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jwanders32
Samba Member
Joined: March 08, 2011
Posts: 100
Location: LAKE VILLA, IL
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 Posted: Wed Feb 22, 2012 10:01 am Post subject: 62 1200 40 hp convert to dual carb |
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| Hello distinguished Samba members. I'm in the process of restoration of an early Meyers Manx ('67 with no tag, as was with the first 150) with a '62 40 hp motor. Have wanted a Manx since I first saw one in a magazine at my Gramps house in '68. (I was 6 then) I'd like to keep the vintage/period look, but would like to add dual carbs to this single port motor. At a crossroads and have many questions toward the best solution. I have rebuilt 1200 heads already. To find the intakes for the current heads, I'm looking at around $500+ for Dietz/Rethwish dual intakes. Has anyone ever used 1300 heads on 1200 cylinders? Will 1300 Cylinders/pistons fit this case if the prior question won't work? (I ask because I'm looking to get a set of replacement jugs/pistons anyway). Are a pair 28 PICT's good for this application? What linkage would you recommend? SCAT? Anyone have luck with cutting up a pair of 1200 intakes and welding up to be duals? Thank you in advance for any help you can provide. |
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WesleyGarrard
Samba Member
Joined: October 08, 2007
Posts: 541
Location: Pekin, Il
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| Posted: Wed Feb 22, 2012 8:41 pm Post subject: |
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Yes 1300 heads will be a simple bolt on upgrade. You would need to get longer upper head studs. However, this will open up a wide variety of dual carb sets. Also if you are looking to replace the pistons and cylinders you may as well put in an 83mm set. This will bump the 1200 into a 1385. You get a 25% increase over stock hp with just the 83mm pistons and cylinders. Here is my engine.
I used 1300 heads with 83mm pistons and cylinders. I used the CB performance dual 34mm solex carb set. The linkage is very cheaply made but after much fiddling it does work well. HP I suppose, and this is being generous I think, is somewhere around 65? It is surprisingly quick and has no problems keeping up with traffic. Even cruises the interstate at 75mph with ease. |
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jwanders32
Samba Member
Joined: March 08, 2011
Posts: 100
Location: LAKE VILLA, IL
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| Posted: Wed Feb 22, 2012 11:12 pm Post subject: Excellent! |
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| Thanks Wesley for the reply. Glad to see your success story. Your motor turned out nice. Hope to gather enough parts over the next few months and get this buggy up and running for summer. I had a friend in college (SIU) from Pekin. Lost touch many years ago. Wayne Ohltman. Long shot that you would know him, but I've had stranger coincidences. Thanks again, Jim |
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jwanders32
Samba Member
Joined: March 08, 2011
Posts: 100
Location: LAKE VILLA, IL
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| Posted: Thu Feb 23, 2012 6:55 am Post subject: |
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| Wesley, Forgot to ask. Do you need the 1300 pushrods? I see you also are running a vacuum advance distributor. Do you run the hose to both carbs with a "T" connector, or does one carb generate enough vacuum for the advance? Also had a mental block last night. It's John Ohltman, not Wayne. Thanks, JIm |
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glutamodo 
The Android
Joined: July 13, 2004
Posts: 26524
Location: Douglas, WY
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| Posted: Thu Feb 23, 2012 7:34 am Post subject: |
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No, you won't need 1300 pushrods as long as you have the 64mm crankshaft in there, as the pushrods are keyed to the crank's length.
However, there were two lengths of 1200 pushrods, and you would want the longer of the two.
A couple of comments though. The 1300 heads are quite similar to the 1200 heads introduced a few months into the 1965 model year... which are much inproved over the previous "round boss' heads, and required longer upper cylinder head studs.
Here's a side-by-side comparison of the mid 65/later 1200 head vs the 1300SP head - except the angle and size of the ports they are quite similar otherwise.
Here's a comparison between the "1965" square-boss heads and the previous round-boss:
I would mention that a lot of 1300 heads were machined to accept larger 15/1600 cylinders over the years, so availability of unaltered originals varies. I would try to get uncut heads.
Also, it's worth noting that the stock 1200 crankshaft was prone to breakage when stressed at higher RPMs, especially on the poor-tolerance balance specs that VW used in the early 60s. If you tend to push a 40HP engine, I would at least balance your pistons and rods end-for-end as closely as possible.
