40Hp - head work questions

[gerg]

I am restoring a '65 beetle and am just now getting to the engine work. I want the engine to look stock, but have a bit more than 40 Hp. So far I have gotten the Mahle 83mm big bore kit, and a set of new 1.25:1 rockers and an Engle 100 cam. The block is machined for cam bearings and the lifter bores were decked for the fatter late model lifter heads. I plan to up jet the 28 PCI carb as well, and I realize the 28mm throat is a huge limiter here - I have not put much thought into possibly a 30mm or larger. I want the overall engine to look vintage. Figured I could slip in some power undetectable to the eye.
Anyhow, I am fixing to have RIMCO go through the heads and am wondering if anyone can suggest going with 1300 or even 1500 valves since the heads are going to be gutted and rebuilt? I have a good set of the 1 year 373 heads 31.5mm intake x 30mm exhaust, and can only pressume that stepping up to the 33 x 30 or maybe even the 35.5 x 32 could help some. RIMCO did an awesome job with my block.

There you have it. Any suggestions?
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Gerg

. . . I got 99 problems and my bus ain't one . . .

'65 Sunroof Beetle
'65 Vert
'60 Singlecab

[Matthew]

Are you planning any port work? I don't think you would gain anything with larger valves if the ports remain stock. Even then the tiny intake manifold will be the limiting factor but I think you could pick up a few ponies with some port work. Check out A.J. Simms site for pics of some modified 36hp heads. Scroll to the bottom of the page. I'm sure he could do a set of 40hp heads in a similar fashion.

http://www.lowbugget.com/headpricing_street_heads.html

[gerg]

You know - I never even thought about the intake. I am not looking for high HP, just anything that will let the 83mm jugs breath a bit better. Thanks for the lead, I'll look into it ASAP.
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Gerg

. . . I got 99 problems and my bus ain't one . . .

'65 Sunroof Beetle
'65 Vert
'60 Singlecab

[Bruce]

I'd up the CR. Go to nearly 8:1. Then feed it the needed octane.

[vicsvw]

Try to find an oldtimer that raced Class 9 Offroad, they had hundreds of tricks to gain small amounts of HP. The Big Bore P&C will do the most and the cam will most likely hurt the HP. The came will not work well with the small intake manifold. Up the compression only if you have the good gas 100% of the time. Always carry a can of 104 octain boost. Your extra HP will cost 5 times as much as putting in a stock 1600cc motor but if you must look stock then good luck. Vic www.vwhelp.com

[Matthew]

I agree with vic on the cam selection. The W100 may be a little too much since the intake manifold is so small. A new stock cam with the 1.25 rockers set up for proper geometry may be the way to go. Remember the 40hp rockers were 1:1 and the 13-1600 rockers were 1.1:1 so the 1.25's would add significantly to the lift. Let us know how this project turns out. I have the original low mileage 40hp motor for my 65 sedan and may want to warm it up like this some day while keeping it looking bone stock.

[Dr. Jeckill]

What you could do is hunt down a set of 1300 dual port heads, these would fit straight onto the jugs you have. And yes they do exist, we are almost stockpiling them here in Europe. It would compromise your stock look, but hey you'd be looking at an okrasa look-a-like, and I think that's even better. You'd have to change the tinwork a bit here and there since the angle of the inlet ports is sligtly different but it can be done.

Since I'm online anyway, can anyone tell me where to find those slip-in p/c 83mm kits that would fit my 40 horser. Are they still manufactured or do I have to scavenge Ebay. I seem to have a hard time locating them here in europe. But that could be just me.

[gerg]

Thanks for the info.

I got mine here:

http://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=111198057ABB


I am pretty sure that www.bfyobsoleteparts.com carries them too.
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Gerg

. . . I got 99 problems and my bus ain't one . . .

'65 Sunroof Beetle
'65 Vert
'60 Singlecab

[Dr. Jeckill]

I do have some questions about those mahle kits. Could you tell me what the underside outside diameter is, because apparently there have been 2 different 40 hp cases, one with 87mm and one with 90mm. Bore and stroke are exactly the same, as is top outside diameter of 90mm. I'll open up my engine as soon as possible to check my jugs, to see if I can use the 40hp big bore kit, wich by the way I found indeed at wolfsburg west and also at serrano's.

I was also wondering if someone could tell me if there was a difference, in the rods between a 36hp a 40hp and later 13/15/1600 engines. Other than the journal size at the big end and the hole size at small end. This because I can order rods which fit on a standard 69 or 74 stroke crank, which by the way drops straight into my 1200 case I have been told, and have the 20mm hole at the small end, needed for the use of the big bore kit. But in order to use these they would have to be aproximately the same in size as the OG ones.

If this would work, I'd be able to up my stroke up to 74mm without any machining of either case crankshaft or rods, this way having a displacement of 1610cc. According to how to HR a vw engine.

Anyone any thoughts on this?

[Steve22]

I believe that the 40hp rods are thicker at the crank than the later 1300/1500/1600 rods. Somebody correct me if I'm wrong.
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'65 Karmann Ghia 'vert
'73 Super Beetle
'59 Beetle ragtop
'73 Sunroof Transporter

[Dr. Jeckill]

I've done some more looking up and indeed, they're a bit fatter around the waist, You'd have to machine 0,02 inches off of both sides to make them fit.

any difference in lenght that you know of