Engine Build

Good upgrade.

Keep the header at 1-1/2" and the carbs at 40's. What are your valve specs?

I would go with a longer stroke too and better breathing heads.a motor that makes good easy power isant loaded as hard so it dosent have to work hard, witch usualy ends up with better performance&mpg when it's all done.it's all there nothing special,plenty of parts on the shelf now days form oh so many venders. just make sure whoever does it realy knows what thier doing,not realy thinks they know what thier doing.be sure to balance the rotating assy & use a fully counterweighted crankshaft. good luck and have fun when it's done.

A longer stroke will quickly add $500+ for a new crankshaft and case clearancing. I'd invest in better thank stock heads.

You'll really like it. A longer stroke crankshaft and better heads would be nice (as Mark said) , but as Wolfie pointed out, the motor starts costing a lot more. Some properly ported stock valve (35x32) heads will add nice all around power on you 1915. Don't forget a 1 1/2 quart deep sump and a full flow oil filter.

Yeah decent upgrades. The cam and exhaust will be a nice boost. Solid shafts are more reliable.

 

I agree, the heads are a priority over stroke if you could only go for one. If you go stroke first, the engine'll be itching for new heads anyway. And exhaust, and carbs, etc.

i'm with Mark.  this is by far the easiest / fastest way to add HP - just add a 84-86mm crank.

 

roland should know exactly where to clearance the case and the fordged CB crank itself is $289.

 

i WISH i could pay $289 to increase my displacement 1/2 L and add ~30hp

 

if you do this - then upgrade to 44IDF's from 40's

 what kind of fuel are you going to run  a split duration cam would help you even more..

I'd go with Roland's recommendations.  The cost for these engines can get out of hand very easily (ask me how I know).

I just got off the phone with Roland actually. I have a non ethanol station about 5 miles from my house so ethanol free for me. We are talking about a couple things to do but not sure yet which route I will go. I trust he will take me down the right path but all the suggestions are great!!! Keep em coming. I dont wantro miss anything!

so $500 for a more reliable, more powerful,better mpg, more fun, is too expensive? well Ive only built one stock stroke vw motor for an old fart,it was however a fully counterweighted crank.all my motors are strokers.I have also never used stock size valves, but then again Im not in the slow lane either.but I dont work on my stuff either,do it once do it right and be done and forget it &go have fun.or build an underpowered motor that is beating it's self to an early grave just trying to keep up with a pinto. I gess I dont get the $peedster with a 40 hp motor thing.but then again my other street car was 618+ hp.

Are 1915 really that slow?  

!915s can be fast or slow.....  The "Mexicrate" 1915 with 94mm cyls, stock heads, cam, crank is an improvement over a stock engine, but limited in capability.... A CB Perf 1915 with forged counterweighted crank, performance cam, big valve heads, and reinforced case, can produce 120+HP in a dependable daily driver.....  I put over 30,000 mi. on the engine in my Beck Spyder, and I believe Lane Anderson has gone farther than that....

36k miles so far, with no issues other than the inevitable clogged Webers (largely due to ethanol).

My 1915 CB was stroked to 2054, supposedly 145 hp, but i was really looking for the increased torque for quicker takeoffs from stoplights around town. About 13K miles in 3 seasons and absolutely no issues, carb or otherwise.  Well, I did have a sticking throttle linkage last summer (wouldn't return to idle), but a shot of deep creep on the joints and it went away.

 

The power in these motors is only limited by the heads; stock dual port heads (35x32 valves) are capable of 85-90hp, and 120-125hp when ported properly. 40x35 heads (again, properly ported) will support close to 180hp if everything is right. Whether the motor is a 1679 (69mm stroke x 88mm bore) or a 2332 (84x94), the heads will dictate the power output. The 1679 (with the right cam, intake and exhaust) will reach the breathing limit of stock heads at about 6000rpm, while the 2332 will be done somewhere around 4000rpm. The bigger motor will have unreal torque (because of it's size) and pull like a train all the way to this limit, but will make no more hp than the smaller motor.

