any reason not to use stainless head bolts in outboards?

[derekfl]

they are plain jane steel. i think a little better than home depot quality, but still just steel bolts. i know a busted stainless bolt is way harder to get out, but odds of one snapping i think would be a lot lower. i posted in the for sale section by accident. so deleted and moved it here.

[H2OPERF]

Not really except in places like head bolts/main case bolts where torque/bolt strenth matters... if you want stainless there you need to go with ARP. Brush the theads on all bolts with gasket sealing compound and they will usuall come right out even on the gearcase/water pump.

[Capt j]

Stainless will weld itself into an aluminum block. 2 dissimilar metals.

[rgsauger]

Stainless will weld itself into an aluminum block. 2 dissimilar metals.

even with antiseize?

[H2OPERF]

Salt is the issue we have not galvanic corrosion, you cant get the bolt out if the heads rusted off either. The sealnt on threads cures both of those problems anyway...

[Revenge22]

in my view stainless is they way to go for head screws and powerhead / adapter mounting screws. obviously with sealant. its the shoulder that gets crusty and seizes anyway, not the threads in 90% of cases. i wonder if fully threaded screws would actually be better, or would that compromise stability somehow?

[fatlenny]

Other than the obvious issues that will occur with SS in aluminum, you may have to retorque a few times. I dont believe SS bolts will stretch when torqued. This stretch that head bolts do is to compensate for the heating and cooling and casket compression. This is just my opinion, coming from small engine repair education from 30 years ago.

[derekfl]

so the consensus is stay with grade 5 steel?

[LakeFever]

Critical fasteners all need to be carbon steel and they need to be torqued properly for the right amount of stretch. Stainless is gummy and doesnt have much carbon so this is why stainless is not used for critical fasteners. Stock bolts are best. Search out jsre member on here who offers the best advice on bolts and torque specs what lube to use etc

[H2OPERF]

Yea go with steel... factory steel fasteners are best especially around salt water and make sure you get that torque wrench calibrated for the proper bolt stretch.

[cali kid]

[QUOTE=H2OPERF;3387328]Yea go with steel... factory steel fasteners are best especially around salt water and make sure you get that torque wrench calibrated for the proper bolt stretch.[/QUOTE Half the outboards in production use stainless for headbolts as well as for most of the fasteners on the motor. Put steel bolts in a lower unit, or water pump housing and see how that goes.

[Aaronhl]

Steel head bolts non merc do they stretch? What about titanium bolts?

[derekfl]

i don't think any steel bolt stretches when it is 5/16 or 3/8 and bolted into aluminum. i think you will stretch the threads outta the aluminum first...

[Aaronhl]

i don't think any steel bolt stretches when it is 5/16 or 3/8 and bolted into aluminum. i think you will stretch the threads outta the aluminum first...

OK but do the steel bolts need to stretch because the aluminum heads heats up or is the stretch only for the initial torque, and since the steel doesnt stretch is that ok?, I might try steel or titanium bolts in some longer thermostat bolts...

And merc 3.0 liter head bolts arnt stainless ???

[BarryStrawn]

i don't think any steel bolt stretches when it is 5/16 or 3/8 and bolted into aluminum. i think you will stretch the threads outta the aluminum first...

That isn't correct. If any metal bolt is torqued or loaded at all, it is stretching. How much torque or load will determine how much elastic stretch, if it yields, breaks, or fails the threads in the block.

[derekfl]

I believe the torque required to do any significant stretching of the bolt would damage the aluminum thread. You generally need fine threads to apply enough clamping force to get appreciable stretch. Aluminum just isn’t strong enough to hold fine thread bolts, at least at these sizes. Subaru uses fine thread head bolts, but they are 12 mm. And very long threads and bolts. And they require 90 or 180 degrees of turn once a certain torque is reached for bolt stretch. And it scares me to pull that hard on any bolts in aluminum.

