Thread size / pitch for Kubota D950 exhaust studs

[Mark15]

Short version:

Wrong parts came that I needed for installing the head onto the D950 diesel out of my Kubota B20 tractor. I need to figure out the thread for the external portion of the stud that attaches the exhaust manifold to the head, so that I can source some nuts for it locally.

Stud Kubota Part number: 15381-91532
Nut that threads onto stud: 02056-50060


Long version:

Had a bad experience with Coleman Equip. Ordered a new head off ebay (where I usually expect some aggravation, but that part went very smooth), and a head gasket and the exhaust manifold studs
& nuts (since the old ones all snapped) off from Coleman Equip.

Ordered both on May 5th. The Coleman Equip website took my credit card info, said order successful, and sent me a confirmation.

On May 10th (one day before head from ebay arrived) they called me to tell me they lost my credit card info and needed it again over the phone. Not sure why the late notice, but after confirming it was really them I gave them the info. Then they said they didn't have everything in stock and I would have to wait 2-3 additional days for them to order the stuff themselves, and then when it gets in they can ship my order. Frustrating since they had had several days to start that process ordering the stock on their end, but fine, whatever.

Order finally arrives on May 15th, and I check to see if I have all the parts. Everything appeared correct initially, part numbers on bags all match my order.

While installing the exhaust manifold last night, I realized they grabbed 6 - 5/16" SAE nuts from their bin, threw them in a bag and wrote the part number I actually needed on it with a sharpie. At least they sent the correct studs!

I am thinking they may be a M6, but I don't have the proper tools to verify and have no clue on the thread pitch. Does anybody know a way to look this up by the Kubota part number?

 

[100 td]

I don't know the answer but I do own one of these thread pitch gauges which is very handy.
https://www.amazon.com/Grip-Thread-Pitch-Gauge-SAE/dp/B004ROIU2A

Generally the studs will have COARSE thread pitch where they screw into the head and FINE thread pitch for the nuts. So if they are 8mm studs the nuts will be 1 or .75 pitch, or if they are 6mm they will be .75 pitch. Take the studs to an industrial nut & bolt store and get them to supply some nuts to suit. YMMV.

 

[Mark15]

I don't know the answer but I do own one of these thread pitch gauges which is very handy.
https://www.amazon.com/Grip-Thread-Pitch-Gauge-SAE/dp/B004ROIU2A

Generally the studs will have COARSE thread pitch where they screw into the head and FINE thread pitch for the nuts. So if they are 8mm studs the nuts will be 1 or .75 pitch, or if they are 6mm they will be .75 pitch. Take the studs to an industrial nut & bolt store and get them to supply some nuts to suit. YMMV.

Thanks, yeah I may just have to remove one of the studs and take it in somewhere. Already installed them with the threadlocker before I realized the nuts were wrong.

I should get a metric thread gauge too, thanks the link! My tap set has an SAE one, but no metric.

 

[Mark15]

I don't know the answer but I do own one of these thread pitch gauges which is very handy.

Wow, never realized these bolt / nut thread identifiers were so inexpensive. Just ordered one of these along with the metric pitch gauge.
http://amzn.to/2rqG3rU

 

[D2Cat]

I thought metric thread pitch was 1, 1.25 or 1.5. Was not aware there was a .75 pitch.

 

[North Idaho Wolfman]

Thanks, yeah I may just have to remove one of the studs and take it in somewhere. Already installed them with the threadlocker before I realized the nuts were wrong.

I should get a metric thread gauge too, thanks the link! My tap set has an SAE one, but no metric.

The studs on that head go into the water jacket so you should use Teflon thread sealer on them.
The bolts are standard metric thread, Home Depot, Lowes, or just about any good hardware store will have the nuts to fit them.

 

[100 td]

One other thing to consider, the grade of the nut you buy from different sources, I would be looking for a grade 8.8 minimum. YMMV.

 

[Mark15]

The studs on that head go into the water jacket so you should use Teflon thread sealer on them.
The bolts are standard metric thread, Home Depot, Lowes, or just about any good hardware store will have the nuts to fit them.

Thanks for the additional info. The studs came with a reddish paste pre-applied. I assumed it was simply thread locker, but it was probably to act as a sealant as much as a thread locker then. I will be sure to re-apply a sealant to the stud I remove to take with me into town when it comes time to reinstall it.

 

[Mark15]

Just for future reference for anyone else needing to replace crusty exhaust stud nuts on a D950. They are M6-1.0

Thanks for assistance everyone!