Author Topic: valve shims getting thinner  (Read 1980 times)

June 19, 2019, 04:08:38 pm

sgnimj96

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valve shims getting thinner
« on: June 19, 2019, 04:08:38 pm »
So I'm adjusting the valves for the first time in a 1.6D CR that runs pretty good.   Last I checked compression was excellent.
All the but two are tighter than spec,  mostly exhaust being about .010" too tight.

So I check the shims and their all pretty thin allready,   like mostly 3.25-3.35mm
The sizes I'll need are in the very minimum range of most shim kits. 

I do see that I can the get the shims I need,  but my question is ;
  What's going on with my valves the be pulled up higher than normal like this?

I even have a spare head and checked those shims and they're all way too thick for what I need.


81 Scirocco 1.6D (conversion)    86 Gofl 1.6D      2003 Golf Tdi   1985 300TD

Reply #1June 19, 2019, 10:32:06 pm

ORCoaster

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Re: valve shims getting thinner
« Reply #1 on: June 19, 2019, 10:32:06 pm »
Are you wearing away your cam lobes?  Wear marks in the shims themselves?  In order for them to get tighter something has to be wearing down allowing the slack to be less and less over time. 

Reply #2June 19, 2019, 11:49:46 pm

sgnimj96

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Re: valve shims getting thinner
« Reply #2 on: June 19, 2019, 11:49:46 pm »
I guess it has to do with whoever rebuilt the head.
The cam lobes and shims seem alright and the shims measure accurate to thickness markings.

It just seems strange that the entire range of shims is between 3.10-3.40mm.
   Six of the shims need to be reduced .10  to .20 mm

At least I can actually get shims close enough.  I want a 2.95 for one but have to settle for a 3.00 from what's reasonably available for single shims.   I'll get the new shims in; Run it and check again after a few thou.   
81 Scirocco 1.6D (conversion)    86 Gofl 1.6D      2003 Golf Tdi   1985 300TD

Reply #3June 20, 2019, 10:43:38 pm

ORCoaster

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Re: valve shims getting thinner
« Reply #3 on: June 20, 2019, 10:43:38 pm »
Perhaps the shop rebuilding the head took the time to grind the valves off on top to get a more uniform set of shims under the lifters.  They may have had a large stock of that range and tried to use them up.   

Reply #4June 21, 2019, 01:54:45 am

Dakotakid

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Re: valve shims getting thinner
« Reply #4 on: June 21, 2019, 01:54:45 am »
Your need for the shims is not at all out-of-the-ordinary. Did you install NEW valves...or have the old cut?

Valve seats get beat....esp. exhaust in these engines. When rebuilding the head, on these OLD engines, I ALWAYS opt for new valves. The seats get as lightly-cut as possible to mate with the new valve contact area.

A new valve on a lightly cut seat will NOT thin the shims as much as the old valves. Plus, this is why it is NOT the best idea to wait to rebuild a head until the seats are beat to sheet.

The 2.95 shim makes me a bit nervous. But, the lobe on the cam should still clear the sides of the lifter just fine. Autohausaz.com has consistently made these shims available.

At some point in the future....this head will retreat to the happy hunting grounds. Time to step up to an ALH auto at that point. Rebuilding the heads on those is MUCH less tricky than the old pre-combust. heads.
The mask and the shot(s) are actually an IQ test. If you are wearing or circulating, you just failed the test. I can't feel sorry for you.

Reply #5June 22, 2019, 10:27:50 am

sgnimj96

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Re: valve shims getting thinner
« Reply #5 on: June 22, 2019, 10:27:50 am »
    I was thinking maybe it means the valve seats are so beat that it's the last time around for that head.
No telling what the PO's mechanic did.    I bought the car from Waco, TX from some kid that was destroying it.

The engine seems to be rebuilt well by somebody,  even has the better exhaust manifold and bigger exhaust pipe...

I've had to ponder many times what whoever had worked on that car was thinking.  The PO wished it was some kind of hot rod (posted a video of himself reving the hell out of it right at startup).  He sold it because the fuel lines clogged with rust and it would die on the highway,  even with an electric pump added (using an expensive car stereo power relay).   The IP was so dirty inside I ended up not using it.
 He also put some fat aluminum rims on because they looked cool.   The rim bolt pattern was slightly off, but they were impacted on anyway,  bending all the lugs and permanently damaging all the internal threads on the hubs and drums.

  I won't really know about the head unless it's taken off.    It run ok for now,  but I wanted to be able to recognize if something is going wrong.    Thanks for the replies

BTW,   I have thought ahead.  Got an ALH Golf -  has the the EGR delete and a new head from the PO's mechanic.    That guy was destroying his car too,   had sticking brakes,  extremely warped rotors,  and a broken alternator casing from a stuck slider bushing.    It's a sweet car now, despite some of over-engineering and cheap interior..     Cruise control is nice, even has a/c  :o,  but I still love the old ones without cpu's.     


« Last Edit: June 22, 2019, 02:33:41 pm by sgnimj96 »
81 Scirocco 1.6D (conversion)    86 Gofl 1.6D      2003 Golf Tdi   1985 300TD

Reply #6June 22, 2019, 03:44:22 pm

RustyCaddy

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Re: valve shims getting thinner
« Reply #6 on: June 22, 2019, 03:44:22 pm »
The local shop that rebuilt a cylinder head didn't grind down the top of the valve stems.  The clearance was to close for the thinnest shims available.  Had to take it back in and they ground the stems down slightly.  That did the trick.  Like Coaster was getting at.

Reply #7June 22, 2019, 07:55:47 pm

Dakotakid

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Re: valve shims getting thinner
« Reply #7 on: June 22, 2019, 07:55:47 pm »
the problem with a shim kit....is that you will have waaaay too many thick ones. The heads came from the factory brand new with 3.80 to like 3.65.....or even thicker.

Those shims are useless for the most part. Unless you have a professional grinding table.

Myself, I have always been reluctant to remove material from the top of the valve. Why? Because the keepers are VERY close to that end and things could get disastrous rather quickly.

In my case, I have a multitude of heads sitting on shelves. Plus, a well-repaired head will go a loooong time.

In the last alh, I did "recycle" the original valves at 200,000 miles with a light cut to the seating surfaces. I still had a lot of margin left....so, I did it as the "Frank" guy on tdi-club is a big proponent of that......for what THAT is worth. My private machinist did remove a very slight amount of material on the top of the valve stem.....and, all seems very well.

I rebuilt an alh that early, as it was clear the original owners were not good at intelligent oil changes.
The mask and the shot(s) are actually an IQ test. If you are wearing or circulating, you just failed the test. I can't feel sorry for you.

Reply #8June 23, 2019, 11:54:05 am

sgnimj96

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Re: valve shims getting thinner
« Reply #8 on: June 23, 2019, 11:54:05 am »
Yea those shim kits seem to reflect that VW never intended for thinner shims to be used except in abnormal situations.    I still am concerned, but not near as much.   Got some 3.00's from FCP pretty cheap.

Thanks again

« Last Edit: June 23, 2019, 01:55:42 pm by sgnimj96 »
81 Scirocco 1.6D (conversion)    86 Gofl 1.6D      2003 Golf Tdi   1985 300TD

 

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