Setting valve lash on Isuzu 4BD1T

[T_Gunn]

I just pulled the valve covers off the engine on my Link-belt LS2700. All of the original gaskets and rubber grommets were heat hardened and brittle. There was oil leaking all over the engine and has been for a long time. It looks like the previous owner tried taking it apart and resealing everything with gasket maker. It didn't work. I can't understand why someone wouldn't just spend $100 on a gasket set and fix the problem the right way! Anyway, I was thinking I might set the valves while I've got the covers off. I will get the clearances from the local engine dealer. It has been at least 10 years since I've adjusted a set of valves. Does anyone have words of wisdom? How do I turn the engine over to get the rockers in position for adjustment? Am I crazy to be doing this on my own?

 

[willie59]

Well, I don't want to call you crazy...unless you want me to call you crazy.
Seriously, if you have the clearance specs, shouldn't be a problem, but you do have to be able to turn the engine over. Getting something on the crank pulley is usually the best way, but I know some engine installations just don't allow you to do that. You could also do it with the starter by just bumping the engine. It works best if you have a starter button connected to the starter so you can bump the starter while your at the engine. I rigged one up with a Borg Warner PB-10 push button switch, two wires, and alligator clips. As for the valves; it ain't exact, but a close rule of thumb for adjusting valves and position of cam is "end of intake and beginning of exhaust". Bump your starter while your watching the valves on piston #1. Watch for the intake valve to do it's stroke. When the intake valve finishes it's stroke of opening and then closing, just at the end of closing (end of intake), adjust the exhaust valve. Likewise, watch the exhaust valve; when it just starts it's stroke (beginning of exhaust), adjust the intake valve. That should get you close enough.

 

[John C.]

Those engines cook out those seals no matter what. If they don't get hard from overheating they do it because of age.

Cummins has a jacking bore on the flywheel housing and an adapter that fits into it. The outside has a half inch square drive and there are gear splines that fit the flywheel gear. If you have to do this job more than once you need that tool. The small bolts on the crank pulley will snap off if you try turning the engine with one of those. The only other way is to adjust the fan belts tight and use the fan to pull the engine around.

Do not warm up the engine before you do this. A warm engine will have full compression and you will not be able to turn the motor from the front. The valves are all set cold anyway.

The proper order for the valves is easy. Put the engine on top center number one and adjust the valves on number one cylinder. You then adjust number two cylinder's valve that is loose. I don't recall for sure whether that is intake or exhaust. Number three will be the other valve. They alternate that way to number five. Now rotate the engine one turn to number six top center and repeat the process on six and then go back the other way doing the alternating valves.

It generally take more time to clean the crap off the top of the motor than it does to adjust the valves.

Good Luck!

 

[DRMCO D600]

Hi gents,
With regards to setting valve clearances on any even number cylinder engines this is the way that works for me .
Write down the firing order one half under the other half.
Eg. 1 5 3
6 2 4
Next bar the engine in direction of normal rotation until you observe any cylinder that has valve rock and set the valves on the cylinder opposing it.

For example valves rocking on number six cylinder set valves on number one. It now gives you a starting point because the next cylinder to set is cylinder five and you watch for valve rock on cylinder two to verify approximate top dead centre.This method is very usefull when you do not have access to timing marks. Check the manifold port location to check that you have the inlet and exhaust valves identified correctly and set to recommended clearance.
Hope this description was not to long winded or basic.