Combustion Chamber Measurement

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MountainPrana
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Location: Jackson, Wyoming
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Re: Combustion Chamber Measurement

Post by MountainPrana » Wed Dec 12, 2018 6:24 pm

Amskeptic wrote:
Sat Dec 08, 2018 11:25 am

You camshaft will diminish vacuum at low speeds/idle.
Fuel injection does not like that. Cold idle does not like that. Take off from stop lights does not like that. Emissions tests do not like that. High elevation engines do not like that.
A loaded Vanagon at high elevation NEEDS TORQUE low down so you can launch from a stop light or start on a hill at 7,700 feet.

If that is your chosen camshaft, you will need a little more compression than stock, like 8.0:1.
You will need higher idle timing, but you cannot have more upper end advance, so you need a distributor that can hit you with 12-14* centrifugal at IDLE but not exceed 28*-32* centrifugal at 3,400 rpm (the 28* is the limit at sea level, 32* the limit at 7,000 ft)

Am I done?
Yes.
Colin :blackeye:
Being that the Camper Special kit was a gift, that cam is what I got. I do appreciate the numbers. The word back from the type 4 folks was 7.5 to 8.0 for the CR and our new friend at Reynolds machine said 8.0 was what he thought for the numbers on that cam. So it is reassuring that everyone is on the same page. Incidentally, we are only in Jackson in the Summers and that may change in the next few years. Is there any reason to go lower than 8.0:1? Like if we moved to Arizona or something? Not saying that we would choose AZ or TX or anything, but that's pretty much the opposite of Jackson WY...and I'm curious if different ambient conditions would play a roll in choosing a combustion ratio? Do you have a write up on that already here somewhere? I know you drive all over in all conditions so would I also be able to do the same? I know everything is a compromise... but what are the vagabonds to do about CR?

The project is having a little winter nap right now as we busted out a 24 hour drive in our Subaru to Illinois. Molly's Mom is having some health issues and could use the help around the house so we figured we would extend the time on both sides of our holiday visit to help out as much as possible. I thought I would make the time to start a post for the van build when we were in San Luis Obispo but got caught up in Thanksgiving Family stuff and going to the climbing gym as much as possible. I'm also probably a little embarrassed that the build isn't stock.

Thanks again Colin,

Cheers,
Tim

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Amskeptic
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Re: Combustion Chamber Measurement

Post by Amskeptic » Thu Dec 13, 2018 6:13 pm

MountainPrana wrote:
Wed Dec 12, 2018 6:24 pm

Being that the Camper Special kit was a gift, that cam is what I got.
I'm also probably a little embarrassed that the build isn't stock.

Tim, it is that I am as drunk on the beauty of this amazing country as you are. It is that I am driven to drive wherever the heck this country takes me at whatever the ambient circumstances can throw at me, and I demand a car that takes me there and back. That is all. That is it.

I trust Jake Raby implicitly for doing top-drawer work with real answers and real experience, but Jake has not strafed the country's dirt trails in 120* heat. It is not what he does, It is not what his engines do.

Be prepared for a good highway engine that is a little cold-blooded and maybe a little balky on the 1st gear creeper trails.
Let me know how it does, and if you need any detail tuning tweaks once it is running. Build that engine withe the same craftsmanship that went into the machining and design of it. I have yet to meet a Raby engine that I did not admire.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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lilpig88
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Location: SW Montana
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Re: Combustion Chamber Measurement

Post by lilpig88 » Thu Dec 13, 2018 10:59 pm

I haven't been keeping up here lately, but have a fuel injected but with raby heads and a 9590 cam that really does just fine in Montana. I'll send you a PM!

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Bleyseng
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Re: Combustion Chamber Measurement

Post by Bleyseng » Fri Dec 14, 2018 7:27 am

I set up my CS to 7.6 to 1 per my discussions with Jake years ago (2005) using a 9550 cam. That is the same as a 914 2.0L. Set the idle rpm to 1000 to 1100 rpms for a smooth idle. Take off's aren't a problem with the extra 20-30lbs of torque so I am not sure what you are talking about Colin. In 115F heat I had problems with gas tank boiling from the heat dumps not a running problem. Problem solved with late style heat dumps with tubes to the rear. My engine has gone 50,000 miles now with a piston change at 10,000 miles due to loaning the bus and they lugged the shit out of it busting the rings. Please rev these animals!
Geoff
77 Sage Green Westy- CS 2.0L-160,000 miles
70 Ghia vert, black, stock 1600SP,- 139,000 miles,
76 914 2.1L-Nepal Orange- 160,000+ miles
http://bleysengaway.blogspot.com/

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Bleyseng
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Re: Combustion Chamber Measurement

Post by Bleyseng » Fri Dec 14, 2018 7:51 am

Amskeptic wrote:
Thu Dec 13, 2018 6:13 pm
MountainPrana wrote:
Wed Dec 12, 2018 6:24 pm

Being that the Camper Special kit was a gift, that cam is what I got.
I'm also probably a little embarrassed that the build isn't stock.



