Torque heads type 4

[Rikard]

Last time I torqued my heads I used a sequence to simulate the expansion of the engine. I liked the idea but I can't find the instruction again. From what I remember the sequence was pretty easy.
1. Torque the heads per manual
2. Increase torque to simulate the expansion of the engine
3. Back of a bit and torque heads per manual

Anyone that knows where to find the instruction?

Cheers,
Rikard

[Rikard]

I found the info I was looking for in another forum.

Do you really need 40 ft/lbs? Sounds like alot to me.

"The IAC certified faux heat-cycle-simulation torque is where you torque the heads to 40 ft/lbs overnight, then back down one at a time from 8 down to 1 on the Bentley diagram. This simulates the first heat cycle of an engine break-in, where the gaskets crush a little, the cylinder barrels seat a little, and your retorque helps to diminish the inescapable drop in clamping pressure that occurs over the first few miles."

Rikard

[Piledriver]

IMHO:

The idea makes some sense, but I personally would not go near 40 on what are effectively ~8mm studs.
It risks effectively ruining (stretching, of the permanent variety) perfectly good head studs for dubious gain.
Maybe 30lbs, you MIGHT safely do 40 on properly installed CrMo 10mm in properly installed case savers on a T1.
It wouldn't surprise me if thats where the procedure came from as T1s can effectively use head gaskets.

On a T4, you shouldn't be using head gaskets at ALL, or really cylinder base gaskets if not required to set deck.
Without gaskets, its a useless procedure, the only thing that's going to "give" are the heads, case or studs.

Also, if you are just checking the head seal, use toothpaste as grinding compound.

(gives away where I largely build my engines, cleanest room in the house with a HUGE parts cleaning tub )
It contains a very fine abrasive, and washes off easy.
It will still leave a (hopefully) uniform dull gray ring once cleaned up.
It won't remove enough material to worrry about unless you keep at it for hours.

if you actually NEED grinding compound, you should probably consider having them properly decked flat, instead.
Check the case registers for flat first, frequent problem, usually skipped.
Center main area droops, creeps up around the studs a tiny bit.

[Rikard]

Thanks Pile! I checked the head seal with toothpaste and it worked well. I torqued the heads according to specs and then to 30lbs. Left it over night and backed the torque to specs (Bentley).

A strange thing was that I was not able to turn the upper nuts anything with the higher torque.

Rikard



Sent from my D5803 using Tapatalk