40hp replacement pistons/cylinders

[iaccy]

This being my first post in the Vintage Speed section, I hope to read and find useful information regarding a 40hp rebuild. I'm in a bit of a tough decision to make. I'm trying to rebuild the motor out of my '63 beetle with good quality parts. This engine was rebuilt (by Mofoco I believe) around 1996 with not many miles on it since I bought it three years ago.

While it's apart, I want to replace the pistons and cylinders with a set of stock replacements. The local parts distributor has a set of NOS 77mm '61-'65 Kolbenschmidt pistons for $650.

I want this motor to be as reliable as possible. Is there another piston manufacturer that you would recommend, or should I go with these? I'm trying to stay away from a cheap China repop set.

Mofoco case

_________________
'67 Beetle (sold) http://www.thesamba.com/vw/forum/viewtopic.php?p=3289202#3289202
OG '63 Beetle http://www.thesamba.com/vw/forum/viewtopic.php?t=444566

[*Darren]

You can check out this forum's Matt's aka Mr. Motorheads aircooled research website for alternatives - whether you go with Kolbenschmitts or not, the asking price you are looking at is way too high in my opinion. You can pick up other make p'c's for about 1/3 the asking price and while you might have to search for other offerings of Kolben's you could pay up to $200 less (including shipping). That' just my opinion - I simply would opt for a cheaper alternative from Mahle, AA or somebody else.

[Kjell Roar]

What is wrong with the pistons and cylinders on the engine? Worn out?
_________________
I got a historic car, every scratch got a history...

My car, Aug. 4th, 1955 / an early 56: http://www.thesamba.com/vw/forum/album_page.php?pic_id=610438

[Danwvw]

Man I can't imagine putting 77mm p&C's in when the 83mm are available for $200. Yes they are made in China. But AA has the bugs worked out of their process. If you want your engine to last forever then proper maintenance and not over revving it and don't drive it as fast as it will go for hours on end. Wonder if there is a cam similar to the W-100 for the 40 horse engines?
Here are the Piston and cylinders I was talking about: http://vwparts.aircooled.net/83mm-Piston-Cylinder-Set-40hp-Slip-In-1384cc-p/vw8300t40.htm
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[*Darren]

77mm from aircooled research $159 http://aircooledresearch.com/docs/parts_40_piston_liner.html

you want to go bigger (83mm) go bigger.

[iaccy]

[iaccy]

[Danwvw]

Yes the 83mm Piston & Cylinders are designed as a direct replacement, (3mm thiner cylinder walls though!), gasket's everything will work. I would check the deck height and cc the heads though just to set the compression at 6 or 7 to 1 or whatever it is a 40 horse engine needs to be. Which 40 horse heads are you using?
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[iaccy]

[[email protected]]

That's pretty cool. Those might actually be 83's. If you take a close look at the rockers, they have 2 lines which means they are the 1.1 to 1
_________________
Please "LIKE" us on facebook to see what we are working on.

https://www.facebook.com/mofoco?ref=ts&fref=ts

www.mofoco.com

Cylinder Head Reference Sheet

[sub-hatchtim]

if you want some legit period correct 40hp try out some deano npr 92's
_________________
58' pg/sg silo fridge westy
58 Dove blue singlecab
76 911S

[Danwvw]

http://cal-look.no/lounge/index.php/topic,14718.0.html
_________________
1960 Beetle And 1679cc DP W-100 & Dual Zeniths!

[Stocknazi]

[keysas]

Hi all - literally my first post to TheSamba. I too am doing a 40hp rebuild and have recently received a set of AA 77mm pistons. I know you can go 83mm, but I'm doing all original stock.

Here's my problem - the original pistons that came off of the engine had a deck height of about 0.050 inches (1.27mm). The new AA 77mm pistons have a deck height of about 0.092 inches (2.3mm)! When comparing new to old, using the distance from the top of the pin hole to the top of the piston, there is a full 0.040 inch (1.0mm) difference. Has anyone else noted this difference? I'm guessing 0.092 is too deep for reasonable deck height. Should I get the cylinders machined down by 0.040 inches? Is this covered elsewhere? Lots of questions.

[bugmandave]

77mm won't make it more reliable. There are plenty of big motors that are very reliable. It all comes down to build quality. You can slap a bone stock motor together and it could really suck. Imo, if you are coming here for advice you are already behind the 8 ball. There is a wealth of knowledge here as well as plenty of bad info. If you are a novice at VW engine building you need to do a lot of research before a half hearted attempt at it. VW engines are very unforgiving. I've seen a lot of "pro" built engines fail for careless mistakes. I'm within 100 miles from MOFOCO but wouldn't use them for machine work or engine building it were free. They have a bad reputation around here. I know of several guys recently with big problems and always has some tie back to them. Good luck
_________________
'63 Karmann Cabriolet L456 Rubin (Ruby Red)
'71 Westfalia campmobile tourist delivery
January '59 SWR panel
'63 Karmann Cabriolet L54 Poppy Red

[Kjell Roar]

[Mr. Motorhead]

Explained in another forum:

http://www.thesamba.com/vw/forum/viewtopic.php?p=7819167&highlight=#7819167
_________________
30 years experience in the sales of new and used auto parts!
36 horsepower parts for sale at http://www.aircooledresearch.com/
Or the new site at http://www.bugparts.com
Check out the Bonneville project:
http://aircooledresearch.com/docs/thebonnevilleproject.html#

"All limitations are self imposed."
Some Chinese guy