Head gasket orientation 1990 4hp E4RESR

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cprodave

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Replacing the Cylinder Head and Head Gasket. What is correct orientation of the head gasket? Diagrams show correct gasket orientation would be that20210228_073420.jpg 2 large holes for water circulation go at top during assembly. I "get that" . But why is there a small hole at bottom of gasket (see lower arrow in photo)? Also what is the purpose of Upper Metering Rod (which presses against the Head Gasket in between the 2 large holes)? Metering rods generally lubricate Crankshaft Bearings upper and lower, correct?
Also on the outer edge of the Gasket there is a Tab. Does it matter if tab goes Right/Starboard vs. Left/Port? I can't see any function for the Tab other than to indicate orientation on an otherwise symmetrical component.
Thanks for any input.
 
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Crosbyman

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tab up and holes lined up top left and right are not symetrical like the middle and bottom bolt holes


so you must line up the top bolt holes with the gasket
 
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cprodave

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Crosbyman said:
tab up and holes lined up top left and right are not symetrical like the middle and bottom bolt holes


so you must line up the top bolt holes with the gasket
Click to expand...
Crosbyman, you're right! There is a very slight asymmetry at the top. Thanks a lot.

BTW reason for Cylinder Head replacement is shown in photo below. Head blew/eroded a hole at Lower Cylinder on Right/Starboard side (see pencil point). The Cylinder wall itself is OK so I did not need to resurface. I was able to find/buy a Used Cylinder Head (although it had some pitting which i resurfaced out using SiC paper laid on window glass).

Has anybody had success repairing such holes? If so, how? I don't have access to welder for cast aluminum, and am thinking JBWeld patch wouldn't endure even if area was ground-out such that cylinder internal pressure would help (not hurt) keep the patch in-place...sorry photo is upside down.20210228_074105.jpg
 
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racerone

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That rubber hose is NOT a " metering rod " at all.-----It merely guides cooling water around the engine.------Water does NOT flow through that hose either.----A product called ---LUMIWELD -----can be used to repair that defect.
 
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cprodave

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Racer thanks for clarifying Metering Rod vs. that hose. Have you used Lumiweld personally on a similar repair? If so, did the repair last for a reasonably long time? I aim to sell this motor ("thinning the Herd") and I wouldn't want to saddle any Buyer with a lemon...been on the receiving end of that..it stinks. If i were keeping this motor, I might take a different approach.

Crosbyman, thanks for idea on the High Temp JB Weld. I will check out the reviews and may give it a try on another project. I once used regular JB Weld to patch a cooling jacket on a 2.5hp Mercury. I was surprised how long the patch lasted until I had to redo it. If i had used the HighTemp JBWeld the redo might have been needed.

I reassembled the motor yesterday and tank tested. Seems to be running good...on-the-water test i hope to complete within next couple weeks.

Thanks again All.
 
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cprodave

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Thanks Crosbyman. I am starting a 1960 18hp Lightwin project where Alumiweld and/or JB Weld will be needed.
 
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