-Andy
Last edited by glutamodo on Thu Feb 23, 2012 4:37 pm; edited 1 time in total |
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WesleyGarrard
Samba Member
Joined: October 08, 2007
Posts: 541
Location: Pekin, Il
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| Posted: Thu Feb 23, 2012 9:16 am Post subject: |
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| jwanders32 wrote: |
| Wesley, Forgot to ask. Do you need the 1300 pushrods? I see you also are running a vacuum advance distributor. Do you run the hose to both carbs with a "T" connector, or does one carb generate enough vacuum for the advance? Also had a mental block last night. It's John Ohltman, not Wayne. Thanks, JIm |
I am no longer running the vacuum distributor as the vacuum signal was not correct after switching to dual carbs. here is the distributor I switched to.
It is identical to the Bosch 019. Works very well with the setup.
Glutamodo always provides excellent advice on 40hp applications. He is correct about the pushrods not needing to be longer with the 64mm stroke. Balancing is also a must like he said. I hopefully eliminated the crank breakage problem by sourcing a brand new 64mm crank and having the whole rotating assembly balanced to within a gram. |
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jwanders32
Samba Member
Joined: March 08, 2011
Posts: 100
Location: LAKE VILLA, IL
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| Posted: Thu Feb 23, 2012 4:34 pm Post subject: |
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| You guys are great! Thank you so much. Feel like I have a clear direction and you likely saved me some cash. Thanks again! |
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tigerdyr
Samba Member
Joined: May 22, 2009
Posts: 35
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| Posted: Sun Mar 18, 2012 9:03 am Post subject: |
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| WesleyGarrard wrote: |
Yes 1300 heads will be a simple bolt on upgrade. You would need to get longer upper head studs. However, this will open up a wide variety of dual carb sets. Also if you are looking to replace the pistons and cylinders you may as well put in an 83mm set. This will bump the 1200 into a 1385. You get a 25% increase over stock hp with just the 83mm pistons and cylinders. Here is my engine.
I used 1300 heads with 83mm pistons and cylinders. I used the CB performance dual 34mm solex carb set. The linkage is very cheaply made but after much fiddling it does work well. HP I suppose, and this is being generous I think, is somewhere around 65? It is surprisingly quick and has no problems keeping up with traffic. Even cruises the interstate at 75mph with ease. |
What crankcase are you using?
Regards Henrik Hagen |
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WesleyGarrard
Samba Member
Joined: October 08, 2007
Posts: 541
Location: Pekin, Il
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| Posted: Sun Mar 18, 2012 3:46 pm Post subject: |
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| tigerdyr wrote: |
| WesleyGarrard wrote: |
Yes 1300 heads will be a simple bolt on upgrade. You would need to get longer upper head studs. However, this will open up a wide variety of dual carb sets. Also if you are looking to replace the pistons and cylinders you may as well put in an 83mm set. This will bump the 1200 into a 1385. You get a 25% increase over stock hp with just the 83mm pistons and cylinders. Here is my engine.
I used 1300 heads with 83mm pistons and cylinders. I used the CB performance dual 34mm solex carb set. The linkage is very cheaply made but after much fiddling it does work well. HP I suppose, and this is being generous I think, is somewhere around 65? It is surprisingly quick and has no problems keeping up with traffic. Even cruises the interstate at 75mph with ease. |
What crankcase are you using?
Regards Henrik Hagen |
It is a factory recycled 1961 block. Standard mains, standard thrust, and was cut for cam bearings. |
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Mr. Oizo
Samba Member
Joined: August 22, 2008
Posts: 75
Location: Aadorp, The Netherlands
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| Posted: Tue Mar 27, 2012 5:05 am Post subject: |
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Hello,
This is my project:
AS41 / 1200CC Engine
1300CC SP Head
Dual 28 PICT Solex carbs
Bosch 009 distrbutor
Homebrew inlets
I'm still working on it, but it's almost finished!
This is how I bought the engine!
Old 30hp fanshroud!
Some respraying!
More respraying!
Looks great!
The status from last night!
Almost ready to give it a start! |
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Mango_64
Samba Member
Joined: August 04, 2011
Posts: 97
Location: Central Valley
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| Posted: Fri Apr 06, 2012 1:30 pm Post subject: |
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| WesleyGarrard wrote: |
Yes 1300 heads will be a simple bolt on upgrade. You would need to get longer upper head studs. However, this will open up a wide variety of dual carb sets. Also if you are looking to replace the pistons and cylinders you may as well put in an 83mm set. This will bump the 1200 into a 1385. You get a 25% increase over stock hp with just the 83mm pistons and cylinders. Here is my engine.
