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Tue Sep 04, 2012 3:43 pm

Here's a real interesting motor combination that always generates lots of conversation - It's an 86 stroke by 86 bore high torque bus engine! I'm sure lots of people will be stating that this displacement in other combinations will be just at torquey or efficient or whatever, but hopefully this motor combo will put out some real high torque numbers in respect to it's current size -

I planned this motor several years ago, but I'm finally building it - I started builidng it 2 weeks ago, but it's more helpful when fellow sambanistas are offering late night drunken or sober encouragement!!

Lets go through the build sheet - most the parts are CB performance which I've always had good luck with!

86mm cb performance crank
CB performance stroker case - clearanced for 86mm
CB performance 5.6 rods
Engle FK-65 cam
CB performance 1.4:1 rocker arms
CB performance Los Banditos heads with dual springs
Stock cam gears
CB big-foot lifters
Chrome-moly pushrods -(found in the parts drawer!)
Dual Webber 40IDFs
and for Pistons -
Stock GM L850 pistons 86mm bore -
Stock VW 85.5 cylinders (bored out to 86mm)

When all is said and done - the rod ratio ends up being a small 1.65 :1
Compression ends up being about 8.73:1
and the best part - is that the entire motor ends up being stock width.
Yes - stock width. All that efficency and torque with a stock width motor.

The pistons are the key to this motor - and hopefully I'll add some more pics and be able to describe these pistons furthers. Enjoy!!

Here's the start! I'll add more pictures as I go!

Tue Sep 04, 2012 3:54 pm

goferit.

Tue Sep 04, 2012 4:01 pm

One thing I'd change is the lifters. I'd go with CB Performance Lightweight Racing Lifters. They match up well with just about every cam out there, very few people have had bad experiences with them and they are way lighter than the bigfoot lifters which you don't need. You may want to consider a set of AC.Net aluminum pushrods too, again, way lighter than the CroMo pushrods.

Tue Sep 04, 2012 4:20 pm

The first thing to do was to figure out if this combo would work!

Quick detective work showed me that vw pin diameter is 22mm and the L850 N/A piston pin diameter is 20mm - Yes this can work with a re-bushed rod!

This is a pic of us re-bushing the rod to 20mm from a stock v-dub of 22mm.

Remember - the L850 has a turbo version with a larger 23mm pin - this piston will not work with v-w rods!!!

Tue Sep 04, 2012 4:32 pm

The next thing to do - is figure out my left -over wall thickness -

A quick samba search showed me this! (thanks glenn!)

.179" = 92mm thickwall
.177" = 88mm machine-in
.163" = 85.5mm
.148" = 90.5mm
.140" = 94mm
.118" = 92mm thinwall

My bore diameter is going up .5mm which is .25 mm per side! This equals .0196" or I'll round up to .02 per side! After boring, this will give me a wall thickness of .143" - This is comparable 90.5s and 94s. It's also .040 larger than 87s! I'll do it!

Don't forget to hone them to size!!

Tue Sep 04, 2012 4:36 pm

I performed all the calculations - measured cylinder heights, calculated rod lengths, measure case to deck heights - everything should just fit perfectly if it's all done right! You're always scared until you try! That's a brand new case - stock cylinder with no shims! This will be stock width!!

The first fit looks perfect !! Success!! Please note the dish on this piston - that must be taken into account when calculating CR!

Tue Sep 04, 2012 4:45 pm

Inside shows what a tight little beastie it be!

Look out case top!! Look out cam shaft!! You can barely see it in this pic, but the crank is riding too far forward in respect to the cam!

Quote: One thing I'd change is the lifters. I'd go with CB Performance Lightweight Racing Lifters.

Great idea! I have a set on hand I can use! I'm stuck with the chromoly pushrods. The funny thing is - that during valve train mock-up, the dual springs were bending the stock push rod!

Tue Sep 04, 2012 4:55 pm

Aren't Los Banditos unported, or am I mistaken? Seems like a waste to build such a cool combo and then use unported heads, unless you're planning on doing a port & polish. If it were me, I think I would've opted for Los Panchitos instead, especially for a torquey engine

Tue Sep 04, 2012 6:12 pm

Wheelie Pete wrote: The funny thing is - that during valve train mock-up, the dual springs were bending the stock push rod! Not surprised at that, the stock pushrods are very light weight aluminum, just barely strong enough to hold those massive stock valve springs!

