Thought I'd detail the bush (re)build of my 1600 engine. The PO took the engine apart after a reported spun bearing and I now have the puzzle to put together - at least I think I have all the pieces. This is just a fun exercise, done on the cheap and for me to learn a bit on building a VW engine before investing in new parts for a stroker build at a later date. If this starts and gets my car to the TMR to be registered then mission accomplished.

The parts have seen water so first thing to do was to get rid of the rust starting with the crank.

Before:

After a dose of WD40 and 400 and 600 wet and dry.

I think the spun bearing was a bearing failure due to this piece still embedded in the con-rod??????

Did a bit of polishing again to try and get rid of most of the damage to the rod.

Looking at the rod I think (in fact I am sure) you will find the rod bore is egg shaped and that journal is worn meaning that the crank should be eground and the rod replaced to prevent a similar failure in the future.

Yes I also noticed the extra wear around the edges of the journal as well. The spun bearings are not uniform on the edges so I think they were floating sideways either before or after spinning. I took a reasonable number of measurements on that one journal but I don't have the gear to accurately measure it. The measurements did show something interesting - the case is well used and one of the rods is an odd size to the rest.

Measurements:

Crank
54.75
54.75
54.74

Case
Thrust
21.85
22.00
21.78

Line bore
66.54
66.44
66.43

Rods
54.72
54.72
54.50
54.72

The smaller rod above is the problem rod so my thinking is that the wrong bearing size may have been used by the previous builder and this promoted the bearing failure and spinning....or the spinning took away the perfect amount of metal to take the rod down a size.

Based on my searching the measurements would indicate the case has already been line bored 3 times with one line bore left in it and the crank has been ground once already. Seems the engine has been well used over time.

I'm pretty sure I've measured it as accurately as I could and am now trying to figure out which bearings to buy. Your suggestion of another rod would be a benefit as I could then get all the rod bearings at the same size......I think???

The con rod with the spun bearing needs to be binned. Not worth trying to repair. Find a second hand replacement.
The crank will need to have the big end (con rod) journals reground. the main bearing journal may just need a linish.
Take it to a professional crankshaft grinder and have him measure it up to see what it needs.
From what I saw of your crankcase, until that is measured up and checked, it may be reusable with just a clean up.
I have a feeling your motor may have been rebuilt, and a con rod bolt has come loose, causing the spun bearing.
Do you have the piston and cylinders for the engine? If so, put up a picture of the piston tops.
Dave

Don't have a picture but the piston tops are all coked up, the cylinders seem reasonable some still have the cross hatching but one has a very slight lip.

I should have explained a it more in the first post that I'm giving this a go:

http://www.thesamba.com/vw/forum/viewtopic.php?t=533158

Make my mistakes on this pos and not on the good build, so aim is to be as cheap and cheerful as possible. I'm sure it will be cringeworthy but for me it fills the time while I can't work on the body or chassis.

Pulled out the rest of the parts boxes and got to work on some more measurements today

Bore 92mm
Stroke 69mm
Which makes it an 1835cc motor bonus!!!

Heads are AMC

Measured the rod lengths, eye to eye and got
97.15
97.13
97.00
97.01 this was the bad one.

Not sure why there are two different lengths unless I got unlucky on taking crappy measurements.

Take the rods to have the cap shoulder machined so the rods big end can be bored back to OE. The rod big ends take much of the beating of the bottom end and ovalling of the rods big end is fairly common.

The engine shop can also rebush and ream the small end as fairly likely they'll need attention too unless you have a

Thanks psimitar.

....and as requested a photo of the pistons before and after a clean up today.

You're certainly good with your WD40 and sand paper!

Lol, the piston tops were a strip wheel job

When a big end bearing fails, it will allow the piston to move further in the cylinder, eventually the piston will hit the cylinder head. This is the noise that lets you know something has gone wrong.
I can't say for sure that piston has been hitting the head from the picture, but you can see how the edges of the piston have been washed clean. That is the tell tale sign that the oil ring is not controlling the oil, allowing too much oil to pass into the cylinder which will be burnt and exit the exhaust as blue smoke.
What you will need to measure on the piston is the ring grooves. This is where the rings sit, and it is the gap between the side of the ring and the piston groove that needs to be measured. Let me know if i need to explain more.
Dave

I think I have it, so measure the remaining vertical space in the ring groove with the ring in place? What size am I looking for?

Looking for 0.0045"/inch of bore
92 need around 0.016" by memory

Vertical space left in the piston groove with the ring in it, yes (piston ring land clearance).
I rekn once it's past .004" time for new ones if you want it to last and have good comp, new sets are 1/2 that usually.

Got a new set of feeler gauges today and they are all around .004, won't take a .005.

Con rods have arrived today thanks to landfall, looking good and will use these instead of mine.

Quick clean of the heads. Before and after.

What did you use to clean the heads with? Seems to have worked pretty well.

A can of degreaser each and left overnight in plastic bags. Then used a wire end brush to clean them up. Might need to be a bit gentler with the brush next time.

Ah yea, the steel wire will bite into the softer ali heads but using a brass bristle drill brush just doesn't have the bite needed to remove carbon build up of either oil or combustion process.

No biggie as a mild flycut of the barrel seating face of the head would be advisable anyway to ensure no leaks once reassembled

Quote:

Originally posted by psimitar s a mild flycut of the barrel seating face of the head .... to ensure no leaks once reassembled

Started assembling the crank today and continued learning the hard way.....I heated the gears up on the BBQ but didn't get enough heat into the timing gear and it ended up stuck half way. Seeing as I didn't have the proper puller it took two torches to get it hot enough to remove. 2nd time round it was still a bastard to fit. I put the crank into the freezer for a half hour before I tried the distributor gear and that ended up getting a bit beaten before it too went on. I should be better at this when I'm doing the good engine......

Just chuck em in a preheated oven for 30mins at 200C

Quote:

Originally posted by Bizarre Quote: Originally posted by psimitar s a mild flycut of the barrel seating face of the head .... to ensure no leaks once reassembled As a minimum

....so my bearings and gasket kit arrived and I started putting the motor together. Bit of a juggle to get the crank into one case half but got there and a bearing jumped out of place......had to seperate the case 3 times.

Then onto the pistons and jugs which had to be done twice so I could get all the gudgeon pin clips in correctly. On to the heads, again done 3 times, last time with then tubes and push rods. Forgot about the 2 tin pieces, found one but have to take the heads off again to fit them.

Then the real fun started.....the distributor drive. I did not understand that you needed to have the distributor in before turning the engine so it would not walk off the crank gear.....took a long time to get it back out. Went to bed.

Up this morning, drive is in, distributor is on, have problems.

The drive is still able to ride up even with the distributor clamped in. Also have a lot of end play....60 thou when the crank is moved rocked back and forward by about 2 degrees. I'm stumped now and don't know what I've missed.

Shot of the end play from the pulley end. Seems to prefer to turn anti clockwise rather than clockwise. Any clues on where I have gone wrong.

Is the flywheel fitted?