I trust Jake Raby implicitly for doing top-drawer work with real answers and real experience, but Jake has not strafed the country's dirt trails in 120* heat. It is not what he does, It is not what his engines do.


Colin
This is not true as Jake drove all over the country testing his engines/ideas for real world results. The 9590 cam is a evolution of a VW cam with longer duration on the exhaust to cool the heads.
Geoff
77 Sage Green Westy- CS 2.0L-160,000 miles
70 Ghia vert, black, stock 1600SP,- 139,000 miles,
76 914 2.1L-Nepal Orange- 160,000+ miles
http://bleysengaway.blogspot.com/

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Amskeptic
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Re: Combustion Chamber Measurement

Post by Amskeptic » Fri Dec 14, 2018 11:04 am

Bleyseng wrote:
Fri Dec 14, 2018 7:51 am
Amskeptic wrote:
Thu Dec 13, 2018 6:13 pm
I trust Jake Raby implicitly for doing top-drawer work with real answers and real experience,
but Jake has not strafed the country's dirt trails in 120* heat.
It is not what he does, It is not what his engines do.
Colin
This is not true as Jake drove all over the country testing his engines/ideas for real world results. The 9590 cam is a evolution of a VW cam with longer duration on the exhaust to cool the heads.

Hello Geoff,
I absolutely stand by what I said.
The inability of people to listen to each other, to lay off the friggen "automatic play button" of vomiting their own experience and assumptions is exactly why we have people who suffer needlessly in this hobby. And here you are, blathering about "longer duration on the exhaust to cool the heads" which does not address the needs of the dirt trail in the slightest, nor does it address just starting off from a stop at 11,000 feet.
You did not read what I wrote, and you do not understand what I said, and you do not serve the people who need accurate information for their requirements.

So, yes, Jake drove across the country on the interstates to see if his engines were happy in the heat at highway speeds, and they do absolutely fine. I would enjoy the day I get to drive one his engines on the I-15 16 mile incline outside of Baker CA in third gear at 65 mph. I am sure that I would exult in beautifully balanced Type 4 music.

That is NOT trundling up a rock path where you are praying praying for payout in 1st gear at 1,000 rpm, because you just don't have an option if it doesn't get up to the crest.

Thank-you for your contribution, Geoff. See you on the interstate.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Bleyseng
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Re: Combustion Chamber Measurement

Post by Bleyseng » Fri Dec 14, 2018 11:59 am

My CS trudges up rocky paths at 1200 rpms just fine with the extra torque it has. Plus I have limited slip in the transmission. I went up a track once to find a group of 4x4 Jeeps parked and they all stared at me. Finally they cam over saying “ how did you get up here!”
Try it sometime with a CS powdered bus....yes I have started up at 5F in the snow at 5000 ft with no problem
Geoff
77 Sage Green Westy- CS 2.0L-160,000 miles
70 Ghia vert, black, stock 1600SP,- 139,000 miles,
76 914 2.1L-Nepal Orange- 160,000+ miles
http://bleysengaway.blogspot.com/

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Amskeptic
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Re: Combustion Chamber Measurement

Post by Amskeptic » Fri Dec 14, 2018 10:55 pm

Bleyseng wrote:
Fri Dec 14, 2018 11:59 am
My CS trudges up rocky paths at 1200 rpms just fine with the extra torque it has. Plus I have limited slip in the transmission. I went up a track once to find a group of 4x4 Jeeps parked and they all stared at me. Finally they cam over saying “ how did you get up here!”
Try it sometime with a CS powdered bus....yes I have started up at 5F in the snow at 5000 ft with no problem


This is YOUR graph. Your credibility is evaporating.

Image
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Bleyseng
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Re: Combustion Chamber Measurement

Post by Bleyseng » Sat Dec 15, 2018 6:25 am

Ok, this shows Horsepower not Torque! Sheesh! Torque at low rpm crawling is what matters.
A CS has more torque than a stock engine but as I have said you must increase the idle speed to 1000-1100rpms to increase the vacuum at idle so the FI reads correctly. The cam grinding profile is based on a 411 cam and then modified for increased exhaust cooling.
It is just fine if you want to stay stock with your engines, other people just might want to modify theirs. 100hp/120+ftlbs of torque VS 70hp/95ftlbs is a huge difference plus cooler running. Technology/engineering does improve over the years.
Geoff
77 Sage Green Westy- CS 2.0L-160,000 miles
70 Ghia vert, black, stock 1600SP,- 139,000 miles,
76 914 2.1L-Nepal Orange- 160,000+ miles
http://bleysengaway.blogspot.com/

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Amskeptic
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Re: Combustion Chamber Measurement

Post by Amskeptic » Sat Dec 15, 2018 10:12 am

Bleyseng wrote:
Sat Dec 15, 2018 6:25 am
Ok, this shows Horsepower not Torque! Sheesh! Torque at low rpm crawling is what matters.
Indeed it does and you are busted again.

Since horsepower is torque X rpm, if the stock engine has more horsepower at a lower rpm, it is all in the torque.

Please, we're done here.
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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