1975 W100 360 Falls on its face under load

[buzter]

That was in the back of my mind...but with an engine with only 80K on it?? That is also why I dismissed it...Thing is after the stumble..it runs great...It runs better now than it ever has...other than the stumble from taking off fast..or going under a load...if you slightly push foot pedal down it will go fine...so that again is why I did not think timing chain...but open to any thoughts like I said..I am at wits end on this...

[Gordon Maney]

A timing chain should last longer than that, but some don't. It could also be a sprocket wear problem. It should be evaluated. The very best way to do that is look at it. This requires disassembly.

Also, I still want to know if this engine has a 2-piece vibration dampener that could have rotated, moving the timing mark.

[buzter]

And I do believe the vibration Dampener is a one piece

[Gordon Maney]

Find out for sure. Look at it closely.

[Don Williams]

You guys may get tired of my suggesting this but it worked so well for me I really can't emphasize it enough.

My son's 318 had similar symptoms, especially the having to feather the throttle part. At 110,000 the timing chain was worn enough to jump a couple of teeth on the sprocket. I think at 80,000 yours is no doubt stretched some and is partially responsible for the problem but I doubt it needs to be replaced.

After a new timing chain my son's 318 still didn't run like it should. I decided to try setting the timing and adjusting the carb using a vacuum gauge instead of a timing light and tachometer. Made all the difference in the world. No more feathering the throttle. Slam the pedal to the floor and the engine just picks up and goes. You can google for the procedure, it's easy to find info on it. The procedure is no more complicated than using a timing light and tachometer.

Tuning the engine using a vacuum gauge compensates for the wear on an older engine as compared to a new one.

[buzter]

Don that is where I am at..I am going to try that this weekend...I have it now at about 11-12 degrees..but gonna take it a bit more..like I stated I do have a mild rv cam in the truck..but cant find the info on what I put in to know where it should be...I have had the truck for almost 20 years...shes a little rusty..but I tell ya what..she can move some snow..thanks for the info

[Gordon Maney]

I would never put in all the labor to disassemble to visually inspect and touch an 80,000 mile timing chain and not replace it while I was that far. The parts are too cheap.

[buzter]

Oh I totally agree Gordon..if I do get to that point of checking the timing chain....I will definitely replace..

[Don Williams]

Agreed! I didn't mean to suggest that the timing chain not be replaced if disassembled for inspection. I just suggest trying tuning with the vacuum gauge before tearing the front of the engine down.

[buzter]

Well lets see what that brings this weekend...I hope there is a light at the end of the tunnel...and an end to the madness...

[greg rider]

I have been reading this and I wonder if your distributor is shot. It may not be advancing enough when you need it or it may be stuck in advance too much. Initial timing should be around 6 or 7 degrees. Go to a boneyard and get a distributor and put it in, see if there is a difference. With the low usage of your truck it is easy for the parts inside to stick. Advance can be checked with a good timing light that has that feature. As stated earlier though, the vaccuum gauge method is best. Small adjustments at a time with the carb then the disty.

[buzter]

In the back of my mind...I was wondering about the springs and all in the distributor...there is no play in it at all..but I do hear what you are saying...wonder if when I take intake off...take dist. apart and clean and refurb it??

[buzter]

Like I stated right now with timing I am at say 12 BTDC...that is with a rv cam installed..everything else factory

[Gordon Maney]

there is no play in it at all

Specifically what does this phrase mean?

[buzter]

That I can not feel any play when grabbing the dist and moving it...as far as internal..I can not say