As above, used/new

Im after a set for a job.

 

What for ?

 

lol oh yea, thats me thinking faster than typing

YB head studs.

 

Please don't use them.

I have a cracked block here due to those.

 

Lots of people say they crack blocks but I think it MUST be a fitting issue as ARP would change their design...interested in your thoughts and findings.

 

200 or 205 block?

 

Toby if Tony will not use them and there are so many threads regarding these studs

Mine was fitted as per instructions and being an engineer by trade I tapped all threads and cleaned out etc. Yet they still cracked my block.

Trouble is the head expands at different rate to the block and causes them to come loose and if you torque up higher they can and will crack the block.
Hence why the cosworth and ford designers opted for the stretch bolts.

Or the other option is long studs but only on a 200 block.

 

Mine was a 205 but they have cracked 200.blocks aswell

I just don't want you to crack a block.

 

I have 8 if any use mark

 

Sorry make that 6 lol

 

message me what you want for them please.

 

Thanks. I hear you 👍

 

Interesting and I trust if that you say you checked then there must be a problem...I know there are lots of posts. When we took the cover off my old Engine we saw ARP written on the studs...do not know the spec but as far as I know it was ok for 15+ years

 

Pm sent mate

 

I personally wouldn’t use them either but I also wouldn’t use 6 long studs alongside 4 stretchbolts.

 

on the turbo sport forum theres is a long explanation about the correct use of these studs by Clint (aka Brands Hatch Motorsport)

 

with regards to std head bolts - these are difficult to get hold of. the proper bolts have "KK" on the heads whereas just about everything you see on ebay / burtons / etc is just a high tensile bolt which happens to be the correct size. you even see the wrong ones advertised (even by 'respcted' tuners) as 'genuine Reinz head bolts' which is true - but they are not genuine fitment on a YB.

if the ARP studs crack the block because of the differences in expansion (alum v steel bolt) then that same problem will likley occur with the use of the 'wrong' type of std head bolts.

the correct bolts are 'torque to yield' which means that you stretch them past thier elastic limit into the plastic region and permanently deform them. in the case of high tensile replacements you are stressing the block threads and (my opinion) is that this is a bigger problem if you use a metal head gasket which has no 'give' in it.

there are some bolts on ebay where an attempt has been made to mitigate the effects of this problem by machining the shaft of the bolt down so that the waisted section will stretch. no idea if this resolves the problem and the outfit who supplies them are unreliable anyway

 

That was a pic of my block on turbosport.

Clint does state that he has seen lots of 200 blocks crack too.
And if you have to modify arp studs then they are not fit for perpose.

 

Are all the 200 blocks cracking in the head stud area?

 

The original wasted HT alan bolts were a cosworth GPA head bolt and came with a Steel top hat spacer that required machining of the head and inserting. BBR used a lot of these in the early days

 

Not all but too many.

Hopefully Tony will explain why he don't like them and give you some technical reasons too.

 

If/when a 200 block fails they all fail round the deck.

 

whilst we are talking about someone holding the head on reliably (which is not the same as holding someone reliably for head) its worth mentioning that there are more than one breed of long stud - I've had 3. some are designed for a 17mm (approx) hole in the deck and others about 11mm. i've had 2 lengths of 17mm ones and one was about 3mm longer than the other and the short ones don't 'bottom' in the lower part of the block earlier than the shoulder supporting the o ring seal pulls down against the counterbore in the deck. this means that if you torque them into the block as per spec you have now got a distorted block face. burtons supply these of the same length as one set of mine. SCS supply studs of the smaller diameter seal which are longer and the same size as my 11mm ones (prob got em from SCS originally).

also, the 'short' long studs don't engage with a lot of thread length in the block which is a concern given that the block is only cast iron. that said, I've found that once they are thread locked in they are happy to hold correct torque on the nuts without pulling out though I've heard of others who have had the lower threads pull out which sounds like a disaster. the fact that the shoulder hits the counterbore and pulls against it means you have a way of ensuring the thread locker doesn't compact when you put the nuts on the top.

I've posted about this before and when i first discovered this problem 15 tears ago i spoke with Ahmed Bayoo (rip) who was a little confused by what i was saying but the block and studs were machined / supplied by mount tune so i imagine that unless the machinist was having a bad day others will have suffered a similar fate. it would be possible to machine the counterbore further to achieve greater thread engagement at the bottom but that would reduce the dowelled section for aligning the gasket / head which the long stud provides. those that burtons supply are the 17mm shorter variety (as per mountiune) and they have not failed in my engine even though they have caused sleepless nights!

instead of torquing the studs into the block to x/lb, use strong thread locker and a dial gauge to determine the point when the deck starts to deform then back a bit. 30k miles without a problem.

 

The short long studs were a mistake and soon replaced by the longer ones. The short ones often pulled out of the base of the block

 

I suppose the problems with using standard headbolts are that the 'standard' bolts are no longer available.
Just thought I'd route through my old bolts box to compare.
Found some with 'KX1000' on them, the rest are waisted 10.9 M12 bolts.

The onset of MLS gaskets does bring this spring effect upon expansion and contraction but will the gasket allow the head to expand if I bolt the head with 12.9 bolts.

I have some debating with myself here. Great to hear points and experience.
Certainly lots of blocks have been cracked but is that because the old fibre gaskets didnt absorb the contraction without failing?

My block is a 205 and I don't believe/won't be buying a 200 block to long stud. It was a 'best fix' in the 90's. The real fix is a through stud block from S&J.

In all my years this is the first MLS gasket separation I have had on my rally car (running 2.4 bar through a restrictor)

I think the bolt tensile strength has been compromised rather than gasket failed.

Hmmmmm reduce CR, reduce boost.

 

Nothing wrong with the arp studs but there just not suited to the substandard mounting points on the 4 weak areas in the YB block.

Mark

 

You found any suitable standard fitment headbolts on a par with the OE Mark?

 

typo in my earlier post - the thinner long studs are 14mm not 11mm.

also in an email from burtons in January this year requesting details of thier long studs they told me that the ones they supply are 17.25mm o ring and measure 108.5mm from the underside of the o ring shoulder to the end of the thicker half (the end that screws into the block). these are 4mm shorter than the longer ones i have and will not bottom in the block as discussed in my earlier post.