Type 4 2.0L AMC cylinder heads

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cjacaruso
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Type 4 2.0L AMC cylinder heads

Post by cjacaruso » Sat Apr 03, 2021 7:10 pm

So I have put on a pair of new AMC heads on my type 4 2.0L engine. As I am assembling I am having a lot of trouble getting the engine tin to fit and the intake manifolds to go on. When comparing the AMC to my old cracked VW heads I notice the outside castings are a bit different than the VW heads. This seems to be the reason for the trouble fitting the tin and intake manifolds. Has anyone else had this problem? I can use a Dremel to remove some of the excess aluminum casting material. I can force the sheet metal and intake manifolds on if necessary but I would prefer to get the fit better. Any info will help. Thanks!

cjacaruso
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Re: Type 4 2.0L AMC cylinder heads

Post by cjacaruso » Sun Apr 04, 2021 5:00 pm

I ground away some extra aluminum flashing from the AMC heads just above the valve covers and just below the intake area. Now the intake manifolds fit nicely. The AMC's had some extra flashing/casting which sat about 1/4" higher than the original VW heads. I'm still trying to figure out how to get the tins to fit better. Both main tins which fit over the cylinders and heads hit the heads which prevents them from seating all the way down. The AMC heads are about 2 mm (42.5 vs 40.5) wider than the VW heads across the fin area closest to the case. I don't want to take too much off of the last fin but would also like the tins to fit correctly. They are original VW tins. Each fin is about 3.5 mm so if I take off 2 mm..... Maybe I'm being too picky and should just put 'em on and call it good enough.

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satchmo
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Re: Type 4 2.0L AMC cylinder heads

Post by satchmo » Mon Apr 05, 2021 7:08 pm

You won't hurt anything by grinding away a bit of the cooling fins.

The new AMC heads should have any extraneous casting flashing ground down anywhere you can reach it.

Satchmo
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

cjacaruso
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Re: Type 4 2.0L AMC cylinder heads

Post by cjacaruso » Thu Apr 08, 2021 7:23 pm

Thanks Satchmo! Kind of what I thought. I wish I would have looked more carefully before bolting up the cylinder heads to the cylinders. I'll get there.

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satchmo
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Re: Type 4 2.0L AMC cylinder heads

Post by satchmo » Thu Apr 08, 2021 9:45 pm

Haha, yes, we’ll all get there.
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

RandyM
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Re: Type 4 2.0L AMC cylinder heads

Post by RandyM » Wed May 26, 2021 6:02 pm

I bought the Bus Depot AVP 2.0 type IV engine with new AMC heads. I'm still in the break in period. I have a Dakota Digital CHT under #3 plug. Engine was professionally installed with all tin and thermostat. Oil pressure is normal, oil temp is always below 200 BUT CHT seems to run hot. 400 +/-, and 450-460 on occasion (hill, long runs at 60mph). Several mechanics here with long creds say everything is spot on, and one says AMC heads are Vanagon type and run hot like that.

What say you all?

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satchmo
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Re: Type 4 2.0L AMC cylinder heads

Post by satchmo » Thu May 27, 2021 8:42 am

450-460 seems really hot, and, if the engine seems to be running well in every other regard, I would suspect the accuracy of your gauge reading (Note that I said gauge reading and not gauge. Dakota Digital gauges have a very good reputation).

The first, and easiest, step to address this would be to get another measurement of the head temperature via another modality, like a laser thermometer. With the tins in place you would need to find an area near the exhaust manifold to get your reading.

A second check would be to pull the spark plugs and look at the electrode tips. If they are a medium to light brown, then you know your CHT temps are good, and the gauge reading is off.

I have heard that many folks have trouble with the ring terminal CHT sensor not sealing well, which leads to anomalous readings (too hot). There isn't much room in the spark plug well for the required 90 degree bend of the ring terminal, which causes the ring terminal to deform during installation. Failure to remove the original spark plug sealing ring before installing the CHT sensor will also cause problems with sealing, so make sure that was done.

Good luck, Satchmo

PS: I call BS on the mechanic who says "AMC heads are Vanagon type and run hot like that."
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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Amskeptic
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Re: Type 4 2.0L AMC cylinder heads

Post by Amskeptic » Wed Jun 16, 2021 5:12 pm

" I call BS on the mechanic who says 'AMC heads are Vanagon type and run hot like that.'"

Ah yes, the famous feint, the escape, the sheer irresponsibility.

AMC heads are *especially sensitive* to heat, and must be kept at *cooler* temps than the factory heads due to a softer alloy that does reduce cracks but suffers from distortions in the combustion chamber ceilings/rocker supports above.

AMC needs to be run no more than 400* consistently. Brief hillclimbs at 420* sure, but check your valves frequently as the heads take a set. It took mine almost 20,000 miles to settle.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 206,865 miles
Naranja - 77 Westy . . . 132,040 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 91 Lexus LS400 . . . 94,225 miles

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