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Discussion Starter · #1 · (Edited)
Hey guys! I have a '96 Romeo iron block and I just finished assembling the shortblock. Per many ModFord forum threads, I liked the idea of the fully flanged #5 thrust bearing. My crank has been turned 0.010", so I ordered the King set MB5219SI0.25. I couldn't find any information on why that entire bearing set wouldn't work for the Romeo iron block, so I went with it. Bearings came in and everything went together beautifully. Main bearing clearance, rod bearing clearance, rod side clearance, and crank endplay were all right where I wanted them. Crank spun freely in the block, and the entire rotating assembly spins over nice.
My question is that I recently came across multiple posts saying that the MB5219SI thrust bearing, or bearing set for that matter, would NOT work in a Romeo iron block. Why is that, and do I have anything to worry about? I used the entire MB5219SI0.25 main bearing set in my engine. Just curious if it is hit or miss with different variations of the iron block, or if it is something I am not seeing and these bearings shouldn’t be run. Appreciate any info you guys can give me!
 

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The 5219 bearing set was made for a special version of the engine that was used by Ford from January of 1991 to December of 1992. The engine was a SOHC 16 valve LNG engine if my memory and today's information is/was correct. I stumbled over it in the King Bearing Catalog while searching for something else. Ford used a Romeo cast iron block for this engine. The thing that caught my eye was the #5 thrust bearing because it was both fully flanged and also had no registration tang on the bearing OD. Digging through bearing specs the bearing insert used a main web thickness that was identical to the Teksid and WAP aluminum blocks.

I ordered a set of the bearings to investigate and in fact the #5 upper bearing insert exactly fit the aluminum blocks and the absence of a registration tang meant no fancy massage work to install the inserts. The MB5219 lower had a registration tang in the wrong location to fit either the Teksid or the WAP baluminum blocks. Additionally all of the other bearings in the set had registration tangs that did not align with any of the other bearing saddles in the aluminum blocks either so they basically became throw away bearings. To complete the bearing set a MB5281 bearing set needed to be ordered to get bearings for journals 1 - 4 and the lower flanged insert for #5 thrust.

You discovery of the 5219 bearing set fitting the your iron block is good news for you — if that is true. Br sure to check the #5 thrust upper to make sure it fits the upper saddle webbing in the your iron block. If it is loose then it can not be used. If this bearing set fits your block it will be the first current day iron block application I know of that the bearing set works for. That would open it up for use by a number of iron block enthusiasts.

Let us know what you discover.


Ed
 

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Discussion Starter · #3 ·
Yeah I mean as far as I know, everything is perfect. The upper thrust bearing fit firm in the #5 saddle like it was meant to be there other than the bearing not using the locating tang. Everything went together perfect and all of my clearances were great. End-play was 0.0065”, main clearances were 0.0024-0.0026”, and rod side clearance was right at 0.020” across all of them. If you see anything in the pictures that looks wrong, please let me know.
 

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Discussion Starter · #5 ·
Does anybody know if there is any differences in the 91-92 iron blocks vs the later iron blocks? Have any other people tried these bearings in their later iron block? If so, I’m curious to know what didn’t work for them. Seems like most if not all of the chatter has been about aluminum blocks
 

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I know they will not fit the original Cobra iron block but uncertain about others because I don't use iron blocks for engine builds. It may be that you have discovered a very attractive bearing alternative for Iron block engines Bryan.


Ed
 

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The #5 thrust main upper shell was too wide for the #5 main web in the block and would slide back and forth.

Correction, it was not the Cobra block it was the Boss 5.0 iron block. There is a good chance your block and the Cobra block are virtually identical.


Ed
 

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Discussion Starter · #9 · (Edited)
As far as I know, literally every iron block is almost identical, with the exception of the changes between Romeo vs Windsor. The only changes they made to the iron block happened sometime in the early 2000's where they started casting the iron block with a little extra clearance on the center main web for the cobra crank that would come in 03-04, since the cast cranks didn't have a center counter weight. I had to clearance my block in this area for the center counter weight on my cobra crank. I also test fit King HP main bearings in my block before deciding to go with the King SI bearings. These HP bearings fit any 96-04 Romeo iron block. I see no reason why the 5219 bearing set wouldn't work in any late model Romeo iron block.
 

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Discussion Starter · #11 ·
I randomly thought about this thread today and I always hate when threads don't have a conclusion with the information you need. The King SI bearing set with the fully flanged thrust bearing work in iron blocks. They should at least work from the early 90's iron block through the 96-04 Mustang GT/Cobra iron block. I'm assuming all the way through the late model iron blocks that came in the panther platform as well because to my knowledge, they're all the same. I'm running the MB5219SI full set of bearings in my '96 Mustang GT block. My clearances were perfect, assembly was perfect, and now my car runs perfect with perfect oil pressure.
 
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