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Addressing Timing Chain Stretch in SOHC Engines

4:50
52:58
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At 4:50 in

The Ford 427 SOHC: Through The Eyes of Legendary Engine Builder Ed Pink (His LAST Engine Build)

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What happens here

Ed Pink describes the biggest challenge with the SOHC engine when used with superchargers and nitro fuel: the timing chain would stretch under immense load, causing timing issues. Traditional methods of adjusting timing (like "throwing more spark lead in") were unreliable. After much experimentation with fuel and ignition systems, Ed Pink realized the core problem was the chain stretch affecting valve timing. His solution was to create an "offset" in the camshaft timing, effectively giving each bank of cylinders a different cam spec to compensate for the stretch. He installed the drive cam (leading bank) with split overlap and the trailing cam with a 7-degree advance. This simple change dramatically improved performance and reliability.

Goal: Detail Ed Pink's critical innovation to overcome timing chain stretch issues in supercharged Ford 427 SOHC engines for drag racing.

Tools and materials

  • Camshafts N/A — Key components in the timing adjustment
  • Ford 427 SOHC Engine Ford — Visual reference during explanation
  • Timing Chains N/A — The component experiencing stretch

What they say

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they're paying for their stuff they want to have somebody doing things that knows what they're doing rather than just close their eyes and going for it we ended up with the 426 running 75 degree sparkling 75 degrees this is barely halfway [Laughter] that's what you had to have because of this decide back in the day if you didn't run one of my engines you didn't win and I'm going to tell you didn't qualify thing was you had a John Butera car in a dead pink engine and you were killer that might be the opening line of this video if you didn't have one of my engines you didn't win yeah we had that about two years you go to a big drag meat and there'd be like uh 16 say 16 money cards and 10 or 12 of them would be a Butera car and it had pink engine when you heard one of ours fire up you knew right away whose it was because I kept the sparkling thing pretty quiet yeah yeah yeah that much more CC's the Piston guys that had to done just like a nightmare then for them to fit me that'd be just a massive Dome and but remember also we were running low compression so you know imagine hey there were about six and a half seven to one okay all right so then all right it was almost a flat top piston so making that move from Chrysler to Ford was actually a huge step for you yeah it was a huge step luckily I I did have a little bit of 426 experience not much most of them was all 392 experience in the 427 is a Hemi yeah it is a Hemi okay yeah so what happened the first time you tried to run this with Nitro the first time we tried to run it with Nitro it ran okay and uh the biggest thing that I noticed over the Chrysler engine is when we ran it one side complete side of the spark plugs looked like they hadn't done anything and the other side were just about burned out I tried all kinds of things to try to fix it I tried changing the fuel system I tried changing the ignition system and nothing nothing would fix it nothing changed it it was always the same I got to looking at the chain thing I had to right cover off the engine had to change oil on it looking at it and then turning the engine over dawned on me that there's a chance that the chain is going through stretch because the fact when the engine was designed by Ford it wasn't designed for a Supercharger I'm sure there are many times at the end of the 9000 RPM by the time I get to the end of the quarter mile especially on a good run so it saw RPM that the engine didn't initially see it saw the Boost going into the…

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