Would you run this cylinder head- in this condition-?

**Aaronhl** · 07-29-2020, 08:15 PM

Would you run this ?damaged? cylinder head on a budget build?

Picked up a 94 FF block sitting on a pallet with leaves n dirt over it for $175. A piston was sticking, looks like the gasket let some sand/corrosion in

Here is dirty and then cleaned up best I could

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**lpugh** · 07-29-2020, 08:21 PM

I would not, only in a pinch till I could get a replacement

**rgsauger** · 07-29-2020, 11:56 PM

Yeah, that kinda sucks, bud

**LakeFever** · 07-30-2020, 04:36 AM

Soda blast, Mill, CC it and see if that will work for you. Mill and finish the other side to match. Can always hand sand or hand finish the shape too. I’m sure there are quench profiles here somewhere you can find to upgrade performance. Most of this work is all elbow grease and very little cost. Failing that there is always welding and reshaping. It doesn’t look that bad to me from the pics at least. Could be as simple as polishing the chambers and getting it milled. Lots of options

**Ribber** · 07-30-2020, 05:34 AM

The last pick doesn't look that bad too me, you could try sandblasting it a little too. Just not too much and not the mating surfaces.

As long as the mating surfaces are still level and not porous or cracked it will probably work. However if the mating surface is eaten away you need to get it milled and flattened.

When a gasket fails there's always the risk that something else is wrong though so check for anything weird and misaligned.

If you try it I'd give it a gentle break-in, varied low to medium rpm and low load for the first 3-4h.

**H2OPERF** · 07-30-2020, 08:39 AM

I dont see any pitting in the gasket fire ring area, the pitting tn the squish area doesnt look any worse than the factory lost foam surface in the combustion chamber. I would bolt it on check compression... make sure that the plug/piston tops not miky or have dots of water after a test run ,run it on the lake check it again and enjoy.. tons of motors running around with dinged up heads from ring failures with no issues.

**FUJIMO** · 07-30-2020, 08:53 AM

...i would not use it...

**FMP** · 07-30-2020, 12:14 PM

dimpling, that cost extra

**Aaronhl** · 07-30-2020, 12:35 PM

good info everyone...The squish area does have some slight pitting but looks like the gasket area is ok, see pictures

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**LakeFever** · 07-30-2020, 02:37 PM

A quick soda blast and you would never be able to tell there was any shmoo on there. You can also use scent free oven cleaner but it does eat aluminum so you have to be careful. Practice on some other aluminum first. It does bring aluminum back out brilliant bright clean. Wash thoroughly with water and spray with WD40 after to protect

**Aaronhl** · 07-30-2020, 05:46 PM

Ok experts here another few for you
Seems like the stuck piston had been replaced before, it was the only piston with a center dot on the top of it, the other 5 did not have the dot, any ideas on why this one had the dot?
When putting a piston back in, if I do not see “UP” because of carbon build up, what is the positioning in relation to the rod n cylinder?
I think this piston wasn’t put in correctly because the rod part number wasn’t facing the flywheel. Is that required according to the manual?

**Chaz** · 07-30-2020, 06:38 PM

Originally Posted by H2OPERF

I dont see any pitting in the gasket fire ring area, the pitting tn the squish area doesnt look any worse than the factory lost foam surface in the combustion chamber. I would bolt it on check compression... make sure that the plug/piston tops not miky or have dots of water after a test run ,run it on the lake check it again and enjoy.. tons of motors running around with dinged up heads from ring failures with no issues.

Parts with those lost foam "big pores" welds marvelously …

I got tired of jigging and fixturing up every part that had rot , warpage , or a surface cleaned via chisel mechanic , just to take a skim cut. I got a 16" x 96" belt sander .. wax on ~ wax off , Mr. Miyagi .. done ..

**Merc 2.5** · 07-31-2020, 05:54 AM

Originally Posted by Aaronhl

Ok experts here another few for you
Seems like the stuck piston had been replaced before, it was the only piston with a center dot on the top of it, the other 5 did not have the dot, any ideas on why this one had the dot?
When putting a piston back in, if I do not see “UP” because of carbon build up, what is the positioning in relation to the rod n cylinder?
I think this piston wasn’t put in correctly because the rod part number wasn’t facing the flywheel. Is that required according to the manual?

I had put mine out of a runnin 150 in ultra sonic cleaner and barely seen the up and down. Without seeing that idk how u would do it.

**Aaronhl** · 07-31-2020, 07:42 AM

Originally Posted by Merc 2.5

I had put mine out of a runnin 150 in ultra sonic cleaner and barely seen the up and down. Without seeing that idk how u would do it.

I think I could tell by the location of the ring pin gaps and the skirts of the piston. Could anyone explain the piston positioning or does it look symmetrical by eye?

**Merc 2.5** · 07-31-2020, 02:18 PM

Originally Posted by Aaronhl

I think I could tell by the location of the ring pin gaps and the skirts of the piston. Could anyone explain the piston positioning or does it look symmetrical by eye?

Yes its is a 2.5 , mine was 2.0. The 2.5 has a short skirt or notch on 1 side?. I think.? I'm not home to look ?