25hp barrels and pistons....

[RichOakley]

I need some advice please!

I have stripped down my '47 engine and the barrels are worn beyond the specified tolerances. My options are as follows:

1. Find a set of good, used pre-1949 25bhp barrels. Difficult!

2. Find a set of good, used 1949-53 25bhp barrels. Easier, but they won't look 100% correct.

3. A couple of people have mentioned to me that you can use watercooled pistons from (I assume) am 1100cc VW Polo/Audi 50/Golf/Rabbit, which are slightly oversize and will require the original cylinders to be bored out.

I guess my questions are as follows:

a) does anybody have a decent set of pre-1949 barrels (preferably in Europe due to cost and time!!)? Or failing that, a good or NOS set of 49-53 barrels?

b) perhaps more interestingly, has anybody had experience with fitting watercooled pistons to these early barrels? If so, which parts were used? Would any extra work be required on the piston skirts where the gudgeon pin fits through, or would anything else need to be considered such as raised/decreased compression?

I'm half tempted to start stripping down the engine in my wife's '77 Polo, but seeing as it's her daily driver, she would not be overly happy.

[johnshenry]

Not sure I can help you Rich, but what is the difference between the early and late(r) 25hp cylinders? Is it the fin design? Are the early ones the kind where the studs don't go through complete holes in the fins, rather cutouts? I might have 1 or 2 of those early ones.


You wouldn't be able to see them with the engine tin on anyway, right? (I know, but you wouldn't sleep well....)
_________________
John Henry

'57 Deluxe
'56 Single Cab

[Richard Hartel]

You have the early cast iron kdf style cylinders like I do. You can bore them .10 over and get a set of over size pistons and then get the oversize rings from Grant Piston Rings in Anahiem California for not much and retain the look but boost your hp to maybe 27hp!!

[RichOakley]

[RichOakley]

[52HoffmanSplit]

Here is what looks like a nice set that are 1 over and are the early style. Many of the OE Makers still used this "Open fin style" all the way to 1952 and beyond... Good Price Too!!

http://www.thesamba.com/vw/classifieds/detail.php?id=960498

Stick some oversize Deves rings on these and I will wager you are in business.
_________________
DB

11/1966 Porsche 912
7/1968 Type 265 Double Cab
4/1955 Type 117 - 3 Fold

[RichOakley]

[RareAir]

[[email protected]]

My 47's og engine was running for years with 36 hp pistons in the org bored out cyliners. I talked the man that onced owned my 47 form the early 50's up into the early 70's. He is now in his 90's and remebers the car well. He told me that he bored out the jugs and ran it that way for years up to the time he sold it still running.

[RichOakley]

[RichOakley]

[oval56]

how thich is the cylinder at the botom ( outer diameter?)

if the have 80mm outside normaly machine it to 77mm 30hp pistons ond ready...old barels kept, improvement on the torque and power the start of vintage speed
_________________
www.oval56.com

1956 Oval, 2364ccm typ4
1957 Oval Ragtop 1584ccm singel port modified
1950 Hebmüller, 1584ccm okrasa modified

DBK Germany!!!!!!!!!!
www.dbkvw.com

[RichOakley]

Gentlemen.

Thank you all for your help and advice. I have been lucky today and have found a complete set of NOS barrels and pistons just down the road from where I live. Very convenient! So that's now sorted out.

One other question....

The old cylinders off the engine were worn excessively in a horizonal direction with far less wear in a vertical plane. To me, this would point at a worn crank/main bearings, but there is absolutely no end float in the crank whatsoever. I can only assume that these 'worn' cylinders must have been taken off another well-used engine at some point.
Does anybody have any other thoughts on this horizonal 'wear' issue?

[virtanen]

My proposal: twisted connecting rods. 25hp rods are twisted very easily if piston pins removed wrongly, VW has a tool to measure and straighten them.

[RichOakley]

[rod_vw]

For anyone looking for genuine 2nd oversize rings I have the following...

Piston Ring Set for 25bhp 1131cc
Part number SP109A (111 198 255) 2nd oversize for 76mm bore

These are New In Box comprising...

4 x 111 107 309 Piston ring, upper
4 x 111 107 319A Piston ring, lower (narrow face contact)
4 x 111 107 329 Scraper ring

£25 plus shipping.
_________________
Rod,
Please visit http://www.historicvws.org.uk
https://www.facebook.com/historicvwclub/

1946 Beetle (Back on the road after over 50 years! Last major outing - Hessisch Oldendorf 2022)
LWB MAN TGE Camper.

[splitjunkie]

How bad is the wear?

Crank flex will cause the wear you describe.
_________________
Chris

You know, a lot of these scratches will buff right out... Jerry Seinfeld

[kiwisteve]

Rich, sounds like you need to talk to Ian C at WPS about all things engine related! nothing like an oldie to throw you a few curve balls!