Cleaning carbon off valves and cam chain replacement

[dbeardslee]

I got the heads of old Betsy and removed the valves. I soaked them for 24 hours two-at-a-time in carb cleaner, and while it got the black stuff off I was left with thick, rock-like deposits on the exhaust valves. Carb cleaner wouldn't touch that stuff. In a previous post XSchop mentioned Methylene Chloride (paint stripper ingredient) as the right chemical for the job. I went up to Walmart and got a can of paint stripper, and boy did that ever cut the job down to size. Still had to do a little scraping (with the edge of an old bicycle seat wrench - you know the el-cheapo stamped metal variety), but the paint stripper loosened it up enough to get the deposits off. It took three coats/scrapings but it was relatively fast and painless.

As my cam chain is getting pretty stretched I thought I would throw a new one in while I was there. I ordered a spare link with the chain and used it to attach the old chain to the new one. I replace the chain with the head off and turned the timing plate (an idea from a previous post) and it just drew the new chain through - no muss, no fuss. I had to go slow at first until enough of the old chain was through keeping a little tension on the emerging end. After that the weight of the old chain was sufficient to hold a little tension on the emerging end of the chain to keep it running through.

This should work equally well with the heads in place as long as the cams are removed. I don't think this would be a good idea with the cams in place.

My thanks to all for the great advice.

[mro]

Short of pulling the engine, changing cam chain be one of the tuffest jobs to do. Sounds like it went well.
If you have a lot a miles on your engine, even if running well might not be a bad idea to lap the valves before reinstalling head.


mro
BTW,
There be enough space under crank to slip the linked chains around without turning the engine. Also enough space to (with the right tool) retrieve the cam chain from under crank if you happen to drop it down there

[fredintoon]

Q & D valve clean

Hi Doug,
Kudos on the camchain swap, I dread the day I have to do mine but your post gives me hope that it won't be as bad as I feared.
What I do to clean up valves is to not bother with a chemical attack, just spin them in my drill press. Rough clean with the 1/2 round end of an old hacksaw blade used as an ersatz lathe tool then a final polish with emery tape. Takes no more than a minute or so per valve.

[dbeardslee]

MRO - Your absolutely right about lapping the valves. Did 'em yesterday. Betsy sat for several years before I got her and there were some minor pits on the seats as well as being generally grungy. She's only got 34k on her, but the job needed to be done. My biggest problem now is that two of the lifters want to be a PITA to get back in. Got one in the freezer even as I type.

I can't wait to start checking clearances. A friend (without who's help I never could have got her running) loaned me his shim set. There must be a thousand shims in that box (drool!). When I get done I have to replace the ones I use and get them back to him. Geeze that thing's going to be hard to let go of If you're out there lurking, thanks again P.J.

Fred - I love the idea of using a machine to do the work, but I guess I feel more comfortable doing the job by hand as I only want the carbon coming off - no metal. Takes longer but my peace-of-mind index (as opposed to piece-of-mind, which you can only get with a labotomy) goes up. I'm not a fast mechanic, and I'm not a slow mechanic. I'm a half-fast mechanic

BTW - My old dentist's name is Fred Hill. Has a son who he named Sam. What a comedian.

DB

[gareth]

What a coincidence...
I have the head off the bike and last night was trying to remove the carbon from the exhaust ports too..
First thing I tried was Easy-Off oven cleaner-in-a -can. Sprayed it on all over and when I got back a few minutes later the head was foaming away as the lye based solution hacked into the aluminium of the head. I washed that off as fast as I could before it had a chance to do any more damage. It seemed to make some dent into the carbon, though, so it's probably worth trying on cast steel heads...More internet surfing suggested household bleach. So I packed the ports with cheesecloth and poured some in and left it overnight. This morning I started chipping away at the black stuff with a sharpened plastic stick and the carbon was definitely softer and easier to remove, but its still a hike to get it all off. It's over 1/16" thick in places and was so hard and even, that it wasn't until the black layers softened up that I realized how thick the build-up was.
I'll try the paint stripper and monitor the progress. We use it occasionally at work ( I have a woodworking shop...) and the industrial, take-no-prisoners stuff that we use will be a good test of its' carbon busting ability. Methylene Chloride, by the way, is a fairly heavy chemical. It tends to settle down to the bottom of the containers in which it is kept, so, in case you didn't know, you need to mix it up from the bottom of the can for it to be most effective. Its also possible to check the quality of the stripper at the home-store outlets by weight. All other things being equal, the better-quality stripper brand will feel heavier...

[dbeardslee]

Gareth -

You'll find it a lot easier to clean those valves if you take them out. The stuff I was worried about was on the stem, not the face (might be the wrong term - the part of the valve you can see). It creeps up the stem and can cause valves to stick if it gets up there high enough. I cleaned the faces too, if for no other reason than to get the suction cup on my valve lapping stick to stick to the valve.

They are easy to take out and put back in. I wouldn't put the paint stripper on them while they're still in the head as there is a rubber o-ring at the bottom of the valve guide and I don't think those two things will get along well. Oven cleaner is an interesting idea. As MRO has already stated, removing the valves also gives you the opportunity to lap them. You can also replace the stem seals while you have them out.