Need help

[Mrowe1986]

Hi I'm new here and need a bit of help I have 1986 f150 2wd automatic 351w factory I had a replacement engine installed recently and have about 3500 miles on it the other day go to start it and it did start like it always does and I was letting it warm up and suddenly it just shut off like someone just turned off the key I tried restarting it but it whould not and then it backfired it sound like a cannon went off  what I found was the distributor gear teeth were gone on one side what would cause this and what kind of damage has this caused as well as when it backfired do think it damaged any thing I'm sorry this is so long I just need help fixing this it is my only ride and it is hurting me not having it running

[Gary Lewis]

Hello, and welcome!  But I need to ask some questions as I'm struggling a little bit getting my head around your post.

First, is your carb a 2bbl or 4bbl?  The 351W came both ways that year, and the 2bbl version had a computer and the 4bbl didn't. So we need to know what we are dealing with.

Second, was it running correctly just before stopping as if someone turned off the key?  Any backfires or poor running?  And especially, had the oil pressure been changing?

I ask the above because the crankshaft turns the timing chain, which turns the camshaft, which is geared to the distributor, which has a shaft down to the oil pump. I bought a 351W on which the oil pump seized, which stopped the distributor. But the engine was still spinning so it broke the teeth off of one side of the distributor. I wasn't there when it happened, so I don't know if there was a huge backfire, but I can see that could happen as things come to a screeching halt.

The fact that your dizzy has teeth broken off says the dizzy stopped while the rest of the engine kept turning. That can happen with either the oil pump or the distributor itself seizing. In either case you have the teeth that must be found. And the culprit must be found.

What warranty on the new engine do you have?  Hopefully you have one as it is possible damage has been done due to loss of oil pressure.

(And, by the way, it would help us help you if you could use a little bit of punctuation in your posts. We can only truly help if we understand, and it wasn't easy reading your post.)

[Gary Lewis]

I should also have said that if you have to troubleshoot it yourself, meaning you don't have a warranty, you should see if the distributor will turn freely. If it will, then see if the oil pump will turn. Do that by reaching down into the engine where the distributor sat with a socket tapped to an extension so it can't come off. I think it is a 5/16" socket, but don't remember for sure. But you want to engage the oil pump shaft and see it it turns. In fact, you can prove it works by using a drill to turn it, and you should see the oil pressure come up - with the key on.

[Mrowe1986]

I'm sorry this is my first time posting it is a factory 4bbl 4180 and it was running great no oil pressure problems at all it was running great all up till the night before that night it kept wanting to fall on it face when I would give it gas i would have let off the gas to get it going i got it home parked got up the next day and that is when all hell broke loose it had a bronze gear on it I don't know it that means anything

[Mrowe1986]

Thank you for  reading all that and helping me

[Gary Lewis]

No problem. It just takes a bit longer to work through things without punctuation.

Anyway, check the distributor to see if it turns easily, and if it does check the oil pump. Something caused the problem. But one question is what cam you are running. A bronze gear should work well with any combination, but something caused the gear to break.

So, check the dizzy and the oil pump and let us know what you find.

[Mrowe1986]

Hey I just wanted to let you all know it was my distributor it was frozen I'm now just waiting my new on that was ordered. what gear do I use in it do I go with the same or not the motor that is in it is a 1996 roller motor. Once again thank you for all the help as well for this website and all of the information provided.

[Gary Lewis]

I'm glad you found the problem, and appreciate you letting us know. And I'm glad this forum and website can help.

As for what gear to use, that depends on the cam in the engine.  If it is original to that engine you need one type of gear, but if it is a billet cam you need another. However, Engine Builder says that you can use a composite gear and it'll work with any cam.

And, by the way, note what they say for the bronze gear you had. 🙈