314-8 motor mount bolts falling out

[csvt99 173]

I discovered that the mounting bolts on my 314-8 are falling out. 1 is MIA, 1 I was able to recover on my garage floor, the other two are still in but loosened almost the whole way. I'm having a heck of a time getting them tightened, and especially rethreading the one that came the whole way out. Is there a trick to this? Thanks!

[gwest_ca-(File Mod) 10,499]

New lock washers may be the solution

https://www.partstree.com/models/73449-314-8-toro-garden-tractor-sn-200000001-200999999-2000/engine-assembly-17/

[953 nut 51,720]

12 hours ago, csvt99 said:

rethreading the one that came the whole way out. Is there a trick to this

With all four bolts loose use a couple of wooden wedges (one on each side) to slightly lift the engine and allow it to move a slight bit in all directions. Use some Blue Loctite on the threads as you insert them. Once all four are started remove the wedges and tighten them to 30 foot pounds. Use a crowsfoot mounted to the side of your torque wrench to obtain an accurate measurement.

Edited May 25, 2023 by 953 nut

[John2189 407]

1 hour ago, gwest_ca said:

New lock washers may be the solution

https://www.partstree.com/models/73449-314-8-toro-garden-tractor-sn-200000001-200999999-2000/engine-assembly-17/

Why not use nylock lock nuts?

 

[Wild Bill 633 770]

Another option to the nylock nut is the distorted thread or torque prevailing nut.

Edited May 25, 2023 by Wild Bill 633

[gwest_ca-(File Mod) 10,499]

Does not look like there is a nut used. Bolt probably threads into the aluminum oil pan.

[ranger 1,639]

For jobs like this I tend to use “Nordlock” washers. Two piece washer with serrations on one side and “Ramps” on the other once tightened the two sections can’t loosen, without a fair amount of twisting force being applied, due to serrations gripping bolt/nut face, and “Ramps” locking together!

[JoeM 7,636]

2 minutes ago, ranger said:

“Nordlock” washers

Used those on mining equipment, they are the bomb! 

[John2189 407]

5 hours ago, gwest_ca said:

Does not look like there is a nut used. Bolt probably threads into the aluminum oil pan.

There are bolts with a nylon plug in the threads too.  Don’t know the name of them 

[ri702bill 7,326]

IF the engine is indeed mounted with nuts and bolts, I can see where Nylok nuts, once removed and reinstalled WILL loose their retention ability with the added "Help" from engine heat and vibration....

How about using steel distorted body nuts - a true total PITA if you have to wind them down about 10 threads - BUT they work....

[953 nut 51,720]

4 hours ago, John2189 said:

bolts with a nylon plug in the threads too.

That sounds like it would be a very expensive dealer only item. Here is one possibility you may wish to consider.Take a look at these bolts from McMaster-Car and see if they will work for your application.

tainless Steel Thread-Locking Hex Head Screws

Fully Threaded

 

Partially Threaded

 

Made from 18-8 stainless steel, these screws have good chemical resistance and may be mildly magnetic. A nylon patch bonded to the threads adds friction to resist loosening from vibration. Length is measured from under the head.

For technical drawings and 3-D models, click on a part number.

				Head
Lg.	Threading	Min. Thread Lg.	Thread Spacing	Wd.	Ht.	Thread Locker Temperature Range, °F	Tensile Strength, psi	Pkg. Qty.		Pkg.
18-8 Stainless Steel
3/8"-16
1"	Fully Threaded	__	Coarse	9/16"	15/64"	-55° to 250°	70,000	10	91412A450	$7.68
1 1/4"	Fully Threaded	__	Coarse	9/16"	15/64"	-55° to 250°	70,000	10	91412A460	9.69
1 1/2"	Partially Threaded	1"	Coarse	9/16"	15/64"	-55° to 250°	70,000	10	91412A470	10.78

[Rick3478 374]

On 5/24/2023 at 7:28 PM, csvt99 said:

I discovered that the mounting bolts on my 314-8 are falling out. 1 is MIA, 1 I was able to recover on my garage floor, the other two are still in but loosened almost the whole way. I'm having a heck of a time getting them tightened, and especially rethreading the one that came the whole way out. Is there a trick to this? Thanks!

