K301 bearing plate bolts

[JimSraj 430]

Is there any reason that SEMS bolts must be used to attach the bearing plate to the block?  I want to replace the ones that were in it with new bolts and new 3/8”x1”-16 hex head SEMS are proving hard to find. I can’t see any reason why the same size and grade bolt with a lock washer wouldn’t be ok. 

[Searcher60 209]

I replace those bolts with grade 8. On 2 Kohlers I have done, I felt that the original bolts were going to break while I was torquing them to spec. They just kept on stretching and I knew if I went any further at least one or two would break. Of the four bolts,  2-3 mite torque, and the fourth would just keep on stretching. I’d have to look it up to be sure, but I think torque was only 35 ft. lbs. No problem with Grade 8 bolts. Just my opinion. I’d look up that torque to be sure. My memory ain’t what it was. 

[squonk 41,150]

You are trying to seat the bearing while you torque those bolts. Go criss cross a.little at a time. New bolts are always a good idea.

[Gregor 4,846]

Whenever I rebuild anything, it gets ALL new hardware, wherever possible. Replacing the original sems bolts I think is fine.  I am also a big believer in locktite on bolts and nuts. Always make certain the bearings are FULLY seated into their respective bosses BEFORE installing the bearing plate. You have to have end play in your crank, after everything is tight.

 

While on the subject, can anyone explain the reasoning of a sems bolt, over a regular bolt and lock washer?

Edited October 28, 2021 by Gregor

[Achto 27,601]

57 minutes ago, Gregor said:

can anyone explain the reasoning of a sems bolt,

 

Ease of manufacturing. Person on the assembly line does not have to put the washer on the screw before installing it. Also quality, the assembler does not forget to put the washer on the screw.

Edited October 28, 2021 by Achto

[Gregor 4,846]

12 minutes ago, Achto said:

Ease of manufacturing.

Yeah, I read that in an article. I have to wonder though, if that's their only reasoning, why weren't they used on everything, wherever possible? $$$$$

I guess you have to be educated to figure that out.

[Achto 27,601]

21 minutes ago, Gregor said:

I have to wonder though, if that's their only reasoning, why weren't they used on everything, wherever possible? $$

 

Working in the manufacturing world, I wonder "WHY ?" quite often. Heck I've even asked our engineers. Never do get a strait answer.

[gwest_ca-(File Mod) 11,046]

Is the bearing retainer aluminum?

An SAE flat washer and Loctite may be a better choice.

I believe all socket head cap screws that use an Allen wrench are grade 8

[pacer 3,173]

OK, while we're 'wondering' - what does "SEMS" stand for?  I got curious and did a quick 'google' - heres one quote:

 

"machine screws with lock washers pre-attached to save users assembly time". 

 

Didnt really say what exactly each letter was, but generally means "machine screw thread"

 

After owning a Massey GT and finding they use 'flanged' screws almost exclusively, I have really took a liking for them and as I replace hardware on the horses, I go back with flanged.....

[Gregor 4,846]

SEMS screws (or SEM screws) are machine screws with lock washers pre-attached to save users assembly time. They combine two separate parts into one pre-asSEMbled, low cost fastener. With washers under the head, SEM fasteners allow for fast installation, permanence, and easy adaptability to many applications.

[Achto 27,601]

As long as we are on the subject of hardware, I'd like to bring up the subject of split lock washers. The useless fantasy used by many manufacturers and mechanics for years.  They are generally more harm than good.

 

 

https://engineerdog.com/2015/01/11/10-tricks-engineers-need-to-know-about-fasteners/

Edited October 28, 2021 by Achto

[squonk 41,150]

The 2 K181's i just did had copper sealing washers under the bolts. The big blocks I just scrapped has lock washers.

[Gregor 4,846]

I read the entire article referred to by the link posted by @Achto. Do I believe everything that is said?   ????  It's hard to give up on an idea, when it's been taught to you your entire life, but then again, science is science, and science is EXACT. There is no "close enough", or "just about right". Per the article, (and many other articles and videos available) split lock washers are useless, as far as doing the job they are intended to do. That also goes for internal, and external tooth lock washer. That being said, I will probably continue to use them anyway.

 

In the article there is a product called "Saper Lock". I watched a video on that product, and it does seem do do the job that a "lock washer/nut" is suppose to do. So far, I have not found them for sale in the US.

