289 with 302 rods and pistons
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Tuned
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From: C-town,MD
289 with 302 rods and pistons
I have a 64 289 with basically a stock flat top piston. I got small cam for it and a set of AFR 165s. Well the piston hits the valve. Since I own a set of 302 rods and pistons from a XXX roller block that have valve reliefs, could I use them in the 289 with the 289 crank?
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How close is it? Can you cut a relief in the piston?
Going to the 302 rod will sink your pistons and kill compression.
But, I do not know the compression height on all those other than what is said about the 289/302 using the same piston, just a different rod. Later 302s....unsure.
Is the cam timing right? What cam do you have?
I reading through some Mustang stuff no one talks much about the piston/valve issue, but they do talk about springs and the pressed in studs. So if you have some really aggressive cam, you have more work to do anyway.
I had a 289 with flat tops with valve reliefs, but I think my cam was pretty mild.
Going to the 302 rod will sink your pistons and kill compression.
But, I do not know the compression height on all those other than what is said about the 289/302 using the same piston, just a different rod. Later 302s....unsure.
Is the cam timing right? What cam do you have?
I reading through some Mustang stuff no one talks much about the piston/valve issue, but they do talk about springs and the pressed in studs. So if you have some really aggressive cam, you have more work to do anyway.
I had a 289 with flat tops with valve reliefs, but I think my cam was pretty mild.
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289 and 302 engines used pistons that have the same compression height, pin diameters etc. The 289 used a rod that's 5.155 long and the 302 used a shorter rod of 5.090. This is how they made up for the difference in stroke from 2.87 to 3 inch. Best bet would be to use all of the 3 inch stroke 302 stuff in the 289 block. This would be easier if you use a 2M crank because the balance factor is the same as the 289. The 5.0 2MAE crank uses the 50oz hardware.
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Tuned
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From: C-town,MD
Correct, my 289 has no valve reliefs. I also don't have an early 302 crank. I was just looking for a quick fix with parts i have laying around. It appears that the 302 setup would lower the compression more than i would like. I'm just going to have to flycut the piston because apparently an XE256 cam is too much for this old engine
Cargo Master
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I think that it would easier to swap the pistons than to fly cut the old ones. If your heads will work with a "stock" Ford valve relief then I would switch to a set of the 5.0 pistons. They weigh the same amount as the 289 pistons, the compression height is the same but they come with valve reliefs and they are also cut for a metric ring pack which will reduce the friction a tremendous amount vs the stock 5/64 ring pack.
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Tuned
Joined: May 2017
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From: C-town,MD
I think that it would easier to swap the pistons than to fly cut the old ones. If your heads will work with a "stock" Ford valve relief then I would switch to a set of the 5.0 pistons. They weigh the same amount as the 289 pistons, the compression height is the same but they come with valve reliefs and they are also cut for a metric ring pack which will reduce the friction a tremendous amount vs the stock 5/64 ring pack.
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Brett Foote
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Compression height is a measurement of the piston from the centerline of the pin to the top of the piston.
Deck height clearance is the issue with the shorter rod in your case.
You have nothing to lose trying to cut those pistons if you have the right tool. Good luck!
Deck height clearance is the issue with the shorter rod in your case.
You have nothing to lose trying to cut those pistons if you have the right tool. Good luck!
Cargo Master
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You're correct that the compression height is the same, but only when they are on their correct crankshaft. Because the rod is shorter, it makes the combustion chamber larger reducing my compression ratio to about 7.5:1. And I'm pretty sure I only need to cut the intake.
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Tuned
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From: C-town,MD
So you're saying swap the pistons but not the rods. Sounds like more work than i want to do. If i pull the piston I'm going to want new rings and bearings. I'm trying to not spend a lot of time and money on this engine because i will be pulling it to replace it with a much better one
Cargo Master
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Here you go! No engine removal required. Pull a head, put some clay on a piston, set the head back on and turn the crank.
Figure out where the reliefs need to be and go to town!
https://youtu.be/a1w6YoUm4gE
Figure out where the reliefs need to be and go to town!
https://youtu.be/a1w6YoUm4gE
