80 SN 351W issues FINAL UPDATE

Wow, intake manifold replacement without pulling the distributor... would never have thought to try that. Interesting approach.

I agree that you need to go through your ignition system, the timing is especially suspect.

8122pbrainard wrote: MourningWood wrote: Backfiring suggests something amiss with the ignition, like timing. Do any work there? MrMcD wrote: I would put a timing light on this engine and watch the timing as your engine revs up. Timing should advance smoothly and consistenly as the RPM climbs from idle and it should stop climbing somewhere around 3,000-3,500 RPM with a maximum advance somewhere between 34 and 36 degrees. I don't know the exact factory setting off the top of my head but these numbers are very close.   This quick check will tell you if your distributor is properly advancing. If it is not working correctly you can have very poor performance. Sometimes the distributor weights get rusted and stop working or the springs rust out and allow total advance far too early. This is one of the basics needed before an engine can run correctly. . TRBenj wrote: I agree that you need to go through your ignition system, the timing is especially suspect. When you check the timing and see if the advance isn't rusted up, that's a good time to see if you have points or an EI conversion in the distributor.

Will do!

A little bit of my morning coffee came out my nose.... :)

I'm not positive but I don't think a Ford will run correctly if painted Chevy Orange.
(I run the 351W and it is a great engine but I'm still a Chevy guy at heart)

I happen t agree it is a known fact that Ford engines will not run well, they tend to skip and have bad plugs when painted Chevy orange. A can for Ford blue will probably fix the problem with no other work needed. Hope you get done in time to run it at the lake before it gets cold.

You mean like my Avalanche from Mexico or like a Toyota or vw from the US

I was on my work week (I work seven days on seven days off). I just moved the boat back to the driveway and will start your troubleshooting tomorrow.

I think you need to paint it Mopar baby blue and then change your firing order to 1 8 4 5 6 2 7 3 and give it a shot

If this engine is an 80 RR 351 with the original cam that would be your firing order. What you listed today and a while back is the early 302 RR firing order

I looked back thru this thread and didn't see any mention of the firing order discrepancy.

Like you said, counter clockwise around the cap and your cylinder numbering is correct

It should be RR. It wouldn't run at all if it was normal rotation with the RR firing order.

You did mention that it was rebuilt in the 90's, maybe somebody used an early 302 cam which has the firing order you mentioned.

To check your firing order look at the thread in the link, On page 2 about halfway down there is a post on how to check your firing order with some small rags over the plug holes

You could do that to see what firing order your cam requires.

Read the whole thread, there may be some similarities with your problem

link

What should the timing be at idle, what about at high rpm? Also what RPM to i set it to when I adjust the timing. Does the idle timing matter anyway? I don't think there is a way to adjust the curve on these.

What's my course of action if there are no visible timing marks on the harmonic balancer ? I have not rotated it through yet but I have a bad feeling ....

sailsail wrote: What's my course of action if there are no visible timing marks on the harmonic balancer ? I have not rotated it through yet but I have a bad feeling ....

Never seen one yet that was not marked TDC

15/16

Sounds like your making progress.
If your timing light is adjustable and you are setting base timing leave the light at zero and time the engine to 10. It is important that the engine be at idle when this is set so you won't have any mechanical advance coming in messing you up.
I think my 78 351W said to set timing at idle 650 RPM.
Set the timing, readjust the idle back to 650 and check the timing to make sure it did not move.
Now idle is set at a true 10 degrees base timing.
Next turn the dial on the adjustable timing light to 35 degrees and check your timing again with the engine now turning 3,500 Rpm.
Looking at your marks this time the timing should be pointing at 0, zero.
This will confirm your distributor is operating correctly and advancing to 35 degrees at 3,500 rpm.
When watching the timing Mark move as you bring up the RPM you should see it advance smoothly and consistently .

If your light has the advance dial, use it. You only need to see the TDC (0deg) mark on the balancer with an adjustable light.