Machine Shop found some EXTREMELY interesting info about our Blocks
Senior Member
Joined: Oct 2002
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From: Bridgeport, MI
Originally posted by Ruslow
Neal brings up a good point,How is the cnc measuring the deck ie. off of the cylinder centerline or off of the mounting dowels in the back?Stan
Neal brings up a good point,How is the cnc measuring the deck ie. off of the cylinder centerline or off of the mounting dowels in the back?Stan
I talked with our process engineers today that said there is a 50-micron twist tolerance over the length of the block. They also said to tell everyone that we do a one hundred point deck inspection on our deck surfaces. For flatness and we also perform a leak test on every block.
I'm not saying that mistakes are never made we all know better than that. I'm just saying that when it was said that the factory machined block was .007" out from end to end it was hard for me to believe.
I can't speak for the 5.4L block because we at Romeo do not machine that block I manage the 4.6L cast iron block dpt. on afternoon shift at Romeo.
Suavy
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Joined: Oct 2002
Posts: 2,840
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From: Bridgeport, MI
Originally posted by 01 XLT Sport
This is an interesting thread. The question I would have is first I am sure there are allowable tolerance due to mass production therefore are these tolerance derived from what Ford has currently specified as “stock”?
In other words, are these tolerances acceptable for a stock motor but unacceptable when you begin to modify the stock design parameters by adding more hp items to the motor which then cause more stresses?
Have any stock motors shown symptoms of having issues with the # 7 bearings, lifting heads etc? When I state stock I mean just that, no pulleys added, no juice added, no tunes added etc, just your ordinary stock motor like I have in my L.
I know our transmission with the stock motor are running close to the edge so could it be very likely are stock motors are running close to the edge due to tolerances specified by the engineers in order to keep cost down in production BUT that the design tolerances are acceptable for a “stock” motor?
I know from my limited experience that generally nothing has to be perfect “unless” you are going to be running at the edge of the envelope then every 0.001 or 0.0001 is the difference like night and day.
This is an interesting thread. The question I would have is first I am sure there are allowable tolerance due to mass production therefore are these tolerance derived from what Ford has currently specified as “stock”?
In other words, are these tolerances acceptable for a stock motor but unacceptable when you begin to modify the stock design parameters by adding more hp items to the motor which then cause more stresses?
Have any stock motors shown symptoms of having issues with the # 7 bearings, lifting heads etc? When I state stock I mean just that, no pulleys added, no juice added, no tunes added etc, just your ordinary stock motor like I have in my L.
I know our transmission with the stock motor are running close to the edge so could it be very likely are stock motors are running close to the edge due to tolerances specified by the engineers in order to keep cost down in production BUT that the design tolerances are acceptable for a “stock” motor?
I know from my limited experience that generally nothing has to be perfect “unless” you are going to be running at the edge of the envelope then every 0.001 or 0.0001 is the difference like night and day.
I am no expert at this I'm just the manager, if you guy's have any more questions I can try to get you the answers.
Suavy
Last edited by Suavy; Jan 25, 2005 at 12:23 AM.
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Joined: Mar 2001
Posts: 830
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From: Plymouth, MI
The Ford flatness spec for the head decks on the 5.4L block is 6 thou from the best fit plane. In other words if one spot is 2 thou low, no other spot can be more than 4 thou high.
I've seen data on at least a dozen new blocks and several used blocks and none of them varied by more than 4 thou.
I've seen data on at least a dozen new blocks and several used blocks and none of them varied by more than 4 thou.
Senior Member
Joined: Aug 1999
Posts: 5,438
Likes: 1
From: Palm Coast, FL
UPDATE ON THE MACHINING
I just picked up Robs motor and discussed what info the engine builder found that I previously mentioned....
Basically what it was, was that the left deck of the block, was not flat. When he did the first light pass on the deck, it only touched on one small spot on the back, then on one of the oil return holes (interesting considering the external oil leakage problems) and then it hit the whole area around the two front cylinders. It required a 3 thousands mill to clean it up fully.
Now on the right deck, it was also out of whack. BUT, it was also not even with the left deck! The deck height on the right side was 4 thousands taller, so to make both decks even, it required a 7 thousands mill on the right side.
What my engine builder found interesting, was that the measured deck height on this block, was UNDER what the Ford spec was in the motorsport book.
As for that 4.6 block, I was mistaken, it was also a used block. However it had all the exact same issues. The deck heights were NOT even, and they were both undersized as per the Ford motorsport spec.
So that's the scoop on what he found.
Basically what it was, was that the left deck of the block, was not flat. When he did the first light pass on the deck, it only touched on one small spot on the back, then on one of the oil return holes (interesting considering the external oil leakage problems) and then it hit the whole area around the two front cylinders. It required a 3 thousands mill to clean it up fully.
Now on the right deck, it was also out of whack. BUT, it was also not even with the left deck! The deck height on the right side was 4 thousands taller, so to make both decks even, it required a 7 thousands mill on the right side.
What my engine builder found interesting, was that the measured deck height on this block, was UNDER what the Ford spec was in the motorsport book.
As for that 4.6 block, I was mistaken, it was also a used block. However it had all the exact same issues. The deck heights were NOT even, and they were both undersized as per the Ford motorsport spec.
So that's the scoop on what he found.
