ARP Studs and spacers

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I am putting together an engine (XU10 RGX with 1.9 Mi16 cylinder head) and need a solution to fit the cylinder head to the block using studs. What I have is a set of 'custom head studs' 145 mm in length and a set of Honda F20C ARP studs (170-ish mm in length) which also happen to be M12x1.5. If I use the 145mm ones I will not have enough thread above the waterpump, the washer + nut is sticking out above the stud, this is when no head bolt spacer is used. If I use the spacers on the 9 other ones I will have the same problem (nut sticks out above stud, about 3 or 4mm). If I use the ARP Honda studs, above the waterpump I would have enough thread for the nut to hold but only if I use a headbolt spacer as the stud is too long, for the 9 other ones I would need double spacers because the nut would just fall into a place without thread (socket will be too short also). A specialist told me to always use the head bolt spacers to prevent damage to the cylinder head (ARP washer is not enough to spread the load?). I was wondering if it is safe to put double spacers or if a set exists where I can use 1 spacer per bore and not have studs too long or too short. Does anyone know a way to safely do this, maybe with the parts I already have? I have looked on the forum before and someone mentioned the 'AU6.195-2LB' single stud but I cannot find this part anywhere and I am not sure which stud set was used. Hope someone can help me, I already spent a lot of money on parts and overhaul (and time waiting for a 16v turbo manifold which took over a year to make)

 

 

 

 

[petert 586]

I documented it all here:

Just buy the Dodge kit and one extra long bolt for over the water pump. Any ARP dealer can order the bolt for you. You'll have parts left over, but it's the cheapest way to do it. I use the XU10J4 oem washers as well. I may have made a custom spacer for over the water pump. I'll check length, as I have two engines apart presently. Interestingly, APR won't tell you what torque to use, as it's a custom installation. You need 120Nm. Don't forget to re-torque.

 

Edited October 26, 2023 by petert

[petert 586]

Correction. If you use the specified bolt over the water pump, all you need are 10x XU10J4 washers. Nothing else. You can see how much I’ve turned off the OD of the nut.

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8 hours ago, petert said:

Correction. If you use the specified bolt over the water pump, all you need are 10x XU10J4 washers. Nothing else. You can see how much I’ve turned off the OD of the nut.

I did not seem to have a problem with the nut not fitting in the holes, used the custom set but looks like the Honda set has the same washers and nuts. Top part is M12x1.25 I believe, nuts also have this written on them. Any chance I can keep the Honda stud above the waterpump? I think nobody uses studs for Honda F20C engines so trying to sell this will be difficult in the Netherlands, I really would not know where to find the single stud that you used. Are XU9J4 headbolt spacers the same as XU10J4? I think I've found a website that sells XU10J4 headbolt spacers in case they are any different, I have the cotton reel type. What is the re-torque procedure? The man who sold me the Honda studs said that when installing I should first tighten the nuts to specified torque, then loosen everything, put more ARP lubricant on and tighten it again (to 95 ft lbs/128.8 nm). I could take some more pictures on saturday if you want to know what I have now, I really don't know what parts I should use and need help figuring this out.

[petert 586]

"I bought the parts from Titan Motorsports, Florida. The single stud was US$12. Ebay prices seem to be exorbitant compared to what I paid. "

 

Pretty simple process of buying online really. I'm not going to comment on using the parts you have.

 

The washers shown above are standard on an XU10J4. The XU9J4 are the taller, cotton reel type.

 

The studs should be installed loose, but yes he his correct.

 

95ft lbs = 127Nm

 

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21 hours ago, petert said:

"I bought the parts from Titan Motorsports, Florida. The single stud was US$12. Ebay prices seem to be exorbitant compared to what I paid. "

 

Pretty simple process of buying online really. I'm not going to comment on using the parts you have.

 

The washers shown above are standard on an XU10J4. The XU9J4 are the taller, cotton reel type.

 

The studs should be installed loose, but yes he his correct.

 

95ft lbs = 127Nm

 

So the washers you have in the picture, on the black plastic cable tie, are XU10J4 head bolt spacers?

-If so then I could use the 145mm stud kit I already have for all except above the waterpump as with cotton reel spacers I am only 4 mm too short.
I think I can use the Honda stud with 1 cotton reel spacer above the waterpump (titan motorsports and google show no results for AU6.195-2LB).

 

Please correct me if I'm wrong: cylinder head -> XU10J4 washer/spacer -> ARP washer -> ARP nut?
Also, are the headbolt spacers directional?

[petert 586]

Yes, 10 washers held with a cable, come from underneath the head bolt on an XU10J4 (Mi16 or S16).

 

You will need to make contact with Tital, via email or phone, and place a special order for the part. I don't understand why you wouldn't use your local dealer however.

 

cylinder head -> XU10J4 washer/spacer -> ARP nut

 

Post a pic of your nut. You said it differed to mine?

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On the picture you can see what I have, MLS gasket, 145mm stud for XU10 engines, black stud for Honda engines (170 mm) and washer and nuts that came with the XU10 set. Washer outer diameter is just under 22.2 mm, part number 200-8537, nut outer diameter just under 21mm with part number 300-8337. Cotton reel spacer 22.1 mm. The ARP washers fit but need a screwdriver to guide them in order to go straight, I used them to check if it would fit as the thickness is about 3 or 4 mm, looks like your XU10 spacers are about the same size (everything fingertight for now as I am only checking). I will contact the dealer to check if he can provide me with the single stud you used but do you think (in case it is not available anymore) I can use the Honda stud with the cotton reel spacer above the waterpump? And should I use an ARP washer on top of that as well or use the XU10 spacer?