351W timing chain question

Reply Subscribe

Thread Tools

Search this Thread

Jul 31, 2011 | 02:33 PM

BossFan

Thread Starter

Elder User

Joined: Jul 2011

Posts: 609

Likes: 1

From: Stockholm, NJ

351W timing chain question

Since I was going to be replacing the timing cover gasket, I figured I'd replace teh timing chain while I was in there. I have no idea how many miles are on the engin in this truck, so I figured it would be cheap insurance. I ordered an Edlebrock double-roller fromSummit (part #7814) but I cannot get the keyways to line up.

I am breaking this into three posts so I can get to the 25 minimum to start posting pictures....(EDIT: I realized I had to become a premium member to post pics directly from my PC into the messages. Doh!)

Jul 31, 2011 | 02:35 PM

BossFan

Thread Starter

Elder User

Joined: Jul 2011

Posts: 609

Likes: 1

From: Stockholm, NJ

The factory cam sprocket shows the keyway at a slant when the truck when the two dots are lined up (picture 1) but the Edelbrock cam sprocket shows the keyway at a straight horizontal when the dots are lined up. There are no other 'dots'. Did I get the wrong part?

Hoping I can post pictures with next post...

Jul 31, 2011 | 02:51 PM

BossFan

Thread Starter

Elder User

Joined: Jul 2011

Posts: 609

Likes: 1

From: Stockholm, NJ

I put the pictures of the timing chains in my gallery (still not sure how to just attach them to a post). see how on the origianl sprocket, the keyway is on an angle when the timing marks line up but the new chain the keyway is straight across. What to do?

Jul 31, 2011 | 07:00 PM

xlt4wd90

Lead Driver

Joined: Sep 2003

Posts: 7,015

Likes: 208

From: SoCal

I don't think there's a keyway on the cam sprocket, but the pin hole below the bolt hole allows the pin in the end of the cam shaft to get phase locked to the sprocket.

Aug 1, 2011 | 05:42 PM

BossFan

Thread Starter

Elder User

Joined: Jul 2011

Posts: 609

Likes: 1

From: Stockholm, NJ

There has to be a keyway. Why else would there be 'slots' cut in the cam sprocket. Are you saying the hole for the fuel pump eccentric helps keep the cam phased?

I went on eBay and some of the timing chains listed there do have what appears to be the correct sprocket like this one:

Attached Images

Aug 1, 2011 | 09:29 PM

xlt4wd90

Lead Driver

Joined: Sep 2003

Posts: 7,015

Likes: 208

From: SoCal

Well, there is only one way that the cam sprocket will fit onto the cam, with that pin and hole. I don't recall seeing key ways on the few cams that I've installed.

In your first picture, where the old cam sprocket is installed onto the cam, was there a key?

Looking at the other pictures, the slots on the cam sprocket do not appear to be finished like the key slots on the crank sprocket. Oil slots?

Aug 2, 2011 | 05:04 AM

lew52

Postmaster

Joined: Jan 2009

Posts: 4,558

Likes: 2

Like xlt said , there isn't a keyway on the cam , just the pin that goes into the hole on the cam and sprocket , as long as the marks line up it shouldn't make any difference where the slots are....