Straightening valve

Hi, I'm hoping someone can help me. The other day, I changed the timing belt on my wife's car, a Renault 19, 1.4 80hp. The thing is, when I tested it, the belt came off. I must have done something wrong; I left it too loose or something, but it came off, and even though I put it back on, something was broken. I lifted the cylinder head and saw that the pistons are slightly scored. They turn fine, and nothing looks bent or broken except for one exhaust valve on cylinder 1.

I removed this valve and straightened it, grinding the seat with lapping compound. It was quite a bit of work, but it's done. I also checked the rest of the valves, cleaned and removed them, and took the opportunity to grind the seats on some that weren't quite right.

My question is, do you think the valve will work fine or will it break soon? I haven't removed the head gasket from the block either, even though it would make sense to replace it. Do you think I can put it back on? It's not burned or anything.


I'd appreciate your opinions.

Don't even think about putting that valve back in, because it's most likely damaged and could break, and that would really ruin your engine. Buy a new valve and install it, or take it to a machine shop and have them install a new one and check the valve guides

Okay, as explained before, don't install it with that valve. Besides, if you really want your engine to run well, you need to do a thorough check. From what I read, you said the pistons are scored. Well, that's very bad for engine stability. If you install it like that, I'm sure that in another 1000km you'll have to take it apart again. Most likely you'll have to replace the pistons, at least the ones with scratches, since that causes hot spots and the ignition often won't be due to the spark plug spark, but rather to what I mentioned before: detonation. You could end up ruining the whole engine. It's best to check it more carefully and definitely replace the valve guide and guide seal, as well as the head gasket, because even if it looks fine, it's already been subjected to torque and is compressed. If you install it like that, the final torque you apply won't be accurate.

I hope this helps, and I wish you success in assembling your engine.

Hello again. Well, I've finished putting everything back together; I finished last week. Although I think you were right, the normal thing would have been to at least put the bent valve back in, reseat it, and use all the gaskets, but I wanted to spend as little money as possible, so I decided to try it out and installed the straightened valve with the seat made from the grinding compound and the same gaskets. I didn't even remove the head gasket from the block; I retorqued it according to the manual, and that's it.

I've driven about 100 km, and so far everything is fine. It doesn't overheat, it doesn't build up excessive pressure, there's no oil in the coolant, the car responds well, fuel consumption is normal, etc. The valves aren't making any noise; it shouldn't have bent again or anything.

Thank you very much for your advice, but I'll keep you updated on how the car runs and how long it lasts because, to be honest, the repair I did is a bit of a makeshift job, and it's not guaranteed to work well for very long.

Greetings to all.

I hope the repair goes well for you , but from my point of view, I wouldn't recommend that job since you might damage the engine more than necessary, and you could end up spending the money you were trying to save, and even more than you thought. It would have been better to replace the valves, check all the valve guides (in case they have too much play), valve stem seals (or guide caps, as the other person mentioned above), the head gasket, and thoroughly check the pistons.
What I recommend is that you go to a mechanic's shop and have them check the compression pressure in each of the cylinders (make sure they remove all the spark plugs for this measurement to rule out a blown head gasket or leaks in any of them due to improper tightening or problems in any cylinder due to the valves or pistons). The lack of noise in the engine does not mean that the work is in perfect condition since the valves and pistons are a very delicate part of the engine because they are the ones most subjected to the heat generated by the explosions .