Can I use a mexican case as the basis for a mild 2010 motor?

[TechnicalNut]

Hi folks,

I'm currently running a new vw-mexico 1600 dual port engine, in my 69 bay. The engine has covered less than 5,000 miles from new. I'd like to turn it into a 2007 (90.5x78).

To keep costs down, I intend to utilise the engine case, heads and rods. My missus (...and me!) want to keep the heat exchangers, so that's why I will be running the stock heads.

We intend to use the bus as our main vehicle, and forsee a lot of long motorway journeys with a full load onboard. So a reliable, torquey and decent mpg motor is what we're after.

My virtual shopping basket currently has the following in it:
Engle 110, HD springs, Kadrons, 78cm (possibly an 82 crank) & 90.5(b) B&P's, full flow kit, 1"1/2 merged header and mondo exhaust and the balancing of components of course.

I appreciate the carbs maybe small, but my pocket won't stretch to dual double barrel carbs just yet, and I guess stock heads won't be needing them anyway!

I'm still very much in the planning stage and gathering as much advice as possible.

And finally, my QUESTION:
Is it worth having my current case clearanced & machined or should I go buy new?


Thanks in advance everyone,
TechnicalNut.

[aircooledtechguy]

I would use the case you have. If it's only got 5Kmiles on it, you likely will not have to align bore it. I would send it out to be clearanced for 82mm stroke and have it drilled and tapped for a full-flow oil filter. You will find that stock rods are going to cause a lot more clearancing to be done and may consider some "stroker rods" which have shaved caps and bolt bosses for more internal clearance.

Nothing wrong with using stock heads on a bigger motor. You won't have the ability to get power up in the higher RPMs, bit this is a bus, so who cares about 5K+ power, it'll be a hwy bomber for long trips and scooting around town. . . You'll find that the smaller valves and carbs will up your port and chamber velocities and get you a lot of power and torque down low where you need it in a bus. Should be a nice motor. Good Luck with it!!

[TechnicalNut]

After markets rods (such as the CB Ultralite) do seem cheap enough to buy. So I can see sense in buying a set, (especially if they come balanced).

Any reason you'd go for a 82 instead of the 78 crank?

Thanks for your reply and providing an informative website.

[aircooledtechguy]

It sounds like you were looking at their H-beam rods, which are overkill for what you are building. A set of CB Unitech Plus rods are not too expensive (about 1/2 the price of H-beams). I've used lots of these. They come with ARP type bolts and are stoker type rods with thinner caps and overall leaner forging over stock. They come in balanced sets ready to install.

Let me clarify on the case, sorry. If you take your case into a VW machine shop for clearancing, tell them you need it clearanced for an 82mm crank. Still run the 78.4mm crank though. 82mm is kind of a "clearancing standard" for cases not the size of crank you must run after clearanced. If you look at Cb Performances "super case" it comes clearanced for 82mm.
Hope this clarify's things. God Luck!!