Motor back together, first start, goofy idle timing advance

[Lee_in_KC]

My current thinking is a I have a significant mixture issue. I got interrupted by a neighbor while I was getting set up to check TDC (always a risk when I have the garage door open and I'm working on the car!! ), so I haven't got that done yet. My timing light is an MSD product guaranteed to work with multi-spark ignitions.

 

[Lee_in_KC]

OK, TDC is checked... timing indicators are dead nuts ON!! Now I'm going to re-stab the distributor.

 

[one finger john]

Here are my plugs. They are definitely sootier than when I put them back in on re-assembly. These plugs have a couple thousand miles on them and were nice and dry and tan when I pulled them on dis-assembly last fall.

Going out to check TDC right now.

So these are the plugs from the "old engine" ? Throw a set of brand new, non fouled plugs in it and take more pics. They should be close to being white.

John

 

[Lee_in_KC]

Yes, these are the old plugs. I have a new set to go in... changing one thing at a time!!

 

[one finger john]

With no little black speckles on the electrode. If you have little black speckles at idle you are dangerously advanced in timing. Or lean, or both. At idle even.

 

[Screaming Metal]

OK, 2 motors identical, same everything will not run the same....as far as timing is concerned, alot of motors like to run at 35+ degrees....as you back down toward TDC the motor will start laboring hard. Timing sets have diff. keys, diff springs in distrib's, alot of things can happen to get your timing off. Take your time, set everything to the exact point....you should be fine.
On a blower motor, fluffy mixture is good....best too rich than too lean. Don't call in the Marines until the bad crap starts to fly!
We build alot of motors for race folk, and each one we index everything so everything is the same. Then, run them on the dyno. Each and every motor, though totally identical does produce within 50 horses of each other. Your talking about 4500horses, 50 is something you can't feel at the accelerator. Every motor, even after we dyno it, and makes with a few horses of one another, each one pulls differently....more power here, more power there....

Verify TDC, check everything, leave nothing to chance, same springs, same distrib. weights, same shimmed distributor end clearances. If your running a button in your timing gear cover, this will also change your overall timing. If your running a vacuum advance, does it have the adjustable can? Or is the system electronically advanced? IS the cam degreed in?
As you can see, getting to where you were with a new motor, even though the same motor, can be a chore. Motor vaccum also plays a part in this, as well as vacuum leaks....

Its a hotrod, once you get everything as you want it, things should not move again until a piece of the puzzle is changed.
On a blower motor, make sure you are rich mixture wise, all the time....if you don't you'll torch your pistons. Also, run your motor a little on the warm side, with a piece of cardboard over the outside of the radiator, with holes cut in it to restrict airflow....that way you can get your rings to seal.... run the motor for 3 or 4 hours like that....get her to about 220-210, very your rpm slightly, rev every once in a while....

 

[Lee_in_KC]

"On a blower motor, fluffy mixture is good....best too rich than too lean."

Yep, it is set up rich. Same rods, jets, springs, etc. as previous build.

"Don't call in the Marines until the bad crap starts to fly!"

Don't need to... I was one!!

"Verify TDC, check everything, leave nothing to chance, same springs, same distrib. weights, same shimmed distributor end clearances."

All done at least twice!!

" If your running a button in your timing gear cover, this will also change your overall timing."

Yes, running the same aluminum button as before. No apparent wear.

" If your running a vacuum advance, does it have the adjustable can? Or is the system electronically advanced?"

No vacuum or electronic advance. Magnetic trigger distributor with MSD 6AL ignition box (multi-spark and rev limiter only).

"Is the cam degreed in?"

Cam was very carefully degreed... came in at 2* advanced using "0" keyway.

"Motor vaccum also plays a part in this, as well as vacuum leaks...."

Vacuum integrity checked as thoroughly as possible.

"On a blower motor, make sure you are rich mixture wise, all the time....if you don't you'll torch your pistons."

I have run this motor rich from Day 1 specifically because I was worried about detonation. That is also why I am so stressed about the 35* initial timing!!

