Reassembleing engine

[HAS]

I have some questions about reassembling my 1985 50hp. 4cyl. mercury engine. Should Loctite
be used on the bolts?, if so what type?. What about some kind of sealer?. Or should the bolts be clean
and dry?. Should bolts be retorqued after engine is run at operating temperature?. Should bolts
be retorqued when cooled down after run at operating temperature?.
THANKS AGAIN HAS

 

[mr 88]

Re: Reassembleing engine

I would use a bench grinder with a wire brush and clean all bolts.I use a thread chasers as well to clean out the threads in the rebuild as well.NO loctite should not be used unless the next time something goes wrong you are planning on junking it.If anything never-seize should be used sparingly.If torque was 20ftlbs for a section of bolts I start at 15 then 18 then 20 using the criss cross pattern that should be in the manual.I would think most of the bolts would be hard to access after the engine was put back together,so no you do not have to go back and check.

 

[MercMan82]

Re: Reassembleing engine

According to the mercury factory manual, loctite is to be used on specific applications such as rod bolts and fly wheel. I just completed rebuilding my '71 115 today and I used gasket sealer on the water jacket, baffle plate and cylinder block cover. Not on transfer ports or crankcase cover. I would recommend buying a factory manual if you are going to attempt a rebuild. It will cover all these questions and more.

 

[Texasmark]

Re: Reassembleing engine

Blue Locktite is made for removal. Red is for a one time insertion with no hope for removal.

Considering the problems SS bolts have in alum blocks, especially in marine applications, I certainly would use anti-sieze (like you get at the auto parts store for coating spark plug threads) or blue locktite on the threads. I have used the blue in industry for many 10's of years and never had a problem removing a threaded fastener I used it on.

Additionally, I never install a dry gasket (carburetors excepted) including head gaskets regardless of what the instructions say....unless it is of the newer flexible silicon insert type, and have NEVER had to go back and fix a leaking gasket......I use Kopper Koat on head gaskets and blue silicon on all the water passage gaskets. On my thermostat housing, I don't even have to change the gasket (usually don't have one handy). I just put it back together (usually tear while removing...new or used) with blue and while still fresh, install it.

So to each his own. Everyone has a maintenance pattern with which they feel comfortable. I just gave you mine and I am not a tinkerer. I don't like to do mech work any more and if I have to fix something I don't want to have to address it again so for me, it's "do it right the first time".

Mark

 

[Sprky]

Re: Reassembleing engine

Use loctite on everything but head bolts and carb nuts, otherwise you will have issues.

Red or blue, both are removable with minimal effort.

The wire brush bit is good, chasing threads not so much. Use compressed air to remove debris. The aluminum in these blocks is junk and you need as much of that junk as possible to hold bolt torque.

The anti sieze on head bolts is a good idea.

 

[Texasmark]

Re: Reassembleing engine

Use loctite on everything but head bolts and carb nuts, otherwise you will have issues.

Red or blue, both are removable with minimal effort.

The wire brush bit is good, chasing threads not so much. Use compressed air to remove debris. The aluminum in these blocks is junk and you need as much of that junk as possible to hold bolt torque.

The anti sieze on head bolts is a good idea.

From the Locktite www: "Loctite? Threadlocker Red 271? is designed for the permanent locking and sealing of threaded fasteners. The product cures when confined in the absence of air between close fitting metal surfaces. It protects threads from rust and corrosion and prevents loosening from shock and vibration. It is only removable once cured by heating up parts to 500?F (260?C)."

On Head Bolts, if I recollect, the 4 cyl mid hp Merc is a newer version of their original 4 cyl cross flow engine and the head was cast as an integral part of the block. It did however have a water jacket cover plate where one certainly wants to use a thread release mechanism.

Mark

 

[Sprky]

Re: Reassembleing engine

It is only removable once cured by heating up parts to 500?F (260?C)."Mark

Inacurate info.

We use 271 on everything we assemble...............

No more difficult to remove than loctite blue.

 

[sschefer]

Re: Reassembleing engine

Sorry guy's there's only one correct answer so far. Get the Merc Service Manual. It tells you exactly what to use where and when and it's the definitive guide. The numbers referenced are to LocTite products unless otherwise noted. Use it, follow it and your reassembly will go exactly like it's supposed to. I've done them with and without following the specs and trust me, following the specs is definitely gonna produce the results you want.

