1996 Mercury 225 EFI Head Bolt Torque

[jazzbass]

Had to pull power head to do what I thought was going to be
lower swivel pin bushing. Turned out to be the yoke was worn.

It was a good thing looks like exhaust plate gasket was ready to
go soon. Two bolts broke taking exhaust plate off.

Thinking of some preventative items while I was this far in, I would replace
poppit valve and thermostats in preparation for the rally at Lake Cumberland.

Well many of you already know what happened there. One head bolt broke
on each side. Been trying to get them out for a couple days.
What were they thinking when they used a head bolt to hold a thermostat housing?


A few questions.

If I am unsuccessful at removing the bolts and need to do Time-Serts
Do I use stainless or the carbon steel?

Head Bolt Torque. Much controversy over reusing old yield to torque bolts.
I ordered new bolts. Torque two steps 25lb then 35-38lb and stop
or the torque to spec and 90 degrees.

What is the head bolt material? Stainless, What grade, Carbon steel zinc or chromate plating?

[Tripps]

Those bolts r a mfkr don't break them in block they r long. Into block bad merc deal. Go slow heat and juices

[outasite]

I will assume this is a 3ltr,I Have no knowledge of that layout,but have removed a few of the 2.5 ones. I made a hardened steel drill bushing that slides into the head,and guides the bit.I forget the drill# but you can successfully drill the body of the broken bolt out (go slow) if you overheat the drill or the bolt,it will work harden.Then you will need a solid carbide drill.Once drilled you can go in with a bent end pick and unwind the thread coil.Helicoil does make a long insert that works well,don't use the shorter ones.Some of the other brands are to thick and make the boss very thin.good luck!

[jazzbass]

Thanks for the replies.

I have gone through a bunch of washers and nuts welded on. Worked on the exhaust plate.
Every penetrant in the cabinet, acetone and atf, candle wax etc.

I picked up a couple #10 x 5/16 x 1" at Home Depot. A couple wraps of masking tape and they centered
up nicely in the bolt hole in the head to act as a quide.

I am at the point where I can see the threads but have not been able to pick them out.

Waiting till Time-Sert kit arrives to make sure I don't go too far.