[patchesII]

I’d use factory head bolts or a proper set of head studs from somebody reputable
like Brendan Powers

[pcrussell50]

Nobody has said:
1) which specific sealer they use for head bolts
or
2) the fact that anything that lubricates the threads will invalidate the torque specified by the manual, unless it gives a torque for the case where you use that particular lubricant/thread sealer.

I have some ARP head bolts on one of my v4 crossflows and I used the ARP torque spec to achieve the preload that they specified for that bolt. The ARP bolts were cheaper than the Evinrude ones.

-Peter

[LakeFever]

Cant go wrong with ARP, they are the best fastener source available imo. Titanium is also not great for fasteners. Titanium tends to sheer off. Do a search for titanium bolt failure and theres a lot of material to read from the airline industry about this.

[tlwjkw]

Nobody has said:
1) which specific sealer they use for head bolts
or
2) the fact that anything that lubricates the threads will invalidate the torque specified by the manual, unless it gives a torque for the case where you use that particular lubricant/thread sealer.

I have some ARP head bolts on one of my v4 crossflows and I used the ARP torque spec to achieve the preload that they specified for that bolt. The ARP bolts were cheaper than the Evinrude ones.

-Peter

a light oil only ta head bolts.. NO type of sealer/sealant...................

[Aaronhl]

Nobody has said:
1) which specific sealer they use for head bolts
or
2) the fact that anything that lubricates the threads will invalidate the torque specified by the manual, unless it gives a torque for the case where you use that particular lubricant/thread sealer.

I have some ARP head bolts on one of my v4 crossflows and I used the ARP torque spec to achieve the preload that they specified for that bolt. The ARP bolts were cheaper than the Evinrude ones.

-Peter

I like what you said there because I inadvertently used anti-seize on some threads one time and was unable to torque them, the bolts started to lengthen, without much damage to the aluminum threads

[CUDA]

Galling is a common problem with stainless bolts, Vaseline/petrolem jelly will help prevent galling and promote accurate torque readings.

SS bolts comes in many grades, and not well marked, be careful with the kind you use in critical areas.

Much SS is weaker than grade 5, 316 stainless is the common marine grade.

I know some that use 2-cycle oil on their head bolts for lube.

[Aaronhl]

OK so the consensus , other than the possible rust , it is ok to use grade 8/10 steel/zinc bolts on a merc head?

[CUDA]

Yes grade 8 are alloy steel, thru -heated and thru-hardened with CR+5 zinc plating, the treatment adds superior strenth and corrosion, little 2 cycle dip and

forgetaboutit, we are only talking 20-30 ft lbs high compression, some of the drag guys are in the 300 psi compression zone, but they only run under 10 seconds in 800 ft kissing 11,000 rpm

[pcrussell50]

a light oil only ta head bolts.. NO type of sealer/sealant...................

That’s what I figured for steel. ARP sometimes gives separate torque figures for dry or 30WT. The figures are different.

The reason I asked about thread sealer on HEAD bolts was this:

Not really except in places like head bolts/main case bolts where torque/bolt strenth matters... if you want stainless there you need to go with ARP. Brush the theads on all bolts with gasket sealing compound and they will usuall come right out even on the gearcase/water pump.

In my automotive engine rebuilding experience, I have only used lubricants specified by the bolt maker or the manual, or used them dry, also as specified by the bolt maker, (usually ARP). As I side note, Santa Barbara is not far from ARP. I had often gone to them in person and picked up bolts right there at the walk-up counter.

===

Galling is a common problem with stainless bolts, Vaseline/petrolem jelly will help prevent galling and promote accurate torque readings.
…snip…
I know some that use 2-cycle oil on their head bolts for lube.

The trouble here, would arise if the bolt manufacturer does not give you a torque specification for the use of a specified lubricant, say, 30WT. If you use a lubricant not specified, or use any lubricant when only a dry torque is given, you’re basically guessing in the way of getting the right preload on the bolt.