I used 1300 heads with 83mm pistons and cylinders. I used the CB performance dual 34mm solex carb set. The linkage is very cheaply made but after much fiddling it does work well. HP I suppose, and this is being generous I think, is somewhere around 65? It is surprisingly quick and has no problems keeping up with traffic. Even cruises the interstate at 75mph with ease. |
Wesley -
Your setup looks and sound like something I would like to persue in my build. I do have a rookie ? though.. what size motor runs the 83mm pistons and cylinders? and could this be done to a 1300 using the same method?
Thanks in advanced
Mango |
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glutamodo
The Android
Joined: July 13, 2004
Posts: 26524
Location: Douglas, WY
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| Posted: Fri Apr 06, 2012 2:38 pm Post subject: |
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| Mango_64 wrote: |
I do have a rookie ? though.. what size motor runs the 83mm pistons and cylinders? and could this be done to a 1300 using the same method?
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1200 (1192cc) engines were 77mm pistons/cylinders stock. 1300 (1285cc) were also 77mm stock, and they have the same size opening at the cylinder head, which is whey these can be switched, (providing you use the correct length studs for older 1200s)
Now, the 1200 and 1300 are different stroke, 64mm vs 69mm, and that makes the piston/cylinder sets non-interchangable. (in addition to the stroke being different, the wrist pin size on the connecting rods was 2mm different)
For the 1200, they made a couple of different sizes of "slip-in" big-bore piston/cylinder sets, but over the last couple of decades the 83mm is about the only one made. That's what is being talked about here. Again, these only fit the 64mm-stroke 1200 engine. These were not stock VW parts, these are aftermarket, and yield an engine size of 1385cc (and note, most of the time these are referred to as a 1385 engine, and not a "1400")
Now on the 1300, 69mm stroke engine, VW made 83mm piston/cylinder sets, those were the 1493cc "1500" engine - and the 85.5mm sets, those were the 1584cc "1600" engine. These bolt up to and work with the 1300 engine block. Most 1300 engines have had this done to them, actually, since the 85.5mm 1600 piston/cylinder sets became the cheapest and most common replacements back in the mid 70s.
However the 83mm and larger cylinders will not work with the 1300 heads because those heads have cylinder openings which are too small for them. As a result, many 1300 heads have been bored out to accept these over the years. The 1300 heads also have smaller valves than the 1500/1600 heads and while those make for smooth running at lower RPMs, they can restrict power at higher speeds, so using the later 1500-1600 heads is usually preferrable to using opened-up 1300 heads.
Does that explain it well enough?
-Andy |
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Jens-Ole
Samba Member
Joined: March 30, 2010
Posts: 74
Location: Beyond Reason (Norway)
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| Posted: Fri Apr 06, 2012 11:28 pm Post subject: |
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If you are not to hung up on the classic vintage speed formula you could source a pair of 1300 twin port heads from Europe. Replace the 2 outer upper head studs with longer (forgot the excact length but will meassure on my engine in the garage if you want) and it's bolt on!
This will open for more carb kits, but don't know what the vintagevspeed guys say to the head swap  |
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glutamodo
The Android
Joined: July 13, 2004
Posts: 26524
Location: Douglas, WY
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| Posted: Sat Apr 07, 2012 12:37 am Post subject: |
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I personally do not recommend trying to source 1300 twin-port heads. I did so, in fact, twice... I have two sets. And after cleaning these heads up with the bead blaster, found that all four heads are horribly cracked in the combustion chambers, among other things. As they are now, there's now way I would trust these heads. For me, I wasted a lot of money on those. 
Oh, and it's the upper inside two studs that need to be replaced, with shorter ones. |
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Jens-Ole
Samba Member
Joined: March 30, 2010
Posts: 74
Location: Beyond Reason (Norway)
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| Posted: Sat Apr 07, 2012 1:40 am Post subject: |
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That's strange the inner were perfect length but the outer were top short on my 63 40hp. Might be different to earlier engines?
But it's true about the cracks. You need to trust the seller. Most I've seen are fine. |
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glutamodo
The Android
Joined: July 13, 2004
Posts: 26524
Location: Douglas, WY
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| Posted: Sat Apr 07, 2012 2:45 am Post subject: |
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| Ah, yeah, that is right, was thinking SP vs DP. With the older 40HP engines it's diferent. Depends if you're set up for round boss or short boss heads. Round boss 40HP heads use 177mm upper studs, square boss 40HP heads use 193mm upper studs. |
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Mango_64
Samba Member
Joined: August 04, 2011
Posts: 97
Location: Central Valley
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| Posted: Sun Apr 08, 2012 9:03 am Post subject: |
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| glutamodo wrote: |
| Mango_64 wrote: |
I do have a rookie ? though.. what size motor runs the 83mm pistons and cylinders? and could this be done to a 1300 using the same method?
