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Bub Samba Member
Joined: June 10, 2004 Posts: 1143 Location: Central Washington
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Posted: Wed Apr 13, 2022 10:09 am Post subject: 1386 Single Port Build-- |
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Just a share of my recent project -
40Hp big bore 83mm on a stock base w/ WW Okrasa carb setup and camshaft; 8.4: 1 compression. STOCK heads Pretty fun little project, with the exception of butchering the cylinders. THAT part feels like so much hacking but the end result is a pretty good combo. Not quite fully done yet- I need to make a bracket for my filter, redo the fuel lines and maybe shorten the manifolds an inch?
Prior to this it ran good but felt like an average 36hp, smooth but gutless~ 3rd gear would top out at 43mph/ 3500rpm.
I gained 15mph in 3rd and can cruise down the highway at a sustained 65mph and not have to downshift at every incline.
Carbs installed right out of the box and I have no complaints. They adjust great and seems to run just fine. I could probably tweak the accelerator pump, but other than a sputter or two when its super cold it has no lag and no hesitation.
https://photos.app.goo.gl/gaYyMt3xDSeiDPNy5
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hitest wrote: |
Had a girlfriend once who shall we say, nearly arrived at the mere sight of a semaphore in action- easy to please she was... |
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oldslow Samba Member
Joined: July 27, 2019 Posts: 98 Location: Cape Cod
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Posted: Sun May 01, 2022 6:33 am Post subject: Re: 1386 Single Port Build-- |
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How did you get 8.4:1 compression with a stock head? _________________ - better to drive a slow car fast than fast car slow - |
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Bub Samba Member
Joined: June 10, 2004 Posts: 1143 Location: Central Washington
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Posted: Sun May 01, 2022 9:24 am Post subject: Re: 1386 Single Port Build-- |
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oldslow wrote: |
How did you get 8.4:1 compression with a stock head? |
Had to shim the cylinders to get it that low. I assume it’s the 40hp pistons/cylinders. Wrist pin location was the same, but I had less than 1mm deck height to start. With No shims it was over 9:1 .. _________________
hitest wrote: |
Had a girlfriend once who shall we say, nearly arrived at the mere sight of a semaphore in action- easy to please she was... |
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mukluk Samba Member
Joined: October 18, 2012 Posts: 6985 Location: Clyde, TX
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Posted: Mon May 02, 2022 10:10 am Post subject: Re: 1386 Single Port Build-- |
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You'd have to flycut the heads to get the compression that high. Either that or run a .015" deck height. _________________ 1960 Ragtop w/Semaphores "Inga" |
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Bub Samba Member
Joined: June 10, 2004 Posts: 1143 Location: Central Washington
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Posted: Mon May 02, 2022 10:27 am Post subject: Re: 1386 Single Port Build-- |
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mukluk wrote: |
You'd have to flycut the heads to get the compression that high. Either that or run a .015" deck height. |
From memory I think my figures were
0.60mm deck height and my heads cc'd @ right over 42cc - I bought them rebuilt, so they may have had a slight cut. I used a shim to get it to *about* 8.4.
I dunno - what's that work out to?
83mm X64 w 1.0.mm final deck height and 42cc heads? I rounded down a little to stay on the low-safe side if my stone age measurements weren't super precise)
8.3~8.4 CR ? No problem clearing the plugs, so I figured send it! _________________
hitest wrote: |
Had a girlfriend once who shall we say, nearly arrived at the mere sight of a semaphore in action- easy to please she was... |
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