It's for my B16a, but what diameter washer?

You've heard people talking before and they've said 1/4 washer, or 3/8 washer, etc.

Which .04" hardened stainless washer do I need? I've searched, but found nothing.

 

measure it, I usually make my own machined and surface ground to .040"...it's more work but they're solid...

 

You know, I got to looking at the newly released/revised B16 OEM Honda LMA's that are spring type, and the little spacer on the bottom is .090," but we're only adding .040" worth of spacer to the H22 lma's? Hmmm. Maybe I and others ought to reconsider what it is that we're doing with these things. Consider the following pic that compares the newly designed b-series lma on the right versus the H22 lma on the left. Then notice that the H22 version has a long way to go to meet the same height as the updated one on the right. You see, part#PCB-305 has a .090" shim on the bottom, but if we are only putting a .040" shim on the prelude ones, then we still have another .050" left to go. Maybe if people were to use two washers they would be alot better off, that is, considering that Honda designed the PCB-305 lma to work in B16 heads and the like.

 

Funny, when I did this to an old pr3 head I had the same questions.

"Why is everyone using 1/4 Diameter when the bore is more like .700 ish?"
"Why are we using .040 thick instead of shimming to the old overall length?"

Regarding the diameter-
The 1/4 dia would work fine and is tried and true by many.
I chose to use .625 dia because it was close to the bore size.
I knew that the bottom of the coil spring was only so big, and also the biggest dia on the spring doesent allow for too much side to side slop. I just chose to have the most max floor possible for it. Also made sure the washers I chose didnt have a huge id hole going thru them. Some looked more like a ring at that size dia.

Shim to Length-
This still confuses me and maybe someone can elaborate on why .040 is sufficient.
When I did mine I noticed the same thing with the difference in lengths.
Why would we not be shimming to the old lma height instead of just using the .040 thick? Whats weird is the new style spring (pcb-305) is supposed to be the same spring as the
pcb 003 with the difference being the length. So shouldnt we should be able to shim to that height without any issues like coil bind ect. Strange that using .040 wouldnt create some noise from the looser clearance too. I went with a washer that was in the .070's with thickness. Kinda split the diff some.

Like I said .250 x .040 has proven its self for years by many.
I chose to deviate a bit from that with no issues.

Maybe someone with some lma skills can explain why you dont shim to the old height.
I know it has worked for people either way, gap or none. HTH

 

1/4" is the bolt size of the washer that is supposed to be used. Not the actual OD. The standard 1/4" ID washers have the right OD to work with the springs. I personally used some 0.040" thk #10 fender washers which were a liitle larger in OD. I don't remember why 0.040" was the advised thickness. Bind height maybe? I'll have to do some searching.

 

I have found that .040 has proven itself over the years to work just fine. But I would like to know for sure before I put my head together if I should use .090 instead of .040.

 

In your opinion when you say " 1/4 have the correct od to work with the springs" im curious why would it matter since the floor is the floor regardless of diameter?

Wouldnt the surface its sitting on work the same regardless of size?

 

Yes as long as the washer sits flat in the hole and is larger than the spring it will work. The washers I used fit very well inside the head and didn't have much room to move. When I test fit the 1/4 washers they were a smaller dia and could slide around more than I liked.

I used #996 fender washers here.

 

oh 1/4 referring to the ID...gotcha.

Whats weird about the shim to height creating bind is assuming both springs are the same coil wise, the new b-series style (pcb 305) was shown by combustion contraption to bind at about .400 or 145 lbs pressure which means you should be able to shim the old style to the same height. Assuming the coils between the 2 are indeed the same.

.040 is tried and true, just would be nice to know how this came to be.

 

I think it's because of the taper at the bottom.
The washer sits higher then the lowest point of the hole.