Cylinder head shims- any experiences using them?

beat_truck

Addicted Member
I gambled and bought an '04 Kia Rio that needed a head gasket for $200. The oil and coolant never mixed. It was pressurizing the cooling system and missing as it warmed up.

I took the head to the machine shop, and they said the head wasn't cracked, but it needed resurfaced a little past the the service limit, so a shim between the block and head gasket is needed. That, and it had 3 slightly bent valves, probably from whoever worked on it before installing the timing belt wrong and attempting to turn it over.:rolleyes:

Any thoughts?
 
I've heard if people using 2 head gaskets successfully. Not sure if that's what you're referring to.
 
Compression would't be an issue, but on some engines, milling too much off the heads mating surface can cause the valves and pistons to collide or make the valves unable to totally close due to lack of adjustment.
 
Compression would't be an issue, but on some engines, milling too much off the heads mating surface can cause the valves and pistons to collide or make the valves unable to totally close due to lack of adjustment.
Pretty much what I was thinking. The tiny bit of added compression wouldn't bother me. As 4-2-7 said it might have actually added a little power. The machinist really didn't give me an option. He just said the shim was needed, so I'd assume it is for valve to piston clearance, since this is an interference engine.

I did a search and didn't come up with a whole lot. Most of the results were from guys building Toyota 22r four bangers. I was curious as to how well they worked and sealed since the head gasket is only on the top side of the shim. Both the machinist and the posts on the 'yota forums said that the block side of the shim is just coated with copper gasket spray... no other gasket.:idea:
 
Personally I build HP engines, if a machine shop tells you they had to mill the head a little bit out of spec. They are telling you this so your aware of other fit issues might be present. They didn't mill it a 1/4 inch out of spec, maybe 100/1000th.

So you should have no trouble with valve clearance.
I also don't know the engine and would think it's a OHC, but if not 100/1000th is tinny with push rods and hydraulic lifters.

Manifold fit can be a bit of an issues because what ever they took off the heads, doubles at the manifold mating. and with a v block the bottom of the manifold can start hitting the top of the block before mating with the heads.

I don't assume anything, do a dry run build. I'd get you gasket kit and put it together without any sealants and don't tork anything down hard just tight. Pay attention to the fit of the mating surfaces. Cycle the engine by hand a bunch of times, looking at the valve train and what it's doing. Wiggle the rockers on closed valves, to see if there is play, you can also check with a feeler gauge what the gap is.

Also when you have a exhaust valve fully open, pry it down further with a screw driver or something. This will show you how much more clearance you have to the piston, do the same with a intake valve. If you have some feeler gauges you can slip 20/1000th worth between the valve tip and the rocker and cycle the engine also to check clearance.

Engines expand when hot so the general rule is at least 20/1000th gap at the rocker/valve tips.
 
Personally I build HP engines, if a machine shop tells you they had to mill the head a little bit out of spec. They are telling you this so your aware of other fit issues might be present. They didn't mill it a 1/4 inch out of spec, maybe 100/1000th.

So you should have no trouble with valve clearance.
I also don't know the engine and would think it's a OHC, but if not 100/1000th is tinny with push rods and hydraulic lifters.

Manifold fit can be a bit of an issues because what ever they took off the heads, doubles at the manifold mating. and with a v block the bottom of the manifold can start hitting the top of the block before mating with the heads.

I don't assume anything, do a dry run build. I'd get you gasket kit and put it together without any sealants and don't tork anything down hard just tight. Pay attention to the fit of the mating surfaces. Cycle the engine by hand a bunch of times, looking at the valve train and what it's doing. Wiggle the rockers on closed valves, to see if there is play, you can also check with a feeler gauge what the gap is.

Also when you have a exhaust valve fully open, pry it down further with a screw driver or something. This will show you how much more clearance you have to the piston, do the same with a intake valve. If you have some feeler gauges you can slip 20/1000th worth between the valve tip and the rocker and cycle the engine also to check clearance.

