40 Horse with FK41?

[theastronaut]

I'm buying a '63 vert that has the original, but worn out 40 horse. I have some spare 40 hp parts laying around and I want to keep the original engine with the car so I'll be rebuilding the engine. I have a set of Mahle 83's and the FK41 leftover from the 1679. Since I can't leave well enough alone I'll probably be cleaning up the ports, but nothing too crazy. Would the FK41 with stock rockers be too much for a stock-ish 40 horse?
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[OLD VW NUT]

For a 40hp with big bores it might be an interesting choice. Its actually milder than the W-100 that I would likely recommend for a 40hp motor. With a good 3 angle valve job and some mild head work it might work pretty good. A set of small dual carbs could wake that combo up nicely. Although it comes with hi lift rockers recommended by Engle I wouldn't use more than 1.25:1 rockers - and it probably wouldn't give you much more omph over stock ratio rockers.


Here's the specs for that cam:

FK41 camshaft- .364 lift at bore x 269 degrees duration- for use in mild to larger street engines- for ratio rocker arms. Engle camshafts have been the standard for performance in the VW industry for over 20 years. Made from specal billets and ground to exacting tollerances- Engle cams deliver reliability and performance that is unmatch. Engle offers a very comprehensive choice of over 20 different grinds. NOTE: many lifters (followers) are not compatible with performance camshafts. The potential for lifter / cam failure makes the installation of hi-performance lifters mandatory to maintain the Engle Camshaft Warranty.
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[theastronaut]

Dual singles and an Abarth style four tip exhaust would be the plan. I already have the cam and matching lifters in excellent condition so I thought it might work. Just couldn't find anyone who had used one in a 40 horse.
_________________
Strive for perfection in everything. Take the best that exist and make it better. If it doesn't exist, create it. Accept nothing nearly right or good enough."
-Sir Henry Royce, co-founder of Rolls-Royce

'64 Beetle Sunroof OG Bahama Blue
'63 Beetle Vert
'66 Beetle
'88 Festiva L
'89 Festiva L
'64 Chevy C10
'66 Chevy C10

[Dan Ruddock]

Dual Port heads will fit. 69mm crank will fit.

Dan

[GTV]

Numbers look great to me. 40hp rockers are 1:1, use 13/15/1600 rockers, they are 1.1:1. Valve lift would be right around .400". Bush the lifter bores!
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[MODIFIER]

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I knew one of us had to sell to the other eventually.
Broken trans was the trump card I suppose
At least she will be going to the home she deserves.
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[Matthew]

You may not find anyone has tried it. It is not much more on .050" duration than the W100 that it seems many have used successfully with big bore 40s. I think it would make a cool build, but I am in to engines that most people think are a waste of time like 40hp and single port 15/1600 based engines.

I really like your 1679 build too; most here would make it a 1915.
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[Matthew]

That particular fk41 is on 112 LC right?
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[Matthew]

Maybe this topic would get more replies if moved to the vintage speed forum.
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[dbo@samba]

It seems the 1.4 rockers worked on a stock mill. http://www.hotvws.com/content.php?contentID=38

[theastronaut]

Reviving this from the dead, I've started building the vert and just split the short block. Looks good internally so far, the crank and block are still std/std and no signs of the bearings being pounded into the block. I'm still planning on using the FK41.

A couple questions before I start ordering parts...

I think I'll need to use single HD springs, or maybe not since I'm only using 1.1 rockers? If I need heavier springs should I also upgrade the pushrods, or will the stock ones be ok?

Would a oil pump/filter combo like a CB maxi pump 2 work well on this engine? I had one on a 1600 DP for a few years and never had any problems with it. I like the idea of having a filter, but would rather keep the build simple and not have a remote filter and associated plumbing.

http://www.cbperformance.com/product-p/1791.htm


Build combo would be:

Balanced stock crank/rods, lightened flywheel.
Mahle 83 big bore P&C's.
Engle FK41.
1.1 Rockers.
'65 only heads, ports lightly cleaned up, three angle valve job, slightly flycut.
Dual single barrels (stock 28's? Still need to find a set).
Modified stock muffler to flow better and resemble an Abarth 4 tip.
_________________
Strive for perfection in everything. Take the best that exist and make it better. If it doesn't exist, create it. Accept nothing nearly right or good enough."
-Sir Henry Royce, co-founder of Rolls-Royce

