1993 4.3 valve adjustment

[Markhodges78]

I will be replacing a head on a 1993 OMC Cobra 4.3 Model number 432APRJVN The manual that I have states to torque head in 3 steps to 25, 45, 65, and torque valves to 40 ft. Ibs. on 1992-96 V6 engines. so this means no lash adjustment for this engine? does this sound right?

 

[AllDodge]

The Merc 1993 GM V6 list 1 turn after zero lash for hydraulic lifters

Shows head in 3 steps to 75

 

[Markhodges78]

The Merc 1993 GM V6 list 1 turn after zero lash for hydraulic lifters

Shows head in 3 steps to 75

yes I agree with this that is why I was confused when seeing this

 

[Markhodges78]

 

[Markhodges78]

 

[Markhodges78]

 

[AllDodge]

If the rocker nut is "Not" a self locking type then I can agree

 

[Markhodges78]

If the rocker nut is "Not" a self locking type then I can agree

Part number 3853649 its the same nut used on the 1996 penta 4.3

 

[makomark]

does the engine have hydraulic roller lifters?

 

[Markhodges78]

does the engine have hydraulic roller lifters?

I have not started the project but according to the parts list it does

 

[makomark]

ok...FWIW, the 4.3 engines went thru a lot of changes in the early 90's, so referencing a "model year" doesn't always yield the best answers.

Who published the manual you cited?

Is the engine the original one?

 

[Markhodges78]

I do not know Who published it it doesn't say any where that i can find I only was given the few pages relating to the head replacment

Yes original engine

 

[makomark]

I'd go with the cylinder head torque as AllDodge suggested.

The rockers will need adjusting (vs a flat torque value)...you can do it when you assemble it or while its running. Unfortunately, what you posted from the manual pages doesn't give you all of the info to do it during assembly...

 

[makomark]

I'd be inclined to see if you can get the engine ID data off the block - there should be a 'milled ledge' on top of the LH water pump mounting boss when looking at the front of the engine. casting numbers also help determing what you have...

 

[AllDodge]

P/N 3853649looks like a torque nut and not self locking

If this is what is on the rockers then you should be good with just torque and forget

As a backup and method to double check, before you loosen/remove any rocker nut

Rotate crank until one of the valves on a cylinder is partly or fully opened.

Now loosen the other rocker until push rod is loose.
Tighten nut feeling for zero lash. When zero lash is met, tighten nut.

If you get much more than 1 full turn let us know because something isn't adding up

VP is known for not making a good manual and not keeping obsolete parts updated

 

[Markhodges78]

I'd be inclined to see if you can get the engine ID data off the block - there should be a 'milled ledge' on top of the LH water pump mounting boss when looking at the front of the engine. casting numbers also help determing what you have...

I'll look and report back

P/N 3853649looks like a torque nut and not self locking

If this is what is on the rockers then you should be good with just torque and forget

As a backup and method to double check, before you loosen/remove any rocker nut

Rotate crank until one of the valves on a cylinder is partly or fully opened.

Now loosen the other rocker until push rod is loose.
Tighten nut feeling for zero lash. When zero lash is met, tighten nut.

If you get much more than 1 full turn let us know because something isn't adding up

VP is known for not making a good manual and not keeping obsolete parts updated

Ok thanks ... If it has roller lifters then its torque and leave?

 

[Markhodges78]

Another piece of info is that ii has an electric fuel pump and the block is not drilled for a mechanical. Also the head casting is 064 I know this because I took the valve cover off to check before ordering the head but I did not think to check the rockers

 

[AllDodge]

Ok thanks ... If it has roller lifters then its torque and leave?

No in my opinion
It has to do with the "IF"s

If it has self locking nuts, then no

If it has nuts as pictured in the link in post 15 then most likely yes

 

[Markhodges78]

No in my opinion
It has to do with the "IF"s

If it has self locking nuts, then no

If it has nuts as pictured in the link in post 15 then most likely yes

Just remembered I have a picture from when I was trying to see what head I needed

 

[AllDodge]

Looks like torque and forget

 

[Markhodges78]

Looks like torque and forget

Great thanks ... one last ? Would any one know what I set the timing at on this ? Mercruiser normal has it listed on engine but not

 

[AllDodge]

Points 8* BTDC
Electronic could be 8* or 10* but depends on which ignition system

 

[Markhodges78]

Points 8* BTDC
Electronic could be 8* or 10* but depends on which ignition system

Thank you

 

[Markhodges78]

Ok it gets worse.. pulled the intake off and found that the block was cracked..

Can I replace the engine with an 88 omc 4.3 ?

 

[AllDodge]

It should if it's a 4.3 and not a 3.8
Look close at the bolt holes to ensure your accessory brackets will bolt up

 

[Markhodges78]

It should if it's a 4.3 and not a 3.8
Look close at the bolt holes to ensure your accessory brackets will bolt up

The 88 engine I have is definingly a 4.3 it was in a glass sport

 

[Markhodges78]

It should if it's a 4.3 and not a 3.8
Look close at the bolt holes to ensure your accessory brackets will bolt up

3.8 ? is that a ford engine?

 

[AllDodge]

No, it was used in Chevy and Buick

 

[Markhodges78]

No, it was used in Chevy and Buick

Oh ok.. This is for sure 4.3 .. SBC Bellhouse and steel SBC timing cover.. I know about the 2.8 but never had any dealings with the 3.8 engine I had to look it up