Does anyone know the size of the bolt that holds the rotor into the engine block. Currently the bolt that holds my rotor in rattled out and fell on the floor while I was driving. I think the thread that holds the bolt in is warn out and can no longer stay in there tight to hold the rotor tied so with engine vibration it rattles out and falls.

Does anyone know the exact specifications of the bolt so I can go pick one up maybe a size bigger so I can not have this problem again and I can tighten down the rotor.

 

Not sure what you mean by "rotor". The only rotor I know of is the one in the distributor, and that doesn't require a bolt.
Most all threaded bolts on the 20R block are either 8x1.25mm or 10x1.25mm.

 

Yes Fred its the distributor rotor bolt. In the image, the rotor that is upside down there is an eye whole on the left side of it. After the timing is set you tight it down with the bolt, that bolt fell out while I was driving home last night. I'm pretty sure the thread inside the engine block is worn out so I will need to add something in there so it wont rattle out again.

 

You mean the distributor hold down bolt, the rotor does not have a bolt.

It should be an M8x1.25 bolt with a 12mm head.

 

Yes, that is the one. And I did not know how long they are so I bought 3 sizes: 16mm, 30mm, and 25mm. Also I wanted to ask you guys what would be the best way to approach this? The bolt rattled out since the car is old im sure the thread on that engine block is worn out. I also purchased some 3M tape for thickening the thread. Would that work or is there some seize liquid that I have to add instead of the tape? Something that works better with the heat?

http://s21.postimg.org/6xhgclzyv/20160315_133056.jpg

 

That is the distributor hold down bolt as first80 stated.
You can try chasing the threads with a M8x1.25 tap. If that doesn't work, consider installing a short M8x1.25 stud. Use locktite on the threaded portion that goes into the head. Then slide your distributor over the stud and lock down with an M8x1.25mm nut with lock washer.
The stud will allow more torque without stripping the thread.

 

That's a good idea Fred, I will try that if this wont work correctly. I have to reset the timing now since the bolt fell out while I was driving I'm sure the distributor/rotor moved around a bit. The truck was not running correctly before the bolt fell out. My plan was to turn the truck and rotate the rotor until I like how it runs, I do not own a timing gun. Then adjust the carb a bit to run smooth. Drive it around and see how it runs.

Do you guys have any suggestions?

 

Hard to set timing without a gun. Most places like advance auto or auto zone have a tool loan program. Or just invest in one.
You can try setting your crank timing pointer so it sits at TDC on the compression stroke of your #1 cylinder, then install the distributor so the rotor rests on the #1 spark plug position on the distributor cap. Rough setting, but should get you running.
Remember, you don't need a lot of torque to lock the distributor down. This is why people end up stripping the threads on aluminum engine parts.

 

Im going to try renting one. I have never used one before does it come with instructions? Lol.. This is going to be fun.

 

You still have to do the initial time set up as described earlier. (you removed the distributor).
If no instructions with the light you can google the instructions.
You will also need a tach to set initial rpm,s.

 

If it starts and runs, simply advance it until it pings then retard just enough until it stops.

 

Its a simple process bro dont over think it. Make sure you use a lock washer too, should help keep the bilt from backing out (if the threads are good)

 

Also, if the threads in the head are bad I'd suggest using an insert or helicoil and fix it. If you use a stud it may interfere while putting in or taking out the distributor.

 

The stud is the same diameter as the bolt. Unless you put in something like 4" long , it'll work fine.
Helicoils can be tricky to install, especially in aluminum. You drill too deep and you could ruin the head. It's not the same as a sparkplug port where you can run the drill bit deep.
Besides, I suspect helicoils may be beyond the posters comfort level.

 

Thats why you go to the junkyard and practice lol. Or measure how far to drill and put a drill stop on the bit

 

I've done it a bunch, it's really not bad. Especially where that hole is, there is plenty of room for a drill. And if you don't have a drill stop like jetas said just measure and put a piece of tape around the bit and go slow..

But I do agree it may be beyond his comfort level.

 

Thanks for the info guys. These are all great ideas. I'm going to inspect the the damaged area and figure out what method to go for. The previous owner seem to use what ever made the truck run and the bolt that was in there could of been wrong all together. I do plan on keeping this truck for a while and I would like to make it run great. So if the threads are bad then I will look into doing the helicoils. They are not out of my comfort level just think it could be a little over the top. Also could I pick up helicoils at a auto parts store?

 

Yea i picked up a helicoil kit at pepboys years ago, came with the drill bit, thread tap, and the helicoils themselves. Might have come with a little tool to set the helicoil in place, cant remember

 

I bought my kit at napa. Initial kit price is kinda spendy, I think I paid like $50 for it which included the bit, the tap, the install tool and a couple of the helicoils. But after that you can get a pack of like 20 for a couple bucks..

 

I would try chasing the threads with a tap first. Many times it's the first 1/2" that's cross threaded. Try a new bolt with lock washer. Remember, don't over tighten.
I've used studs on both intake and exhaust manifolds to replace bolts. They do a great job and minimize the chance of stripping the threads.