^ This. If you are happy to do the top end, the bottom end is the easier bit I think. As above, you are unlikely to find any horrors (and if you do, surely better now than after making a nice new top end!), its more a case of measure, check, whack some new bearings in (and possibly a new cam) and you are away.
If you want to do the big ends but don't fancy doing a full strip down, you can do them through the cylinder holes in the case. I have seen the Americans refer to it as the reach around method although to me that's something quite different. Basically using a socket and extension you can release the con rods and caps and inspect crank and change the bearing shells, whilst you leave the crank and cam along with their bearings in situ. You just need not to drop anything!
Get yourself the Jake Raby VW type 4 engine rebuild DVD. It’s worth it for a good reference on the stripping down & rebuild. https://www.ebay.co.uk/itm/25602292...5epioigQwO&var=&widget_ver=artemis&media=COPY
Or so I thought. Checked the heritage parts website to see where the order was and it had a status of... cancelled. Looks like I didn't complete the order as no email and nothing on the CC. Order now placed and confirmed. Was hoping to be rebuilding this weekend but that's in unlikely now. Will focus on sorting the fuel tank and getting the gearbox back in this weekend.
So...the pistons and barrels come ready assembled so no faffing with fitting rings or trying to compress the piston into the barrel - result The cylinder heads come with a big notice advising not to fit head gaskets. So that means that based on the current engine setup with head gaskets, 0.7mm is going to be removed from between the top of the barrel and the head. Does that mean I have to use a thicker shim at the bottom to help with the deck height and keep the compression ratio in the sensible range.
You will have to remove the rings to check the ring gap. There is a "shelf" machined into the head to compensate for not using the gasket.
If it's to small the piston will seize in the barrel when it warms up. Peace of mind if nothing else. You'll find it incredibly awkward to fit that whole lot onto the conrod and seal it to the case anyway, they just send them out like that as it's a good way to pack them. It's much better and easier to fit the pistons, then the barrels. Ring compressors are cheap, just a simple band of spring steel.
OK - the videos on YouTube that I've seen doing a rebuild always show the pistons in the barrels being attached to the con rods - not attaching the pistons and then fitting the barrels (I'm not saying who's right or wrong on this by the way)
The box contains the barrel with piston installed, gudgeon pin, and circlips - nothing else. The piston is tight in the barrel (moves with a bit of force and the barrel is oiled). Unless I'm missing something, they look preassembled to me.
Piston top looks very scratched as if they've been around a bit, I wonder if someone previous sent them back. That alone would have me checking everything. I don't see any honing criss cross pattern on the barrels? In the 70's you could buy parts from VW and chuck them together without a problem. Not so now. It's just advice.
I remember when I built that type 4 way when & you suggested that I remove pistons from barrels, remove rings, give everything a good clean with brake cleaner etc. On rebuilding, do the ring gaps and take your time. The amount of dirt which came out made the suggestion you made more valid , that motor is still running now as good as ever and gets used weekly.
Chuck it together why not . You’re not touching bottom end which is a big mistake . You should take them pistons out and clean them multiple times until spotless
They are pre-assembled for shipping but they are not ready for use. The barrels will not be clean and need to be washed in soapy water and dried with paper towels until the towel is clean. The pistons also need to be cleaned and the ring side clearance and end gaps checked, they might be correct but how do you know? The gudgeon pins will need the shipping grease removed. Those pistons can be fitted on the con rods in the barrels but I find it easier to fit the pistons then compress the rings to fit the barrels. What shims you might need at the bottom of the barrel depends on the deck height measurement, the combustion chamber volume and the compression ratio you want. I hope I'm not using invisible ink, I seem to have written this all before.
