No Valve Lash

I checked my valves today and 14 of the 16 were within spec (albeit all on the tighter end (0.006 for intakes and 0.010 for exhausts)).
One intake was 0.005- easy enough to figure out the proper shim BUT one exhaust valve had NO clearance down to 0.002.
Where do I start for that valve? I haven’t yet removed any valves as I don’t have the tool. But, in preparation, should I just order the smallest shim and see where it is from there?

 

You need to take out the shim and measure it to determine what the proper lash should be. For example, if your target lash is 0.010" and you're measuring 0.002", that means that you need a thinner shim by 0.008".

Take out the current shim, measure it, then subtract 0.008". That is the new shim measurement you need. You need to do this for your intake side as well. You don't know the proper thickness unless you measure the current one.

 

You might also do a compression or leak down test - there is a chance that valve could be burnt

 

IF you can get that size you need....there's a lot people hear that have spares....
think I have doz of the smallest two sizes.....likely needed as that exhaust valve sinks/seats over time...

IF you need one of those I could pop that in the mail for you....

 

0.002 isn’t able to get in the gap and that’s the thinnest feeler I have. I believe the valve is riding the cam lobe and I have no way to know how much pressure the shim is putting on the lobe- so, where do I start with the new shim? What my plan is, if no better plans revel themselves, is to just use the smallest shim I can get and start the measurements from there.

I’ll do a compression test hopefully soon.

 

Damn that's pretty bad if you can't get 0.002". I would get the smallest shim you have in there to see if you can get a reading and then work from there. Make sure to turn the crank over a few times to set the shim in and then measure.

 

..That .002" is exactly the step size between each shim size...

 

The exhaust valves determine the life of the head....
you can only go so low.....

unless your into butchering......


I would examine that valve closely and do the press/leak down test...

It would be nice if you had one of those $60 boro cams off amozon....
one of those with the milti cams....

 

Yeah, I just ordered a valve shim tool. Once that gets here I'll be able to take some measurements- although that will have to wait till July unfortunately. I'll try to get some compression numbers this weekend though.
I mean, for all I know they have a 3.3mm shim in there; or equally they have a 2.5mm shim.

 

If you're gonna tackle those....make sure you watch several of the videos......

you need several options to be able to push down on those...
like a bent screw driver or brake tool.....and super strong magnet to suck that shim out....


and be careful about the lobes getting caught in the buckets when the shim is out...
keep lhe lobe way up away from the bucket.


Make sure you pre lube that lob too...before you turn it over...

 

Compression test numbers:
1: 147
2: 135
3: 142
4: 145

Valve gaps:
Exhaust --- Intake
1: .010/.010 --- .006/.006
2: .012/<.002 --- .006/.006
3: .010/.010 --- .006/.005
4: .010/.010 --- .006/.006

 

Your compression numbers are fine and I bet cylinder 2 will increase after you adjust the lash.

 

That’s good news. The compression numbers did jump around a bit as I went through each cylinder multiple times but overall I’m happy with them.

 

I've sanded down shims before. Just make sure you leave the surface finish very smooth. I used a set of calipers to measure total thickness then sanded down however much I needed to and reinstalled. Can save you from ordering the shim measuring tool and having to order new shims. I always liked my valves on the tight end for the most lift but keep it within spec.

 

The factory ones should be all middle of the road numbers if I recall. Seems like i have a pile of 2.8s-3.0s

 

I've thought about that. I'll be measuring with a caliper as I'm not about to order a micrometer for this job. May see if O'Reilly's has one for their loaner program though.

 

I hope there is room for me to go to a smaller shim. Would suck if that valve already had the smallest possible shim.

 

You need a micrometer for this job but I guess you can also just throw shims in there until something fits.

 

I have a little box of 16 stock ones from a 4 cylinder I'd be happy send but after looking, they are all 2.75-2.95. Mostly those numbers right there.

What you do is pop quite a few of yours out and see if you have a short one to take a better measurement of your tight valve.

There is a kit of shims to be bought somewhere that has a assmt. I forgot where. Maybe HotCams™

 

Harbor Fright has a digital cheapo that's suitable for this. I wouldn't build a watch with it but hey.