Valve Guides

[RedWilly]

Any one have valve guides go bad after 300 miles? I have two cylinders with 0 compression. Did a cylinder leak down test and found both to be leaking past the intake valves. I pulled the head and found the valves to be in the seat crooked. I can tap the valve side to side and get it to seat so I am assuming the guides are worn. Any tips to replacing the guides?

[F Bill]

Are you sure it is not the valve sticking in the guide, holding it off the seat causing it? Sometimes guides can be fitted too tight and this will occur, or poor storage conditions will cause rusting of the valve stem and sticking valves..

I'd be really shocked if they wore badly enough to * the valves in the guides in 300 miles. Just pulled apart a lawnmower engine with 650 hours on it that had that problem. It actually * badly enough to stick the valve hard enough to bend a pushrod. (Briggs Intek 2 cyl.)

[RedWilly]

I don't believe the valve is sticking but I will know more when I remove the valve springs and pull the valve out. I ran out of time today and not sure when I will get back to it.

[Carls_jeep]

Quality valve guides would not wear out that fast. Look for an American made valve guide or NOS valve guides.

[RedWilly]

The valve guides were not replaced when I rebuilt the engine 300 miles ago, but they were in good shape. Only one guide is bad so either the machinist who did the valves missed it or it has worn for some reason in a short period of time. Trying to pull it using threaded rod, but no luck so far.

[Carls_jeep]

I doubt using threaded rod will pull it. They are a tight press fit.

[gmcjr]

This is what happened to me....When I had my engine machined about 9 years ago, the machine shop didnt replace the valve guildes, instead they reamed out the old guides and pressed in a brass sleeve. (Why I dont know, and I didnt catch on)The result was that after a few hundred miles, the sleeves would gall and the valves would hang open for a little bit, then they would cool down and start closing. It drove me crazy troubleshooting. By the time it was figured out, a few years and a lot of head gaskets later, it was too late to go kick a machinist's backside, so I replaced them with the valve guides from a another engine.

It takes a lot of force to pull the old guides out, I used grade 8 bolts in progressively shorter lengths (all thread is way too soft) and a socket on top of the block to get them out, a machinist friend of mine made a tool to drive the guides back in without damaging them. It is pictures below. I put a locking collar on the tool that would stop at the top of the block to insure I drove the "new" ones to the proper depth.

[RedWilly]

I finally got the guide out. I ended up drilling and taping it with 1/2 thread, then threaded all thread into the guide and pulled it using a socket and washers for the spacer. I heated the block slightly and once it popped loose it came out fairly easy. Hopefully between the rags on top of the tappets and the magnet right below the guide I caught all the shavings. Now I need to acquire a driver and wait for the parts to come.