850 T3 head bolts

[bobra5037]

Any engineers out there?

The 850 engine (Eldorado and T2/T3) has a short engine stud bolt with a hex socket nut.  The nut sits under a screw in cap.  So, my questions:

1.  Why is this not a regular hex nut like all of the other studs?

2.  How do you get the nut off? 

It is frozen tight and I'm not sure if it's fused to the head or fused to the stud.  I suspect the former because it will not budge under extreme torque and I would have thought the stud would unscrew if it was just the nut seized to the stud.

I've tried force, lubricant, heat (albeit rather gentle), a toque wrench and percussion but neither of them will budge.  No problems with the other head nuts.

Cheers

Rob
 

[Antietam Classic Cycle]

Any engineers out there?

The 850 engine (Eldorado and T2/T3) has a short engine stud bolt with a hex socket nut.  The nut sits under a screw in cap.  So, my questions:

1.  Why is this not a regular hex nut like all of the other studs?

2.  How do you get the nut off? 

It is frozen tight and I'm not sure if it's fused to the head or fused to the stud.  I suspect the former because it will not budge under extreme torque and I would have thought the stud would unscrew if it was just the nut seized to the stud.

I've tried force, lubricant, heat (albeit rather gentle), a toque wrench and percussion but neither of them will budge.  No problems with the other head nuts.

Cheers

Rob

1. Because there's no room for a regular hex nut?

2. It'll probably need more heat and a good penetrating fluid. I like to heat the offending nut up, then spray it with CRC Freeze-Off. The thermal shock helps loosen things pretty well.

Put the other head nuts back on and torque them down to alleviate any stress on that nut.

[Moparnut72]

If you have a rattle gun set it on low and let the vibration work on it. Soak it with something like Liquid Wrench for a few days prior.
kk

[TOMB]

I would agree with the other comments here.However, just a thought the head has probably been off sometime in the past.And somebody forgot to put the washer underneath that hex bolt or excuse me, hex.Nut, so do these suggestions from the people above when you get it off.There should be a washer underneath it.It's not your regular diameter, washer.The hole is the same as the other bolts.However, the outside diameter is smaller and it may or may not be a wave washer.Take your time work at it.It will come loose with a big snap, and your arm will probably hurt.When it happens
TOMB

[n3303j]

Can't emphasize enough that you have the stiffest wrench combination possible so that no shock input is lost into winding up the wrench arm or hex key.

[wirespokes]

Shock it both ways - clockwise as well. And shock it end-wise also. Use a punch or rod and tap on it, not pound. The idea is to create shock waves, not pound it loose. The bolt will vibrate at a different frequency than the aluminum helping to separate the two. The heating/cooling/vibration/torqueing will help the penetrating fluid penetrate.

The trick is knowing this will eventually work, even though it seems it never will. So don't drag in the heavy artillery and make a mess of things. It will eventually break free.

One other thing - I don't know what's so special about Power Steering Fluid but it's an excellent penetrating fluid. Mix it 50/50 with acetone and it makes short work of problems like this.

[John A]

I would agree with the other comments here.However, just a thought the head has probably been off sometime in the past.And somebody forgot to put the washer underneath that hex bolt or excuse me, hex.Nut, so do these suggestions from the people above when you get it off.There should be a washer underneath it.It's not your regular diameter, washer.The hole is the same as the other bolts.However, the outside diameter is smaller and it may or may not be a wave washer.Take your time work at it.It will come loose with a big snap, and your arm will probably hurt.When it happens
TOMB

That washer is sometimes stuck on the head and it’s hard to see if it’s there. A small magnet on a stick helps identify if it’s in place when you put it back together.