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TheRookie
Samba Member
Joined: September 24, 2022
Posts: 107
Location: Western Cape
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 Posted: Mon Jul 14, 2025 2:50 pm Post subject: CB 2242 Cam and Compression ratio for 1776cc |
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Hi Guys
I have CC'd my heads and it's at 51cc with a deck height of 1mm well slightly under. I calculated my Compression ratio at 8.9:1
Hoping this will be enough for my 1776cc to take full advantage of the 2242 cam
Engine specs
1776cc
Cw crank
041 heads bowl blended port job
Scat 1.25 rockers
36 Dells /30 vents jetted accordingly
Im hoping for 100HP from this engine |
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jeffrey8164
Samba Member
Joined: January 06, 2018
Posts: 4145
Location: Georgia
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| Posted: Mon Jul 14, 2025 3:36 pm Post subject: Re: CB 2242 Cam and Compression ratio for 1776cc |
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Seems great, especially with the rockers.
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Volkswagen!
Turning owners into mechanics since 1938.
“Let he that is without oil throw the first rod”
(Compression 8.7:1) |
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Rob Combs
Samba Member
Joined: December 30, 2020
Posts: 494
Location: South Bay LA, California
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| Posted: Mon Jul 14, 2025 9:31 pm Post subject: Re: CB 2242 Cam and Compression ratio for 1776cc |
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CB recommended 9.0 when i got my 2242.
I don’t know if you’ll notice the difference between 8.9 and 9.0:1. |
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TheRookie
Samba Member
Joined: September 24, 2022
Posts: 107
Location: Western Cape
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| Posted: Mon Jul 14, 2025 11:41 pm Post subject: Re: CB 2242 Cam and Compression ratio for 1776cc |
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Thanks Guys
My 1st time building a performance engine ,well sort of .I was an engine I bought that im fully reconditioning and took it from 1835cc to 1776cc |
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TheRookie
Samba Member
Joined: September 24, 2022
Posts: 107
Location: Western Cape
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| Posted: Mon Jul 14, 2025 11:45 pm Post subject: Re: CB 2242 Cam and Compression ratio for 1776cc |
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| Rob Combs wrote: |
CB recommended 9.0 when i got my 2242.
I don’t know if you’ll notice the difference between 8.9 and 9.0:1. |
I'm sure anything over 8.5 should be good |
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BFB
Samba Member
Joined: November 03, 2014
Posts: 2629
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| Posted: Tue Jul 15, 2025 4:41 pm Post subject: Re: CB 2242 Cam and Compression ratio for 1776cc |
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Im sure 8.9 will be fine, but if it was me, and your wanting to hit / break the 100hp mark then id flycut the heads and bump the compression up.
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"how am i supposed to torque the rear wheel nut to 250 ft lbs??? " - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
Most experts aren't. |
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StefansBus
Samba Member
Joined: November 20, 2015
Posts: 243
Location: Germany
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| Posted: Tue Jul 15, 2025 11:53 pm Post subject: Re: CB 2242 Cam and Compression ratio for 1776cc |
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| TheRookie wrote: |
Hi Guys
I have CC'd my heads and it's at 51cc with a deck height of 1mm well slightly under.... |
A tight deck is great but 1mm or less probably too tight.
Regarding compression: Depending on your typical ambient conditions and available fuel I'd rather be a bit above 9:1 instead of below with that cam. It'll work fine with 8.9:1 but you may be leaving some power on the table. I run 8.9:1 with an old 2239. My deck is around 1.25mm if I remember correctly. |
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Rob Combs
Samba Member
Joined: December 30, 2020
Posts: 494
Location: South Bay LA, California
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| Posted: Wed Jul 16, 2025 9:50 am Post subject: Re: CB 2242 Cam and Compression ratio for 1776cc |
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[quote="StefansBus"]
| TheRookie wrote: |
Regarding compression: Depending on your typical ambient conditions and available fuel I'd rather be a bit above 9:1 instead of below with that cam. It'll work fine with 8.9:1 but you may be leaving some power on the table. I run 8.9:1 with an old 2239. My deck is around 1.25mm if I remember correctly. |
Interesting point here. While CB recommended 9.0 for my 2242, I've also been recommended (not by CB) to run 9.0 with the 2239 I had initially decided to run.
My 2239 cam card states 240* at .050", and my 2242 cam card states 252* at .050". I verifed the 252* at one of my recent mockups.
Now that you bring it up, it does strike me as a little strange to have the same 9.0 recommendation with cams this far apart in running duration.
It's likely that in my head I'm not correcting for all of the variables, however...
Just another idea for the OP to consider. I think we all want him to get the most he can out of his project, within whatever practical constraints he's facing. |
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TheRookie
Samba Member
Joined: September 24, 2022
Posts: 107
Location: Western Cape
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| Posted: Wed Jul 16, 2025 1:57 pm Post subject: Re: CB 2242 Cam and Compression ratio for 1776cc |
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Hi Guys
I dont have much access to lathes and milling machine but the plan is to lap the jugs to the heads and hopefully get some 1000th of mm from that.
More so I ve watch videos regarding 041 heads and majority of them measured at 50cc's |
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Alstrup
Samba Member
Joined: July 12, 2007
Posts: 7822
Location: Videbaek Denmark
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| Posted: Wed Jul 16, 2025 4:26 pm Post subject: Re: CB 2242 Cam and Compression ratio for 1776cc |
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| TheRookie wrote: |
Hi Guys
I dont have much access to lathes and milling machine but the plan is to lap the jugs to the heads and hopefully get some 1000th of mm from that.
More so I ve watch videos regarding 041 heads and majority of them measured at 50cc's |
That depends heavily on the actual model. The old 041´s were rated 52-54 cc. and of the lot I have measured that holds. Then comes the newer "GO3) 041´s. There are 2 models from waht I have seen. One model which stays about true to the old Brazil version, and a later one which typically has 56-57 cc chamber volume. So, once again, CHECK, do not assume.
Wrt CR. 8,9 static is ok for the cam. Personally I would have liked a hair more to get more usable torque, but if youre good with setting up a nippy timing curve along with having a good ignition capacity, you can somewhat make up for that slightly low compression.
Your deck height/squish quality is more important than the last digit in static compression, so be on top of that.
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BFB
Samba Member
Joined: November 03, 2014
Posts: 2629
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| Posted: Wed Jul 16, 2025 7:31 pm Post subject: Re: CB 2242 Cam and Compression ratio for 1776cc |
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Depending on OP’s driving preference, could always advance the cam
_________________
"how am i supposed to torque the rear wheel nut to 250 ft lbs??? " - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
Most experts aren't. |
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