Fastener Goop

[Cadence10m]

A good car mechanic once told me that he puts goop of some sort on EVERY fastener he puts back in an engine or on a car body. Anti-sieze for anything he wants to be able to remove again, and locktite for everything he wants to remove again.

Is that a good approach to take on my Yanmar?

Is the anti-sieze effective and appropriate?

In addition to the benefit locktite gives by keeping things from rattling loose, it seems to me that it may also ensure the fastener threads don't rust and permenantly bond to the engine. I generally don't believe in permenantly bonding fasteners in place, so I would use the less aggressive locktite throughout.

Thanks for any wisdom.

Craig

[never monday]

Craig,
i don't believe in, neither does Yanmar when they built the engine. DO use a quality gasket sealant.

[NoTies]

A bit hard without knowing the brand names where you're from but I always use a copper or nickel based anti seize lubricant on exhaust studs and bolts. These type of anti-seize products should not be used on any other fasteners where there are disimilar metals involved as they just add to the electrolysis equation. There are a number of products available in NZ for thread lube including lanoline based ones that remain soft and others that harden and act well to insulate disimilar metals, mainly stainless to aluminum. I can't for the life of me remember the brand but it's yellow and is excellent for putting in between such things as stainless fittings to an aluminum mast.
All that being said, if the manufacturer says no goop, don't use it. (my only exception would be exhaust fasteners). If there is an issue with things working loose then find the cause (vibration etc.) An important point to note is that a lubricated thread will tighten a lot more with the same torque than a dry thread and the manufacturer takes this into account with specifications. A lot of manufacturers say to oil cylinder head studs for this reason.

[Cadence10m]

never monday once whispered in the wind:
DO use a quality gasket sealant.

At the risk of sounding like a moron, where would that gasket sealant go? I have bought all new gaskets for the cooling system and exhaust systems (the parts for which I've removed, cleaned and re-painted) but they are all solid polymer gaskets. I didn't see any liquid/goop gaskets when I took those systems apart.

Are you suggesting putting some gasket sealant on the fastener threads?

Another unrelated question for you - should I paint the OEM bolts? I used a brass wire wheel to remove all the rust from the fasteners. They cleaned up very nicely and I only had to replace 3 that were suspect. For the ones I want to reuse, do I paint them? Was there any paint on them when the factory installed them?

Thanks,

Craig

[NoTies]

Main reason for using gasket goo is where surfaces are damaged or been cleaned so often they are not true. Helps to take up the gaps a bit. An anaerobic sealant is my preference over silicone.
Yep, paint the bolts if they're mild steel, makes life a lot easier down the track.
Pete

[never monday]

pwederell once whispered in the wind:
Main reason for using gasket goo is where surfaces are damaged or been cleaned so often they are not true. Helps to take up the gaps a bit. An anaerobic sealant is my preference over silicone.
Yep, paint the bolts if they're mild steel, makes life a lot easier down the track.
Pete

Exactly what Pete said.
I'll use Permatex Ultra Gray as my sealant of choice. Generaly used sparingly in thin coats to assist the gasket. Yanmar gaskest have material that surounds the bolt, in theroy sealing it so goop on the head isn't necessary.

[NoTies]

I thought there had been a ban on two consecutive posts agreeing with each other lately.

[Matt Hager]

If you have spark plugs use the anti-seize on the threads m as well.

Before you paint your parts I would spray them with OSPHO. a product that you should be able to find at any marine dealer. It will etch the metal and is like a primer. Let it set overnight them paint.

Goodluck,
matt

[Richhh]

Cadence -
Using a wire wheel to clean the bolts that require precise torque isnt a 'good' idea. The 'cleaning' may result in very different 'frictional' characteristics and the resultant forces may not be 'close' to the OEM spec. If you 'can' afford it, simply replace the 'critical' bolts, etc. with 'new' or simply run them into a proper die (and properly re-tap/dress the threaded bores). Torque values are 'extremely' important ... and if you change the 'characteristics' of the component you may not be assembling to the correct 'clamping'/pressure values.

