2.0 head question

[kerian159]

Rebuilding my engine and lapped my cylinders to the head and in doing so they Rock back and forth a bit so. I hoped torquing the head down would help close the gap, but after doing that when turning the engine over I'm getting blow by between the head and cylinder. Can a type iv head warp slightly and if so is it fixable (without breaking the bank)[/list]
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1976 Type II Westy P22

"Growing older, but not up!"

[SGKent]

you need to pull them off and lay a straight edge across the cylinders when they are firmly seated. Make sure they are flat. If they are uneven then the heads are warped. Another cause could be uneven shims under the cylinders, or a mismatched set of cylinders. If they rocked when you were lapping them I would guess it is the heads. They can be fly cut if they haven't been already.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[busdaddy]

How much lapping did you do?, less than a minute per jug?, or 5 minutes+ per hole?
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[kerian159]

I lapped them for about 5 min each.
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1976 Type II Westy P22

"Growing older, but not up!"

[skills@eurocarsplus]

[timvw7476]

Being the devoted head gasket perV that I am,
I'd lapp that stuff three more minutes & install EIGHT head gasket assemblies
on those four tweakd spigots.

And drive it. : ) edit: like I stole it.

[SGKent]

get a hold of Colin if he is still in Pensacola. Lock up your ice cream though.

He has been known to scrape heads with a razor blade to get them to seal up. He can show you how.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[cmonSTART]

I use this stuff religiously on whatever I'm building.

https://www.permatex.com/products/gasketing/gasket...p-sealant/

Might help..
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'78 Bus 2.0FI
de K1IGS

[kerian159]

You use that between the head and cylinder?
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1976 Type II Westy P22

"Growing older, but not up!"

[cmonSTART]

I did. I masked off what I didn't want coated and sprayed the sealing surfaces. It's not a miracle product and not a substitute for proper work, but I'm in the habit of using it on anything older I work on.
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'78 Bus 2.0FI
de K1IGS

[SGKent]

it forms a temp bond until carbon seals. It does not make up for irregularities in the sealing surface like a warped head. I hate to say it but the main problem going on here is failure to spend in money and time what it needed to put a 45 year old foreign car back on the road.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[airschooled]

[skills@eurocarsplus]

^^^

that stuff is good till 500*, so about 10 mins of running and it all gone.

just fix it right instead of throwing band-aids at it. honestly, you were on the right track until you went too far
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[kerian159]

I wasn't thinking about using that as a fix. Just trying to figure out my next step. 😄
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1976 Type II Westy P22

"Growing older, but not up!"

[SGKent]

So I didn't look but guessed we were talking about Permatex Copper Coat. It is a sealant that carbonizes very quickly at combustion temps. It typically fills small voids and helps kick off the carbonizing process. It is not designed to act as a gasket. However it does help with small pinhole voids. A physical seal is needed and Copper Coat does not substitute for that.

One question that has not been asked here but should be, did the person installing the heads follow the torque sequence properly? Failure to do that will result in a warped head. Finger tight on all nuts. Usually I go 5 ft lbs in the correct pattern, then 50% specified torque, then 80% specified torque, then 100% specified torque. Then come back a 3 hours to a day later and check specified torque again. DO not exceed the specified torque, and be aware that with a clicker wrench you can easily exceed specified torque, especially if your wrench has not been serviced and calibrated. If you click, then click again, then click again to make sure it is tight, you've probably exceeded the torque. When rechecking it doesn't hurt to back off a few degrees until the nut starts to move then come back to the correct torque again - in the specified pattern. In 500,000 miles in air cooled engines or more, I have never had a head leak following that method.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[kerian159]

I tightened the nuts up enough to pull the head up to the cylinders and then switched to the torque wrench and did 15lbs in the correct pattern then up to 23lbs same way. Went until the wrench clicked then I hit the click one more time and then moved to the next one.
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1976 Type II Westy P22

"Growing older, but not up!"

[orwell84]

When I first tore down my GEX engine, I noticed that it had been leaking a lot in spite of decent performance. It had the original head gaskets. One cylinder always read like 10-15 pounds lower in compression; like 95 compared to 110. When I rebuilt this engine for the first time, I used basically the same parts, minus the head gaskets. I used base shims to make up for the difference. I did a lot of lapping of the cylinders to the heads and even wearing a slight groove into the sealing area it was still deep enough to make a flat surface all the way around. That cylinder then gave like 85 psi for compression without the head gaskets. I know lapping is not meant to done that way and will not cure surfaces that are that far off. It probably made it worse.

When I replaced the heads with HAM heads they sealed so much better to the cylinders. I had them on and off after spraying on copper coat and could see how much better they were sealing. Tearing the engine down for my last rebuild, I noticed there was still some slight leakage. I put this down to the case not being decked and possibly not rechecking torque enough.

The head studs definitely need to have the torque rechecked over time as everything settles in. I have read about people overtorquing, leaving it overnight, backing off and retorqiung to spec. I think the same thing can be accomplished as SG Kent explained...just rechecking over time, there are always a few nuts that seem to need some snugging up. I have a HF click wrench that has not seen much use. I still like my old Craftsman pointer wrench...half decent affordable tools for the serious shade tree mechanic at least at one time they were.

The same holds true for the exhaust headers. I think they need to retorqued a number of times after the engine has run. I always drive away in my newly rebuilt engine...golly jee-whizz what fun and forget to do this. When the inevitable exhaust leak makes itself known, I finally retorque, But I usually find upon rebuilding a deformed copper gasket that has shifted and deformed from when it was torqued too late that second time.

When you consider how old these engines are, how after market or old cylinders can be dimensionally out of spec, the case deck sagging a little or a lot where the cylinder spigots are close together, it makes sense how it can't be cured by lapping once all this potential out of spec stacks up. You can't lap two things that are not flat together and expect to get flat.

I decided not to use my original heads because my machinist said he was not set up for fly cutting. Kudos to him. He was not an air cooled guy, did not have jigs for doing this and probably either didn't have the time or experience to set them up for a good fly cut.

This go around, I am starting with a decked case, good German cylinders and HAM heads. I will be measuring as I stack it all up, but still I have considered using thin copper gaskets for the head sealing surface. Getting the head and cylinder to seal metal to metal and stay that way is still no easy thing. I think the original head gaskets covered a lot of sins. I wouldn't hesitate to use them on a beater motor and plan to at least recheck the top end at 40-50k. A VW engine will still run great with minor leaks but will shorten it's lifespan.