New timing chain set installed

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BigBlockMopar
Posts: 332
Joined: Sun Sep 02, 2007 3:29 pm
Location: Netherlands
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New timing chain set installed

Post by BigBlockMopar » Sat Dec 23, 2017 6:46 pm

Just prior of my planned engine swap, where I will replace the 8.6:1cr 318ci engine in my Dart for a 11.3:1cr 360ci, I decided to replace the timing set on the 318.

I already replaced the timing set in this engine some 4-5 years ago too, but I installed a simple/cheap/stockish timing chain and sprocket set. Reason was I thought I would be swapping engines much sooner.
In the beginning I felt an obvious increase in low rpm torque with the new timing set. But as those few years passed, that nice low rpm torque felt missing.

As a test I tried turning the engine's crank by grabbing the pully and try to feel for slack being taken up as I turned it both ways a couple of times.
To my dismay, I thought I could feel a noticable amount of play in the timing chain already.

I couldn't stand it anymore and decided to open up the 318-engine on the front and have a look at the timing chain.
Sure enough, the chain was rather sloppy and had retarded the cam some 4-5 degrees already in those 4-5 years.

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This time I had a lightly used double roller timing set laying around, with a 3-way crank sprocket. I didn't have time to properly degree the stock cam, but went ahead and installed the timing set on the 4-degrees Advanced keyway and buttoned up the engine again.

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After resetting the timing mark in the digital MegaSquirt ECU again I took the car for a spin back home.
At first I didn't notice *that much* difference during the 20min drive.

But as days progressed I started noticing the engine was a bit happier a low rpms.

Decided to start playing and retuning the digital ignition advance map and curves again, and that's where I started finding more improvements.
I was able to lessen the timing a few degrees, mostly in the low rpm ranges upto around 2500 rpm, with a more noticable increase in torque and acceleration as a result.

During the few trips I've made so far I've already noticed higher engine vacuum during light acceleration and steadystate highway driving.
https://www.bigblockmopar.com
'73 Dodge Dart - 318ci - IMPCO E vaporizer / 425 mixer - A518-OD trans - 3.55 gears - 225/50/17" tires.


storm
Posts: 559
Joined: Wed Jan 10, 2007 10:10 pm
Location: NSW, Australia

Re: New timing chain set installed

Post by storm » Sat Dec 23, 2017 8:50 pm

Any change in fuel consumption?
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BigBlockMopar
Posts: 332
Joined: Sun Sep 02, 2007 3:29 pm
Location: Netherlands
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Re: New timing chain set installed

Post by BigBlockMopar » Sun Dec 24, 2017 5:27 am

I'm still running on the same tank so don't know yet.
It would surprise me if mileage didn't improve by this, but I've been "surprised" with lack of change more often then I like to remember...
https://www.bigblockmopar.com
'73 Dodge Dart - 318ci - IMPCO E vaporizer / 425 mixer - A518-OD trans - 3.55 gears - 225/50/17" tires.

BigBlockMopar
Posts: 332
Joined: Sun Sep 02, 2007 3:29 pm
Location: Netherlands
Contact:

Re: New timing chain set installed

Post by BigBlockMopar » Wed Apr 04, 2018 4:44 pm

Small update:
No change in mileage. Still lousy.
But then again, temps have dropped considerably since the timing gear refresh in Dec, so my mileage was bound to drop like a rock anyway.


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https://www.bigblockmopar.com
'73 Dodge Dart - 318ci - IMPCO E vaporizer / 425 mixer - A518-OD trans - 3.55 gears - 225/50/17" tires.

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