Head cylinder tightnings Dino 308 Gt4

What kind of help do you need?

 

Hold this wrench.

 

you're holding it wrong..

 

The copy of the service manual that I have lists cylinder head hold down nuts torque as 10 Kgm, I do not have a tightening sequence drawing or description, but I doubt it is different from standard cross hatch pattern.
I recommend downloading the service manual:
All Ferraris

 

The tightening sequence is in the WSM. As mentioned , download this, lots of help there.
/Peter

 

The real question is whether to loosen each bolt separately then retorque , That is what many good techs and other mechanics told me, which I did about 10 years ago, however since I have had no leaks I just checked them last time….

 

I have been given the same advice. I have also been adviced that when starting the engine the first time after renovating the cylinder heads, my situation, retorque once directly after the engine has been warmed up the first time. Let it cool down first of course. Then, drive it for 1000 km, retorque again.

Any comments? It is really necessary to do this first retorque? Is it enough to do it after 1000km?
/Peter

 

This is primarily because the proper stretch on head bolts can be influenced by several factors. The fastener is torqued to a specific value in an attempt to obtain the proper stretch (which is what maintains the clamping force) and even with the proper thread lube it takes a few cycles of tightening & loosening to stabilize all the factors (friction, temperature, lube, thread type, contaminates...). This is especially true for a new fastener, as it has not been stretched before, but unless one can determine the amount a head bolt has been stretched it is recommended to use new ones.
I have never loosened & re-tightened individual bolts because of concern about warping, I follow the recommendation of always using the tighten / loosen pattern.
ARP fasteners has some good information in their catalog on the subject.

 

The 308 GT4 uses head studs, with 12 point nuts on top of that. It is extremely unlikely that a rebuild requires the replacement of head studs.

To the OP. The sequence I recommend is:

Use lubrication on the threads and the surface of the washers, Don't reuse the washers they are cheap.

From center out in a criss-cross pattern, go to 40 Nm. Stop wait for 10 minutes. Go to 75 Nm, Stop wait for 15 minutes, Final torque at 100Nm. Make sure you arrive at the final torque in one smooth motion

If you really feel like going back in again after first run in. Ok, your choice but it is not required at all.

 

+1 per Newman


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So, just to make it clear, retorque after the first 1000 km would be ok.
/Peter

 

Did Ferrari require that the car be brought in at X miles after purchase to retorque the heads?

 

Yes they did.


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3000 miles


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Or did they start it once, retorqued, and thats it, ready to go. The first stage my mechanic recommended.
/Peter

 

Ok, thanks.

 

No problem. I will be making the trek back north at 3k to have mine done as well.


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