Greetings, been having a conflab MBG and have determined the following - prior to the now not so extortionate (€800) ish, cost of a big bore kit to 695 (700cc) the price of going bigger was avoided by boring out 77mm barrels to 80mm and fitting 126BIS pistons (cheaper) this made the barrel skirt rather thin and there have been instances of bits breaking off with the resultant damage. I believe this is the basis of the mod to my engine and that it was done some time ago. I am informed that to over bore a 77mm barrel to 79.5mm is ok. With the cost of the 'big bore' kit(s) reducing, the over boring to 80mm has fallen out of favour. Is there anyone else out there with this mod that continues to run with the barrels thus modified???

Greetings, by way of an update on this saga I have been back to engine man to discuss options. We have found that my original barrels, besides being bored out to 80mm (from 77mm) the cylinder top surface has also be lowered by approx 4mm. (exact measurements not made - just a side by side comparison) This morsel of information has further confused the situation as we believed that the barrels retained their 70mm stroke length. The only reasons for this skimming must be to reduce the overall deck height to 1. enable a higher C/R 2. enable the use of a very slightly shorter conrod 3. enable the use of a piston that has a shorter compression height 4. enable the use of a crankshaft with a different stroke. So now the situation is even more confusing bearing in mind that the engine initially did not run with base gaskets or cylinder head gasket???? We are trying to obtain replacement pistons - watch this space!!!!!!!

Ian.

Greetings, have done some more investigation and this has resulted more confusion!!! Using an original, unmodified 126-652cc barrel and placing it into my crankcase I find that it's a very sloppy fit!! (the barrel has a good 2-3mm of movement) Approx measurements of my crankcase are - aperture(s) 84.71 and 84.73mm - the original 126 aperture measures between 82.95 to 83.08mm?
I know that my pistons are original 126 BIS 80mm, but what of the barrels. If my crankcase has been modified to take these larger barrels, then what or where have they come from???? I know that parts exist for the 79.5mm bore (700cc) upgrade, and that parts are available for 740cc and above, but, I cannot find any info on a larger barrel that only accommodates a modification to 80mm bore and 704cc (126BIS) Has anyone got any info on the possible origin of these barrel parts???????????????? HELP!!!!!

Ian.

Bleeding Knuckles said:

Greetings, have done some more investigation and this has resulted more confusion!!! Using an original, unmodified 126-652cc barrel and placing it into my crankcase I find that it's a very sloppy fit!! (the barrel has a good 2-3mm of movement) Approx measurements of my crankcase are - aperture(s) 84.71 and 84.73mm - the original 126 aperture measures between 82.95 to 83.08mm?
I know that my pistons are original 126 BIS 80mm, but what of the barrels. If my crankcase has been modified to take these larger barrels, then what or where have they come from???? I know that parts exist for the 79.5mm bore (700cc) upgrade, and that parts are available for 740cc and above, but, I cannot find any info on a larger barrel that only accommodates a modification to 80mm bore and 704cc (126BIS) Has anyone got any info on the possible origin of these barrel parts???????????????? HELP!!!!!

Ian.

Click to expand...

Probably modified VW items, although it is conceivable, if unlikely, that they originated in a Citroen flat twin or Citroen GS/GSA four.
I have heard that BMW bike barrels can be adapted too.

Morning Ian;
"Dragonwagon" may just have found the answer. When we fitted the 'Nardi' kits at Radbourne Racing I seem to remember that the barrels still had the VW part numbers on them! Try somebody like 'MEGABUG' who have a large range of VW barrel kits. They may be able to help you out with dimensions. Also, due to the fact that the VW barrel has a large upstand at the top, machining this off to enable them to fit the Fiat maybe what has brought the barrel height down. 'AIR-COOLED.NET' and MEGABUG are 2 good site to start with in obtaining dimensions from. Another way to go is to find out if there is a (air-cooled) VW specialist in your area and have a word with them. See if you can compare your barrels visually with VW ones shown on the various sites. I wouldn't be a bit surprised if that is the way your Italian engine builder went.

Ian
Are you considering a used crankcase and a big bore kit? I also noticed two Ferrari Dino con rods for sale .... They could make for a high reving machine...

Hi Andrew;
have you got an e-bay number for those con-rods please?

Numero oggetto eBay:
112136681740


http://www.ebay.it/itm/2-BIELLE-DIN...681740?hash=item1a1bddf90c:g:S~AAAOSwZVlXredn


Guess who's not working very hard???

Thanks for that Andrew. If 3 forum members want to club together (or 1 member make some money), look on e-bay number:- 311389403824---a complete set of 6 Dino rods for a shade over £600 (plus carriage).

Hi all, I have been researching using VW 1600cc barrels for an 800cc 126 air cooled conversion. This conversion has been done in the past, the cylinder head bolt positions are different and you have to cut a slot at each of the bolt holes in the VW cylinders, machine the top raised lip to give the correct deck height and machine the barrel skirts to miss the crankshaft to get them to fit. If using VW pistons the gudgeon pin hole in the conrod has to be machined to allow for the larger VW part, from memory 22mm dia. I believe this would be required for any VW barrel conversion. Are the slots cut into your barrels? If not they more than likely come from another source.

