Hi from down under

hi , My name is Shane, i just wanted to say g'day , long time reader, love the site and fact that it's real world information and experience . I like the fact that I can want information on one topic but three hours later I forgot what I originally wanted and am sifting through materials totally unrelated, keep up the good work.
I do have some questions on different cams and gearing sets as I am changing a few things on my 400 Chev in the quest for a bit more power specifically mid range hp.
Thanks for the ad

welcome too the web site!
yeah! I see you found the rabbit hole!


http://garage.grumpysperformance.co...-the-rabbit-hole-with-alice.10933/#post-66925

of course posting detailed questions and ideally pictures of your car would be helpful here!

Thanks Grumpy,

Heres a few of my 1949 Chevy Pickup.
I will ask some questions on my 400chevy in the engine forum.
Thanks Shane

Welcome to the madness, Shane. That's a stunning ride you have there!

I had a 400 for many years and I miss it to bits. Finding quality headers that are large enough is one of the issues I had.

Welcome aboard I see you have been looking around with out tethering up first. Be careful it can lead to project snowballing!!

DorianL said:

Welcome to the madness, Shane. That's a stunning ride you have there!

I had a 400 for many years and I miss it to bits. Finding quality headers that are large enough is one of the issues I had.

Click to expand...

Thanks Dorian, it's a work in progress. Someone else started it and i am changing it to my tastes, probably would of been cheaper to start from scratch but I can still enjoy the truck while I change little things as compared to it sitting in s shed on jacks.
The 400 is good and I have to finish setting up the rest of the vehicle to suit. Bigger flowing headers is next , and I think I have just found an elusive 3.77 gear set for my jag rear end more suited to the existing lunati cam , which might change the way I progress with the build.

Welcome Shane.

Not sure how I missed this, that one nice truck! Got any pics of the engine?

Hi Rick, here are a few of the engine before install and just after. I have since added a 1' phenolic spacer and 1'super sucker. The headers have been heat wrapped also but new 1 3/4 long tube header are coming after Xmas to go with the compression upgrade and new Cam. The heads are Dart SHP 64/200cc which are also going to be port matched to the manifold and opened up a bit. AFR 195s would be ideal but not in the budget just yet.
Unfortunatly i was a bit niave first build around and bought some mismatched combo parts from the person who was going to build the engine first. he turned out to be not what i thought and wanted to use inferior parts and not balance the rotating assembly which for even me waved a red Flag so i decided to part ways.
My current engine builder built the engine with the inherited parts as i was under pressure from the wife to stop spending,which really was just the wrong piston dish size which netted me , its good for about 400-420hp . But.... i was under the assumption that it would be 460-480 which would put me where i wanted and still have a reliable streetable engine. It ran a best of 13.1 @104mph with a newby drag racer behind the wheel. Mid 12s would make me happy. We are going to put in 7cc forged flat tops which with the head gasket and final quench we are aiming for close to 11.1 give or take depending on final assembly. That compression should match the Crower 00471 , my 3000 stall and my 4.09 rear gears. I run a 28'' tyre on the street and 26 et street at the drags.
Gearbox is a built T700r4 and i would not trade the overdrive for anything.
I have not heard or could not find anyone who actually has the cam in question so was very interested in your thoughts and real world experiences. Thanks for the video link , much appreciated and makes me very excited to get the second phase of the engine sorted.
Can i ask what engine vacuum your combo makes?

that looks like a nice clean and well laid out engine combo.

Job well done on the engine, looks terrific!

Shane oakhill said:

We are going to put in 7cc forged flat tops which with the head gasket and final quench we are aiming for close to 11.1 give or take depending on final assembly.

Click to expand...

I figured my SCR was 10.7 and that was with a 5cc flat top piston. But more important is the DCR,
which figured to be 8.27. I have run into some problems with detonation on 91 octane (100% gas).
What octane do you plan on running? How will you install the camshaft, that will have a significant
effect and determine the Intake Valve Closing angle (IVC) and therefore your DCR.

Shane oakhill said:

Gearbox is a built T700r4 and i would not trade the overdrive for anything.

Click to expand...

I have the 200-4R trans with the overdrive and I feel the same way. It's the best thing since canned beer.

Shane oakhill said:

Can i ask what engine vacuum your combo makes?

Click to expand...

You know, it's been a couple of years since I put a vacuum gauge on the motor. I'm not sure. I bet
Grumpy will have a good idea what that would be.