-Peter

[CUDA]

Not talking about motor applications per se, a general issue with SS is the need of lubrication to prevent galling, I would not use a SS head bolt unless it was a factory part, much

SS is weak, Back in 1978 I was installing solid motor mounts in my 200hp Merc Hydrostream Viking, I over tighten the SS bolt and it snapped it off in the adapter plate, I took it
to the local

machine shop that had a EDM machine to burn that SS out of the aluminum, Technology at work.

I remember learning about helicoils at 15, I stripped the spark plug threads in a aluminum head in my snowmobile, always tend to over tighten.

[Chaz]

A plethora of useless , misinformation in this thread. :eek:

For a moment I thought , i was on fakebook. ;)

A drop of oil under the bolts head and another drop on the threads ... done. :thumbsup:
The exception being, if the fastener is going into an open ended hole, then a smear of Teflon paste on the threads is better than oil. Still use a drop on the underside of the head .. for obvious reasons .. :smiletest:

All mfg. and retailers (worth buying) have a printout of the system they use for identification, torque specs and yield strength for both metric and NC as well as NF American sizes in all available materials.

Plating's and coatings have nothing to do with a fasteners strength. But do give the uninformed a way to identify a fastener without having to learn what the identification
markings actually mean.

Nor is there any place for steel fasteners in a marine environment.

Galling issues with stainless fasteners .. LMAO .. I'll just say, read the directions. :rolleyes:

[CUDA]

https://chriscarsonmarine.com/product/racing-outboard-v6-2-5-liter-head-stud-kit/

You better tell Chris to change to aluminum

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[H2OPERF]

We are not taking about rod bolts... probably the only bolts on the engine that will fall in any class or category of a high strength fastener... around 180-200+Ksi . As a ball park value you can determine the the bolt strength and part clamp up by the torque listed in the engines manual, if i remember right they call for 30ftlb on the 3/8 not much... sooo they are regular ass bolts maybe gr8 120-140ksi max strength, they are steel and if used in salt water they rust like hell and get frozen just like in the recent post about broken bolt removal, pretty common to have a hand full of bolts break on an older salt motor even with an oxy /acetylene torch, those who have been there know... and there is no penetrant in the world that will touch it. If you live up north or have a garage queen covered in wd40 every trip none applys use the factory stuff and be happy. If you live on a coast it doesnt take you long to figure it out... you end up replacing most of your hardware with some sort of stainless and as i said in my first post the head and center main case bolts are probably gr8 ish so you should use arp 300 stainless i think they are about 180Ksi... not your junk china stainless hex bolts that you can use on waterjacket covers and water pumps or what ever else is rusting away. Sealer/ neverseeze/oil choose your own, but the sealant that comes in the can with the brush that they call out for in most places on the motor works best for me... it never hardens solid, it seals out the salt /moisture so years later when you have to remove a bolt it usually will come right out. All my opinions only... do as you wish.. MY post on use original steel and the torque wrench was a rant if you didnt notice.... funny how post sit for days un-answered then once one person posts the everyone has an opinion.. just like the burnt piston with the long reach plug kinda sat for days I call it out then 5 post later someone else is the expert Kinda Done with this site. Have fun All

[pcrussell50]

We are not taking about rod bolts... probably the only bolts on the engine that will fall in any class or category of a high strength fastener... around 180-200+Ksi . As a ball park value you can determine the the bolt strength and part clamp up by the torque listed in the engines manual, if i remember right they call for 30ftlb on the 3/8 not much... sooo they are regular ass bolts maybe gr8 120-140ksi max strength,

Ok now we're getting somewhere. Compared with head bolts on say, a head gasket-era USA-domestic automotive V8, I was shocked at how low the torques were when I first got into boating in summer 2008. It made me guess that low strength bolts were actually the better choice here, (again, only for heads not rods), because I was suspicious that you might not be able to even achieve proper preload with low torque on a high strength bolt. So I have always suspected that you could probably use SS for heads on a stock outboard fishmotor, (which are the only kinds of motors I use).