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1200 (1192cc) engines were 77mm pistons/cylinders stock. 1300 (1285cc) were also 77mm stock, and they have the same size opening at the cylinder head, which is whey these can be switched, (providing you use the correct length studs for older 1200s)
Now, the 1200 and 1300 are different stroke, 64mm vs 69mm, and that makes the piston/cylinder sets non-interchangable. (in addition to the stroke being different, the wrist pin size on the connecting rods was 2mm different)
For the 1200, they made a couple of different sizes of "slip-in" big-bore piston/cylinder sets, but over the last couple of decades the 83mm is about the only one made. That's what is being talked about here. Again, these only fit the 64mm-stroke 1200 engine. These were not stock VW parts, these are aftermarket, and yield an engine size of 1385cc (and note, most of the time these are referred to as a 1385 engine, and not a "1400")
Now on the 1300, 69mm stroke engine, VW made 83mm piston/cylinder sets, those were the 1493cc "1500" engine - and the 85.5mm sets, those were the 1584cc "1600" engine. These bolt up to and work with the 1300 engine block. Most 1300 engines have had this done to them, actually, since the 85.5mm 1600 piston/cylinder sets became the cheapest and most common replacements back in the mid 70s.
However the 83mm and larger cylinders will not work with the 1300 heads because those heads have cylinder openings which are too small for them. As a result, many 1300 heads have been bored out to accept these over the years. The 1300 heads also have smaller valves than the 1500/1600 heads and while those make for smooth running at lower RPMs, they can restrict power at higher speeds, so using the later 1500-1600 heads is usually preferrable to using opened-up 1300 heads.
Does that explain it well enough?
-Andy |
Nicely done Andy, Thank You
Where can I get this 1385 kit for a 1200 and is it a direct bolt on kit?
Mango |
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Steve22
Samba Member
Joined: March 05, 2004
Posts: 1389
Location: the wild unknown
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glutamodo
The Android
Joined: July 13, 2004
Posts: 26524
Location: Douglas, WY
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| Posted: Sun Apr 08, 2012 10:48 am Post subject: |
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Most of the big bore kits made in the 1960s thru the 1990s were easy bolt-on kits. (82mm was another size that was out there but those haven't been made in a long time now) I think COFAP was one of the last companies to make them.
One potential issue is they often raise compression ratio - that's one thing you'll have to check for when fitting them, and decide if you'll just run high octane or if you want to shim the cylinders to bring the compression ratio down. In the past, I've just gone with higher octane. My current engine ended up with a lower CR than I expected, and I can get away with regular unleaded. (I think I'm running an older Cima/Mahle set right now)
Then in the mid 2000s, Mahle in Brazil (no Cima on them this time) decided to do "one last run" of them... and I don't know how big that run was but they've been available for many years now. However, I think they adapted a piston design from some other application, as it was shaped differently than any other VW that I've ever seen.
They work, but there is a problem, they may not clear the engine case, usually on just one or two out of the four.
If that occurs, the case or the pistons will need to be clearanced. On an assembled engine, it might be hard to do and not get shavings in the works. But if you do pistons, you'll need to do all of them so they will still match in weight.
http://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=111198057ABB
http://www.cbperformance.com/catalog.asp?ProductID=1650
https://bugcity.com/shop/shop.htm?pquery=mahle+big+bore+40+hp
Now, more recently, "AA" out of China has made these. I've not seen them in person to know if they have any fitment issues. They are cheaper than the Mahle/Brazil ones though.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&...&rt=nc
http://www.vwparts.net/AA8300T40.html
http://vwparts.aircooled.net/83mm-Piston-Cylinder-...-in-aa.htm
-Andy |
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Mango_64
Samba Member
Joined: August 04, 2011
Posts: 97
Location: Central Valley
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| Posted: Mon Apr 09, 2012 9:00 am Post subject: |
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Thanks Steve22 for the link and a Big thanks to you Andy for the knowledge about this big bore kit info. There is a lot of info that I did not know about these smaller motors and what they can do. Now for a couple of more questions...
1) Can i run straight cut gears ?
2) If i run 1300 heads, can I run a dual carb setup and if so, who makes a kit?
Thanks again guys for all the help, i'm getting really excited about these vintage speed motors. For me it's not about keeping up with the Joneses as far as motors size but to be just a little different in the motor area of my build that is not just an ordinary 1200 that came in my 64.
Mango |
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