crate engine route , or slap together random components.....this is not and never has been a money making proposition, and I don,t work too a stop watch....if it takes longer and costs a good deal more thats the price of quality, ..but I do have a decent list of satisfied people who like the results they got from building their engine with a good bit of help, many have returned several times over the decades, and I sleep well knowing they did the job correctly.
 
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I can,t say enough about how valid that advice is!
I built a Pontiac 400 engine in a 1967 firebird back about in the early 1970s,
and I got the engine component list from a hot rod magazine ,I thought that I,d followed that magazine article almost exactly, and the results were extremely disappointing.
when, I was thru swapping parts, the engine ran like crap, I re-read the article several times and only then noticed that the car had already been fitted with headers and a low restriction exhaust and 3.73 rear gears, and traction bars,and it was only on the third or fourth time I read thru the article that I noticed the roller rockers,and carb spacer and Id ignored the combustion chamber shrouding clean up, pocket ported heads and port matched intake , and the back cut valves.
what Id done is basically blown thru the article, and noted the cam and intake and ignition that was used and jumped to the erroneous conclusion the other minor engine mods , and drive train components used might have been worth a few hp, but If I was using the same cam,and heads and intake I should make similar horsepower, it was only after Id installed the low restriction exhaust and rear gears , traction bars,that the engine responded correctly, and while it never did make the same horsepower the article claimed it was a very nice performance engine package once I took the time to follow the magazine article more closely.

just for your info, theres a good deal of useful pontiac info already posted on this site

viewtopic.php?f=74&t=2035

http://www.popularhotrodding.com/tech/0 ... to_01.html

viewtopic.php?f=74&t=449
 
youll want the basics

http://www.themotorbookstore.com/resmchstvi.html

this is one of the best books/cds you can find as a beginner

youll want some info

viewtopic.php?f=7&t=339&p=415&hilit=books+hours#p415

viewtopic.php?f=50&t=1249

viewtopic.php?f=50&t=1222



67015.gif


http://www.harborfreight.com/cpi/ctaf/d ... mber=67015

and owning a semi-decent set of tools is mandatory

viewforum.php?f=50

viewtopic.php?f=50&t=989

viewtopic.php?f=50&t=428
 
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