 

Is that how the Command engines mount?  I have not seen one close up before.  No wonder it came apart, there's no solid metal to tighten against.  I guess it would tend to prevent over-tightening and stripping threads, though.  So being aluminum, there's a non-zero chance that the bolts buggered threads on the way out, and it's in a place that's hard to see.

 

So I'd take off all the belts and anything else that pulls on the engine, get new bolts, lockwashers, and blue loktite.  Test fit everything before committing to loktite.  If you can't get any of the bolts started, or if the threads feel wonky, you may need to come apart farther, and possibly drill/tap/helicoil the oil pan.  Reassemble to factory torque spec, don't try to go tighter as you will just bend the "C" channel and make things worse.

 

[csvt99 173]

I managed to get all of the bolts out and bought 4 replacements. Unfortunately some of the threads are stripped in the block. What is the best way to deal with this?

[John2189 407]

2 hours ago, csvt99 said:

I managed to get all of the bolts out and bought 4 replacements. Unfortunately some of the threads are stripped in the block. What is the best way to deal with this?

How long is the bolt and how deep is the threaded hole? You might be able to use a little bit longer bolt to get into the good threads and use loctite, use brake cleaner to remove all the oil inside the hole.  Just be sure not to bottom out the bolt. 
 
or if too bad. A helicoil

[ranger 1,639]

Helicoil then studs with nyloc nuts. Loctite the studs and helicoils in place. Helicoil kits are fairly inexpensive, or drill and tap the holes to the next thread size up if there’s enough material around the hole? Possibly even stepped studs, (two different diameters and threads), if you don’t want to enlarge the holes in the mountings? Studs with nuts, as opposed to bolts, allow for future dismantling without the wear and risk of damage to the threads in the alloy castings, or the chance of the thread inserts, (helicoils), coming out with the bolt, especially if thread locking compound is used on the bolts!

Doug.

[csvt99 173]

Thanks for all the help.  The helicoil option will extremely difficult without removing the motor and putting it on the bench. There just isn't clearance to run the tools with the motor still sitting on the mounts. 

 

5 hours ago, ranger said:

Helicoil then studs with nyloc nuts. Loctite the studs and helicoils in place.

I can't quite picture this. The factory design just uses a bolt that threads into the block so there are no nuts. The bolt with a nut in the picture is the one that secures the c channel motor mount to the frame rails. 

 

I may just need to do my best with new bolts and loktite as long as I can get them threaded. 

 

This seems like a bizarre thing to happen at only 400 hours. Is this common with the Kohler motors?

[ranger 1,639]

8 hours ago, csvt99 said:

Thanks for all the help.  The helicoil option will extremely difficult without removing the motor and putting it on the bench. There just isn't clearance to run the tools with the motor still sitting on the mounts. 

 

I can't quite picture this. The factory design just uses a bolt that threads into the block so there are no nuts. The bolt with a nut in the picture is the one that secures the c channel motor mount to the frame rails. 

 

I may just need to do my best with new bolts and loktite as long as I can get them threaded. 

 

This seems like a bizarre thing to happen at only 400 hours. Is this common with the Kohler motors?