I figured my SCR was 10.7 and that was with a 5cc flat top piston. But more important is the DCR,
which figured to be 8.27. I have run into some problems with detonation on 91 octane (100% gas).
What octane do you plan on running? How will you install the camshaft, that will have a significant
effect and determine the Intake Valve Closing angle (IVC) and therefore your DCR.

Not sure about the installation of the cam, i have not thought about that to be honest. Down here every petrol station sells 98 which i think is the equal of the 95 you can buy in America. Most probable dot to dot will work for me. I will look into it and the advantages/disadvantages of advancing/retarding the camshaft.
I just imputed my details into united Engines DCR calculator and this is what it calculated.
My initail calculations of DCR puts me at 9.1 and SCR at 10.89 which worries me . Maybe i am imputing something wrong, your intake valve closing point is 69 Rick yet the calculator tells me to add the intake closing point at .050 and add 15 degress which gives me 59.
If i use 69 i am at 8.44DCR but 59 puts me at 9.1 DCR !!!

Shane oakhill said:

Maybe i am imputing something wrong, your intake valve closing point is 69 Rick yet the calculator tells me to add the intake closing point at .050 and add 15 degress which gives me 59.
If i use 69 i am at 8.44DCR but 59 puts me at 9.1 DCR !!!

Click to expand...

Adding 15° is an approximation for the IVC if you don't have the manufactures numbers ..... 69° is directly from the Crower cam specs for their 00471 camshaft, it just has to be calculated.

Yes I agree that 44° ABDC + 15° = 59 IVC .... but it's an approximation.



Use the calculator link below (2nd tab labeled "IVC Angle Calc -2") . If you don't have the software, then I can do it for you. Yes it is a calculator that I programmed in Excel, but it allows you to compare 5 engines side-by-side, where the online calculators leave it up to you to write the numbers down manually for every iteration.

Note: There are several numbers that have negligible effect ("1st tab labeled "DCR Calculator -1") that they can be ignored. None the less they are technically are a part of the calculation and I like to be exact.

Use the 2nd tab to calculate the IVC, the (2nd tab labeled "IVC Angle Calc -2").

http://garage.grumpysperformance.co...comp-ratio-cranking-pressure-calculator.4458/

Thanks for the spreadsheet Rick, very interesting to play around with the figures. After ccing my new pistons this afternoon and imputing the information i have so far come up with a rough projected figure of 10.80 static compression and a DCR of 8.37 which should be fine with the premium fuel available here. My pistons advertised 5cc valve relief in the catalogue, said 7cc on the box and when i measured them came to 6.5-7cc which will work better for me to bring the compression down on both the static and dynamic.
Of course nothing is set in stone until the engine is pulled down , heads touched up and cc'ed, measurements taken. But i have learnt something over the last few days that will make a better engine and for that i thank you. will keep you posted.

Indycars said:

Adding 15° is an approximation for the IVC if you don't have the manufactures numbers ..... 69° is directly from the Crower cam specs for their 00471 camshaft, it just has to be calculated.

Yes I agree that 44° ABDC + 15° = 59 IVC .... but it's an approximation.

View attachment 9020

Use the calculator link below (2nd tab labeled "IVC Angle Calc -2") . If you don't have the software, then I can do it for you. Yes it is a calculator that I programmed in Excel, but it allows you to compare 5 engines side-by-side, where the online calculators leave it up to you to write the numbers down manually for every iteration.

Note: There are several numbers that have negligible effect ("1st tab labeled "DCR Calculator -1") that they can be ignored. None the less they are technically are a part of the calculation and I like to be exact.

Use the 2nd tab to calculate the IVC, the (2nd tab labeled "IVC Angle Calc -2").

http://garage.grumpysperformance.co...comp-ratio-cranking-pressure-calculator.4458/


View attachment 9019

Click to expand...

Shane oakhill said:

Thanks for the spreadsheet Rick, very interesting to play around with the figures. After ccing my new pistons this afternoon and imputing the information i have so far come up with a rough projected figure of 10.80 static compression and a DCR of 8.37 which should be fine with the premium fuel available here. My pistons advertised 5cc valve relief in the catalogue, said 7cc on the box and when i measured them came to 6.5-7cc which will work better for me to bring the compression down on both the static and dynamic.
Of course nothing is set in stone until the engine is pulled down , heads touched up and cc'ed, measurements taken. But i have learnt something over the last few days that will make a better engine and for that i thank you. will keep you posted.

