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mxracer Samba Member
Joined: April 09, 2011 Posts: 568 Location: NC
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Posted: Tue Sep 27, 2011 8:54 am Post subject: Jetting advice for 1904 street engine... |
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I'm building a 1904 for my 73 squareback. No intention of racing etc. just trying to build a nice streetable engine with a little more torque/power.
Here's what I've got... looking for some input on initial jetting for my Dell 40's
OG AS41 case from a donor square, didn't even need align bored
CB 4140 74mm CW crank
Mahle 90.5 pistons and cylinders
Scat C25 cam and degree-able cam gear
CB 31mm big foot lifters
SCAT I-beam rods (vw journal, 5.394")
CB 1.25:1 super stock rockers
stock type 3 heads P&P and HD springs
CB chromoly pushrods
Tri-Mil over the top exhaust
Dell 40mm carbs with 30mm venturis (also have 28mm)
8.5:1 CR
Thanks
BTW jfasts808... not discounting your input here from when I got the carbs from you... I don't think I had everything nailed down then though
Last edited by mxracer on Fri Nov 04, 2011 12:09 pm; edited 2 times in total |
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DarthWeber Samba Member
Joined: November 24, 2007 Posts: 7543 Location: Whittier,CA
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Posted: Tue Sep 27, 2011 10:50 am Post subject: |
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I'd say 125 - 130 mains (w/30mm vents), 55 idles and 180 A/C will get you close. Nice motor BTW, good build for a Type 3. What CR are you running? _________________
Mitey62 wrote: |
Swapped the Compufire for a Bosch blue and some points I had sitting around, started 1st crank. Took her out for a drive, pulls harder, more RPM, and runs smoother. I think I'll be sticking with points from now on. |
RockCrusher wrote: |
JB weld the case halves....that'll keep the fretting to a minimum. |
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[email protected] Samba Member
Joined: August 03, 2002 Posts: 12785 Location: Salt Lake City, Utah
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Posted: Tue Sep 27, 2011 10:57 am Post subject: |
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52-53 idles for 40 DRLAs. _________________ It's just advice, do whatever you want with it!
Please do NOT send me Private Messages through the Samba PM System (I will not see them). Send me an e-mail to john at aircooled dot net
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mxracer Samba Member
Joined: April 09, 2011 Posts: 568 Location: NC
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Posted: Tue Sep 27, 2011 10:58 am Post subject: |
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Thanks Darth (edit and John, you posted as I was typing originally)... I have a local engine builder that has helped guide me along the way so most of the credit goes to him. It is good hearing other input that it should be a good setup.
Was thinking 8.5 or 8.25:1 on the CR talking with him. Thoughts???
Jon (jfats808) seems to have nailed it with the limited info I gave him when I got the carbs from him too. They have 52 idle, 125 main, and 180 airs in them right now. Sounds like I at least have a good place to start.
Last edited by mxracer on Fri Nov 04, 2011 12:11 pm; edited 1 time in total |
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jfats808 Samba Member
Joined: December 10, 2007 Posts: 5022 Location: oahu hawaii
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Posted: Tue Sep 27, 2011 12:41 pm Post subject: |
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Dan,
I try.
Glad I got ya close bud. Good luck with your build.
-Jon _________________ 2276 IDA's 86C 11-1 DD !
2017 48 Trijet DRLA's W125
Rockstar Suzuki wrote: |
You might as well put 10 year build in your bullshit sig, as it will NEVER run. Also your a dick |
You can always learn something new, even from a fool.
Check your oil levels routinely! |
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ALB Samba Member
Joined: August 05, 2008 Posts: 3483 Location: beautiful suburban Wet Coast of Canada
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Posted: Tue Nov 01, 2011 6:31 am Post subject: |
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Mxracer- is there a reason you went with the 31mm lifters? _________________ On a lifelong mission to prove (much to my wife's dismay) that Immaturity is Forever!! |
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mxracer Samba Member
Joined: April 09, 2011 Posts: 568 Location: NC
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Posted: Tue Nov 01, 2011 6:40 am Post subject: |
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Honestly just to try them. The theory of them having a little more surface area and reducing wear makes a little sense to me. The rest of the specs seemed to be close to that of the other lifters out there so I figured I'd give them a shot.
The machining on them was nice and they spec'ed out just about perfect. I can't speak to longevity again but there's no indication that they are killing the cam lobes or flattening in 700 miles or so. Time will tell. |
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