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Discussion Starter #1 (Edited)
My 2.3L timing chain failed drastically.. So I swapped to a 2.5L successfully (30,000 mile motor for $325 after old engine core return [8D]) .
The swap went well and I have been smoothing a few things out here and there. overall easy swap would recommend. will likely do a write up about it soon.

One thing that I haven't been able to smooth out is a weird shudder bellow 3k rpm.

It happens when I am very light on the pedal to maintain steady cruising speed on non highway roads (35-45 mph)

Ive checked everything over several times and still can't figure out why it is doing this.. The stage 1 crower cams aren't supposed to have a lope that significant, and they never did this on the old engine. Been working with Tom on the tune to try to smooth this out, but we can't get it to go away..

Thinking that I really need to tune the cams, but really don't want to take the engine back out, remove timing cover and spend $400 on timing gears.

Has anyone tuned their Dtec cams without adjustable gears?? I know it wouldn't be easy..
Thinking to use the TDC notch on the end of the cams as reference and welding up a tool/jig/thingy to set 1° or 2° difference from TDC.

Idk [dunno] feedback appreciated
 

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What plugs are you running ? The Autolite 103 plugs are .750 reach the 2.5 takes .980 reach get a set of Motorcraft SP463 plugs and try those

The shorter plug keeps the plug up in the plug hole and reduces your timing among other things

I dont remember you mentioning any issues with the way it drives a log of this would help

Tom
 

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Discussion Starter #4
Yes ive done a vvt delete. You have to do a vvt to make sure oil pressure is routed correctly through the valve train. Using the stock 05 st wiring harness.

What plugs are you running ? The Autolite 103 plugs are .750 reach the 2.5 takes .980 reach get a set of Motorcraft SP463 plugs and try those

The shorter plug keeps the plug up in the plug hole and reduces your timing among other things
Ah gees. I didn’t know the 2.5 had a different reach. I’ll get those plugs in soon and shoot another log over

I dont remember you mentioning any issues with the way it drives a log of this would help
Ive sent several logs with snippits of this happening. The last 3 ive sent ive included time stamps of where its happening.
The log really doesn't reflect it in the load plot, but its very noticeable in the car
 

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Discussion Starter #5
Motorcraft SP463... Is there a copper equivalent? I’d preffer copper plugs for the benefits
 

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Discussion Starter #7
got em! smoothed everything out a ton. low end power is back.

I just got your latest tune, I'll flash the car and data log it with the new plugs. Its still slightly hesitant, expecting that to be because the tunes have been from data taken with the wrong plugs
 
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