16 hp spark plug thread

[John2189 509]

The threads for the spark plug stripped out so i bought a 14mm thread repair kit. Well the the plug blew out while I was mowing. So. Now the hole is too big for the 14mm threads. Why couldn’t I rethread it to 18mm or even a 7/8 threaded spark plug?

[ebinmaine 70,916]

I'm thinking it would depend on how thick the boss is for the spark plug threads 🤔 

 

Do you or a friend have the capability of welding aluminum? 

[ebinmaine 70,916]

Delete double post

Edited June 26, 2024 by ebinmaine

[moe1965 752]

I recommend a helicoil. The kits can be found on line . Also I think most auto parts store might carry them

[lynnmor 7,595]

I would first look for a replacement head, and then make a decision according to price and availability.

[John2189 509]

1 hour ago, lynnmor said:

I would first look for a replacement head, and then make a decision according to price and availability.

Heads are very expensive. I don’t want to put that kind of money into it 

[John2189 509]

3 hours ago, moe1965 said:

I recommend a helicoil. The kits can be found on line . Also I think most auto parts store might carry them

I tried a repair kit, it blew out.

[ebinmaine 70,916]

15 minutes ago, John2189 said:

Heads are very expensive. I don’t want to put that kind of money into it 

 

What are you finding for prices? 

[John2189 509]

1 hour ago, ebinmaine said:

 

What are you finding for prices? 

125 plus 

[ebinmaine 70,916]

3 minutes ago, John2189 said:

125 plus 

 

 

Have you checked with our two vendors? Brian Badman and a to z?

[John2189 509]

2 minutes ago, ebinmaine said:

 

 

Have you checked with our two vendors? Brian Badman and a to z?

I have a ezloc thread insert ordered from McMaster carr

[rmaynard 15,937]

What type of thread repair kit did you use as mentioned in your first post? A good quality kit such as Heli-coil should not blow out if drilled, tapped, and inserted correctly. If drilled and tapped incorrectly, another type of kit won't fix it and you may have to find a replacement head. The K341 is a great engine, and even $125 is not too much to spend to make it right again.

[John2189 509]

15 minutes ago, rmaynard said:

What type of thread repair kit did you use as mentioned in your first post? A good quality kit such as Heli-coil should not blow out if drilled, tapped, and inserted correctly. If drilled and tapped incorrectly, another type of kit won't fix it and you may have to find a replacement head. The K341 is a great engine, and even $125 is not too much to spend to make it right again.

I used the kit that has 4 different lengths of inserts and the tap. 
I have an insert ordered that is steel and you drill and tap to 3/4-16,  so this one should work very well. 
Its really not about the money, its just I only use the tractor once or twice a year. 

[rmaynard 15,937]

So, did you get your insert? Did it fix your problem? Curious minds awake your answer?

[John2189 509]

On 7/5/2024 at 3:05 PM, rmaynard said:

So, did you get your insert? Did it fix your problem? Curious minds awake your answer?

I know this is an old thread but no the insert didn’t hold 

[ebinmaine 70,916]

25 minutes ago, John2189 said:

I know this is an old thread but no the insert didn’t hold 

 

What did you end up doing to repair the engine? 

[adsm08 2,738]

Timeserts are the only things I trust for spark plug repair.

 

These things in a pinch: https://www.amazon.com/OEMTOOLS-25647-Spark-Plug-Saver/dp/B000CMHL1C?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&smid=ATVPDKIKX0DER&gQT=1&th=1

 

And always always red or green threadlock on the OUTSIDE of the insert, antisieze on the INSIDE.

[John2189 509]

2 hours ago, adsm08 said:

Timeserts are the only things I trust for spark plug repair.

 

These things in a pinch: https://www.amazon.com/OEMTOOLS-25647-Spark-Plug-Saver/dp/B000CMHL1C?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&smid=ATVPDKIKX0DER&gQT=1&th=1

 

And always always red or green threadlock on the OUTSIDE of the insert, antisieze on the INSIDE.

That is the style that I used with the red loctite. It didn’t hold. The aluminum must be too soft or something 

[Fordiesel69 268]

Im quite certain you will be able to find a replacement head if you look hard enough.

 

Lots of tractors get parted out.  

 

But yes you can goto a larger diameter plug.  Head is already shot so no harm in trying.  

[ebinmaine 70,916]

3 minutes ago, Fordiesel69 said:

Im quite certain you will be able to find a replacement head if you look hard enough.

 

 

 

 

You can get a new one from the pulling tractor vendors for not much more than you can find a used one from an unknown source on the interwebs.

 

I don't have a need to buy a cylinder head right now but if I did, you bet I would purchase new and possibly even get a little extra compression.

[Fordiesel69 268]

And I belive most K321 heads will fit as well, as long as they have the same size ex and in valve.  The 14HP engine was weird as some had the small ex valve, and some had the large.  

[ebinmaine 70,916]

1 minute ago, Fordiesel69 said:

And I belive most K321 heads will fit as well, as long as they have the same size ex and in valve.  The 14HP engine was weird as some had the small ex valve, and some had the large.  

 

 

I only have a couple of 14 engines here but both of them only have nine head bolts. All of my 16s have 10.

[John2189 509]

23 hours ago, ebinmaine said:

 

What did you end up doing to repair the engine? 

I have a good used head coming in the mail 

[ebinmaine 70,916]

31 minutes ago, John2189 said:

I have a good used head coming in the mail 

 

Be sure to hand plane it before installation.  

[adsm08 2,738]

20 hours ago, John2189 said:

That is the style that I used with the red loctite. It didn’t hold. The aluminum must be too soft or something 

 

I've used those repairs in many aluminum heads. More likely the thread depth is not there. Not enough threads = not enough surface area.