'64 Beetle Sunroof OG Bahama Blue
'63 Beetle Vert
'66 Beetle
'88 Festiva L
'89 Festiva L
'64 Chevy C10
'66 Chevy C10

[SBD]

I ran a Claude's Buggies filter pump on the 40 horse motor I built in the mid 1980's. No internet or anybody else to tell me not to. Had to grind the fins a bit to clear the pulley tin. At the time the pumps came with both 8mm and 6mm bolts so you could use them on either kind of case. Didn't do anything about matching the sizes of the holes in the pump and case. Don't know if I should have or not. It was the first VW engine I ever built. Ran a mechanical pressure gauge on it and never had any problems.
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[theastronaut]

I do have a new forged/counterweighted CB 69mm crank that's just been collecting dust, and a set of rebuilt 1600 rods. Should I use those and find a set of 1500 83mm pistons (22mm pins) to get away from the weak 40hp crank? Are 40hp cylinders spacers available (or needed) with this set up?
_________________
Strive for perfection in everything. Take the best that exist and make it better. If it doesn't exist, create it. Accept nothing nearly right or good enough."
-Sir Henry Royce, co-founder of Rolls-Royce

'64 Beetle Sunroof OG Bahama Blue
'63 Beetle Vert
'66 Beetle
'88 Festiva L
'89 Festiva L
'64 Chevy C10
'66 Chevy C10

[Matthew]

The easiest way is to use 40hp rods on the 69mm crank. This way you can use the readily available 40 hp 83mm P&C set. The 40hp rods need .020" per side machined off the big end to fit the crank journal.

The 83mm 1500 jugs would require you to machine the case spigots. This is a slippery slope as you will pretty quickly end up with a 1600 cut into a 40hp case.
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[theastronaut]

I was thinking of using the 83mm big bore 40hp cylinders with the 1500 pistons for no machine work. I know nothing about building a 40hp though so I didn't know the rods could be narrowed to work.
_________________
Strive for perfection in everything. Take the best that exist and make it better. If it doesn't exist, create it. Accept nothing nearly right or good enough."
-Sir Henry Royce, co-founder of Rolls-Royce

'64 Beetle Sunroof OG Bahama Blue
'63 Beetle Vert
'66 Beetle
'88 Festiva L
'89 Festiva L
'64 Chevy C10
'66 Chevy C10

[Matthew]

Edit: double post
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[Matthew]

[raul arrese]

I have one sitting on my garage floor right now , but I used 1.4 rockers on it . 10.1 compression with ported stock heads , ran ok but I never put to much time into it.. oh and it was on E 85
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[modok]

Basically everything about the 1300/1500 is better than a 40 horse, and fits. So you have to decide where to draw the line on improving it and still being a 40 horse.
One guy had me cut the heads to fit 85.5 cylinders and he's got a 1600 with 40 horse heads.....is that good? Is that a 40 horse? I don't know.
I'd rather keep the shorter cylinders and rods. Keep it narrow. You could use the long rods run the 85.5 B pistons that are useless for most other uses and make it fit the tin that way.

Not a fan of the 2.0 rod ratio, but rod ratio matters very little.
Mainly I'd rather put 1500 heads on it.
I like SP engines but they do allow, and flat out NEED, a larger intake size.
DV in his research found in most cases intake runner should be 75-85% of valve size, but with siamese ports that changes to 95, even 100% of valve size, and that IS a very significant difference.

And the vintage speeds guys are totally messed up too, because they put dual port heads on it and don't realize this works both ways.

[theastronaut]

It's a matching numbers car so I want to keep the original 40hp, or else I'd just build a 1600 based engine for it. But I figured since I had all these other parts already I'd put them to use and not be stuck with only 40 hp.

So I'll use the 69mm crank with the 40hp rods and have them narrowed so I can use my current pistons and keep the engine narrow.

I need to track down the tins to convert it to a doghouse setup and take the crank/flywheel/rods/pistons to the machine shop to be balanced. I already dropped the heads off to be checked out and have a 3 angle valve job done. I'll update here as I make progress.
_________________
Strive for perfection in everything. Take the best that exist and make it better. If it doesn't exist, create it. Accept nothing nearly right or good enough."
-Sir Henry Royce, co-founder of Rolls-Royce

'64 Beetle Sunroof OG Bahama Blue
'63 Beetle Vert
'66 Beetle
'88 Festiva L
'89 Festiva L
'64 Chevy C10
'66 Chevy C10