Is there a reason why ARP says not to use washers in conjunction with their flexplate bolts?

Problem: ARP flexplate bolts are not full thread. The non threaded part is wider than the flexplate(4mm). A washer under the head of the bolt would fix the issue except there is a piece of paper that came with the bolts that says they are not designed to be used with washers. I cant think of any reason why using washers would cause a problem other than clearance. Thoughts?
ARP bolts have a 22mm UHL. A 20mm full thread UHL would be perfect.

Other things to consider:
1. Stock bolts won't work.
2. M11 x 1.50 bolts are VERY difficult to find.

Help

 

I'd give ARP a call. I've found them to be very helpful in the past.

 

Is the underside of the bolt head grooved like some locking nuts are so they will bite into the metal?

 

negative

 

will do

 

i would say like you clearance but what you can do is put one on and turn te fly wheel and see if it will hit the block

 

The explanation as to why ARP says that certainly lies with ARP.

 

I ran into this same problem with my bolts that I still have. I bought them from the local speed shop here and a buddy of mine that works there said put some hardend washers in there. I told him the same thing that the instructions said not to add washers and he said so........it's not going to hurt anything. Just get some hardend washers and be done with it. Well, I never installed them. Wait, I did install them but my ordeal was that the bolts went through the FP but bottomed out onto the crank. After taking a few test drives, the FP was making all kinds of noise. I figured out what the noise was and tried to return them but I didn't have the cardboard and plastic shrink rap. So he couldn't give me a credit. I just put the stockers back in. I'm going to do another Fuddle verter swap next week, I'll put the ARP's in with hardend washers. Oh just FYI, I have a SFI app. Hughes FP.

James

 

that's about what I expected/thought. Excellent info, I just so happened to have some machined hardened washers handy

 

Where did you get the machined washers??? ARP.....some place like this???

James