 

Now we put the ported stock valve heads on the 1679; with the right combo the thing will sing to 7000rpm (or a little more) with power and be a beast! Being a pint sized motor it won't have a ton of bottom end (torque), but will still be manageable in everyday traffic (drivers with less high perf experience may find it a little lacking). The 2332, on the other hand, will rev to about 5000rpm with the same hp; but because of the engine size it will have a sh!tload of torque from idle on up, which is what makes the everyday/toodling around driving experience so much more fun.

 

We could put the 40x35 heads on the small motor; now with the right parts it will rev to somewhere up around 9000rpm and make that magical big power number, but with not enough torque to skin the peel off a banana until 4 or 5000rpm this motor will be no fun in traffic at all. On the 2332 though, the motor will only need to rev to a little over 6000rpm to make the same hp but will still have lots of torque and be sooo much fun to drive!    

 

A 1915cc motor is a decent size (after all it is getting close to 2 liters) and (within reason) can be anything you want it to be. With some stock heads it will be limited to a little over 5000rpm?, and being a substantial size increase over a 1600 it will be fun to drive. With the ported stock valve heads (and a slightly longer duration cam) it will now rev to a little over 5500 rpm? with power and still have decent bottom end. 40x35 heads will allow more rpm (and more power!), but when you get into the 6500-7000rpm range reliability starts to suffer (it's no longer a jump in and go anywhere, anytime driver), heads need maintenance more frequently (I've done in a set of dual springs in less than 15,000 miles), and you may or may not feel the bottom end/midrange power (where we do most of our driving) is adequate. A stroker will fix that though (think really evil laugh here) . A larger than 2 liter lets you have the best worlds; enough rpms so there's waayy more horsepower than you need and a ton of low end/midrange so the thing is easy to drive. You've probably heard the expression, "speed costs; how fast do you want to go?", and it applies with these motors as well. This is the problem; bigger motors cost more to build. It's a slippery slope... 

well sorts kinda maybee.the smallest vw motor I have done was a 1641 with the new scat prostreet heads(china version,there cheep if you get them straight from scat) they have 40x35 stainless valves chromoly retainers,hd springs,duell springs for an upgrade,larger than stock ports,and ported from scat(pocket ported,possiably a quick cnc port job, as it was the best looking pocket porting I have ever seen,and I had gotten 2 sets of these heads about 4 months appart&both looked the same) they went on to the 1641 with a engle w100 in it, cut the step in the head down si I could have zero deck&.060"quench.(about 8.3 cr).the motor has plenty of low end torque and plenty of top end(for an old guy in a bug)it still has the std carb on it so top end is limited, he sold the duels because he didnt need more top end.he wasent happy with me using a light weight flywheel,he said it was going to have no torque& be a turd.well he was tickeled shitless with the light flywheel.it was plenty for him,a lot more power&torque than the engine it replaced that was less than a year old,it would not of been enough for me,and I dont thing it would be enough for a speedster.how much power did the speedster get from porsche any way?& Ive heard many times it was still underpowered.But thats like strawberry&vinilla