Interesting build, nice documentation! :wink:

Tue Sep 04, 2012 8:03 pm

tmcdade wrote: Aren't Los Banditos unported, or am I mistaken? Seems like a waste to build such a cool combo and then use unported heads, unless you're planning on doing a port & polish. If it were me, I think I would've opted for Los Panchitos instead, especially for a torquey engine

Yes - CNC'd but not really ported - they are bigger than stock, but not what this engine needs - I would like to get this motor on the dyno with these heads, then in a year throw on some bigger ones. Los Banditos still have 40mm intakes - and ports that about match, but they are not huge wedgies. I agree this motor could benefit from them.

Thu Sep 06, 2012 8:18 pm

Make sure the cam gears are compatible - if you rotate the crank clockwise, and the cam jumps up, the gears are not compatible!

Thu Sep 06, 2012 8:22 pm

Check your cam thrust clearance - .004 is what you need!

Sand the thrust surfaces until .004 is reached. Use a feeler gage to measure it! Start with 80 grit until .003 is reach - use 400 grit to get the last .001 off.

Notch the cylinders to match the inside of the case! Double check your clearances! I used half round file to notch all 8 notches of the four cylinders.

Thu Sep 06, 2012 8:54 pm

Boy, talk about getting 2 liters the hard way! I am interested in hearing how it runs though...

Thu Sep 06, 2012 9:10 pm

ALB wrote: Boy, talk about getting 2 liters the hard way!

:lol: :lol: :lol: But it's still 2cc's short!

Thu Sep 06, 2012 9:25 pm

DarthWeber wrote: ALB wrote: Boy, talk about getting 2 liters the hard way!

:lol: :lol: :lol: But it's still 2cc's short!

Exactly! :wink:

Thu Sep 06, 2012 9:33 pm

Quote: Sand the thrust surfaces until .004 is reached. Use a feeler gage to measure it! Start with 80 grit until .003 is reach - use 400 grit to get the last .001 off.
I wouldnt sand the cam bearings for thrust clearance until you seat the cam bearings in the case with the cam, otherwise you risk having too much cam shaft end play

Fri Sep 07, 2012 2:07 am

chrisflstf wrote: Quote: Sand the thrust surfaces until .004 is reached. Use a feeler gage to measure it! Start with 80 grit until .003 is reach - use 400 grit to get the last .001 off.
I wouldnt sand the cam bearings for thrust clearance until you seat the cam bearings in the case with the cam, otherwise you risk having too much cam shaft end play
Thanks! I'll remeasure it when it's in!

Fri Sep 07, 2012 9:18 am

make sure the cam bearings grab the case,your brave honing like that.have you ever checked how much torquong down a vw cylinder on the case distorts it?you might want to make a torque plate setup if you do very many.you could also bore the piston pin larger for the vw pin size and move the pin ht if needed, or just hone up to size.be sure to deburr the cylinder bottoms good.deburr the cam lobes good too. be nice if the dish was 1/2"-1" smaller& alittle deeper, or a bathtub dish would be great.keep up the great work it should fly with that head on it.awassom in a bus or tall tired car.... or any car.

Fri Sep 07, 2012 11:46 am

This is what I meant by "seating the cam bearings"

From Jake Raby:
Before you grind or remove material.

Install the bearings into the case and then install the camshaft..

Tap the cam fore and aft end to end using a soft piece of wood or a brass drift and use some force..
Do this 4-5 times back and forth and then check your end play.

Report back with what you find. (I already know)
Then you'll see what happens IF you had removed the material required to gain the clearance...

http://www.thesamba.com/vw/forum/viewtopic.php?t=375857&highlight=cam+bearings

Fri Sep 07, 2012 2:06 pm

Im not fond of that way to do it,it can spread the bearing, but yes you need to make sure the bearing is seated,flush,I my self have never had a vw that needed the cam bearing worked on as far as sanding it for clearance.