The issue I had with your first post was... If you use quality SS bolts for the heads (which by purely guessing I suspect is fine), in conjunction with a lubricant/sealer, how do you know which torque to use? Unless you use the same lubricant that say ARP tells you to use? OR... will it be "good enough" just to use ARP's torque with any old lubricant? With my mechanical engineering degree*, all I have is "book" knowledge. I don't have enough experience to know what to do if I go "off-book". You guys do. Which is why I'm here. :)

Say, could you be more specific about the sealer you use? Is it that aviation Permatex #3? Comes in a bottle with a brush, is dark brown, and doesn't harden?

*I also never worked in the field. I became a pilot straight after graduation.

-Peter

[CUDA]

https://www.zoro.com/loctite-anti-seize-marine-8-oz-brush-top-can-lb-8023tm-299175/i/G2990933/?utm_source=google&utm_medium=surfaces&utm_campaign=shopping%20feed&utm_content=free%20google%20shopping%20clicks&gclid=CjwKCAjw67ajBhAVEiwA2g_jEEUODcnZ5Ncczh4jCd0BHplw45FKxuM8ZkPQpxPAL6Y3JlQEDl-KBBoC5NgQAvD_BwE

[H2OPERF]

Ok now we're getting somewhere. Compared with head bolts on say, a head gasket-era USA-domestic automotive V8, I was shocked at how low the torques were when I first got into boating in summer 2008. It made me guess that low strength bolts were actually the better choice here, (again, only for heads not rods), because I was suspicious that you might not be able to even achieve proper preload with low torque on a high strength bolt. So I have always suspected that you could probably use SS for heads on a stock outboard fishmotor, (which are the only kinds of motors I use).

The issue I had with your first post was... If you use quality SS bolts for the heads (which by purely guessing I suspect is fine), in conjunction with a lubricant/sealer, how do you know which torque to use? Unless you use the same lubricant that say ARP tells you to use? OR... will it be "good enough" just to use ARP's torque with any old lubricant? With my mechanical engineering degree*, all I have is "book" knowledge. I don't have enough experience to know what to do if I go "off-book". You guys do. Which is why I'm here. :)

Say, could you be more specific about the sealer you use? Is it that aviation Permatex #3? Comes in a bottle with a brush, is dark brown, and doesn't harden?

*I also never worked in the field. I became a pilot straight after graduation.

-Peter Hey cool,what do you fly, I did the opposite worked in maint engineering 15yrs then i finally built up enough enough time to sit up front in an AW139 SAR.. I use the evinrude stuff merc makes one too looks the same, goop the crap out of powerhead studs lowerunit bolts ect... steel bolts n studs too, the head bolts i usually put on sparingly you dont want it on the gasket in that location just light coat on the threads and under the head to seal out the moisture, torque to factory numbers...your going for original clamp# up not a % of yeild unless your running studs and 200+psi. If you really want to go by the book just lube threads and put sealant on the washer/heads of the bolts. I dont like the permatex so much. Just the way i do it.

[H2OPERF]

Allens fasteners has good prices on arp stuff if you decide go that way...

[cali kid]

OK but do the steel bolts need to stretch because the aluminum heads heats up or is the stretch only for the initial torque, and since the steel doesnt stretch is that ok?, I might try steel or titanium bolts in some longer thermostat bolts...

And merc 3.0 liter head bolts arnt stainless ??? 3 liter Merc bolts are stainless.

[cali kid]

3 liter Merc bolts are stainless.Every bolt on a 3 liter is stainless

[pcrussell50]

Allens fasteners has good prices on arp stuff if you decide go that way...

I’ve used them before when I don’t go to ARP headquarters in person.

-Peter

[Chaz]

https://chriscarsonmarine.com/product/racing-outboard-v6-2-5-liter-head-stud-kit/

You better tell Chris to change to aluminum



I call Chris .. the professor.

I call you the village idiot.

Thanks for opening your mouth and proving , I have had it right all along ... :thumbsup:

[Aaronhl]

3 liter Merc bolts are stainless.

And they stretch and snap at least on the two 3 liters I have worked on
So maybe the nonstainless option would corrode but probably wouldnt twist and snap taking them out !??

