BHG block indentations

[Integrity]

Some head gaskets are specifically designed not to require re-torquing, but I don't have a problem when someone re-torques a non re-torque gasket on a NA daily driver. I recommend re-torque especially if the engine has seen higher heat loads than usual, or has to hold high performance cylinder pressures.

 

[IJ.]

I've gone over the recommended 5 heat cycles with burping the coolant and driving to work for 3 days but I will most certainly be doing the retorque after I get back from the Reno Air Races. From what I have gathered the procedure is to break the stiction on each bolt and retorque individually in the assembly pattern right?

Correct.

 

[AFQC]

I wasn't in much of a mood for turning wrenches after the events in Reno but I tackled the retorque this morning. Some of the bolts were definitely "stuck" more than others but all the time spent chasing and lubing the threads in the block paid off. Nothing broke. A tip to any who might be reading this from a search- make sure you set your timing to TDC before its time to loosen head bolts. If your cams aren't at TDC you won't be able to get the socket down to the bolts.

 

[ianstaley]

Interesting post Integ, May I suggest in future could you break it up into paragraphs as no-one will bother reading past the first couple of lines

Wel I did, it is a very interesting. You are aware of the old addage, he who doesn't read the full artikel is only geting an estimation. RTFM.

 

[ianstaley]

One thing I didn't notice mentioned here is be sure to come back, revisit and give the head a retorque after running for a short time.

Perhaps one of the wiser guys here can offer some type of schedule for this operation. I feel it's important though since as perviously mentioned the alu head and cast block have different thermal expansion/contraction and will cause the gasket to squish out and seat slightly which leads to the torque relaxing ever so slightly.

I can't for the life of me find the article I originally read, but I believe it's after a set number of heat cycles. Or is this only done for metal after market gaskets?

My Toyota Dealer tells me it is about 1000 Klicks.

 

[Nick M]

It can. When combustion gases get past the head gasket and enter the coolant jackets it will overpressure the radiator cap forcing coolant to overflow into the reservoir. The air bubble in the heater core comes from the combustion gases and air drawn back in from an empty reservoir when the engine cools down.

Your coolant resevoir was empty?

 

[IJ.]

My Toyota Dealer tells me it is about 1000 Klicks.

I prefer to go with 5 heat cycles as 1000 Km's could be too soon/too late, for instance if you jumped in the car and did a 500 Km trip out and another back might be one heat cycle and things won't have settled in that time, alternativly might do a bunch of heat cycles in that time and maybe take it into boost and lift a layer scouring out the Viton, no amount of retorquing is going to seal it up..

My "suggestion" has worked on everything from dead stock rebuilds to 550+ rwhp endurance type engines, if someone has a better way I'm happy to reconsider.

 

[AFQC]

Your coolant resevoir was empty?

Not when it was overflowing obviously, but on mine I saw it draw the whole reservoir to empty as it cooled down.

 

[Nick M]

Not when it was overflowing obviously, but on mine I saw it draw the whole reservoir to empty as it cooled down.

It is supposed to do that. And it can't do it if there is a leak anywhere. If the cooling system is compromised, the pressure will be equal.