Timing chain and cover issues 72 Mach1

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The Mechanic

Member
Joined
Oct 12, 2023
Messages
5
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Location
Hudson NY
My Car
72 Mustang Mach1
Hi. I tried searching and came up with nothing. Right now I have my friends Mustang apart to replace the timing chain and cover. We did the water pump a while back but there was a leak on the passenger side front and it really looked like it was coming from where the timing cover meets the block.
We ordered a new cover and once we got into it the timing chain was pretty loose so we ordered a chain and gears too. It's a name brand, can't remember which this second. The numbers on both cam gears are the same too.
Starting reassembly and the pin on the cam gear would not stick out far enough for the fuel pump eccentric, (one piece). It is the longer pin. So I kept it centered and tightened it up.
I put the oil slinger on the crank and went to out the new cover on. It would not sit flat. Interference with the slinger and fuel pump eccentric.
So I took everything back off and started comparing. The front face of the new cam gear sticks out a small amount more than the old one. Also can't just use the new chain on the old gears, the teeth on the new one are more pointy.
The timing cover inside in the crank area of the old cover is beveled in while the new one has more of a lip.
The old cover is a bit beat up and a couple of the threaded holes are partially stripped. I think we could use helicoils for those. The bottom edge where the oil pan/crank seal is kind of chewed up.
I'm going to next jack up the Stang, take the starter off and find the numbers. It's supposed to be a 302 that was rebuilt. It has a Lunati can in it.
We are just a little bit baffled right now. I'm including pictures.
Has anyone else ran into a similar issue? The new cover is made in China. I searched for the old one by part number and found a few used on eBay.
Thank you for any insight on this.
Alan

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The earlier Ford engines used the timing gear set which had a flat faced cam gear, "long" dowel pin, and one-piece fuel pump eccentric which is drilled for the dowel to just extend into it to keep it from rotating. These later year engines ('71-'73) utilize a cam gear with an eccentric mounting surface that has a uniquely shaped mounting pad for the fuel pump eccentric, which is also different from earlier designs in that it is two-piece and designed to have the center mount solidly against the cam gear with the outer ring allowed to spin freely ( less rotational drag and wear ), and this set-up uses a "shorter" cam dowel pin so that the "tang" on the stationary center eccentric will fit into the dowel hole to keep it from spinning. Yes, the earlier solid eccentric is thicker from mounting surface to outside edge, so there will be an interference not allowing the timing cover to sit flat properly, when trying to install the early eccentric on a later engine. This is an important detail to know when working on Fords, or any engine, as Ford Chevy, Pontiac, Chrysler, AMC, all of them, make design changes that are in the manuals, and are often overlooked . I worked with an engine builder who had years and years of experience building almost predominately Chevrolet engines, and he was skilled, intelligent, good builder, but ordered the wrong timing sets a handfull of times for Ford engines . He used to tease me about "...those fuc##ing Fords..". Yeah, yeah I'd reply, read the manual...LEARN !
 
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Hi. I tried searching and came up with nothing. Right now I have my friends Mustang apart to replace the timing chain and cover. We did the water pump a while back but there was a leak on the passenger side front and it really looked like it was coming from where the timing cover meets the block.
We ordered a new cover and once we got into it the timing chain was pretty loose so we ordered a chain and gears too. It's a name brand, can't remember which this second. The numbers on both cam gears are the same too.
Starting reassembly and the pin on the cam gear would not stick out far enough for the fuel pump eccentric, (one piece). It is the longer pin. So I kept it centered and tightened it up.
I put the oil slinger on the crank and went to out the new cover on. It would not sit flat. Interference with the slinger and fuel pump eccentric.
So I took everything back off and started comparing. The front face of the new cam gear sticks out a small amount more than the old one. Also can't just use the new chain on the old gears, the teeth on the new one are more pointy.
The timing cover inside in the crank area of the old cover is beveled in while the new one has more of a lip.
The old cover is a bit beat up and a couple of the threaded holes are partially stripped. I think we could use helicoils for those. The bottom edge where the oil pan/crank seal is kind of chewed up.
I'm going to next jack up the Stang, take the starter off and find the numbers. It's supposed to be a 302 that was rebuilt. It has a Lunati can in it.
We are just a little bit baffled right now. I'm including pictures.
Has anyone else ran into a similar issue? The new cover is made in China. I searched for the old one by part number and found a few used on eBay.
Thank you for any insight on this.
Alan

New
View attachment 89718
Old
View attachment 89719

New
View attachment 89720


Old
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View attachment 89722
I am rebuilding my 1971 H code engine and bought a Cloyes timing gear set up but didn't realize that it was thicker so I can't use my stock fuel pump. When you have lemons then make lemonade. I decided to cut off the pump arm and am using an electric pump as the fuel comes out of the tank. The car now is more theft proof with the toploader also as it will start up but not drive very far. I keep the signal transmitter on the key chain and a hidden bypass switch in case I didn't have that set of keys with me at any time. Any comments? Thx, Bill
 
The earlier Ford engines used the timing gear set which had a flat faced cam gear, "long" dowel pin, and one-piece fuel pump eccentric which is drilled for the dowel to just extend into it to keep it from rotating. These later year engines ('71-'73) utilize a cam gear with an eccentric mounting surface that has a uniquely shaped mounting pad for the fuel pump eccentric, which is also different from earlier designs in that it is two-piece and designed to have the center mount solidly against the cam gear with the outer ring allowed to spin freely ( less rotational drag and wear ), and this set-up uses a "shorter" cam dowel pin so that the "tang" on the stationary center eccentric will fit into the dowel hole to keep it from spinning. Yes, the earlier solid eccentric is thicker from mounting surface to outside edge, so there will be an interference not allowing the timing cover to sit flat properly, when trying to install the early eccentric on a later engine. This is an important detail to know when working on Fords, or any engine, as Ford Chevy, Pontiac, Chrysler, AMC, all of them, make design changes that are in the manuals, and are often overlooked . I worked with an engine builder who had years and years of experience building almost predominately Chevrolet engines, and he was skilled, intelligent, good builder, but ordered the wrong timing sets a handfull of times for Ford engines . He used to tease me about "...those fuc##ing Fords..". Yeah, yeah I'd reply, read the manual...LEARN !
Thank you very much. This helps. I am more understanding the differences in the 302 engines.
 
So we have figured out that the engine is a '74 302. 2 bolt main
D4DE 6015 AA 4h15 is the number on the block.
It seems the timing chain that we took out is from before '71.
I think we are going to get a new timing chain for the older model. I'm also going to repair the original timing cover.
 
So we have figured out that the engine is a '74 302. 2 bolt main
D4DE 6015 AA 4h15 is the number on the block.
It seems the timing chain that we took out is from before '71.
I think we are going to get a new timing chain for the older model. I'm also going to repair the original timing cover.
Actually we decided to get the narrower fuel pump eccentric and keep the timing chain we have now.
 
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