Crank Damper Timing Marks!!

[patrickt]

Originally Posted by iwantacobra427

The crank is the builders in-house steel 3.250 stroker crank.

OK, use a brass piston stop. Have it touch the piston before you get to TDC and mark your crank, then remove it and go past TDC, put it back in and back the piston back so it touches it again. Mark that spot on the crank. TDC is exactly between those two marks. It's a pretty reliable method.

[iwantacobra427]

Originally Posted by blykins

OK...the scale for BTDC should be to the right of the 0° mark. Think about it...direction of crank rotation is clockwise as you're facing the engine. As you're rotating the engine over, the pointer is going to come to degree marks to the right of the 0 first....because that's BEFORE top dead center. Make sense? As you turn the crankshaft some more, and the pointer passes the 0, it's going to be AFTER top dead center.

So let me understand something better.....how did you know you were at TDC without a piston stop or a previous harmonic balancer to read off of? You can't really eyeball it and be dead on....you really need to use a piston stop because the crank actually rotates several degrees while the piston is stationary at TDC. Chances are that everything is ok, but I think it would be good insurance to double check everything...and it's not difficult.

Spark plug piston stops are easy to use and they're effective. You can use your degree wheel with the balancer on it.

If you want, PM me and I'll give you my phone number. Sometimes this is easier to explain when someone is talking to you.

Ah.. I see.. that makes sense. There are three separate sets of scales so two of them are BTDC. So after checking the idle timing I estimate the total timing by installing the applicable springs in the distibutor then run the engine at 3000 - 3500 rpm and see if the estimated number shows up with the timing light? I guess a safe number would be 35 degrees? You're right I'll buy that piston stop and double check the TDC. I eyeballed it through the sparkplug hole plus I didn't have the intake manifold on then so I could see the pushrod moving very easily. I'll give it a shot this weekend with the piston stop. Thanks for all your help.. I'm learning a lot! I'll probably take you up on the phone call help in the future!

[blykins]

All 3 scales should be BTDC. It's the same scenario, it's just a universal damper for all of the different SBF combos. Once you find true TDC, you should be able to mount the timing pointer in all 3 positions and it should put to "0" on the appropriate scale.

Do you have a straight mechanical advance distributor, or a vacuum advance distributor?

Initial timing is what you should see at idle. The springs are how quick the timing advance comes in. If you have an MSD, then there should be stop bushings that limit how much advance you get. If you have a Mallory, then you use plastic sticks to adjust it. For instance, a certain stop bushing in an MSD will give you 24 degrees advance. Keep in mind that it's not always perfect, but if your initial timing is at 12 degrees and you have 24 degrees advance, then your total time is 36 degrees. The springs tell the distributor when all of that advance should be applied. But yes, unless something is totally funky, you should be able to set the initial time, then bring the engine to 3000 and check total time.

If you have a vacuum advance, let us know....it requires a different procedure.

[iwantacobra427]

Ok.. I used the piston stop and found my TDC was off by approximately 1 1/2 degrees (behind). I already set the valve lash the other week. I'd think the lash is ok even though my TDC was off a little bit.. I'll paint a thin line at the outer edge of the damper showing the more accuarate TDC position. I still think I need to put the timing tape on because the behind TDC scale is so far beyond the TDC. What do you think? Thanks.

[patrickt]

How far off are the existing marks? Summit sells half a dozen nice adjustable timing pointers for your Ford, like this one. It would be nicer if you could just adjust your timing pointer so that the existing marks were correct.

[iwantacobra427]

The scale for TDC is underneath the pointer. My first message has a picture of it. It doesn't do any good to move my pointer because the scale is underneath the pointer. I think the best thing to do is paint a thin line at the outer edge for TDC then put the timing tape on because I don't see how the BTDC scale can be used. If you see the picture from the first message there's no nearby BTDC scale to use to set the static (idling) timing.
The attached picture shows the more accurate TDC mark. It's about 1.5 degrees to the right of the original TDC of '0'. Each dash is 2 degrees.

[patrickt]

Yes, after studying your picture I would put black paint over your existing marks and then try putting the timing tape on with a thin layer of epoxy.

[blykins]

If you find that your pointer covers the marks, then I think you're using the wrong pointer position on the cover. Like Patrick says, the adjustable timing pointers are the cat's meow.

Also, when you set the preload/lash on valves, are you bringing the cylinder to TDC of the compression stroke and then setting them both? That's ok on engines with extremely mild cams, but you're a lot better off to set them a different way.

On the intake valves, turn the engine over until the exhaust valve for that cylinder is starting to open, then set the intake valve.

On the exhaust valves, turn the engine over until the intake valve is starting to close...then set the exhaust valve.

It only takes 2-3 minutes to run the valves.

[iwantacobra427]

I guess I could take the damper off and use the degree wheel to find TDC. Then put the damper back on while lining up TDC with one of the outside scales. Should I do that instead of the tape? If I reposition the damper then try the other valve lash adjustment method you mentioned. What I did before was: Find TDC for #1 cylinder on compression then set valve lash for both intake and exhaust valves. Then turned the crank 1/4 turn clockwise and set the valve lash for both intake and exhaust valves for #3 cylinder, then another 1/4 turn clockwise and set #7 valves, etc.. I have a 351w based cam. I have a MSD distributor (Part #8479) with vacuum advance.

[blykins]

I think you should take the time and do it as you say. It shouldn't take that long at all....30 minutes tops. Then you'll have peace of mind.

When you find true TDC with the degree wheel, then you know you can put the timing pointer anywhere as long as it's pointing at a 0 somewhere. I had an adjustable pointer, and at TDC, it was covering the 10:00 scale, but worked perfect with the 11:00 scale.

As for the lash, with any aftermarket cam with late valve timing and lots of overlap, you'll probably need to run the valves again. There's nothing wrong with doing it that way(with a stock cam and a damper with 90 degree marks on it), but you'll more a 1000x more accurate with the EVO IVC method. Once you get it down pat, you can run the valves on one side in just a minute or two. You don't even have to pay attention to the balancer, you just bump the engine over by hand or with a starter until one valve is doing what you want.

BTW, you don't have to take the damper off, just pull the balancer bolt out, mount your degree wheel, and run the balancer bolt in. Don't get it too tight, just barely tight. Then you'll have to turn the engine over with the flywheel, or with a couple of flywheel bolts in the end of the crankshaft.