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On 21 Jun 2003 at 8:56, Aaron Clow wrote: > Finally got the heads off my engine last night. > The valves looked fine on 3&4, so I don't think that > caused my compression problem. I think there was a > serious leak between the heads & cyls though because > there was caked oil & dirt on what is the outside of > the combustion chamber, past the "seal" between the > cyls & head. The cylinders are very rusted and caked > with dirt so that there must have been virtually no > air passing through there as well. A certain amount of such dirt/oil in these places is normal and will depend on how long it's been since the engine was last apart, as well as on the conditions the car has been driven in. > Inside the head exchangers on 3&4 was chunks of > charcoal. On the other side inside the HE was some > kind of funny type of acorn or nut that I've found > throughout the car. I imagine the charcoal on 3&4 was > once similar acorns. I assume the nuts were in the outer half of the HEs, not in the exhaust path. Squirrels often seem to leave me "offerings," too. I usually find walnuts on top of the air cleaner. ;-) > The tops of the inside of the cylinders were scored > from the top to about 2cm down. I don't know if this > is normal. The cylinders were otherwise smooth to the > touch inside. Is it possible that what you're seeing is just the space above where the top ring sweeps? This space on the cylinder wall always builds up a layer of hard carbon deposit. This area is more like 1 cm wide, though. You can try to carefully scrape the carbon off with a single edge razor blade; only then can you see the actual ridge left by the end of the ring travel in the cast iron cylinder wall. > Oddly enough, the heads would probably be in good > shape if they were cleaned up. No visual cracks, > valves look like they're seating OK. You still need to check the valve guides. Grab the tops of the springs with a large pliers and try to rock them up and down. The wear is usually in this direction rather than side to side. I find that I almost always want to replace at least the exhaust guides. > Given all that (probable cooling issues, rusted > cylinders, dirt everywhere), and knowing this engine > most likely already has 100,000 miles on it, should I > abandon my previous idea of just replacing the heads > and instead do a full rebuild as long as I have the > engine out anyway? Otherwise, I have new cyls, pistons > & heads and would just redo the top end... The most important thing to do is the heads. I'd just get yours rebuilt (NOT exchanged.) RIMCO can do a very good job of this if you don't want to do it, or if there's no one in your area that you trust. Exhaust valves that have served 25-50kmiles should just be replaced automatically. BUY good valves, and make sure that they have the chrome plated stems that you need for unleaded gas. I often clean up the old pistons, clean the ring grooves, clean up and hone the cylinders and install new rings. Check the wear by inserting a new ring, squaring it up in the bore with a bare piston and measuring the ring gap. You should also check the piston skirt clearance. You want to make sure that the bearings are in good shape before you renew the power producing stuff, or you may find that he old bearings aren't up to the new output. I prefer to go the whole 9 years, including case savers (send to RIMCO.) I also prefer to do as much of the work myself because I don't trust someone else to be as careful with my parts as I would be. -- ******************************* Jim Adney, jadney@vwtype3.org Madison, Wisconsin, USA ******************************* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org