Ralph

thepuddlejumper said:

Hi all, I have been researching using VW 1600cc barrels for an 800cc 126 air cooled conversion. This conversion has been done in the past, the cylinder head bolt positions are different and you have to cut a slot at each of the bolt holes in the VW cylinders, machine the top raised lip to give the correct deck height and machine the barrel skirts to miss the crankshaft to get them to fit. If using VW pistons the gudgeon pin hole in the conrod has to be machined to allow for the larger VW part, from memory 22mm dia. I believe this would be required for any VW barrel conversion. Are the slots cut into your barrels? If not they more than likely come from another source.

Ralph

Click to expand...

Hello ThePJ, sorry for delay have been for a quick break in Dumfries and Galloway and had very limited internet service. I have found that the Nardi kit from the 1970's was only up to 652cc (77mm bore) and this was the only example found (any other sizes Tom??) There are no elongated holes in my cylinders, as far as I can tell the stud pattern is the same as original and there does not seem to be any evidence of machining to achieve a good clearance from the crank! So, I have a set of larger barrels from somewhere - any other idea's people???? Just a thought, but what is the origin of the cylinders for the Athena kit????

Ian.

Hi Ian;
The only size of Nardi kit that we fitted at Radbourne Racing was the 652cc kit--there MAY have been other kits, but I never saw one or heard of one being fitted. With regard to the Athena barrels, they have the word 'Athena' cast onto them and the part number:--A16111103440 engraved on them--it would seem that they have the barrels custom made for them.
This a bit of a grope in the dark---have a look at the "Machine 7" web-site. Go onto 'engine' and then 'standard barrels and pistons'. This company can supply VW barrels and pistons from the early 1200cc engines onwards. Don't forget, when I was at Radbourne Racing late 60s/early 70s the current VWs were the 1200 and early 1300cc versions. It might be worthwhile contacting 'Machine 7' and trying to get a 'stud-spacing' measurement from them (if they will do that for you) of the older 1200 and 1300 engines (which had a---------77mm bore!)

Hi Tom, thanks for the reply - appreciated. I have checked with 'Air-cooled.net' and found that there is an 80mm barrel available to upgrade the 1192cc type 1 engine to 1286cc!!!! but the kit is unavailable at the moment! I'll give machine 7 a go and see what they have, thanks. the clutch bolt has arrived too, thanks again.

Hi, just found this site from a post on the 126 site. You can see the mods required to VW cylinders to get them to fit the 126. Hope this helps.

Ralph

You need to scroll up to the top of the page to see the photos of the engine parts.


http://www.terytorium126p.pl/topic/22481-fiat-126p-800-ccm-by-komar/#

Thanks ThePJ, the pictures are clear and I can confirm that my cylinders are not cut and slotted as the items shown. I will say that the non fitting 652 barrel slipped easily over the studs, but as I remember my barrels are a tight fit on the studs - maybe that's a sign of a VW barrel, maybe not. I will contact the US people found and try to determine the spigot diameter on their 80mm barrels.

Ian.

Ian;
Done a bit more checking; the 1300 and 1600 VW barrels have the same external dimensions--you can fit the 1600 barrels straight into the 1300 crank-case, but the barrel walls are thinner (which means that the 1300 barrel walls must be quite thick). The stroke of the 1300 VW is 69mm (Fiat 500/126---70mm). I still reckon that checking with a classic VW specialist is a sensible avenue to explore--possibly lay your hands on a knackered 1300cc barrel in order to check dimensions (the bore of the 1600 engine is 85.5mm as against the 77mm of the 1300 engine).

dragonwagon said:

Probably modified VW items, although it is conceivable, if unlikely, that they originated in a Citroen flat twin or Citroen GS/GSA four.
I have heard that BMW bike barrels can be adapted too.

Click to expand...

Hi DW, can you please give me any more info you have (or location) regarding the use of Citroen parts?? Thanks.

Ian.

Greetings, Well after a great deal of searching I have had to resort to 80.4mm pistons from Italy. My engine man will sort the barrels (very slight bore out and hone) and I can move on with my life. The origin of my barrels is unknown - although I suspect they may be an early VW upgrade for the type 1 1192cc engine (80mm to give 1286cc and 36BHP) that is no longer available. Cannot wait to get the motor back together as the car is gathering cobwebs!! I'll get back with an update as soon as.

Ian.

Its many years back since I last looked at air cooled Citroen bits - used to have a pile of them but no more. I have no idea where you would be able to find any either outside of the Citroen Car Club. Someone there may be obliging enough to measure up some 2cv, Visa twin and GS/GSA items for you.

dragonwagon said:

Its many years back since I last looked at air cooled Citroen bits - used to have a pile of them but no more. I have no idea where you would be able to find any either outside of the Citroen Car Club. Someone there may be obliging enough to measure up some 2cv, Visa twin and GS/GSA items for you.

Click to expand...

Hello DW, Thanks for the info - appreciated. I may try and confirm with the Citroen Car Club, if only to get to the bottom of it all!!!

Ian.