I think you ran the engine for way too long without any coolant in it
Trust me, guys, the engine is fine. I've been a builder (American iron) since the 70's and virtually every engine I fire, I fire briefly to bring it up to temp (I've got a handheld infrared gun), and I then cool it to see how much torque has been lost on initial thermal cycling. Once retorqued, I put the liquids to it and it's prevented me from having water leaks on most of my builds.
On American V8's, I learned this from a few early dyno events, where initial crank up of high compression race engines would have water spraying all over the dyno room, until the thing got hot, and it would seal up after a few minutes of running, and stop spewing water. I just prefer to do the short dry cycle and cool down. Again, the engine is fine.
Now, back to the original question:
The studs DO lose torque: When the aluminum head expands against the backside of the nuts and the head gasket, there is a slight compression of the gasket that takes place, hence the initial retorque.
Slightly more compression occurs after (according to Bentley) about 1000 miles, where the (theoretical) final torque is applied. Once this is accomplished, the "elasticity" of the bolts prevent further relaxation of the torque values.
The only reason I ask everyone here is because I'm not "seasoned" when it comes to these 1.6 engines. I do have a good friend that runs a local German Auto Repair shop that swears he's never been able to maintain torque values for more than a few months at a time, when he's tried the studs, and he's built dozens of these things. Again, his comments prompted my question to you here.
Now, on some race cars I've owned over the years, studs used with Aluminum heads did not have the same elasticity as the original bolt, and thermally cycling, over time, would result in a loss of turque values (i.e. the release of torque is much more subtle, as expansion and vibration work their way into the equation, and I have encountered quite a few engines - especially very high compression engines - some supercharged - that would exude these characteristics).
So, 745, is your setup a street car set up or are you referencing a rally car or ?
Are you running a stock type head gasket ? If not, is it a MLS type, and did you coat your gasket ?
When you initially torqued your head, what value did you use and did you use ARP's Ultralube to bring them up ?
When you say 4-5 years; is that daily service ?
It sounds like you're comfortable with yours, so maybe I'll just stick with these and see how they work out.
Again, guys, thanks for the feedback.
S
Topic: Anyone have mls gasket/arp studs/1.6 block? help me test something... (Read 4380 times)
