blew an engine

mr elevman · Post by **mr elevman** » Thu Sep 15, 2011 7:50 pm

i fell the pain after the storm my port moter (witch was rebuilt last year)hydro locked it started to crank then BANG shered 4 or 5 teath off the fly wheel i pulled the plugs turned moter by hand (ratchet) water in 3 cyl put compreshion guage on 0 psi yes 0 on one cyl water in oil not coolent whair the water came from i dont know yet i love my boat i love my boat i love my boat

Scorpyon · Post by **Scorpyon** » Thu Sep 15, 2011 8:08 pm

are u sure u love ur boat? lmao!

larryeddington · Post by **larryeddington** » Thu Sep 15, 2011 8:10 pm

Heefus,

Give me a call I have four extra used Manifold logs with risers from my f28. I do not have the downturns though only risers and manifold FYI all tjese pieces are available new, check with Beacon.

Give me a shout if interested.

903-896-1610

Larry

Heefus · Post by **Heefus** » Sat Oct 01, 2011 8:46 pm

Ok, after a long month of travel, looking for parts, cleaning up, and general foolishness, I started reassembly today.

I got the heads back on, intake done, and the hull side exhaust manifold and riser installed. New plugs, and she should be good.

I am missing 8 bolts, for the end plates, so I stopped after 5 hours of fine weather. I am going to head back out in the a.m. to wrap up and fire her up.

larryeddington · Post by **larryeddington** » Sat Oct 01, 2011 9:02 pm

Used stainless bolts on end caps and risers. Seemed like a good idea.

prowlersfish · Post by **prowlersfish** » Sat Oct 01, 2011 9:16 pm

I would not use SS . They tend to loosen

alexander38 · Post by **alexander38** » Sun Oct 02, 2011 7:41 am

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...

davidsmith · Post by **davidsmith** » Sun Oct 02, 2011 8:59 am

We use stainless hardware all the time at work and on boat. Never had a problem as long as we use neverseize on the bolts first.

larryeddington · Post by **larryeddington** » Sun Oct 02, 2011 9:51 am

And I did use anti seize. However paul refered to them coming loose?

The originals rusted and snapped grade 8 and anti seize may be the ticket?

prowlersfish · Post by **prowlersfish** » Sun Oct 02, 2011 10:16 am

Stainless works poorly on and part that gets hot and cold , and that means the engine . Also never ever use them for your shaft flange bolts . If you do better have sea tow .

As far as reg. bolts breaking off sometimes thats what you have to deal with on a boat . Making sure you have no raw water leaks goes a long way to reduce rust as using and maintaining the engine

larryeddington · Post by **larryeddington** » Sun Oct 02, 2011 10:26 am

Strange as the exhaust manifold studs and nuts on my original 318 appear to be stainless. I will check my drive coupler bolts as the engines and trannys are out at present but as I recall they were shinny like stainless.

Gonna do some research easy to switch grade 8 and antize.

prowlersfish · Post by **prowlersfish** » Sun Oct 02, 2011 10:37 am

Your boat that way . Butter bolts have no place on a shaft flange . I have seen the SS studs used ( OEM ? ) for some reason SS seem to do better on studs then bolts but do need to be re-torqued at times

alexander38 · Post by **alexander38** » Sun Oct 02, 2011 12:52 pm

well use what you feel is best for your needs, Merc calls for grade 8 and 5 and thats' I used ....the bolts I took out, came out fine all but one ..the SS one. it snapped off.

studs may work better due to you loosen the nut that's been tighten. And not trying to take the stud out of the carbon steel it's been torqued in to...

Paul · Post by **Paul** » Sun Oct 02, 2011 1:09 pm

All of the external fasteners on my engine are Stainless Steel Socket Head Cap Screws with lock washers with the exception of the hex bolts that hold the exhaust manifolds in place which are alloy steel. The studs that hold the exhaust risers in place are stainless and are OEM. The cap screws that fasten the intake have the threads sealed with RTV silicone while the rest of the cap screws have anti-seize on the threads. I have never had one come loose nor have I ever been unable to remove one.

Although it's true that SS fasteners do not have the strength values of alloy steel, I used them in fairly low torque applications such as to fasten the water pump. valve covers, pulleys, intake manifold, thermostat housing, timing gear cover, etc. The reason that I chose SS for these fasteners is simple, I like the way they make the engine look. I put allot of effort in to keeping my engine in top running condition and keeping it clean is part of that. I'd hate to see rusty bolt heads simply because the paint got chipped off of them during general maintenance. Neurotic? Maybe, but I like it that way.

Strength requirements must however be kept in mind when choosing a fastener. As Paul (prowlersfish) mentioned, never use SS in your shaft flange. The reason is simple, alloy steel has higher shear values which is required at this connection. The following is an example from the "Unbrako"engineering guide on socket head cap screws. ASTM A574 alloy steel has a tensile rating of 190,000psi where ASTM F837 stainless steel has a tensile rating of 95,000psi. How does this apply to a prop shaft flange? A 3/8" alloy steel bolt has a single shear body value of 12,600 lbs and a 3/8" stainless steel bolt has a single shear body value of 4,470 lbs.
At a high shear connection such as the shaft flange I think the choice is clear.

Hope this helps

larryeddington · Post by **larryeddington** » Sun Oct 02, 2011 4:12 pm

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.