Although I'm pretty sure the 'modern' torque-to-yield head bolts, etc. havent appeared (yet?) on small diesel engines, it probably wont be long until they do ... and these are one-time-usage only.

[Cadence10m]

OK. I understand the gasket sealant now. I'll get some.

As for the bolts, after spending $700 (ouch!) on various new parts I see no reason to be cheap now. I'll repaint my old, cleaned up ones and keep them as spares. Then buy some new ones to use now.

Craig

[BC Mike]

Don't know watcha working on but when I had my 15 hp twin cylinder Yanmar apart they wanted $180- for piston rings. A set of four for a VW was about $80-. Don't tell Yanmar. Somewhere there is technical info on the variance of torque used for an oiled thread versus non oiled, same thing for washers. One of my tractor buddies posted it so we could properly clamp on the heads of the old side valve Fords. The head bolts on the Yanmar are tightened to 120 foot pounds. The head and block weigh a lot. The older units are one solid unit. On another tractor post was a picture of a unit in a tractor pull. Too much boost and the top of the block blew right off. You could see all the pistons and the camshaft. One nice things about the old Yanmars is they can operate at extreme amounts of tippy. 41 degrees I think.
Michael

[GordMay]

Thomas J. Glover's "POCKET REF" is a good (cheap) source of general scientific & engineering information.

For info' on Lubricated Threads, Goto: http://cruisersforum.com/photopost//...php?photo=1600

Get the book at any good hardware store, or Goto:
http://www.sequoiapublishing.com/nav_products.htm

[Alan Wheeler]

OK, seeing as I teach this stuff to an apprenticship level in my current job.
Firstly, although it is done, it is not recomended that bolts are ever torqued down dry. ALWAYS place a SMALL amount of oil on the thread. DO NOT over lubricate. A thin smear is all that is required. Reasons=
The importance of torqeing a bolt is so as you get the maximum force before the bolt/thread reaches it's failure point. This max is calculated over the length and stength of the bolt AND the thread length and material it is seated into. When the bolt is tightend down, it undergoes both tension and torsion stress. If the thread is dry, the bolt shaft at the top of the thread undergoes more twist than the bolt shaft at the bottom of the thread. Thus an uneven tension is placed on the bolt. This can lead to the bolt "settling" back on itself later on. As the elasticity of the metal wants to eventually line the bolt back up again, it can over time loosen off. The worse case scenario is failure of either bolt or parent thread.
Too much oil can have an even greater problem. The oil can have an hydraulic affect. If it sits in the bottom of the hole, it can not escape and the bolt tightens down onto it. The oil will stop the bolt dead and even though the correct torque has been reached, the bolt has not been seated down hard. At an extreme, the parent material can infact be split apart due to hydraulic pressure.
So, lubrication is essential.. But only a light smear.
HOWEVER..... IT is most important to read the manual. There are some rare occasions that the manufacturer has suggested something important to follow. Follow the advice!

[JGI417]

with the conditions a marine engine encounters I would use the anti-sieize conpound. I also use a small amount of gasket conpound, I found it helps hold a gasket in place.
Thanks my two cents

[Jentine]

Thanks for the reference to "Pocket Ref". I am sure it will be a fine source of the type of information that is hard to find when things are apart.
I would like to add that some manufacturers of engine equipment do not recommend gasket sealers and lubricants to "hold them in place" while reassembling. I was, formerly, an instructor for a major fuel injection manufacturer and the general instruction was to assemble the injection pumps DRY. The gaskets were designed to seal when the fuel was absorbed by the gasket. Addition of an oil film or a little grease caused the gaskets to swell during assembly and leak.
I, also, always reassemble engine and accessory parts using some form of never seize compound, just in case I want to take it apart again.