How to Lap Engine Valves

How to Lap Engine Valves

Don’t replace the engine just yet, Try to Lap the Engine Valves with this guide!


If your car is suffering from poor performance and you have tried pretty much every fix there is chances are it’s going to be only a few things and the majority of them point at a poorly looked after engine. Engines need good maintenance just like every part of a vehicle. Lapping of engine valves should only be considered as a last resort as it means complete removal of the cylinder head. In this guide we will show you how to lap engine valves.

Lapping of engine valves may seem like a daunting task but to be quite honest with you it is fairly simple to do. The hardest part is getting to the engine valves. But once the cylinder head is off you can get to work!

Before considering lapping your valves please follow the following check list to find out if it’s necessary to do so:

Your cars age

Depending on the age of your car really depends on if you need to lap your engine valves. Not to point out the obvious but younger cars tend to run a hell of alot better than old bangers. Even where mileage is concerned. So chances are if your cars over 15 years old it’s best to give the engine a good look over to iron out any problems before they get any worse.

Your cars mileage

This is the most important factor to take into consideration. If your car has done over 200,000km well chances are it is due for a fine tuning and part of fine tuning is replacement of engine valves. Of course you could take it off to a shop to be done for you costing serious amounts of cash or you could just do the job yourself. If your car has done little or low mileage and is showing signs of problems then take it back to the dealership where you purchased it from and get them to run a diagnostics test. These vary in price but it’s much more easier to find the problem on a younger car than it is a car that’s been to hell and back.

Whats your car like after a full service

You get a full service every year and for the first few years everything was fine, not a single thing wrong. Now you feel as though it gets worse and worse every time it goes in for a new health check. Well why not have a look at the engine yourself instead of throwing money at services that are doing nothing for the car at the moment.

Is there signs of engine work needed to be done.

There are plenty of signs to look out for when you suggest that it may be time to lap your engine valves. Just look out for poor performance, juddering car, poor compression, black or white smoke from exhaust just on overall poor running engine. Of course these can be other things but when it gets to that state it’s best to over haul the whole engine, might as well start with the cylinder head and do the valves.

Overall Cost (is it worth it)

Lets face it, when you get down to the nitty gritty money plays a big factor when it comes to doing anything. Before you even begin lapping your valves ask around and see how much it would cost for a 2nd hand “reliable” engine. Sometimes you can get lucky and get it on the cheap. If you can get hold of a cheap engine and have the tools to swap your engine over chances are it would be much more cost effective to do that. But if your hands are itching and you want to give lapping valves a go as a last resort then why not give it a go anyways, valves are not overly expensive when bought from a reliable source (never buy from dealerships $$$ ).

The last car I worked on was a little french number, it was still pretty young but it had 16 valves, all bent and bust. I had to purchase the full set of 16 and re do the cylinder head for a nice price of $95 that included the cylinder head gasket, bolts and valves. So really at that price it’s not too expensive to just give it a go!

Is there something to gain here

Do you know how to lap engine valves? Now is your chance to learn how! This is the choice I choose when I had to do my first ever engine lap. The timing belt had broke on my car wrecking the engine. The car was worth $3000. I visited my local garage who told me an engine would be $500 but it would cost a further $1500 to fit. (yeah right) So I bought the valves and did the engine work myself overall cost was $300, saved myself a ton of money and learnt a lot in the process. Id recommend it to anyone who has the spare time. Even buy a cheap run around whilst you fix it!

Now once you have figured out weather or not it is worth going through the process of lapping your engine valves you can begin! Please note that this is not for complete beginners unless you have a knack for this kind of thing.