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Jdm/japan Spi Mini's And 3X Different Length Head Studs & Arp


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#1 Pops_Guild

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Posted 02 January 2020 - 06:03 PM

I've recently replaced my head gasket (Payen) and had my standard head refurbed by the TCK, including 12tho skim (block was not skimmed). The head needed work and there was coolant blowing from the front. I didnt replace the head studs when I put it altogether but followed all the correct torque practises and it all seemed fine until I've noticed a small amount of coolant weep again. So I'm now suspicious that maybe my head studs have stretched and from various discussions on here there's a lot of positivity around ARP stud sets. 

 

Other than being a bit pricey and generally only used for race engines (which mine is not) I've spotted  a problem for JDM mini's!

 
On a standard Mini the front 5 head studs are the same length but on JDM Mini's with AC fitted from the factory there are 3 longer studs. The coil bracket fits on one, and the alternator top bracket fits on the other 2 (see pic). These studs have a much longer than standard fine-thread ( est. 1 3/4" versus 1" for the standard) so that the extra things can be added above the head nut.
 
What this means is that a JDM Mini owner can buy ARP's 9 stud kit (Kit #: 206-4201) but 3 of the studs can't be used. I suspect this somewhat negates the point of moving to a ARP quality set.
 
I've been chatting to ARP about having the correct sized studs (and threads) made as a custom order and they are going to quote but initial est. cost looks to be eye-wateringly expensive. As much as I have lavished silly money on my Mini over the years, hundreds of $'s/£'s for 3 studs is just too much to get my head round :(. Most of the cost isn't the stud but because of the one-off setup of the multipart process they apply to them to get them to their quality standards. That cost is fixed regardless of how many studs they make.
 
So my thought is, if there are more of you in JDM-Mini land who are considering getting ARP head studs in the future then we could club together and get the price down per stud. They will still lileky be expensive but compared to not being able to use ARP studs at all, it might be something that some of you may be interested in. It's just a thought, Let me know if there's any interest either on this thread or message me.
 
...or maybe someone has already done this?

 

 

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#2 nicklouse

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Posted 02 January 2020 - 06:08 PM

The studs you have should be fine. They are not a stretch stud and can be reused many many times.

 

sounds more like something that is not allowing the head to seat correctly.



#3 Bobbins

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Posted 02 January 2020 - 08:08 PM

Pops, what year is your JDM?

For info, my 1998 JDM is based on an MPi block and has "normal" head stud sizes.

Stu.

#4 Pops_Guild

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Posted 02 January 2020 - 08:49 PM

The studs you have should be fine. They are not a stretch stud and can be reused many many times.

sounds more like something that is not allowing the head to seat correctly.


Thx for that info Nick. Good to know that the studs won’t/shouldn’t stretch. Seen it referenced on the forum a few times

If it’s not studs then yes it does seem like something is preventing it seat properly. I seemed blemish free when the head gasket was put on. It’s weeping from right under the middle front stud. I’ll try the torque on the head studs again at the weekend else it sounds like I’ll have to get it all off again to inspect it again.

Any ideas let me know

#5 Pops_Guild

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Posted 02 January 2020 - 08:56 PM

Pops, what year is your JDM?

For info, my 1998 JDM is based on an MPi block and has "normal" head stud sizes.

Stu.


Stu, its registered 1/1/97 but it’s a 96 built Cooper (C35 LE). From what I know all JDM C35s were also MPi block based.

So you have the coil bracket and high mounted alternator too but on standard studs? I checked if I could do that but there isn’t enough thread for the alternator bracket

#6 nicklouse

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Posted 02 January 2020 - 09:01 PM

 

The studs you have should be fine. They are not a stretch stud and can be reused many many times.

sounds more like something that is not allowing the head to seat correctly.


Thx for that info Nick. Good to know that the studs won’t/shouldn’t stretch. Seen it referenced on the forum a few times

If it’s not studs then yes it does seem like something is preventing it seat properly. I seemed blemish free when the head gasket was put on. It’s weeping from right under the middle front stud. I’ll try the torque on the head studs again at the weekend else it sounds like I’ll have to get it all off again to inspect it again.

Any ideas let me know

 

Did you check for any raised threads?



#7 Bobbins

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Posted 02 January 2020 - 10:48 PM

Pops, what year is your JDM?

For info, my 1998 JDM is based on an MPi block and has "normal" head stud sizes.

Stu.


Stu, its registered 1/1/97 but it’s a 96 built Cooper (C35 LE). From what I know all JDM C35s were also MPi block based.

So you have the coil bracket and high mounted alternator too but on standard studs? I checked if I could do that but there isn’t enough thread for the alternator bracket

I'll double check in the daylight and take a photo!

#8 Pops_Guild

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Posted 03 January 2020 - 11:04 AM

 

 

The studs you have should be fine. They are not a stretch stud and can be reused many many times.

sounds more like something that is not allowing the head to seat correctly.


Thx for that info Nick. Good to know that the studs won’t/shouldn’t stretch. Seen it referenced on the forum a few times

If it’s not studs then yes it does seem like something is preventing it seat properly. I seemed blemish free when the head gasket was put on. It’s weeping from right under the middle front stud. I’ll try the torque on the head studs again at the weekend else it sounds like I’ll have to get it all off again to inspect it again.

Any ideas let me know

 

Did you check for any raised threads?

 

 

I did check all the threads and gave them a light clean and touch of oil but what would a raised thread look like, not familiar with that term. 



#9 nicklouse

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Posted 03 January 2020 - 11:14 AM

The first thread of the holes can pulled above the level of the block. Which is why many builders countersink/relive the opening.



#10 panky

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Posted 03 January 2020 - 11:18 AM

Did you put anti-freeze in straight away? The advice I was given was to use plain water for a week with the Payern gasket then add the anti-freeze later. Anti-freeze seems to find it's way through but using water first expands the fibres in the gasket and seals it. 



#11 Pops_Guild

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Posted 03 January 2020 - 05:22 PM

The first thread of the holes can pulled above the level of the block. Which is why many builders countersink/relive the opening.

 

Thanks for the explanation! That makes sense and is a possibility. If I do end up taking the head off again, which I'm pretty much resigned too now, I'll keep an eye out for that.



#12 Pops_Guild

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Posted 03 January 2020 - 05:24 PM

Did you put anti-freeze in straight away? The advice I was given was to use plain water for a week with the Payern gasket then add the anti-freeze later. Anti-freeze seems to find it's way through but using water first expands the fibres in the gasket and seals it. 

 

That was one of the things I followed. I didn't add the antifreeze until a few weeks later. 



#13 tegski

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Posted 07 January 2020 - 03:11 AM

All of the studs seem to be the same length on the front of my JDM 1997 Spi...?



#14 nicklouse

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Posted 08 January 2020 - 12:55 AM

I have heard today the there are issues with some of the BK head gaskets leaking out of the front of the head.



#15 Pops_Guild

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Posted 08 January 2020 - 08:23 AM

Interesting, i saw you post in the Head Gasket thread. I still haven’t had a chance to have a deeper look at mine yet but if that’s what it is then that makes life interesting. Payen ones are supposed to be reliable.

So if I end up putting a new gasket on should I supplement it with a tiny smear of Hylomar around each coolant hole at the front. I don’t really like that but again I don’t want it leaking or to have to keep taking the head off.




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