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studelover
07-17-2007, 10:08 PM
I was able to have just a little shaved off my block because of the head gasket I used, my block is now line honed and decked.All edges smoothed, It will be cleaned again and put together this month, the heads were completed last month.http://img.photobucket.com/albums/v145/mr1940/IMG_0618.jpg

Studebakers forever!

studelover
07-17-2007, 10:13 PM
Heads were done with stainless steel valves and a nice cut on the chamber. This should produce 9.5 to 1http://img.photobucket.com/albums/v145/mr1940/IMG_0561.jpg

Studebakers forever!

StudeRich
07-18-2007, 02:14 AM
You can use a needle nose pliers to pull that unwanted casting wire out of your water jackets in the heads![:0]

StudeRich
Studebakers Northwest
Ferndale, WA

Mike Van Veghten
07-18-2007, 10:23 AM
studelover wrote -

quote:This should produce 9.5 to 1

You might want to check the actual numbers for the comp. ratio.

I cut my block down to .003" deck height...and I'm still short of my desired 10 to 1. I have done a fair amount of chamber reshaping, but true ratios can only be known by running the numbers.

Going by factory numbers isn't a good way of "knowing" the true compression ratio.

Have fun with your new engine.

Mike

StudeRich
07-18-2007, 03:38 PM
Mike; you do mean by running the numbers: CCing the heads and block right?

Especially with reworked combustion chambers, I don't know any other way to be sure, do you?


quote:Originally posted by Mike Van Veghten

I have done a fair amount of chamber reshaping, but true ratios can only be known by running the numbers.

StudeRich
Studebakers Northwest
Ferndale, WA

PackardV8
07-19-2007, 12:04 PM
Using math and a CC burette will be the only sure way to get the actual static compression ratio. However, static CR is only the first half of the equation. To know what will work, effective CR is the real number.

Might suggest, with the combination of experienced guys, newbies, NA engines, R-series engines and superchargers, the real effective compression ratio should always be calculated and provided as well. Find your camshaft duration and supercharger pressure and then use the link below to get John Erb's formula: http://kb-silvolite.com/calc.php

This is the only way to compare two different engines or even to get an idea if one build will run on pump gas. Longer duration camshafts lower effective compression. A full-race 320-degree camshaft needs 12+ CR to work at all. A standard Stude V8 cam will always ping too much with R1 flattops and 10.25 CR, as many have learned to their dismay. Check it out.

thnx, jv.

PackardV8

Mike Van Veghten
07-19-2007, 12:38 PM
StudeRich -

quote:Mike; you do mean by running the numbers: CCing the heads and block right?
Correct.
CC the chambers, the cylinder with the piston at TDC, current bore diameter and the gasket thickness.

Or...once you have the "actual" deck height, gasket thickness, current bore diameter and the chamber cc's, there are a few places on the net where you can plug in your numbers and it'll spit out the true ratio.

Or...send your numbers to me and I'll run it thru one of my programs and let you know that the final number is.

Mike

55studeman
07-19-2007, 07:57 PM
Hmm, this got me thinking. Two things, one off topic.

1st:
CC'ing chambers has been done for a LONG time, right? CC stands for cubic centimeters. I love the metric system, it's just easier, maybe I like it because I'm also a scientist. So why is it that in the US and with our "English Standard" system of measurement, that we mix in metric? And we've been doing it for a long time! Example, we CC-chambers but shouldn't it be inch'ing-chambers, especially since everything else for engine measurements are in inches to thousandths of inches. Or why were some wheel and brake components metric and the rest of the car is in Standard? Just a mute point but mixing up measurement systems is weird and sometimes very annoying. Luckily, most all new cars, since a few years ago, are now metric. Meaning I break out the Standard for my Stude addiction.