Click to expand...

http://garage.grumpysperformance.com

Indycars said:

Adding 15° is an approximation for the IVC if you don't have the manufactures numbers ..... 69° is directly from the Crower cam specs for their 00471 camshaft, it just has to be calculated.

Yes I agree that 44° ABDC + 15° = 59 IVC .... but it's an approximation.

View attachment 9020

Use the calculator link below (2nd tab labeled "IVC Angle Calc -2") . If you don't have the software, then I can do it for you. Yes it is a calculator that I programmed in Excel, but it allows you to compare 5 engines side-by-side, where the online calculators leave it up to you to write the numbers down manually for every iteration.

Note: There are several numbers that have negligible effect ("1st tab labeled "DCR Calculator -1") that they can be ignored. None the less they are technically are a part of the calculation and I like to be exact.

Use the 2nd tab to calculate the IVC, the (2nd tab labeled "IVC Angle Calc -2").

http://garage.grumpysperformance.co...comp-ratio-cranking-pressure-calculator.4458/


View attachment 9019

Click to expand...

Shane oakhill said:

Thanks for the spreadsheet Rick, very interesting to play around with the figures. After ccing my new pistons this afternoon and imputing the information i have so far come up with a rough projected figure of 10.80 static compression and a DCR of 8.37 which should be fine with the premium fuel available here. My pistons advertised 5cc valve relief in the catalogue, said 7cc on the box and when i measured them came to 6.5-7cc which will work better for me to bring the compression down on both the static and dynamic.
Of course nothing is set in stone until the engine is pulled down , heads touched up and cc'ed, measurements taken. But i have learnt something over the last few days that will make a better engine and for that i thank you. will keep you posted.

Click to expand...

Hi Rick ,
A few months ago you gave me the above spreadsheet for dynamic compression and associated ivc etc.
My combo has changed again to an internally balanced crank,6' rods ,afr 210 heads, i have three manifolds -dart dual plane, weiand teamg lowrise single plane and and a vic jr.
Th cams i have are a Crower 00471 and a crow cams (australia) 242/246 @0.050 290/296 .566/.567 hydraulic roller .
Comp 1.6 pro magnum xd rockers.
My question concerns the cylinder pressure number the program is giving which for all scenarios is between 165-172 psi.
Is this number supposed to be 185-195 for a good street engine or is the computer number different to actual running engine PSI.
Pistons are -12.5cc to give between 10.5 - 10.9 depending on what deck height and gasket is used once the existing configuration is stripped and examined.
Kind Regards,Shane
/index.php?threads/hi-from-down-under.13121/reply&quote=72584

Shane oakhill said:

Is this number supposed to be 185-195 for a good street engine or is the computer number different to actual running engine PSI.

Click to expand...

Since we are trying to calculate the cranking compression, one would hope that it matches perfectly. Numbers
can be misleading, unless you understand what's behind them.

My engine calculated to be 171 psi, but when tested it was actually 190-195 psi at sea level(14.7 psi). The
actual numbers can be affected by how well the rings seal, how fast you crank the engine, etc.

In the calculation is a constant that depends on the composition of the gas in the cylinder. This number
can be assumed to be 1.2 to 1.3 and has a significant effect on the calculated value, I used 1.2. If I raise it
to 1.25, then I get 191 psi. I would be very interested to hear your tested values, if you could
report back on them !!! If you are comfortable with making changes to the Excel spreadsheet, just click
in the cells that report "Cranking Pressure (Gauge) and change the value to 1.25. You will probably have to
"Unprotect" the worksheet before you can make changes. It's in the "Review" menu at the top.

I got the value from the website below and will tell you more than you ever wanted to know. Included below
is the main paragraph concerning the constant.

http://victorylibrary.com/mopar/cam-tech-c.htm

The JavaScript calculator uses 2 errors in opposite directions, which accidently more or less balance out, but
the result does not match actual conditions. Only the most violent ramps have only 30 degrees difference
between nominal and .050” duration, which means that the intake closing point input is too conservative
(early), resulting in a longer stroke than accurate. This is balanced by use of 1.1875 as the exponent
for the corrected CR, a polytropic value used in preference to the traditional adiabatic value
(1.4) for the ratio of variable heats for air and similar gases at the temperatures present. The
usual exponential value for calculations is 1.2 to 1.3 depending on the engine.

great post RICK!