HeIp crazy valve adjustment 4.3 mercruiser question ?

[Heywire77]

Ok this is a crazy one I got a boat with blown head gaskets and found one head cracked it is a 1993 mercruiser 4.3 non vortec motor ok the problem is I had a extra 4.3 mercruiser head sitting around but this head was on a motor that had adjustable valve lash and the other head on the right side of motor ithats good and staying on sn't it is just tighten down and your thru , I would do it on the other head I'm using but the rocker arm studs are the old heads with the pressed in studs and it will just keep tightening till it bottoms out and I'm sure mess up the valves or push rods . Ok my question is can I just do the normal valve lash adjustment like you would do on the old model head for the one head ? And will it be a problem having one head that is none adjustable and the other one I using being adjustable I noticed the motor I took the head off of also had roller lifters just like the motor it is going on . I'm sorry if this sounds like a crazy question . Thanks for any help .

 

[achris]

Let me see if I can't make this a bit more readable. Let me know if I got it right....

Ok, this is a crazy one. I have a boat with blown head gaskets and found one head cracked. It is a 1993 mercruiser 4.3 non vortec motor. The problem is I have an extra 4.3 mercruiser head sitting around, but this head was on a motor that had adjustable valve lash, and the other head, on the right side of motor, is good and staying on isn't. It is just tighten down and your through. I would do it on the other head I'm using, but the rocker arm studs are the old heads with the pressed in studs and it will just keep tightening till it bottoms out and I'm sure mess up the valves or push rods.

My question is, can I just do the normal valve lash adjustment like you would do on the old model head for the one head? And will it be a problem having one head that is none adjustable and the other one I using being adjustable? I noticed the motor I took the head from also had roller lifters, just like the motor it is going on to. I'm sorry if this sounds like a crazy question . Thanks for any help .

Now, that's better

The idea of putting different heads on the same engine is just wrong. You have no idea what those differences are. Could be different compression ratios, different port sizes, the list goes on. You need to use the same head on both sides of the engine. Either find a match for the existing good head, or the existing replacement. And the other thing you need to do is find out why you blew the gaskets, or we'll be having this conversation again. Just saying.

Chris.......

 

[Heywire77]

Blew the head gasket because previous owner ran it hot from bad water pump impeller , I replaced that and I have looked the heads over and there Identical accept for the old one has press in rocker arm studs and then went and checked 4.3 head design about ordering another head the only difference it showed was the rocker arm press in studs instead of screw in studs it showed the same horsepower and valves , the same head gasket design and the combustion section of head is also identical .

 

[achris]

Blew the head gasket because previous owner ran it hot from bad water pump impeller. I replaced that and I have looked the heads over and they're identical except the old one has pressed in rocker arm studs. Then went and checked 4.3 head design about ordering another head. The only difference it showed was the rocker arm press in studs instead of screw in studs. It showed the same horsepower and valves, the same head gasket design and the combustion section of head is also identical.

If that's the case, just deal with each head as it should be. So one side will be adjusted to 1 turn passed zero lash, the other just screwed down.

 

[philbullet]

Don't know if this makes sence or helps.had a simular crazy thing but same Vortec heads.Had to check cam lift difference with a cam lift mic tool, not sure the proper tool name.But with the cam I had in motor the valve lift was off .34 I think, had to shim under springs and get different keepers.
But my problem was back firing through carb.
This motor was a truck motor with reworked heads and the cam out of a original mercruiser 4.3.
All was a vortex.

 

[Heywire77]

Well I actually did pull the valves and springs off the bad cracked head and used with the old head that is going on the motor just in case I lapped the valves in and I installed the heads last night when I ran into problem about adjustment . So today I adjusted the valve lash and was almost to the point of installing the intake and all when the rain hit and bad weather , so maybe it will clear up in afew and I will finish it today and let you know how it turns out . I have been working on it at night because it is so dam hot here . I know I could tell someone else had already been in the motor it had to different head gasket one felpro and on the other head a off brand . I actually did have a set of vortec head also but I could use them because they are 8 bolt intake and the engine is 12 bolt . I was surprised it wasn't a cracked block because I have seen so many 4.3 with cracked blocks from not being winterized .

 

[Heywire77]

It's done I put it all back together and I cranked it with the valve covers off and glad I did because I seen it wasn't get oil up to afew of the lifters when the head gasket blew before all that gunk clogged the lifters , I put a bottle of marvel mystery oil in it and it finally starting getting oil up and all the gunk out I will make sure to change the oil again . But I timed it and adjusted everything and it ran great , dammit you don't know how glad I am to be thru with this boat !