Hi Guys,

Is it normal for the thread to engage only 13mm in the bottom of the water jackets of a 200 block? As a rule of thumb I have always used 1.5 x the dia in thread engagement but that isnt possible with this application. There are plenty of long studded 200 blocks out there without issues so must be ok with 13mm of engagement, although I would rest easier to know that it is normal.

Also are there any hints/tips/advice to look out for when machining for 10 long studs?

Cheers,

Phil.

 

Hi Guys,

Im in need of infomation that is beyond the typical install and torque side of longstud installation. Hopefully someone with experience machining the block reads this and can validate the information I am working with.

I have now had to install 4 helicoils in the bottom of the block, and thats only up to the torque plate honing process of the build!! It has seemed strange since the beginning of the exercise that on some studs, these 4 to be precise, only have 6-7 threads of engagement which equates to approx 12mm of engagement into the block material. Based on never hearing or being able to find anyone who has had issues installing the studs, I have proceeded.

When torquing the long studs to 55ft/lb into the bottom of the block that all goes fine, but once torqued to 95ft/lb with thread lube(as recommended) they let go after a few minutes. The repaired(helicoiled) studs now hold at 95ft/lb but I am seriously doubting the reliability of this set up.

Speaking to a friend with a qualification in mechanical engineering, he says that a 12x1.75mm thread should never be torqued to more than 80ft/lb in cast iron and that is only with at least 25mm of thread engagement.

Can anyone with long stud experience offer any idea's/comments? Is it normal for several of the studs to only engage by 6 or 7 threads? Are some 200 blocks different to others?

Has anyone else seen or had issues installing long studs? Are the torque specs that I have been given wrong?

Cheers,

Phil.

 

That dont sound right.... im no expert but i was always under the impression that the thread was taped further in to the block to give you MORE thread engagement! with regards to 10 long studs you will need to mod the water pump to stop in fouling on the outer studs that are fitted.

 

http://reyland.co.uk/Details.asp?ProductID=155

or

http://www.mattlewismotorsportonline...?productid=109

 

Hi Miller3,

It doesnt sound right but cant be wrong based on a few simple observations. Initially I thought if the studs were longer, this would allow deeper engagement. After some details measuring, in particular on the inlet side of the block, if they were longer the main oil gallery would be compromised as it is merely mm's below the bottom os the stud hole in the bottom of the water jacket.

The studs I have are identicle to the ones pictured on Matt Lewis's site.

The waterpump mod was probably the easiest part of the job!! Lots of custom/extended tooling has been made to do the machining.

I guess answers to the following questions would help clear things up a little...

Do UK machine shops simply tap the thread straight into the cast iron or do they use helicoils?

Have UK machine shops noticed differences in 200 blocks? In particular the extra little platforms cast into the bottom of the water jackets to which the studs are screwed into?

Are these torque specs correct? 55ft/lb with loctite into the block, 95ft/lb with thread lube for the head retaining nuts?

Lastly, from my basic understanding of engineering practices...the rule of thumb for thread engagement is 1.5 times the diameter for thread engagement...is this still considered the case when istalling long studs?

Hopefully we can get some good reference material and information posted here

Cheers,

Phil.

 

Mine was machined straight into the block no helicoils,If i remember rightly,they are all wound in until the midway point,where the rubber O ring,is flush,and stops with the top of the block

 

Hi Matt,

Yes, the shoulder that carries the oring dictates the installed height of the stud I have set the top of the shoulder .5mm below the surface of the block...figuring that every little bit more depth gives a small amount more engagement.

So far I am thinking that the 95ft/lb torque setting should be applied when torquing dry...if using thread lube, the torque setting should probably be more like 80ft/lb. Im interestedto hear what UK engine builders recommend from their own experience.

Cheers,

Phil.

 

Why not email a few builders, I've never long studded a 200 block personally so don't know.
I just use the ARP stud/nut kit in 205 and torque to 120lbft with engine oil on threads.
tabetha

 

When I installed mine I used a low strength thread lock on the studs into the block and torqued to 50 lb/ft, the thread lock was more to stop the water penetrating and rusting the threads should I ever need ot remove them again than anything else, I've heard that some get seriously stuck in when fitted dry and basically get ruined trying to remove them. Both blocks I've installed them in have just had the block tapped, no helicoils or timeserts.

Once the studs were installed I applied some oil to the thread of the stud and underneath the washer and bottom of the nut, then torqued the nuts in stages: 30, 60, then finally 90 lb/ft, in the same order as installing normal head bolts i.e work your way out from the centre.

I haven't got any pics of the studs installed from inside the block as it's a bit difficult to see with the naked eye let alone get a camera in there, but from memory once the studs are installed I can only see 2, maybe 3 threads protruding from above the base of the block. These were both in a 6 stud installation so this was looking at holes 3+4 & 5+6, but I doubt this would be any different on the outer holes in a 10 stud conversion.

Who made the studs?

 

Thanks for the replies Wes and Tabetha,

I did the last repair today and installed the last stud to 55ft/lb. I have taken some pics on the phone which are a bit average but show the thread penetration, hopefully someone can confirm if it looks consistent with most.

Part of the issue with threads pulling was with using ARP thread lube(recommended by the supplier). I have now discovered that with ARP thread lube, 95ft/lb is equivalent to 125ft/lb with engine oil as thread lube...or if using ARP thread lube, no more than 77ft/lb should be used. I guess we live and learn.

Here are some pics...

 

Has anyone else had an issue with threads stripping in the block from long studs?