how often should you be adjusting valve lash?

One of my pet peeves is for a racer to bring his cylinder heads in here that are all beat up and hurt,,,,,,,,because he was too lazy to perform preventive maintence.

Now then, broken valve springs are not that uncommon. It happens all the time. But when you break one, you should catch it, by that I mean you should realize that you have broken one. Own a valve spring tester and USE IT every weekend! The silliest excuse I have ever heard is that it is too much trouble to remove the stud girdle. Don't be so damn lazy! On C-460 heads you don't use a stud girdle because they are shaft mounted rockers. So to use your valve spring tester, all you have to do is remove the valve covers, but some guys act like even that is too much trouble.

I have seen heads come in here with two valve springs broken on the same head, and not only that, but they ran long enough to be broken in two different places, meaning both at the top and at the bottom. It gets worse! Futhermore they were run long enough to totally chew up the top edge of the spring seat cups and break off all that metal from around the perimeter! Where do you think it goes???

Another sign of going too long without a valve job is when you start sinking the edge of the titanium valves and the seat surface becomes cupped instead of flat. Once this starts happening the titanium valve starts wearing out quicker than a normal wear pace. The tool that you should be using is a feeler gauge. Constantly check your valve lash and when it starts closing up a bunch, that is a pretty good indicator that you are sinking the valve.

Steep seat angles such as 50, 52, and 55° are used by a lot of cylinder head gurus in order to increase the flow numbers at high lift and be able to win the bragging rights about how much their heads flow. However, they do NOT wear as long as a conventional 45° seat! If you are going to run steep seat angles, then have a full time crew chief and/or mechanic/engine builder that will tear the engine down very often. If you want to run a full season and make 300 passes a year, you better be running a 45° seat!

Spark plugs. They are the eyes that let you see straight into the heart of your engine!!! Learn how to read your spark plugs, they have a story to tell. In general, the better that you get you air/fuel atomized, or broken up into finer droplets and a more homogenous mixture in the chamber/cylinder, then the less jet you should have to run, and you should be able to pull timing out of it and make more power.

I can tell when a guy is running too much timing by the amount of detonation I see in the chamber. If the chamber has little pinholes that look like porosity holes, thats a sign of detonation. On the alum. heads with two valve seats, there are two areas where the alum. in the chamber comes to a point. When this point or tit of alum. starts to erode, that's a sign of detonation. (As a note of explaination, the current Roush heads have a one piece figure 8 seat. I'm sure that the other top NASCAR teams have one piece seats also).

Alcohol guys pay attention. After every race, R&R the spark plugs and spray light oil into the cylinders! Then reinstall a set of warm-up plugs. Gasoline guys don't have to do this after every race, but you should do it if the engine is not going to be run for 2/3 weeks or more. Likewise you should do it if you are close to the seaboard and have saltwater air or in high humidity situations. The bottom line is, you would be surprised at how bad and rusty the rings get. The second ring even more than the top ring. You can't have good ring seal, if the rings have to spend a 5 minute "warm-up" just scraping rust off of the cylinder walls.

One of the most important tools you can have in your toolbox is a leakdown tester. Use it! Use it while the engine is still warm. Record the data in a log book and continue to use it. If and when the recorded data ever starts changing, that will be a clue, that "Houston, we have a problem"! A leakdown tester also helps pinpoint the problem.
1. Air out the exhaust header indicates a warped or bent exhaust valve.
2. Air out the manifold/carb indicates a warped or bent intake valve.
3. Air through the radiator cap indicates a blown head gasket.
4. Air into the oil pan/crankcase indicates poor ring seal.

Oil filter cutter. Own one and use it whenever you change filters. Cut the old filter open and look at it. Run a magnet through it. Some particles may be magnetic and some may not, such as bronze or babbit. These engines will tell us something, we just have to learn how to read the tea leaves.

On the 850 Hp racing engines and higher, let's plan on replacing parts as often as needed. Develop a good preventive maintence program. You guys that were mechanics in the military know what I'm talking about. Check things often and replace them before they break. It's always more costly after they break. On the bigger Hp engines, valve springs and roller lifters are consumable replacement items, the same as spark plugs. Plan on replacing them at the end of each season, when you do that freshen-up over the winter.

I have leased engines in the past, and the tools that I furnish with a lease engine, if they don't already have them are;

1. Valve spring tester
2. "On engine" valve spring compressor
3. Leakdown tester
4. Feeler gauge/lash adjuster
5. oil filter cutter.

I feel that every serious racer should have at least these five tools with him at all times and he should use them often, in the name of preventive maintence.

Hope this helps,
__________________
Charlie Evans

racinghabbit wrote:that helps.

my only question is how does a 200ft pass in the mud compare to an 1/4 mile pass or a truck pull down the track???