FBO plate over advancing

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RustyRatRod said:
Misleading. You're being too nice. They are flat out WRONG. When you pay 45 bucks for a thin piece of metal, it ought to at least be RIGHT.
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That is one of the reasons I made my own, it took me 3 variations to get it right, but now it is dead on.
 
I wouldn't sell them, but I will give to anyone that wants it the STL, or STEP file for it. Then they can 3D print, or laser cut their own.
 
Agent_Orange said:
one more observation:

Halifax got me thinking, my tbar is a 15, so 30* at the crank. I wanted 16* at the crank, so roughly half the slot. The picture below has the 16* slots under the tbar. The inside of both pieces are flush, the fbo plate should restrict the travel by more than it does.

my micrometer needs a new battery, so I wasn't able to get slot readings last night

View attachment 1716141203
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Excellent comparison. You can actually see how inaccurate the plate is with no question whatsoever. The plate slt in that position "should" be about half the length of the slots in the governor and clearly it's not. We're being fleeced.
 
halifaxhops said:
Thanks Rob always wondered that one.
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Me too so I called him a while back. Took several times but I finally got him. The labor is basically the same to weld and file the slots as it is to install the plate. Tried and true old school wins out again.
 
It does. I just have so many advance cams I do not have to do that. I have seen some really bad ones done then must have been finished with a really corse file and it would hang the weights up. Got to make sure that slot is smooth which I am sure you know.
 
halifaxhops said:
It does. I just have so many advance cams I do not have to do that. I have seen some really bad ones done then must have been finished with a really corse file and it would hang the weights up. Got to make sure that slot is smooth which I am sure you know.
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Oh yeah. You don't need it hangin up on you. That'd suck. But still, in cases like mine, when you need a really SHORT curve, there's no ready made governor for it, so the choice is clear.
 
If you have ever read "Old Reliable The Practical 440 Race Motor" by Don Dulmage, he tells in depth about how to remove and modify the distributor governors. He was a big fan, because of the basically zero cost involved. He was a true innovator of how to build a budget race engine. If you follow his 440 recipe, you will have an honest 500HP 440 on a shoestring.
 
Rusty all 4 I installed in my cars are inaccurate as well. I put them in the least advance slot (10 degrees) but have gotten more like 14 degrees. V8 and slant 6.
 
Have any of you guys let him know his plates are inaccurate? Maybe he can make the proper modifications to it.
 
mopowers said:
Have any of you guys let him know his plates are inaccurate? Maybe he can make the proper modifications to it.
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Yup. I surely have. He wasn't what I'd call rude about it, but the response I got was blunt, curt and more than "to the point".
 
Well, I just installed and FBO plate in my dizzy with the intent to limit it to 10* of mechanical advance on my 340/416. I went with one light spring and one medium, based on threads I searched here.
It's bedtime now but I'll fire it up tomorrow and set/check the timing curve & play with the vacuum advance and report back with results asap. I may still end up going the old tried & true weld method before all is said and done. The FBO "seemed" like an easy way to try different curves. Now I'm a little skeptical. LOL
-still learnin'.
G'night!
 
I spent some time looking in junk yards for electronic ignition advance plates and found a factory 11° plate in a motor home distributor. This was gold to me as I don't have a welder. I am setting up my 340 with 12° initial advance and get 22° crank degrees advance from the distributor for a total of 34° total mechanical advance.

DDG has some videos on this topic as well: and
But there are many more.
 
RustyRatRod said:
I too have found the FBO plates to be inaccurate on both slant sixes and V8s and I've made mention of it here before, but was run over like a freight train with disagreement when I said something about it, so I just kept quiet after that. My experience on the slant 6 was the same as what's presented here. It was getting way too much advance for the given slot length. If you think about it, from the slant 6 to the V8s, those slot lengths should be the same for a given advance amount, since the distributors are the same in that regard. .....and now people with no experience there will come out to argue with me again. But I've done actual measurements and comparisons. Even done some parts swapping between slant 6 and V8 distributors and there was no difference.
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RRR, Is it okay if I pm you about questions on the/6?
 
Well, I fired mine up with the new FBO limiter plater plate set at the lowest level, 10* of crank advance and... it produced 16* with no vacuum advance. I had the idle set at 24* and it shot up to 40*.
There you have it. I'd say it doesn't do what it says it will do, with any kind of accuracy. Save you're money and weld up the slots to what works properly for your combo. I also noticed my fuel pressure is very low so I'm going to replace the mechanical pump now with a new Carter M6270 Super Strip that I have in the box. The AFR was going very lean at higher rpm. I'll get off this thread and start my own going forward. Just wanted to share my own findings, in case it helps anyone who might be thinking of getting one of these limiter plates. Mine will be available if anyone wants one. LOL
 
MobileCustoms said:
Well, I fired mine up with the new FBO limiter plater plate set at the lowest level, 10* of crank advance and... it produced 16* with no vacuum advance. I had the idle set at 24* and it shot up to 40*.
There you have it. I'd say it doesn't do what it says it will do, with any kind of accuracy. Save you're money and weld up the slots to what works properly for your combo. I also noticed my fuel pressure is very low so I'm going to replace the mechanical pump now with a new Carter M6270 Super Strip that I have in the box. The AFR was going very lean at higher rpm. I'll get off this thread and start my own going forward. Just wanted to share my own findings, in case it helps anyone who might be thinking of getting one of these limiter plates. Mine will be available if anyone wants one. LOL
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I would just weld up the plate a bit as you know you don't need much. At the end of the day I personally don't think there will be much noticeable difference in a few degrees of initial timing as long as the all in is right. It will be much better than it was and with lighter springs it will be up to all in much faster anyway.
 
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MobileCustoms said:
Well, I fired mine up with the new FBO limiter plater plate set at the lowest level, 10* of crank advance and... it produced 16* with no vacuum advance. I had the idle set at 24* and it shot up to 40*.
There you have it. I'd say it doesn't do what it says it will do, with any kind of accuracy. Save you're money and weld up the slots to what works properly for your combo. I also noticed my fuel pressure is very low so I'm going to replace the mechanical pump now with a new Carter M6270 Super Strip that I have in the box. The AFR was going very lean at higher rpm. I'll get off this thread and start my own going forward. Just wanted to share my own findings, in case it helps anyone who might be thinking of getting one of these limiter plates. Mine will be available if anyone wants one. LOL
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Yeah, I haven't seen one that does what it advertises yet. Not one. I had my fingers crossed for you though.
 
Maybe someone should point Don to this thread. I ain't doin it. I already tried to talk to him. He wasn't havin it.
 
I purchased mine through his ebay page, so I'm able to return it. I provided an explanation of my results
 
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