Re: Head Bolt Shaft Grease Ideas
Locktiting or not.
Although manuals recommends the use of locktite on head bolts threads, there seems to be a tech contradiction. When you place a new head gasket usually is torqued to it's max allowed torque, but needs a re torque at 20 hours for gasket to sit well, with heat new gaskets tends to cede a bit and what was torqued to it's max torque now is much less. So if locktiting at first torque, will need to remove each head bolt, apply locktite again on threads and torque tu max again. Ain't this issue counterproductive, or it's the way to go ?
Most non tech boaters will asume that once a new head gasket is placed will remain that way untill time for a new one and so on, in plain theory yes, but not in real world practice. Have found that after buying a nice torque wrench and retorquing head to factory specs. What are your ideas, thoughts about this general statement...
Happy Boating
The retorqueing or not and wet or dry installations gets a lot of attention on the other site I visit "Yesterday's Tractors". I have been working around engines marine and regualr engines since about 1957. Over the years I have been exposed to a variety of engines and OEM recommendations, plus general maintenance practices, and some just plain common sense. One thing I noticed, which supports my position, is the last automobile I had to take back to the dealer for a head gasket retorque was a 1964 Rambler American, old design, 3 main bearing, 6 cyl. engines. The following year the badge came out with a newly designed 6 with 7 mains (eliminating the problem I had after 100k miles which was main bearing knock, and guess what: No head retorque. So, you have to ask yourself, how is it that the OEMs have figured out how to NOT have to do it?
It seems that what used to work isn't what works normally now as everything involved in the process has advanced and part of the thinking in that advancement is improved reliability (which we consumers are demanding now) and reduced costs in OEM production, warranty, and maintenance. I think it is a stellar idea and about time OEM's got with the game.
With that said, in short, there are two thoughts on head gaskets especially. My response to that is go with what works for you. I am not going to convince you to change and you aren't going to convince me. Reasons is what you do apparently works for you and I know what I do works for me. There is nothing more irritating to me, in working on especially an engine, to have her all buttoned up and have to go back in and do something, especially when you have her all slicked up with a new coat of paint and all the oil and grease cleaned off and all that. Want some variety, and all that goes with it, the farm site is full of it.
My education came from the Chev 283 V8 engine. It was early in my mechanicing and I was doing an overhaul and the book said to run the engine up, get her to normal temp, shut it off, let it cool down and retorque the heads. As part of that they said to reset the valve preload (hydraulic valve lifters on that engine) which was back off the rocker till you hear it tick (obviously the engine has to be running), snug it up till it quits and add 3/4 turn preload. So now your nice and clean, nicely and freshly painted engine, valve covers, attachment screws and all, plus all the add ons that pile on top of said items (hoses, wiring, etc,) now has to be moved out of the way and is exposed to splattered oil.
Or in the case of a tractor engine, they would say adjust the valves with the engine running at normal temp after you retorque the head and on most of those engines they had a valve train rail whose mounting bolts functioned also as head bolts and moving them meant changing your previous cold valve gap setting. Well, usually this means oil is (scuse the French) PUKED all over your nice clean rebuild making a horrible mess, I don't care how much shielding I tried to apply to contain it besides the paint thing I mentioned.
I said that there had to be a better way.
So, today, I don't install a head gasket dry, period, including on high compression diesel farm tractors, one of which I am running today having overhauled it in the early 2000's. In the case of valve trains with solid lifters I use the cold dimensions.
I apply a product by the name of Copper Coat (they have a www) that is a copper filled high quality adhesive, especially made for head gaskets. I have used it for at least 40 years, have never gone back into an engine and have never had a failure, period.
On torqueing, If I use the old bolts, I clean up the threads on both bolt and block and torque to the recommended spec. (With new bolts obviously the bolt threads are already clean.) in the pattern outlined in the book (center to the extremities in an X pattern) in several steps. After the final step I let it sit for a couple of hours and hit it again. Every time I get some more and that and the CC may be why my engines stay sealed and I don't have to go back after a run in and retorque.....I have already done it.
I don't use sealant (blue Locktite) on cast iron blocks but do on alum marine engines and the reason is corrosion. The Locktite sets up on compression, so going in it provides lubrication of the threads allowing you to get the full torque where it belongs (mating surface) and when you get the locking pressure on the threads it goes into the curing process. Yes if you go back the next day it will be setup and will offer resistance to dilute your torque reading, so I don't do it.
So, there are one guy's comments as requested.
HTH,
Mark