 

There is another product mentioned called, "Nord-Lock". The theory behind them seems good, and they are readily available through McMaster Carr, so I added some to my next order. They are NOT cheap. $0.60 ea. is a lot for a lock washer, when you are use to buying them by the pound. Then I watched This Video.  The Nord-Lock lock washer does not seem to be as effective when used with grade 8 bolts. I believe head bolts, and rod bolts/nuts are grade 8, or at least extremely hard. If you are familiar with my MV16 tear down, you may remember that the rod cap had let go. The threads on the studs and the flange nuts were fine. I could screw them back together, no problem. Leading me to believe they simply unscrewed. This is why I will continue to use red thread locker on my rod caps and nuts, especially when there is no locking device on the bolts. No tabs to bend up in order to hold the bolt in place.

I know the idea of using thread locker is frowned upon, but it makes me feel better.

 

In the video, I was surprised to see the amount of torque required to loosen a bolt that has been torqued to 100 ft. lb. IF (and that's a big IF) I am interpreting the video correctly, it takes considerably less than 100 ft lb to loosen a bolt that has been tightened to 100 ft lb. The idea of this intrigued me. When disassembling an engine, I never take notice of the torque required to tear it down. I simply get my wrenches and rattle gun out, and start tearing it down. My completed MV16 is sitting here so I did a little experiment. The 5/16" intake manifold bolts are torqued to 150 in lb as per manual. It takes a torque wrench setting of less than 20 in lb to remove the bolt. Then I thought, maybe these new fangled ratcheting type torque wrenches don't really work in reverse. I have never tried to torque a left hand bolt or nut. Luckily, I am old, so I have an old needle pointer type torque wrench. Using it, I torqued the bolts to 15 ft lb. (about 180 in lb.) According to my needle torque wrench, it took the same torque value to loosen the bolt, as it did to tighten it. As far as I could tell with this old torque wrench any way.

 

Maybe this was all a waste of time, and actually determines nothing. I don't know. My MV16 is all back together, running fine (mostly), and my other parts are still at the media blaster, so I really don't have anything to do. At least this gave me something to do for a few hours.

 

EDIT   I have 3 clicking type torque wrenches. The paper work with each of them states, "Torque can only be measured in 1 (CW) direction". Also, "DO NOT USE TORQUE WRENCH TO LOOSEN FASTENERS" So why do they make them reversible?

Edited October 29, 2021 by Gregor

[Gregor 4,846]

4 hours ago, squonk said:

The big blocks I just scrapped has lock washers

You scrapped?    

[squonk 41,150]

2 minutes ago, Gregor said:

You scrapped?    

Multiple cracks, parts of cylinders gone, torn up cranks ect.

[JimSraj 430]

The used SEMS bolts(2 of the 4) I had put back through the bearing plate seemed to be stretching as I brought them to 30# after starting hand tight, then 3/8” drive ratchet until the split lock washer was flat, then torque to 25#, on the way to full torque. Chris crossing at each step. The split lock washers also began to cut into the bearing plate more than I was comfortable with. I put very thin steel washers between the split lock and the aluminum bearing plate and repeated the tightening sequence. Snapped a bolt at 25#. Think I like the copper washer idea and new grade 8 bolts. 

Im looking for a new or at least new to me (and in very good usable condition) 235815 bearing plate for this k301. The bearing went into the plate too easily and I think the seal journal is egg shaped bc I had a really hard time getting the seal in from the outside so I removed it and was going to install from the inside when I noticed it was no longer round. Anyone have a good 235815 plate for sale?  It’s my first rebuild and it’s a real learning experience. More lessons to come I’m sure. 

[Howie 886]

Making fasteners is what i di with over 45 years of my life. Like was mentioned the washer being

added before rolling the threads was for the assembly process. 

I do think your bolts had been overtightened somewhere in their lifetime. Hearing what your bearing

plate looks like kind of confirms that for me. Replace and use the lock and a flat washer if you like

and add a drop of blue loctite to the threads. Briggs started putting a patch of locking compound

on their sump bolts to help prevent them from coming loose. Before they did that always put a drop

of blue loctite on the bolts.

[JimSraj 430]

The blue Loctite will be used along with new grade 8 bolts and probably copper washers once I find a good 235815 bearing plate. Thanks for the advice. 

[squonk 41,150]

8 hours ago, JimSraj said:

The blue Loctite will be used along with new grade 8 bolts and probably copper washers once I find a good 235815 bearing plate. Thanks for the advice. 

Pretty sure I have a plate I'll dig it out of the shed today.

[JimSraj 430]

Squonk,

That would be great if you have a 235815 bearing plate. 

Thanks,

Jim