308 - special tool for valve adjustment

The tool currently sold under that part # is trash. Make your own. Actually a screw driver used carefully works fine in a pinch. The important tools to make are A, the one that holds the cam follower down while changing shims and B, something to pry the shim out of the bucket. I'm at home and tools are at work, if you PM me I will send you some pics Monday. Dont worry too much about damaging the cam and follower or shim, they are quite hard I suppose anythimg can be destroyed but you would have to work at it.


PS. PUT A RAG OVER THOSE CARBS IF YOU DONT WANT A VERY EXPENSIVE SURPRISE WHEN YOU GO TO RESTART THAT HOT ROD!!!!!!!!!!!!

 

If I'm not mistaken the Mazda Miata motor has the same type valvetrain. Maybe they have a cheap shim tool kit? Someone with more knowledge needs to help me out here...
Jim

 

i just did a full service on my 308 gtsi if you going to do the cam seals the best thing to do is to pull the cams out do your seals put back or take out shims this is the best way it will take moor time for this . in the long run it is best

 

Home made.
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I bought mine at Ted Rutlands, they are made from brass as not to scratch the metal ask for Brian Keegan
800-233-7820

 

Nice picture. I noticed that there is a puddle of oil in the lower distributor mount housing. Do you know if your camshafts have been plugged? If they haven't, now is a good time to have it done.

It means that you will be removing the camshafts, which makes changing shims VERY easy. Just be sure to get an accurate clearance reading before you remove the cams, then use a micrometer to measure the shim. Do the math and order new shims. Do not attempt to grind the old shims - they are surface treated.

There may be other posts on this subject, but if and when you remove the cams, be sure to mark each bearing shell and replace it in the same place. Loosten the bearing nuts slowly and uniformly, there is a lot of energy stored up in those valve springs.

Good time to replace the camshaft seals as well.

 

the best way to remove the shims is to blow a little compressed air in the gap on the bucket/thimble.

This way you do not bruise the bore in the head which makes the bucket tight.

Just put a rag over it while you do it, so you don't lose the shim or get an eyeful of oil!

 

Excuse my ignorance: What is the danger??

 

Stuff falls or crawls down the throats...........

 

Lopealong: the Miata uses a HLA (like a 355?) rather than a shim.

All, fyi: Elgin strongly advised replacing all shims, independently of how they measure. As the hardened layer of the shim wears through the shim develops a "bucket" shape and wears the cam lobes.

Philip

 

Bucket shaped valve shims can be measured easily with a micrometer. you'll find different thickness from center to edge. The two (out of 20) old shims I have in my hands right now do not exhibit that problem so I must say that the bucket theory does not hold true all the times, and therefore shims can be reused.

 

Mitchell
I don't know the thickness of the hardened layer, assume it is "thin". So the challenge is measuring with an exactness that provides confidence that the shim is robust for the next 15000 miles.

Elgin's observation (borne of repairing many cams over the years [it's all he does]) was particularly directed at 246s which tend to gain very few miles each year and those they do tend to gain are "hard miles" (from infrequent starting and limited mileage on each occasion). Dema showed me cams that had started to wear in this way (you can see a horse shoe pattern on the side of the lobe). Unfortunately once started, if it wears through the hardened layer on the lobe, it is cam repair time which tends to be expensive (as some of us have found out the hard way -- see one of my P6 threads earlier).

By the way, this is why he is also a fan of certain synthetics -- their ability to "cling" to the metal is (he asserts) vastly superior to dyno oil.

Anyway, each person will do what they believe is right/cost efficient/necessary. Just use Elgin as one [expert] datapoint to factor into your thinking.
Philip