2nd:
Static versus Effective compression, -Lets test the experts here.
A natural aspirated engine with 10+ compression must use high octane gas of 93 or more, right? Then with a super/turbocharged car, you want a lower static compression of 7-8 and then the super/turbocharger increases the charge pressure making a much higher effectic compression. So, why can you run lower octane gas in a super/tubrocharged car, when it's effective compression is much higher than a high compression NA engine? Am I just missing a key piece of the puzzle or what? Please clarify, thanks.

Best Regards,
Eric West
"The Speedster Kid"
Sunny Northern California
Where the roads don't freeze over and the heat doesn't kill you.
And an open road is yours to have -only during non-commute rush hours 9am-4pm and 7pm to 7am (Ha, ha, ha)
55 Speedster "Lemon/Lime" (Beautiful)
55 President State Sedan (Rusty original, but runs great and reliable)

studelover
07-19-2007, 08:10 PM
once we put the cam, pistons and crank in the motor we will be able to tell what we have as far as the cam spec's we did not use flat top piston's because we don't want the ping. We picked the pistons between dish and flat. I think they call them semidish. I gave up my dream of 300 horse power because it really is not important. I want the car to have good get up and go, with what I have done to the motor it will run at a good medium. The head work, the cam and carb, ehxast system. This will give the car good sound and presence. The electric ignition. All of the small things together will be enough for the little hawk. The next car I build will be a monster, it's all an adventure to me, the excitement is in the learning;)

Studebakers forever!

Dick Steinkamp
07-19-2007, 09:12 PM
quote:Originally posted by 55studeman
So, why can you run lower octane gas in a super/tubrocharged car, when it's effective compression is much higher than a high compression NA engine?


You can???





http://thenobot.org/images/s2d/s2d_01.jpg

PackardV8
07-20-2007, 12:49 AM
Hi, Eric,

A given effective compression ratio has a given octane requirement at a given load and RPM. Doesn't matter how you generate that effective compression ratio, the net octane requirement is the same.

As a generality, turbocharged and especially centrifugally supercharged engines seemingly can use lower octane because they build their boost at higher RPMs. The low compression '57-58 Golden Hawks are very doggy at lower RPMs. The low compression combined with the inertia of the supercharger makes them bog slow until the RPMs get wound up enough to start making boost and raising the effective compression ratio. A standard 225hp will feel stronger up through about 3500.

At full throttle and higher RPMs, there is no vacuum advance, the mixture is stirred up more and the carb is into full rich/power mode. This is a very different operating condition than most of our old guy puttering around at low RPMs.

Bottom line, you can old-guy-lug a low compression supercharged engine without it pinging, because there is no boost to raise the effective compression ratio. A high compression NA car will ping under the same conditions. Both cars will need the same octane at the higher RPM when they have the same effective compression ratio. Try really running a supercharged car to its full potential on low octane fuel and holes will come in the pistons in short order.

thnx, jv

PackardV8

Mike Van Veghten
07-20-2007, 10:27 AM
Basically what PackardV8 said....add to that that the boost level or pressure has a lot to do with this equasion also.

5 or 6 psi...is a very mild boost pressure

Now install a more efficent (higher boost at lower AND higher rpm) blower, and the fuel requirements jump drastically.

Blown gas or Nitro drag racers will only be running their overdrive ratios between 1.5 and 2 times engine speed at between 6 and 7.5 to 1 static compression ratio. Note ...some of that has to do with the cam grind. Alcohol fueled engines on the other hand are running close to 3 times engine speed and 13 to 1 compression ratio....maybe more.

Note...these are all out drag race engines...not to be used to go to the grocery store!!!

Mike

55studeman
07-20-2007, 03:03 PM
Ahh, thanks JV and Mike. That makes sense about the compression and octane ratings....I just needed someone to fill in some of the blanks in my picture.

Best Regards,
Eric West
"The Speedster Kid"
Sunny Northern California
Where the roads don't freeze over and the heat doesn't kill you.
And an open road is yours to have -only during non-commute rush hours 9am-4pm and 7pm to 7am (Ha, ha, ha)
55 Speedster "Lemon/Lime" (Beautiful)
55 President State Sedan (Rusty original, but runs great and reliable)