| Author | Message | ||
| Neville Pugh (Nevpugh68)
Junior Member Username: Nevpugh68 Post Number: 67 Registered: 7-2001 |
Thanks all for your thoughts and input  Appreciate it .... | ||
| Richard Ham (Hampappy)
New member Username: Hampappy Post Number: 6 Registered: 2-2003 |
my 2 cents - Its better to crack the bolts by loosening by a few degrees. Firstly you're only releasing a minimal amount of bolt load, so no danger of starting any leaks. Secondly it's far better for the bolt. Less risk of shearing the thing off if its seized. This should do the trick and certainly worth a try. | ||
| JRV (Jrvall)
Intermediate Member Username: Jrvall Post Number: 1285 Registered: 11-2002 |
>>I think the proper way to re-torque is to loosen slightly before torquing. << Matt, For the most part you are absolutely correct. >> Be careful here. My experience (not as great as others on F-Chat) is that you DO NOT first loosen the bolt.<< In this case however I'm also from the second school with James.. The problem in this case study imo is age and unknowns. If it was a somewhat newish motor you could get away with lossening first to get what you're refering to as "true torque". However imo trying that procedure on an old motor is very risky in terms of upsetting it's current set. What I'm considering is that 1) the head is as tight as it will get, or, 2) needs to be already, and still leaks, or, 3) it is not to adequate tightness and can possibly be resealed by pulling it to proper spec without upsetting it's current state of seal and stress/compression loads. I;m not real sure there is one definative answer considering that their are many unknowns. But just thinking out loud, I'd consider upping the number some to overcome the frozen state of the nut rather than loosening, because the overall goal is to achieve slightly more compression of the gaskit, if possible. | ||
| James Selevan (Jselevan)
Member Username: Jselevan Post Number: 509 Registered: 6-2002 |
Matt - Be careful here. My experience (not as great as others on F-Chat) is that you DO NOT first loosen the bolt. When re-tightening the head bolts or nuts, simply apply the appropriate amount of torque without first loosening. Follow a sequence that evenly distributes the load (as specified in the WSM). Loosening first allows the gasket to break whatever adhesive seal may have formed. Realize that you will have to go over-spec a bit to break the "static friction" of the nut/bolt. But in general, a few pounds over spec is desired to further compress the gasket. Jim S. | ||
| Matt Boyd (Mattboyd)
Junior Member Username: Mattboyd Post Number: 54 Registered: 1-2002 |
I think the proper way to re-torque is to loosen slightly before torquing. Most likely, if you apply the torque wrench before loosening, you will note that torque is already high enough. Consider that when you first go to loosen a nut/bolt, breaking it loose is going to take a fair amount of effort, but once it breaks loose it is easier. Same thing for tightening. So....crack it loose before torqueing. Agreed? Just makes sense to me... -matt | ||
| Mitchell Le (Yelcab1)
Member Username: Yelcab1 Post Number: 523 Registered: 11-2001 |
The head is 5 inch thick aluminum, I would be really surprised if you can crack it with a 65 lbs feet of torque on a 11 mm studs. | ||
| JRV (Jrvall)
Intermediate Member Username: Jrvall Post Number: 1277 Registered: 11-2002 |
It's safe to check the torque on the head nuts. In fact it's SOP to check head torque when doing a valve adjust or 30K service. Make sure you use a quality torque wrench so that you're checking current tightness against accurate TQ wrench numbers and follow the WSM tighening sequence. | ||
| Neville Pugh (Nevpugh68)
Junior Member Username: Nevpugh68 Post Number: 66 Registered: 7-2001 |
For ages now I've had a very tiny oil leak (say, a drip a day) which about a year ago my local specialist identified as being from the (front) head gasket. They also said that the gasket was leaking EVER so slightly into the coolant, though not enough to be worried about. Because the leak is so tiny, I wondered whether retorqueing the head might solve the problem (it might not of course, but it's a cheap thing to try) My specialist warned me off doing this, saying that he's known retightening heads on old head gaskets to crack/break cylinder heads .... something to do with the design of the heads, being slightly weak. He STRONGLY recommended replacing the head gasket. But then I've got someone else (not a specialist) telling me that's a load of bunkum, and that the garage is just out to get more money out of me. Thoughts anyone ? Cheers ! |