[CUDA]

[QUOTE=Chaz;3389542]

"Plating's and coatings have nothing to do with a fasteners strength. But do give the uninformed a way to identify a fastener without having to learn what the identification
markings actually mean.

Nor is there any place for steel fasteners in a marine environment."



You have a serious problem with reading comprehension, this is what I said

"grade 8 are alloy steel, thru -heated and thru-hardened with CR+5 zinc plating, the treatment adds superior strenth and corrosion protection,

Do you want me to explain to you the difference in case harden and through hardened?

The CR+5 zinc plating is strictly corrosion, I'm sure everyone but you understands, but you always twist others words

I guess Mercury is full of idiots because they have been using Steel head bolts forever, in 2.0 2.4 and 2.5s

Your childish name calling is just that

Childish, your early Substance abuse has stunted your maturity

[Chaz]

CRUD cake, go leave a grade 5 or 8 bolt out in the rain .. let alone take it out in salt water .. see what happens to all the corrosion protection you thought you had .. :rolleyes:

It's not 1995 anymore. Mercury has used stainless steel head bolts since at least then. :smiletest:

Aluminum head stud kits .. LMAO .. Stu'nod :confused:

You already know your place .. no need in me pouring more salt water on that wound for at least another day or two. :p

I bought stock in heli-coil's. It's people like you that have made it's value go, up, up, up.. :thumbsup:

As stated ... read the directions .. ;)

[CUDA]

My 98 300 drag is steel.

[Chaz]

My 98 300 drag is steel.

The ones that get raced, come apart for serviced .. sometimes after every race.

Yours is like you .. old crusty, rusty, and hides in the shadows.

They are talking about a 27 year old saltwater 3.0L motor above .. try to keep up .. :rolleyes:

[FUJIMO]

...you guys remind me of the smothers brothers...only meaner...;)...

[CUDA]

The OP said his motor came with steel head bolts and was just asking If he could use SS bolts...

NOT what you just stated, , "They are talking about a 27 year old saltwater 3.0L motor above .. try to keep up"

You have NO reading comprehension.. at all.

later is was stated that the 3.0 came with SS bolts, I have 2 250hp and one 300hp Optipops and I said I would only use factory bolts,

You just make chit up every day FAKE NEWS

[Glastron1987]

Wow, this thread has a lot to follow. My guess is a little anti-seize would work good in getting the bolts out whenever you want to with any type of metal, but you just have to know how tight to put them in.

[rudderless]

well...I still have popcorn left...

[Chaz]

Poor CRAP cake, he has to make stuff up as he goes.

You have to live two life's. Your pathetic one, and your illusion of mine .. :D

-------------------------------------------------------------------------------------------------

Yes , stainless fasteners are fine. Matter of fact all new marine engines come with them. :thumbsup:

[pcrussell50]

well...I still have popcorn left...

I don’t need any, anymore.

My take on the situation as of now is:
-for rod bolts? Proper high strength bolts. No homebrew hacks, not negotiable.
-for outboard heads? High strength bolts not called for. In fact, the kind of torques required to achieve preload on a high strength bolts might be very hard on aluminium threads. There is room here for homebrew hacks… As long as you have valid data as to what torque to use to achieve proper preload… Or else are an experienced marine mechanic and you know what works from, well, experience. I have book smarts, (engineering degree), but I am not an experienced marine mechanic, which is why I’m here to sponge information off of you lot. :)

That about sum it up?

-Peter

[Chaz]

Yes Peter, that about sums it up. You school boy's design and make it.

Us ole country bumpkins, show ya how ta use it, fix it, make it better ... :D

[LakeFever]

Just use good clean oem bolts and make sure all the threads are clean. Refer to merc manual for lube and torque spec guidance. Done

I read it as wanting to swap from stock to aftermarket stainless which i would never do, ever. As for steel bolts not stretching in aluminum blocks? Better not run and LS/LT motors. Those head bolts are torque to yield and stretch right out.