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DarthWeber
Samba Member
Joined: November 24, 2007
Posts: 7543
Location: Whittier,CA
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 Posted: Mon Apr 25, 2011 12:47 pm Post subject: |
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30 thou shims and 40 coppers would give you:
#1 0.046"
#2 0.046"
#3 0.042"
#4 0.048"
This gives you a little over 7:1 dynamic using #3 cylinder as worst case scenario. A bit much for a Bus IMO. Adding 10 thou to the decks will drop DCR to a better 6.8 - 6.7:1 (about 8.9:1 static). Should be fine on premium gas (with a proper tune) and don't forget to get some extra air to the engine compartment on your '66 Bus, it wasn't designed to supply much more than needed for a 40HP engine.
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| 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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donald.lemay
Samba Member
Joined: March 01, 2009
Posts: 484
Location: Rhode Island
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| Posted: Mon Apr 25, 2011 12:59 pm Post subject: |
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| Hey Darth what do you think if I get the heads opened up to 58cc's |
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DarthWeber
Samba Member
Joined: November 24, 2007
Posts: 7543
Location: Whittier,CA
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| Posted: Mon Apr 25, 2011 1:05 pm Post subject: |
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That's another way to lower CR but you want to make sure you don't start eating into your squish area too much as that is needed to promote good efficient combustion.
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| 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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donald.lemay
Samba Member
Joined: March 01, 2009
Posts: 484
Location: Rhode Island
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| Posted: Mon Apr 25, 2011 1:11 pm Post subject: |
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| So your thinking .04 barrel and .04 head gasket. With .058 and 58 cc I get 8.8 static. Getting closer |
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DarthWeber
Samba Member
Joined: November 24, 2007
Posts: 7543
Location: Whittier,CA
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| Posted: Mon Apr 25, 2011 2:05 pm Post subject: |
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Yes that looks fine. Like RC said though, make absolutely sure your barrels and case are mating flush with one another so you don't get any false readings.
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| 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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donald.lemay
Samba Member
Joined: March 01, 2009
Posts: 484
Location: Rhode Island
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| Posted: Mon Apr 25, 2011 2:27 pm Post subject: |
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I believe all measurements are correct, I made a plate with a 4 1/8" hole so I could torque down the barrels. Also when I was moving things around, all my measurements came out right on the dial gauge.
Thanks
Don |
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donald.lemay
Samba Member
Joined: March 01, 2009
Posts: 484
Location: Rhode Island
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| Posted: Sat Jun 25, 2011 3:30 am Post subject: |
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Just a little report back on this. The heads were cc'd to 56.3 which gave me 9:1 compression. I started with 93 all fine no ping., went to 89 pulled up hills great and head temps went down 10 degrees. All this in a heavy bus  |
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krusher
Samba Member
Joined: September 24, 2002
Posts: 7652
Location: europe
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| Posted: Sat Jun 25, 2011 3:53 am Post subject: |
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| donald.lemay wrote: |
| Just a little report back on this. The heads were cc'd to 56.3 which gave me 9:1 compression. I started with 93 all fine no ping., went to 89 pulled up hills great and head temps went down 10 degrees. All this in a heavy bus |
I run this engine in my bus https://www.thesamba.com/vw/gallery/pix/538268.jpg
I run 87 with no ping or high head temps, I tried a tank of 89 on a road trip and lost 2mpgs.
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