A possible build (finally)- wondering if I could get them estimated on dsktop dyno:

Propane (110 octane) with 600cfm quadrapuke propane carb from carbtech, performer intake, aussie 58cc heads, badger flattop. SCR 10.487:1. Chambers polished, exhaust ported with cragar long tube headers (1 1/2" pipes with 3" collector and 1 1/2 dual - cross flow stainless exhaust with high flow muffs. Full roller rockers 1.73 pedistal. full roller timing chain (double) -not sure if it will be straight up or advanced or what...HEI ignition. Bored 040- line bored and rotating parts balanced. heads and block milled just enough to level- less than 010 I think. crank refurbed etc. Oil cooler, 3-4 core aluminum radiator. HV oil pump and electric water pump with electric radiator fans.

crane roller cam
adv dur 278 ; 286 exh
@050 216 224
lift .562 I ; .586 exh

http://www.cranecams.com/?show=brows...tType=camshaft


I've calculated dcr @ 9.22:1 which is a bit hot- not sure what else you will need.

thanks guys!!!!!!!!!!!

Also... if i was to make up a grind to lower dcr a bit but still want more of an rv look to it...any suggesstions. May have to go with forged pistons still or something as well....but this is a start and I do have a lot of the parts. Damn this engine building stuff is intense - going to have to buy me a dyno program!

 

I came up with a DCR of 8.3:1, using the 70 degrees ABDC IVC of that Crane cam.

Dyno Sim says 385 ft-lbs@2000 RPM, 427 ft-lbs@4000 RPM, and 347 HP@5500 RPM on Propane.

 

Wow, that is a great propane setup.

 

I think that just might work- forgot to mention that the heads will have both intake and exhaust seated with stainless and I will heat coat the piston and chamber. And the cam is a hydrolic roller. With a DCR of 8.3:1 I might be able to mill the heads a bit? would like to get the piston closer to the combustion chamber of the aussie and the ultimate DCR for me would be 8.6:1. ((Or maybe 8.3 will help stability and longevity and is best left as is- can't complain about those ####'s))

I'm working on this as I can and have most of the big $ parts except the cam and lifters,rockers etc. Any other goodies I should consider? (still leaving forged pistons on the tableas I could design DCR down to where I need it with a more rv'ish grind)

I'll be tuning this on a dyno with racing gas ist to break it in and then switch to propane parts to tune before I install it. I bet the #'s with racing gas would be significantly higher!!

Thanks Eric...I think my homework might finally be paying off as i learn this stuff from y'all.

thanks again.

 

The timing on that Crane cam appears retarded. You can gain some more DCR by advancing it 4 degrees and have the IVC at 66 degrees ABDC. This will give you a DCR of 8.5:1.
The dyno numbers are 393 ft-lbs torque@2000 RPM, and 433 ft-lbs@3500 RPM. HP peaks at 356@5000 RPM.

 

i NEED to get that software...would love to be able to research and have THE BEST grind possible for my build. I like this build ...a lot!

wondering...comp cams has a retro kit that includes a retro kit- see link-bottom of page. crane just sells lifters. should I go with the crane cam and comp's lifters and retrokit? or is the retro kit superflouous?

http://www.compcams.com/Technical/Cu...ML/282-283.asp


thanks danlee- you have been an absolute must for me!

 

up late- built a couple of custom grinds (comp): Both HRoller

1: XE 264/273HR110; Intake 264, 212@.050, .544 lift. Exh 273, 224, .590

2. mag 264/274HR110; int 264, 210. .544 exh 274, 220 .544 (milder lift-concerned about .590)

still up for it danlee. Wondering how DCR will react to a bit less duration. Also with the increased exh lift with XE.

 

I like the use of polished chambers and the 1 1/2" primary long tube headers in a propane application. Seems smart to me. I wonder if you'll want a larger LSA in a propane application. A larger LSA will build more compression at lower RPMs.

You can use 5.0L HO lifters/H-bars/spider for your roller lash-up, that should save a bunch of money.

Is it necessary or even desireable to use Oz heads in a propane build? I think OC heads will work well in this application. You could use the 30 degree seat trick and get improved low-lift flow with OC heads, and I think the burn characteristics of propane would favor OC heads. I think propane takes more spark advance and burns more slowly than gasoline.

