Milky oil

[SeaRayboater95]

Learning lots from you guys here. This is awesome. So, I'm thinking these are screw in studs and casting number 181. This is what im looking for? This is the cracked head that came off the engine I'm working on. I'm going to look at a head still on the motor and still in the boat. I have no idea what to expect. Was referred to him from the parts manager from a merc dealer.

 

[Lou C]

looks like that to me
good luck finding a match!

 

[SeaRayboater95]

Do I need and exact match? Will other heads work with the good head I have? Could I take both donor heads and use them? Would I need to use rocker and pushrods from the donor heads? So many questions........ Head out to get the head shortly.

 

[Lou C]

Not sure on those questions, exact match would be best assuming your other one is OK. Maybe ask machine shop, they may know.
I’d guess if you find a matching pair of pre-Vortec heads it should work, I just don’t know for sure. Are you certain the other side isn’t cracked, both of mine were…

 

[SeaRayboater95]

Not sure on those questions, exact match would be best assuming your other one is OK. Maybe ask machine shop, they may know.
I’d guess if you find a matching pair of pre-Vortec heads it should work, I just don’t know for sure. Are you certain the other side isn’t cracked, both of mine were…

Shop tested and said it was good.

 

[Scott06]

Do I need and exact match? Will other heads work with the good head I have? Could I take both donor heads and use them? Would I need to use rocker and pushrods from the donor heads? So many questions........ Head out to get the head shortly.

would think as long as the chamber size is the same should work. Did the other head check out ok? would assume this is from an over heat block deck is likely not flat anymore.

Edit missed the prvious post re second head is ok but still need to check mating surface on block

 

[Lou C]

For sure check the block deck, mine overheated but it was OK.
the challenge with the 4.3 is all the variations that were present over time.
if you look at the Pre-Vortec head list I posted, there are like 5 different versions of the same head, but some with different #s are listed as actually being the same head, but with some subtle difference and different last 3 #s (064/181, one has press in studs, the other has screw in studs), etc. Mine ends in 768 which matches up with the date range 87-91 (mine's an 88).

 

[SeaRayboater95]

This is the one I'm taking off donor boat. Will it work as a straight up replacement. Do I need to take rockers and push rod wirh.me?

 

[SeaRayboater95]

Well, the one I scavenged pressure tested good. Just getting them cleaned up and ready to install. Glad that's over. Going to lap the valves. Might as well.

Ken

 

[Lou C]

I’d like to saw yes to your questions but do t know for sure 100%. If that casting # falls in the same date Range as the original I’d say yes. And I’d take the pushrods rockers and retaining nuts as well,

 

[Lou C]

181 & 064 look like they’re from the same date range 91-95.,

 

[SeaRayboater95]

181 & 064 look like they’re from the same date range 91-95.,

Had the serial number on the engine checked and it's from a 1994.

 

[SeaRayboater95]

And I’d take the pushrods rockers and retaining nuts as well,

I didn't take them. Will I hurt anything by using the.original ones?

 

[Scott06]

I didn't take them. Will I hurt anything by using the.original ones?

As long as the valve train geometry is the same and thus uses the same pushrod length it’s no issue.

 

[Lou C]

the main reason I'd have taken them is to check the pushrod length against the original ones.

 

[Lou C]

One thing you could do:
look up those parts in a mercruiser parts manual online. See if the part numbers are the same for the years 91-95 for the pushrods and rockers.

 

[SeaRayboater95]

One thing you could do:
look up those parts in a mercruiser parts manual online. See if the part numbers are the same for the years 91-95 for the pushrods and rockers.

I just searched how long they were and 181 is 7.192 and the 064 is 7.182. Diameter is 0.312 on both. Are we thinking I'll need to go back to him and get the valve train?

Ken

 

[SeaRayboater95]

Then I looked up on Mercruiser Parts Drawings and by serial number, and it seems they use the the same part number, #17339 and says they are 7.25" and 0.5" in diameter.

 

[Lou C]

I just searched how long they were and 181 is 7.192 and the 064 is 7.182. Diameter is 0.312 on both. Are we thinking I'll need to go back to him and get the valve train?

Ken

I would just to make sure that they were the same

 

[Lou C]

I’m wondering why there’s like .010” difference in length? GM did so many odd things like mixing SAE & metric fittings it’s not surprising. I guess try to get the ones for the head you bought measure what you have & compare. Adjustment of preload might make up any difference. A machine shop guy or engine builder should know.