RB20 fitment issues.

[Adam_Winstone]

Mark, I'm not here to slate dealers but I'm quite happy to point out simple engineering reasons for some products giving problems in use. The bigger the diameter of the stud, the more likely that people will run into clearance/alignment issues. I don't know the diameters of all the studs out there BUT the bigger the stud the bigger the problem.

If I did start to name and shame dealers or products then the thread would quickly be pulled by moderators anyway, which doesn't help anyone.

You would be pretty pissed off if I came on here and started slagging off MB products, which I have not (I don't have your studs so cannot, and have not, named them). In the same light, others would have the same right to be pretty pissed off if I did start naming and shaming their product, without first hand experience of the product that I was having a go at.

There are times that I will quite openly name a product that I've first hand experience of having problems with, so that others can avoid paying for the same problems. However, I'm not talking specific dealers/products here, rather, I am point out the simple issue behind many (yes, many) people running into issues with increased stud diameters. Yes, these issues are much more likely to become evident with certain kits, I've never suggested otherwise, yet in those cases the kit can take 50% of the blame and the fat stud should take the other 50%, rather than the common response of taking 0% blame and pass on 100% to someone else.

I have no doubt that you already know which kits are most likely to give issues with 'fat' studs so why don't you name them? That's not exactly fair though as these same kits fit fine with standard shaft diameter studs, so there isn't an issue unless 'fat' studs are introduced to the assembly. Ian was quite right when he wrote of thinking of a motor as an assembly and the more that we know about what fits (or doesn't) with what, the better for all of us.

What is important about this issue is that it is raised and brought to the attention of the masses, NOT TO APPORTION BLAME, but to help people identify a common problem that they might be facing and give them good advice that rectifies the problem, avoids damage, and (worst case) avoids danger/accidents. I'm very happy to help others and my first hand experience of this issue qualifies me to inform others of it.

Cheers to you all (that'll be me sitting on the fence again) and enjoy the weekend.

Adam

Edit: Please note that I've not mentioned 'straight' once. Straight has nothing to do with this, diameter is what we're talking about here. I'd hope that any manufacturer could make a straight stud, even if they struggle with getting the diameter right.

[soosh]

I've ordered some standard SIL studs now and if it's still a tight fit I know what I'll be blaming.

I'd love to know the outcome,hope you let us know.

[Adam_Winstone]

I'm not sure that I've ever had genuine SIL studs so don't look to blame me if they are 'fat' too!

[Elite-225]

Winstone is a blasphemer ... Stone Him !!

[10 inch Terror]

I'm not sure that I've ever had genuine SIL studs so don't look to blame me if they are 'fat' too!

If the barrel is still a tight fit with standard studs, I'll be blaming the RB cylinder. I've fitted both a standard SIL 150 and Imola cylinders with the "fat" studs fitted and they fit with no issues at all. Unless anyone can think of another reason why the RB cylinder is tight, what else is there to blame?

[Muttley McLadd]

what else is there to blame?

The type of polish you use??

[Adam_Winstone]

I'm not sure that I've ever had genuine SIL studs so don't look to blame me if they are 'fat' too!

If the barrel is still a tight fit with standard studs, I'll be blaming the RB cylinder. I've fitted both a standard SIL 150 and Imola cylinders with the "fat" studs fitted and they fit with no issues at all. Unless anyone can think of another reason why the RB cylinder is tight, what else is there to blame?

Sounds perfectly reasonable. Let us know how you get on, perhaps telling us some diameters so that we can confirm or rule out whether this is playing a factor.

Adam

[10 inch Terror]

As soon as the studs turn up I will fit them and let you all know the out come. I'll also take some measurements of both sets of studs. Thanks guys.

[Adam_Winstone]

Ok, to help understand what I'm going on about, my digital verniers measure the 'fat' studs that gave me issues as having a shaft diameter of 7.90mm, whereas my original factory studs have a shaft diameter of 7.20mm, which is the same as the rolled studs that I've been buying recently.

This difference may seem little but it is enough to give BIG problems depending on the combination of kit and casing. The closer you can get to 7.20mm, the less likely you are to have kit alignment and fitting issues. As already mentioned, if alignment is still poor when using the smaller diameter studs then look to see if there is thread protruding out beyond the casing/gasket face. If so, mark the exposed threads, remove the stud from the casing and then grind or file off the offending threads, then refit the stud and address any others that need the same attention. Note that this method of thread removal will not help where the stud's shaft is the larger diameter along its length.

Adam

[10 inch Terror]

I've measured the MB ones and they are spot on 8mm. I have also measured the ones that came with the casing which is Indian so I assume to be SIL?? They are a bit corroded and they are 7.39mm. I have a new set ordered and will fit as and when they arrive. I'll let you know how I get on. Thanks for taking an interest Pete..