And I'd use Total Seal type zero-gap rings to help with compression. And because propane doesn't wash the oil off the walls of the cylinder, there's less risk of cylinder wall damage from that.

Edit: and use a good ashless oil like they use in airplane engines.

 

Roger,

Go with the Comp Cams Retro Kit and 5.0 replacement roller lifters. They are much cheaper than the Crane Lifters. You do not need the Retro Kit with the Crane lifters, because they have the link bar, but they are expensive.

DCR is a function of the crankshaft angle when the intake valve closes. To determine DCR, you need to know when the intake valve closes. I calculate DCR based on the seating of the intake valve. This is an approximation, because some compression occurs even when the intake valve is open. My method is OK for comparing one cam to another, but it has limitations.

You should get in touch with Comp Cams and tell them what you are doing. and how much Dynamic Compression you want. Let them suggest a grind.

The gapless rings is a good idea also.

 

going with gapless rings. NOW I'm wondering about head selection as I just read up on another site where the guy talked up the open chamber and propane. #$*&! Could save some money but will need to get cr up through milling heads and block without oz.

I think I get the concept of DCR- IVC angle determines how much of the stroke is building pressure.

 

[QUOTE=.I think I get the concept of DCR- IVC angle determines how much of the stroke is building pressure.[/QUOTE]


That is correct. With some cams, you might get 3" of compression from a 4" stroke. The earlier the intake valve closes the greater the length of the compression. A short duration cam or one which is advanced will give a longer compression length, than a long duration or a retarded cam.

 

I think you can get good compression with the right piston height. IIRC, a 400 usually uses a piston that's well below deck. I think I recall people using 351C pistons in a 400 to get the compression up. And I think I've heard that there are some new pistons with the taller height that have the right pin. With those pistons, OC heads, and the right cam, you should get plenty of compression.

 

I will be running the badger flattops but they are 075 in the hole. I will look into milling the block and heads or still may use the oz- more research...I'm hearing that the open cc lends to better combustion of propane but not why..I want to know why! Otherwise I will run with my oz cause it is an experiment afterall and oc heads are everywhere- Since I will rebuild and install stainless seats on int and exh i can tear em off and sell them if I decide to go oc- or.....

So if i do mill .020 of both heads and block I should be close to where I want to be anyway and will be able to use more of an rv type cam without running dcr over 8.75:1 which is my goal. I will plan on using the crane cam since comp is having probs right now.

SOOO DANLEE- what IF: I use the same build as above (initial-but advanced timing) but with oem heads milled 020 with the block milled o2o? Why are my numbers off regading dcr?
exmple
with oz heads and crane cam:
cc vol-60
pistoncc 5
gasket .041
gasket bore 4.08
deck .075
stroke 4
bore 4.040
rod lngth 6.58
IVC @.050...35 plus 15 per united engine site= 50

cr 10.338:1 and DCR 9.135:1

with oem heads and milling same cam:
cc vol- 68 est after 020 removed from head??
pistoncc 5
gasket .041
gasket bore 4.08
deck .055
stroke 4
bore 4.040
rod lngth 6.58
IVC @.050...35 plus 15 per united engine site= 50

cr 10:1 and DCR 8.8:1


I'm fully expecting you to tell me to shut the hell up any time and I will respect your request!

man I love this game

 

Your figures are correct it you use the crankshaft angle when the intake valve is at 0.050" plus 15 degrees. My figures are based on the crankshaft angle when the intake valve seats. The crankshaft angle when the intake valve seats with the Crane cam is 70 degrees ABDC. This is a difference of 20 degrees.

I can't tell you which method is most correct. They are both approximations, but they work well enough when you use the same method to compare one cam/motor to another using the same method. I use the valve seat numbers because I have a reference point of 8.5:1 DCR as maximum for pump gasoline. This figure will not hold true when using the crank angle at 0.050" +15 degrees to calculate DCR.

No matter which method that you use, unless you have some data to use as a reference for propane fuel, then the answer is only a number, and can only be used to compare one motor against another.

 

Got it...finally.

Got comp to give me a grind # that gives 265, 276 adv, 216,224 @.050 and 588/588 lift. Very similar to crane grind I've used above

thanks