You would have to remove the engine to access the threaded holes in the block, for repair purposes. Where the ‘nuts’ part comes in is, the original bolts are replaced by studs after the threads are repaired. These are secured with a thread locking compound to reduce the risk of them loosening. The nuts then secure the engine to the mounting. It’s not always a good idea to use a ‘strong’ thread locker, etc, on fasteners which screw into an alloy casting if they may need to be removed with any frequency, (probably not the case here). If you decide to use bolts as per original, can you fit a nut and locking washer inside the “C” channel part, then after torquing the bolts to spec, tighten the nuts upward to the undersides of the mount to solidly secure the engine to it’s mating surface of the mount, (I’m assuming from the photos that the bolts go through the top and bottom parts of the ‘channel’)? I can’t see the head of the bolt in the photo? If this is the case then I can’t see how the bolts could stay tight, as @Rick3478 says, “there’s no solid metal to tighten to”. You have in effect a ‘spring’ between the engine and the frame! If this is actually how the photos appear to me that it is?🤔 I may be wrong, (I usually am)

[csvt99 173]

1 hour ago, ranger said:

I’m assuming from the photos that the bolts go through the top and bottom parts of the ‘channel’)

The bolt goes up into the engine block. So looking at my original picture, the bolt head is one the bottom. It threads up and the bolt head tightens against the bottom of the top level of the Channel. So when all together the top of the C channel is sandwiched right between the block and bolt head. The bottom of the C channel mounts to the frame rails.

[ranger 1,639]

4 minutes ago, csvt99 said:

The bolt goes up into the engine block. So looking at my original picture, the bolt head is one the bottom. It threads up and the bolt head tightens against the bottom of the top level of the Channel. So when all together the top of the C channel is sandwiched right between the block and bolt head. The bottom of the C channel mounts to the frame rails.

I thought that should be the case, but I couldn’t see the head of the bolt in the photo. Also the bolts didn’t really look long enough to go through both parts of the channels. Maybe they were never tight enough from new? I would also check the holes in the channels to make sure that they aren’t worn, or have raised burrs because this can prevent the lock washers/bolt head from seating properly, and make it easier for vibration to loosen them! You could perhaps also try flanged headed bolts which have radial serrations on the undersides to enhance the grip when tightened?

[peter lena 8,068]

@csvt99  might try a " bottom tap " on those threads , that would go over the original threading cut , there is no  starting taper on that tap.  so the go over of remaining threads , might  be enough .  agree wit others on helicoil , ctc . never had that happen , pete

[Wild Bill 633 770]

The Helicoil is a wire threaded insert. Another option is the E-Z Lok insert. To install, you drill and tap the hole to a bigger size and install the threaded insert. The insert comes as thin and standard wall and with Loktite red on it. I have used these and tend to prefer over a Helicoil.

Edited June 4, 2023 by Wild Bill 633

[Rick3478 374]

9 hours ago, csvt99 said:

The bolt goes up into the engine block. So looking at my original picture, the bolt head is one the bottom. It threads up and the bolt head tightens against the bottom of the top level of the Channel. So when all together the top of the C channel is sandwiched right between the block and bolt head. The bottom of the C channel mounts to the frame rails.

 

That makes more sense, I hadn't seen the latest version with the Command engines up close.  Probably doesn't make it any easier to work on, though.  Don't know how common the problem is on these, but every maker who has ever used aluminum engines has had to address the issue of high thermal expansion coefficient (as opposed to iron).  Blue and yellow Loctite are pretty much standard issue for Harley owners.

 

[csvt99 173]

I might have to see if I can shift the motor off the side enough to get clearance for a helicoil. Either that or take it to a shop. Not sure I have the time/mental energy to take off the motor😬

[csvt99 173]

Well I bit the bullet and pulled the motor. Only one or two of the holes are stripped, but I'm thinking I will just heli-coil them all while I have it out, if it truly makes them stronger. 

 

One thing I noticed is the stripped out hole actually goes straight through the block. Will this work with a heli-coil with no resistance for the tang?

 

 

 

[csvt99 173]

20 minutes ago, csvt99 said:

One thing I noticed is the stripped out hole actually goes straight through the block. Will this work with a heli-coil with no resistance for the tang?

 

One thing I thought of is that I will be drilling out the hole to a larger diameter, so as long as I don't drill it the whole way through, there will be resistance as the hole necks down. So I think I will be okay.