Engines expand when hot so the general rule is at least 20/1000th gap at the rocker/valve tips.

Errr, Uhmm, Sorry 4-2-7 but I don't agree. I worked at a Performance machine shop for 15 years, we used clay on top of the piston to determine valve clearance, place modeling clay on piston, assemble parts, adjust valves, then turn engine over, disassemble and measure clay where valves have made impressions.. I don't advise prying the valve open with a screw driver, that's crude.and possibly dangerous to you and the parts being pried. 0.100 is not tiny, it's only 0.025 short of an 1/8". on a push rod engine you might need shorter push rods to compensate so the valves can be adjusted. Lot of unknowns here, I'd go with the shops advice, do it right once, I hate doing anything twice.
 
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Errr, Uhmm, I don't agree.
Errr, Uhmm, ok, but he's not building a performance engine. But yes one could mic clay if he's got clay and the tools. Pushing down the valve and getting a measurement at the valve tip does the same thing. if it move quiet a ways before touching there is nothing to worry about. What your talking about is when building an engine with close tolerances and pushing limits very close. Using custom pistons and different valves than the motor came with. This engine is not that.
 
This is a DOHC 4 banger. No push rods or rockers. You can't even really get at the valves with the cams and bearing cage in place, so fooling with them is really a non-issue.

The shop has a pretty good word of mouth reputation, so I tend to believe what they say regarding the need for the shim. I'm just going to do it the way they advise, just to play it safe. I'm already sinking more money than I planned to in a car that isn't really worth anything, so I don't really want to risk having to put more into it by experimenting and breaking stuff. The previous owner did a good enough job of half-assing and breaking things for me.

This is just going to be my beater car, at least until the shit they dump on the roads in the winter time eats it away.:rolleyes:
 
If it has a belt drive cam, be sure the valve timing stays somewhat close. Milling the head that much will make a difference in the valve opening and losing points. Time for the dial indicator and degree wheel.
 
I’ve run into that situation with the early sixties aluminum Oldsmobile engine. It’s probably not the best idea, but I use to take that cooper head gasket sealer and two head gaskets to create a thicker head gasket. Like I said....not the best fix but never had a problem if yah let the sealer set up hard before starting the engine after the repair. It’s a junk yard dog repair......
 
Are thicker head gaskets available? Seems like that might be an option instead of a shim plate.
Not that I've been able to find. I checked Rockauto and the other usual parts store's sites. I even checked Kia's site. Nothing but standard replacements.
 
Are thicker head gaskets available? Seems like that might be an option instead of a shim plate.
i had a quick look last night but didnt see any for sale . some have notches for thickness intended for piston protrusion correction .. i didn't see any shims to add . cant be hard to make one having the gasket as pattern
 
i had a quick look last night but didnt see any for sale . some have notches for thickness intended for piston protrusion correction .. i didn't see any shims to add . cant be hard to make one having the gasket as pattern
The shop said that they have a source that custom makes them. I can't imagine it'd be too easy to make one perfectly flat and distortion free without a machine.
 
yes there are machines for sure .. setting them up is the skill and time issue . i might go for copper after asking around to be sure its the right choice . not sure if steel would work here . but thinking about it cant see why not so long as it it can be tightened down enough . we have a product called wellseal for these things developed by rolls royce ..
p.s new bolts are advised .
 
yes there are machines for sure .. setting them up is the skill and time issue . i might go for copper after asking around to be sure its the right choice . not sure if steel would work here . but thinking about it cant see why not so long as it it can be tightened down enough . we have a product called wellseal for these things developed by rolls royce ..
p.s new bolts are advised .
I assume that it will be copper. The readily available shims for other engines are. It calls for new head bolts, and I already have them along with the new gaskets and other parts. I don't want to spend a lot of money on this turd, but I do want do it right so it will hold up.
 
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