 

[Texasmark]

Re: Reassembleing engine

Inacurate info.

We use 271 on everything we assemble...............

No more difficult to remove than loctite blue.

Well, I guess Locktite Corp. doesn't know what they are making, nor how to use it/what to expect from it......Hmmmmm.

Having used both (and the green) for some 36 years, I'd have to agree with the mfgr......course I used/specified the primer that goes with it also which goes a long way in having it meet it's specifications and the scrutinization of US Govt. Inspectors....Oh and it had to be within a prescribed date code to ensure it's freshness and ability to meet the spec.

Mark

 

[sschefer]

Re: Reassembleing engine

@Texasmark - right on the money!

 

[Texasmark]

Re: Reassembleing engine

@Texasmark - right on the money!

Thanks S.

 

[Sprky]

Re: Reassembleing engine

Don't ya just love "sexualintelectuals".... Steve, your the best!

TxMark.............Bla bla bla... Break away torque for a 3/8 by 16 bolt is 150 to 300 inch/lbs 12 to 25 foot/lbs .....not real permanent
The deal with heat.........that is for 0 break away torque. Also the heat value stated is 250* not 500*, not that it makes any diff.

https://tds.us.henkel.com//NA/UT/HNAUTTDS.nsf/web/B25C9259A14B047E882571870000D61E/$File/271-EN.pdf

I get a kick out of people that cannot think for themselves.

I bet both you guys have "Smart Tabs" on your boats!

View attachment locktite pg2.pdf

 

[Texasmark]

Re: Reassembleing engine

Don't ya just love "sexualintelectuals".... Steve, your the best!

TxMark.............Bla bla bla... Break away torque for a 3/8 by 16 bolt is 150 to 300 inch/lbs 12 to 25 foot/lbs .....not real permanent
The deal with heat.........that is for 0 break away torque. Also the heat value stated is 250* not 500*, not that it makes any diff.
https://tds.us.henkel.com//NA/UT/HNAUTTDS.nsf/web/B25C9259A14B047E882571870000D61E/$File/271-EN.pdf

I get a kick out of people that cannot think for themselves.

I bet both you guys have "Smart Tabs" on your boats!

View attachment 117429

Maybe you need to find something else to do with your spare time! You did a lot of blabbing but nothing to tie your comments to scientific analysis/data/published facts/origin of the facts. Professional people list their references and I surely did mine. Have a nice day!

 

[Sprky]

Re: Reassembleing engine

Perhaps you should copy and paste the link..........any professional can do that! lol

Those smart tabs work well?

 

[sschefer]

Re: Reassembleing engine

Don't ya just love "sexualintelectuals".... Steve, your the best!

TxMark.............Bla bla bla... Break away torque for a 3/8 by 16 bolt is 150 to 300 inch/lbs 12 to 25 foot/lbs .....not real permanent
The deal with heat.........that is for 0 break away torque. Also the heat value stated is 250* not 500*, not that it makes any diff.

https://tds.us.henkel.com//NA/UT/HNAUTTDS.nsf/web/B25C9259A14B047E882571870000D61E/$File/271-EN.pdf

I get a kick out of people that cannot think for themselves.

I bet both you guys have "Smart Tabs" on your boats!

View attachment 117429

Not sure what this means except something to try and start some sort of debate or argument. It's actually not debateable when you come down to it. Use the manual, use the recommended product and be done with it. As for smart tabs, not sure how that plays with this either. Have I used them, yes. Did they do their job? Not sure, I had too much HP on the boat to figure out if the Smart Tabs were working or not.. Why did I have too much HP on the boat? Because I wanted to and I could and I didn't give a darn about how safe it was. End of that discussion.

 

[Sprky]

Re: Reassembleing engine

Dude..........after reading all your post on S&F you should refrain from commenting.

 

[sschefer]

Re: Reassembleing engine

Dude..........after reading all your post on S&F you should refrain from commenting.

O.K. Did you read all the post I made about problems I have with my boats... It's a short read, shouldn't take more than about two seconds.