I imagine so, but just want to make sure. i am putting my 5.0 in my 90 F150 back together. its got a bigger cam and shorty headers. i imagine i should probably set the timing to >10 degrees, right? maybe like 12? now i should be able to do this without a timing light, right? if i rotate the crank to 12 degrees BTDC, and set the rotor pointing to the #1 cylinder, it should work, right? do i need to unplug the spout connector when i fire it up? i do not have a timing light, and id rather not buy one right now. will this work out ok? any other recommendations on exact timing i should try?

can i adjust it in the future the same way, with the motor off and rotating the crank to the right position, then setting the distributor, and starting it up with the spout connector unplugged?

thanks guys!!
Andrew

 

You really should use a timing light. If you don't want to buy one, which can be had for as little as $30, see if the local parts store will loan you one.

 

That will work to get your base timing set so it can start, but there is no way you are going to do it by eye and be anywhere near close. Sorry..

You might check with some of the parts stores in your area, they sometimes have tools to loan or rent..

 

What are the specs of the cam?
Since it's a '90 model it's speed density and that won't work with a big cam.

 

specs of the cam are LIFT: int - .462 exh - .474 DURATION: int - 250 exh - 260 Search Results for 31-255-5 - SummitRacing.com

what wont work with a big cam, adjusting the timing?

 

That cam works just fine with the stock SD system. There are some cams that cause problems, but as far as the one you have is concerned, your good.

 

The distributor rotor has to point at the #1 post on the distributor cap not at cylinder 1, but regardless the best you can hope for is a motor that runs you'll never get it timed accurately without a timing light, so try to borrow one if possible.

 

What he said. Try a local search on eBay and/or Craigslist. You should be able to get one for $10-15. If you're not willing to invest that much, sell the vehicle and take the bus.

 

A dizzy cap is about 4" diameter, which means the circumference is about 12". So 1º is about 0.03". That means 10º is about 1/4" of turn. I think you'll be doing well to get it to that point.

What I've done in the past, just to get it running reasonably well, sans timing light, is with the vehicle running, rotate the dizzy each way slowly until the idle starts to stumble, then pick the midpoint. Then go find a timing light, but drive it easy--avoid flooring it and lugging it in case there's spark knock.

Jason

 

Yes that's what I meant, point the rotor at the #1 cylinder on the cap, not the actual cylinder, sorry. Well I ordered a timing light off eBay for 20$. I've never used one before, when I get it how do I use it? I know it has to be hooked up to the battery and to the #1 cylinder plug wire. I unplug the spout connector, point it at the balancer and see what degree it's at when it lights? And rotate the distributor to adjust it?

 

See, you actually DO know how to use it!

The one thing to be aware of however is that there are two sets of timing marks. Ignore the ones on the cover on the driver side of the engine and use the toothed ones on the passenger side (which, conveniently enough, aren't very clear).

There's a good thread in here on exactly how to read the marks. Search for my ID and "timing" and you should find it.

 

i searched timing and your user name, couldnt find it. found a lot for the 4.9L..are they basically the same when it comes to this? the only timing marks i see on mine are on the balancer, and then the bolt on indicator that goes next to it. dont see any on the cover (timing case cover?)

 

Just line up the > part of the pointer with the 10° on the BTC side of the zero 0° mark..

The ATC (after top center) side only goes to 10° or so, the BTC (before top center) goes up to 30° fir sure maybe even more.. (It's been a while since I actually looked one over real good)

Edit: I found this and it might help you understand what all that chatter above was about...

 

Hey guys, ive just gotten around to starting this motor up and getting it timed. i set it to 14 degrees. however, after i plug the spout connector back in, it immediately advances the timing to about 18 degrees. is this normal? will the computer be correcting it as i drive it? my procedure was as follows: unplug spout connecter; start engine; set the timing; tighten the distributor; plug spout back in; shut engine off. - - - - - i also tried it, shutting the engine off, and then plugging the spout connector back in; then starting the engine and checking timing again.

im guessing maybe its normal. but just want to make sure. thanks!!

 

Not using a timing light to set the timing just seems like a really bad idea...

Xenon Timing Light

This is what I have. It's cheap, but for no more than I use it, it works just fine.