    big valves dont make the low end torque go away.but the rong heads,effed up heads,rong intakes,rong carbs,rong CR,rong cam.verry well can and do.the ports in these heads were much biger than the oe heads are, and they come ready to bolt on.I have a good fealing when somebody looses low end power there having other issues,like rong cam,timing,carb,intake,cr,or many other things.but yes you can put a head that is way to big for your app and loose some torque in the lower rpm too.It all has to work togeather. so if you going to have a motor built build 1 motor that 1, will last a long time,2 make you happy for a long time,3 have fully counterweighted crankshaft,4 total seal rings, 5 a good set of heads sized for the application,not well bubba said just knock the boogger off&fluf&buffer them.,6 the right camshaft(I dont like high lift cams,I do like high lift rockers so the heads can work,but there is no reason to wear out the engine case with a cam that lifts the valve way to far when there are somany raito rockers avalible to do it & save the case&cam too.7 oil screen&oil changes!!!!change& filter the oil before 1 hour of run time on any new engine!! then again before 2 hours of good driving(and good means normal&haulling ass hard axcellor8ting.and agin before the weeks uppossiably two weeks.I use synthetic 5-20 oil in my vw stuff,works great.8 add the extra oil gally to the case,slot the lifter bores inward about 3/8" and outward about 1/8" from each oil gally hole in the lifter bores for ful time oiling ,not just spirt when the cam is in a cetin possission.9 use a good oil pump&fulflow system(I use 30 mm pumps).#10, dont cut corners....any where.I also use dfl(dry film )coated bearings & gears&rockers&pistons&lash caps& a few other parts too,ceramic piston tops&chambers&ex ports,valve faces.this can be very expensive if you cant do it your self, but wort it. and finaly the engine builder and machine shop.choose wisely.there are many other aspects of doing this.but in the end it's worth it.

Mark,

You seem to really know your stuff. But...damn! It is a bitch trying to read it.

I can get through the creative spelling but I sail right through those periods and miss the turns!

Any way you can put a space between your sentences?

I'm enjoying the content!

Al's got the right idea.  Keep your paragraphs really short.  It may not be correct, composition-wise, but it's a hell of a lot easier to read.

Ill try.  big fingers,  bad joints,  and sometimes fingers are faster than the brain.& this fricken insert key keeps effen things up worse than me.I was also ed_u_kate_ted all around the usa&aisa,along with some newfangled spelling books in the late 60's that were an experament and tought the spell fenetticly(or by sound,not the way stuff is realy written or spelled) I dont think they fully thought that out before effing up a pile of kids spelling,  For me it seems to of lasted a lifetime.I think they were trying to either make it easyer on teachers or faster for kids, but it hurt us all the way around and all of the teachers for the rest of my school life were screwed. I think I was living in VA at the time dad was at langly .  It might of been a government experament....and we all know how those turn out.

Great advice from the folks here. I believe with Roland's recommendation you're on the right track. I agree I'd go for bigger valve heads; CB 044's are great; just get them match ported and install a set of Weber or Dellorto 40's and you'll be set.

cnc ported 044's? those would be a good choice,I have the wedge ports for my 2332,and got a set of thier mini wedge ports for a 2386 I built for a 912, there great heads. but if your not getting the cnc ported version(they make about 8 versions of the porting to fit the size & usage of your motor) I would either get thier CNC lospanchetos, or the mofoco 050 or 042 heads(I also have the mofoco 042 heads wedgeported on my 2028. they are made in the USA, a very good head.and flow pretty well for a nonported head(better than the unported cb 044 heads) the mofoco heads also have a lot more fins for better cooling.I think there coming out with something new pretty soon too.

I've heard that too.  I have a new set of Steve Timms stage 2 heads ready for my 2276.  Should give my engine a substantial boost in HP.

I have a set of time hear now, I wasent very impresed, but there supposed to be the stage 1.5 what ever that is. but any good head will help these lawnmower engines out. there are many thought&theroys on ports,sizes&shapes.Ive had a few hundrad hours on a flow bench with all kinda of heads(over a hundrad on my v8 mopar heads)testing & reshaping & testing&filling & testing&cutting appart&testing & all kinds of stuff some works some helps some hurts some realy effs them up.  VW heads need a lot of improvements, it seems that eveloution has left this industry behind in a big way. Even the new performance heads are so far behind in development it's unreal.  somuch power,mpg&torque is just left out in the cold with these things. all I can fugure is there is somuch anomosity form the v8&vw guys the vw guys wont or cant see any thing that has comeabout in the past 20 years or so in head developement. like it on not the vw engine is no different than a chevy engine when it comes to airflow&power output.just outwardly shaped diferent.( kinda like a shitzu&a germanshepard & a weenie dog)all the same but different at the same time.