1200 rebuild/upgrade

[Rick Poehlman]

I recently purchased a '58 Ragtop with a '65 40HP motor. The motor idles smooth but has a pretty loud knock that comes and goes at idle, and is constant at higher RPM's. I'm not interested in stuffing a 1600DP in the back, but rather, rebuild the 1200 with some mild performance upgrades. I've built 1600's many years ago, so I'm confident in my ability to rebuild this 40 horse. I'm considering larger jugs (1385CC) and maybe a mild cam to add a little more get up and go. I'm looking for advise from someone that has first hand experience with mild performance upgrades to the 40 horse. Suggestions on carburation if I go with the larger jugs, what cam to use, cylinder spacers, different rockers, etc... It's currently has a 30PIC carb and for simplicity I would like to stick with a single carb. Any information would be greatly appreciated.

[Mark Evans]

You may also want to "ask" in the Engine/Performance forum.
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'63 Ragtop

[EVfun]

For a 40 horse build I'd ask in the vintage speed section below the performance forum. It is also a good one to search for 40 horse builds.
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[Zundfolge1432]

[Mark Evans]

[Sharp64]

[Zundfolge1432]

[Sharp64]

[andk5591]

There are plenty of us that have 1200s or 1200 based engines....And there are a couple current threads on this.
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D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
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There's more, but not keeping them...

[Rick Poehlman]

Thanks for your input. I'm new to The Samba and am just cutting my teeth on this Forum thing, so be patient. I asked the question on this page because I'm not looking to build a single port street racer or to modify my 40 horse beyond recognition. Just wanting advise from someone that has done mild upgrades to their 40 horse (cam, crank, lifters, carburation, etc..) during a rebuild. I have taken you advise and posted a question on the other forums, so thank you all!

[Zundfolge1432]

Definitely a work in progress to study the forums. If you can use search you can dig into conversations past in detail. There are some talented people here and I continue to sharpen my skills but reading these. Good luck and have fun

[kbman]

Rick you are on the right track when you say mild upgrades on a 40hp platform. Other than big bore cylinder kit its best keep these motors stockish. Having the rotating Parts balanced, installing case savers for the head studs, and installing a dog house oil cooler fan housing are good for engine longevity. Other than that a 40hp is best left as a 40hp. If you want more power you be better starting off with the bigger engine.

[KTPhil]

I enjoyed my 40hp with the 1385 P&Cs. I think before I sold it I changed from a 28 to a 30 series carb, using a tapered spacer to match it to the intake manifold flange. Stock appearance, better low end, 70mph cruise (eventually!), and still easy to drive around town.

I think I had to shim the barrels a little to keep compression down, given the shitty no-lead gas of the day (1980-ish).

I had tried an 009 and also an extractor, but the peakiness of the 009 was not enjoyable around town, and I got tired of the dragging muffler, so I went back to stock there. I gave up a little on the high end doing so, but the low-to-mid range response was better and therefore more drivable around town. I wasn't going to win any drag races either way!

I also retrofitted a doghouse cooler/shroud soon after, and it ran much cooler, city or highway. Well worth it!

[Zundfolge1432]

[glutamodo]

Big Bore 40HPs have all that I've ever had in my 62 since I bought the car in 1989. I've posted a lot about the 34bhp 1192cc engine over the years - that was VW's name for it all the way until they stopped making it in 1985, even though the SAE HP rating at some point went up to 41.5. (and due to progressive refinements, I would like to think that in a dyno tug-of-war, the first production "40HP" in August 1960 would be beat by a Mexican 1200 from July 1985.

Anyway, you said 1965, that was a transition year for the 40HP 1200. A few months into the model year VW finally sorted out all the buggery cylinder head issues and put good heads on there. So is your engine from before or after this?

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Andy T.


IMAGE NOTE: It has been noted that Chrome based browsers may have issues in displaying my vast image library, which use non-secure links and are on an FTP server. Images should still be viewable if the link is clicked though.
I do not know how to fix this. All I can say is it all works fine for me with what I use, Firefox.

[EVfun]

I think it depends on intent. If it is just better performance in something not too far from stock I'm pretty sure a 1600 will outrun a 1400 (1200 w/ a big bore kit) any day of the week. If you want something for vintage style or closer to stock then enjoy a good 40 horse build.
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[Rick Poehlman]

Upon further research, it appears it is a factory exchange engine that was available between November '68 thru March '72. The stamped engine number starts with DO (indicating a 40HP) and ends with X (indicating Exchange). I've been told these replacement cases are dual-relief with 100mm oil passages and have cam bearings. That all sounds good to me. I wont know for sure until I split the case. I have also discovered I have a '69 tunnel AH transmission.

[glutamodo]

Factory stamps (one letter and 7 numbers, or two letters and 6 numbers. That's D-ZERO by the way, that "0" is a number, not a letter) always indicate a production line vehicle. Now if it's been milled off and re-stamped, or that whole "X" suffix, well, all bets are off as to what you have now. With that X you can no longer go by any of the production line engine numbers, and have to examine the details.

D series blocks LATER ON, were dual relief, but as I just said, examine the details! And all D blocks made starting August 1965 had cam bearings.
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Andy T.


IMAGE NOTE: It has been noted that Chrome based browsers may have issues in displaying my vast image library, which use non-secure links and are on an FTP server. Images should still be viewable if the link is clicked though.
I do not know how to fix this. All I can say is it all works fine for me with what I use, Firefox.

[Rick Poehlman]

I’m considering using a 69mm crank with 83mm bigbore cylinders. I’m told that would essentially spec out to a 1500cc. It would require 5mm shims for clearance . Does anyone know if the original fan should, cylinder tins and a 1200 exhaust still bolt up?

[FeelthySanchez]

1200 fan shroud & cylinder tins: Yes. Cyl tins will be a bit short, but function fine.
1200 exhaust: No, it's too narrow.