yes thanks for pointing that out doug!!!!!LOL


cheers danny

 

Wow sounds impressive. Bet it wasnt a cheap build!

 

Thing u have to remember is yes montune as well as karl do know their stuff BUT they have spent loads of money and development over the years making/testing long studs etc so of course their gonna tell u their needed!!! They need to make money out of them lol, if they said their only needed on 700bhp engines for example they'd loose alot of money/customers whereas Karl saying not to use them isnt making him anymore money out of it..................

No slagging long studs off thou as the block in my car was already machined for them so have 6 long studs and a wrc gasket in mine

 

my engine cost me 22k mate,well thats when i stopped counting anyway!!lol


cheers danny

 

The problem that Karl is talking about is a gradual bowing of the block, when engines are rebuilt, the block is faced anyway, so if its rebuilt continually its not an issue, its if you want to build it and leave it in one piece for 40K miles that you will have an issue.

If you are building an engine for massive power on race fuel with huge cylinder pressures then that slow distortion of the block is a small price to pay for the sealing that you get, but if you arent doing that then why should you pay the price?

 

As per above, use it when its needed, not when it isnt.

Just like I use 888's on a racetrack because I need the grip, and I accept the shorter life, but I wouldnt use them on a motorway as they offer me nothing I need for that driving and still wear out quickly.


You seem to think that its "one size fits all" with YB's and IMHO that just shows your knowledge isnt as broad as some other people who will build an engine correctly specced to work with what it is required for, which is often moderate power for a long time, not massive power for a short time.

Same with pistons, I think anyone putting cosworth racing pistons in a 400bhp road motor is a fool and if they knew what they were doing they would use Mahle's instead.

 

the above post goes to show that you will just choose to listen to who you want..
How can long studding an engine be speccing it wrongly???
And how does that make me less knowledgeable about engine building just because i choose to long stud one???
Where did i ever say we were speccing a engine for massive power over a short time???
The question is do long studs work and are they needed on 500 bhp+??
The fact is yes on both accounts imo and in yours they are not..dont try and word things to make it look like i dont know what im saying and your far superior when it comes to building a yb because imo your wrong and whatever you say on this matter wont change my mind or many others who build many big power ybs...

cheers danny

 

Well you'll know that it all works as a package then. I think that you can put your toys back in the pram !!!!!!!!!!

 

clearly both Karl and Mountune know what they are talking about but, as with most pros in the tuning world, they would rather keep their secrets to themselves (Karl has even complained on this forum about other tuners divulging information). I have not 1% of the experience of b19 or the knowledge of Chip but i do have some experience of long studs which on two occasions were machined and studs provided by Mountune.

The point of this post is to try and demonstrate how tuners can deliberately (or even accidentally) cause confusion among amatuers and how rumours can craete expensive problems and arguments on forums.

Machining the block for long studs involves removing the metal below the original stud holes and in some cases the metal removed means that there is daylight below the hole when viewed from the block deck. It also leaves a step whic is designed for the O ring to seal against.

The studs themselves have a shoulder which holds an O ring for sealing. Torquing down the studs to the designated Mountune spec (iirc 93 Lbft) means that the shoulder on the stud pulls the step on the machinined hole down towards the bottom of the block and the torque on the stud is actually a function of the stress on the block rather than the stud bottoming in the machined thread in the main bearing saddles. Beacuse of the daylight which now exists under the holes, this means distortion of the block face and it can easily be measured with a dial gauge set on the block deck.

Mountune were 'surprised' and suggested I'd done something incoreectly when i raised this with them but there was clearly an issue. It was frustrating dealing with them so gave up and simply screwed the studs in with thread sealer till the dial gauge showed distortion then backed off hald turn. the engine never gave a problem.

The second time the same thing happened. Again Mountune couldnt explain even though on this occasion they got pictures with written figures etc. Coincendataly i spoke at the same time with a very well known tuner and asked him about this and he said ignore the torque settings Mountune gave you, clean out the block threads with degreaser, dry them and use thread locker. Screw them in gently till they just pull on the block face - then back off - just what I'd previously done in fact.

The person who told me this advice also elaborated and explained that the machining of the block weakened the structure and that the torquing of the studs into the block (as per mountune advice) was indeed correct and that when the head is torqued down the stud will pull on the saddles and the deck will then go straight again!

Well fuck me what a way to introduce confusion into the diy brigade!

and who gave this advice........



Ahmed Bayjoo.

SO, what does all this tell us?

A little knowledge is worse than none!

 

Thats a high torque figure on long studs 93 lbft ? . At least two tuners I have spoken too last year specified 50/55 lbft and i was advised as such by them . .

 

you are correct we normally torque the studs to the block at around 50 lb ft and the the nuts down to 90-95lb ft...
But as he said he ended up doing these far less than 93lb..

cheers danny

 

sorry - yes the studs are 50 but even then they pull the deck down.

 

I find interesting after buying new Cosworth alloy block couple years back iirc next to each other the new one has considerably more meat around head bolt holes running the length from head face down to the threaded part which also much deeper with thicker material around it. On the old cast blocks the threaded area in worse case as in my sods law it cracked through that small amount of material I think sustained high revs rather than power killed that one. The other one had long stud conversion prior to my ownership ate through head gaskets that one eventually broke around same area that’s been machined with long studs so I don’t know which is better but the other interesting thing

 

Not sure what you mean?

Please enlighten me

Pull deck down. . Is That a open statement?

 

I cracked my 205 block sapp on about 370bhp, was running mls h/g and STD head bolts ( gen cosworth ones) . Also seen a mates 200 block crack on STD headgasket and bolts. I have NEVER seen a long-studded block crack or "twist" in ten years of being into cosworths..... I'm not a tuner, but I am an aircraft engineer, so have a good knowledge of stresses/moments etc, and I think the relativly small outlay to get your block longstudded is well worth it, and personally wouldn't build an engine over 400bhp without it being done if the option was there....

My saff is running T4/450bhp+ on a mls and STD bolts, but the engine was built before I bought the car, seems to be ok but when it gets rebuilt it WILL be longstudded.

That's my view, if you are spending 10k on an engine why risk the block for the price of a proven excellent mod? I'm with Danny on this one, I'm sure Karl has built lots of engines with STD head bolts with no ill effects, but IMHO longstudding is well worth doing.

 

Good day everyone.

Sorry to relive a very old thread.

We busy building a YB in South Africa and currently busy with the long stud conversion. No one here had ever done it. So we have actually manufactured all the tools for the task.

My question is a simple one. Do the threads and flange bottom at the same time or not?

Regards
Meent