Trojan Boat Forum

larryeddington wrote:After doing a little research:

This problem is called "thread galling." According to the Industrial Fastener Institute's 6th Edition Standards Book (page B-28),

Thread galling seems to be the most prevalent with fasteners made of stainless steel, aluminum, titanium, and other alloys which self-generate an oxide surface film for corrosion protection. During fastener tightening, as pressure builds between the contacting and sliding thread surfaces, protective oxides are broken, possibly wiped off, and interface metal high points shear or lock together. This cumulative clogging-shearing-locking action causes increasing adhesion. In the extreme, galling leads to seizing - the actual freezing together of the threads. If tightening is continued, the fastener can be twisted off or its threads ripped out.


I am going to switch to Grade 8 and use antiseize compound to avoid potential problems.

thanks for the added info Larry...and the galling is also why they break off when removing them.....

The risers and manifolds came with SS bolts. I use anti-seize on everything, as I cannot always reach part X with a cut off tool, and I hate having to pull out the extractor to get that sumgun out.

I am not a torque monster. I tighten till tight, then leave it be, and adjust/re-tighten after a run. The bolts with specs (head, intake, manifolds) all get torqued properly.

The anti-seize goes a long way towards keeping me happy come dis assembly time.

Heefus, mine has SS in it now but have not run the engines as yet, I am contemplating putting in Grade 8 and antiseize to be sure. Diggin out them twisted off bolts sucks, but there is worse digging out a twisted off SS bolt, stainless does not like to be drilled.

larryeddington wrote:Heefus, mine has SS in it now but have not run the engines as yet, I am contemplating putting in Grade 8 and antiseize to be sure. Diggin out them twisted off bolts sucks, but there is worse digging out a twisted off SS bolt, stainless does not like to be drilled.

Larry, do yourself a huge favor and put those grade 8 bolts in! I had a 3406 caterpiller that decided to snap 4 of the 12 stainless steel studs that cat had put in for the mounting of the exhaust manifold. Two came out fairly easy, the third was about 4 1/2hrs work, the last bugger I had 24hrs drilling to get it out but I did save the head! You are correct, Stainless hates drill bits!!

We produce all of our products in stainless, and yes, it is hard to drill (high chromium).

Galling must be considered. It is most prevalent when equal grades of stainless are torqued together (304 bolt into 304 nut). It also happens with dissimilar stainless or stainless in alloy steel.

In all cases, (even when you're assembling non-stainless parts), clean you threads with a tap or die and use anti seize - you'll thank yourself later (and MUST for stainless).

If you do use stainless, torque the bolts slowly - letting them cool between torque rounds (the galling occurs when the bolt is tightened quickly and heats up). If you feel binding, STOP and remove the bold/stud, check it and clean it with die and the hole with a tap. If it binds again on assembly it is ruined - so throw it away.

I used stainless bolts for low torque bolt-ons on the 454 in my 26, but would not do it again. I have had no problems, but don't think its a good long-term solution. Grade 8 with plenty of assembly lube is the way to go. They'll last for years.

You may be able to get Grade 8 bolts with chrome heads from Summit racing if looks are important.

I agree about the Grade 8 versus stainless steel. Just last week I tried to explain it (unsuccessfully) to a surveyor checking out a diesel engine. He just could not understand the difference. LOL

Fireranger - 71 F-36 with 6V53 Diesels (250hp/each?), 2-1 ratio borg warners & 20X23 props is sweet. Do you run it to the stream or up and down the ditch?

This baby never goes offshore. It was restored as a party boat. Lol complete with dancing area and party lights. We just run up and down the St. Johns River.

alexander38 wrote:Don't use SS any grade....it will loosen they can't be torqued right...and later when you have to remove them they'll snap off. I just went through this with riser's PO used 1 SS bolt and made the whole job a nightmare ...use a grade 8 or 5 . You'll be happier later...

one bolt and I all most had to replace a manifold.... I'll never use SS on my engine....and are these parts the are coming with SS bolts OEM replacements or aftermarket stuff ? The Merc. set I bought had a warning against using SS

ARP makes some serious claims about their header studs:
"ARP has the answer, in the form of their stainless steel header studs. They're made from premium 300 stainless steel, which is rated at 170,000 psi tensile strength. That's much stronger than Grade 8 steel. These studs are also highly corrosion and heat-resistant, for long service under the toughest conditions, and they're polished to a mirror-like shine."

But I don't think I'd use them.

http://www.summitracing.com/parts/ARP-434-1301/

fireranger33 wrote:This baby never goes offshore. It was restored as a party boat. Lol complete with dancing area and party lights. We just run up and down the St. Johns River.

Ditto here - but my "dance floor" only has room for 2

Top speed on that baby?

I have never pushed her to top speed Capt. Ross. I do know she will get up on plane at 2100rpms and run 15mph. After that? it seems I gain about 1-2mph every 100rpms. They are rated to 2800rpms I believe. I went with conservative props (20X23) for better fuel savings and quicker get up and go with 10-12 people onboard.

She came with 19"X 25' props. I'm sure she was a bit faster then.

I have taken heed and I now have 48 grade 8 bolts that will go in with anti seize in place of the SS bolts. Fortunately engines are on pallats and have not been run yet.

There comes a point as one becomes old enough you do not need everything to last forever, time is finite. But for now SS out Grade 8 in.

Well crap...

Got everything back together, fired her, and had a total repeat of what made me shut her down in the first place. Less than 1 minute and she was spewing milkshake all over, running like crap, then not re-starting at all.

Any recommendations on a good engine re-manufacturer? This is a Jasper reman, installed in 2002. I don't consider 9 years to be a good run for an engine. Any other guys out there? I might just call the season over, pull it out of the water, and install a new block.

Do you happen to have a engine oil cooler ?