Engine question

[Dan2973]

Hey guys. I’m new to forum and I’m in the middle of restoring a 66 beetle. Trying to gather info and advice on the engine choice. I posted the numbers here on the samba and according to the charts I have a 1964 40 hp 1200 motor in a 1966. Numbers are 8999799. The body is off and I’m doing body work. Was thinking of pulling the motor and doing a big bore kit because after reading a ton of threads I don’t think I will be satisfied. I’m also thinking do it once ya know. Question is what is a P&C kit mean? Is it worth putting money into the 1200 or just by a rebuilt 1600? Not sure what the cost would be. Not looking to go 100 mph but just cruise nice with a little pep. After reading threads I see some people say that there is not much gain with a big bore kit? Is rebuilding the motor something novice could do. I’m pretty mechanically inclined but never rebuilt a bug motor. Sorry so many questions. Thanks in advance. Here are some pics of the project

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Go with a 69mm crank and 83mm bores will give you 1500cc dual solex 28 pci carbs you should be fine ...if you go 69mm crank there's 3 ways you can go 69mm crank with 1500/1600 rods or 69mm crank with 40hp rods . I would go with the 69mm crank with 1500/1600 311A or 311B rods but if you go this way you would have to get 1500 type 3 83mm cylinders/ pistons 22mmpins ...if you go with 69mm crank with 40hp rods you would have to use spacers under big bore 83mm cylinders the rod jounals need to be cut down to fit the 69mm crank with 40hp rods 20mm pins which is more work ..whatever works best for you. you can also go with a 69mm crank with 36hp rods which gives you a stroke of 74mm with 83mm pistons which gives you a 1600cc you could use the 40hp big bore 83mm pistons and cylinders I would go with aapistons 36hp h beam rods than the stock 36hp rods with this set up ..yes complicated but really aint.....

[Dan2973]

[glutamodo]

Big Bore 40HP (1385cc) is a very good upgrade, and it's often already been done to many old 1200s! I know that's all I've ever had in my 62 since I got it in 1989... every other engine I've put in there to date has been such.

Now the Big Bore Kits sold these days may have interference issues with the crankcase... so they may not be "easy bolt-on" style of upgrade.
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Andy T.


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[Kjell Roar]

[Alstrup]

If all you do is lump around town within the city limits and occasionally go on a regular highway the 1385 BB kit on a 1200 is okay. It gives you more lower rpm pulling power. You can basicly floor it in 4rth from just over idle.
Anything more than that and the engine needs more air, meaning a dual carb set up. It will still be very forgiving down low, but give you back the rpm range a stock 1200 has + a little more.
I´d put it this way. If you see a challenge or have a quest for keeping the stock 1200 case and internals by all means do it. If that is not an issue, but you would like to retain a reasonably stock engine look, go with a 1600 sgl port.
My 02c.
PS. The Flintstone pic is a classic, but still holds water

[PEPPE]

1385 is good but you will not obtain a good "punch". i do often the 1470cc increase and also 1650cc, and both will give a good difference in behaviour.
these are based on cut down 85.5 and 90.5mm barrels. goind more than that is excessive for 1200 heads and the engine will not rev past 3000.

[WickedWagens]

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[Bulli Klinik]

You'e talking about an offset ground crank. The journals are ground smaller further out on the throws of the crank.

It was a pretty common combination to offset grind a stock crank to Rabbit journals and run Rabbit rods. I think you could get 74-76mm stroke without welding the journal.
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I've never met a Bus I didn't like.
Mike K
Bulli Klinik
Colorado Springs

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