"Also, run your motor a little on the warm side, with a piece of cardboard over the outside of the radiator, with holes cut in it to restrict airflow....that way you can get your rings to seal.... run the motor for 3 or 4 hours like that....get her to about 220-210, very your rpm slightly, rev every once in a while...."

Will do!! Thanks for the input, SM!

 

[Screaming Metal]

Lee, glad to hear you've double checked everything. I will try and explain a tried and true simple way to set the timing on a blown street motor....

Start the motor, let it run for 5 minutes. Loosen the distr. hold-down, don't leave it loose, just barely snug it. Get yourself a mechanics stethoscope at O'Reillys or where-ever. Screw the metal rod into the steth., find a place on the heads to wedge the end under. I love cast valve covers for this, sheet metal covers is really tinty sounding, edge of intake manifold is good.
Restart motor, I usually use a remote tach, idle her to 1050-1100 rpm, put the steth. around your neck, start advancing your distr. (turn it very slowly), until you just barely hear the motor start to labor, I mean just barely. At the base of your distr. make a mark with a sharpy, and a mark on the intake.... This is for reference. Some motors are easier to hear the laboring at 1000, just play around with it and see.
Now, unadvance the distr. a little, turning it slightly the other way. Put steth. into one ear, the listen for the motor to labor again....look at your sharpy mark....just barely turn it back, do you hear a rattling in the heads? Hit it hard with a couple of revs, keep listening....do you hear it pinging/spark knock while the motor is loaded with revs?
If not, back off of the distr. again, put both ears into the steth., rotate close to the line again, listening for the motor to labor. Once you hear it just barely start to labor, just barely....lock the distributor down there.

Now, just run the motor there to seat your rings....then drive it around the block a few times to see how she runs, just step into her pretty good, do you hear any pinging? If not, good, drive back to house, put your timing light on it. (you will probably be in the 32-38 range there) You want to have all your advance in as soon as you can, lets say 1500-1800 rpm.
You should be close to optimum ign. timing for the street. Be sure to be running good clean gas....when doing this.

 

[one finger john]

Metal,
How much of a load does a 671 put on a small block at idle when it is producing very little boost ?
Is that why so much advance is needed initially. When would boost retard come into play?

John

 

[Lee_in_KC]

Well, it looks like the motor is coming back out anyway. I have a coolant leak at the back of the motor, behind the flexplate. Either a leaking freeze plug or a cracked block!! Freeze plugs were installed by the machine shop that assembled the short block. Bare block was supplied by the same machine shop.

I have to keep reminding myself... hot-rodding is fun!!

 

[railroad]

Lots of timing is usually associated with starting the fuel burn early enough to get the burn power timed with the downward piston movement.
The more timing needed a low speeds indicate a poor burn rate. In a perfect cylinder, with perfect fuel and ratio, the timing would be near zero. The farther from zero the less than ideal conditions for the perfect burn. This may be due to the mentioned details or effects of the cam or tuning to improve the running at a different rpm.
Since most of the common factors have been checked and double checked, there is left what has not been confirmed. Being boost will throw me a curve, due to my boost cars use a computer.
At idle, no boost, the fuel ratio being too rich will require an early spark to get enough of the gas burned to run decently. I would start here, leaning the ratio. This will be on the idle circuit, no boost and not have to reduce the primary and secondary fuel ratios, under boost.
Compression aids in igniting the fuel, a low compression cylinder does not compress the perfect fuel ratio as much, reducing the ease of ignition. There is not much you can do with the physical dimensions that are fixed, static compression. But, with all being good on sealing of components, the cam timing can change the compression, dynamic ratio. If the issue at hand is not tolerable, and you cannot find another issue, you can time the cam for max compression.
With the cam timing components exposed and set up for adjustment, you can pull all the plugs and run a comprssion test on the different cam settings. The one that provides the most compression will do the same at idle, easier to ignite, less timing.
Although there could be other issues creating the problem, but without hands on, maybe some of this will give you some food for thought.
What kind of fuel are you running?

 

[one finger john]

Sorry to hear about the coolant problem. My money is on an improperly installed freeze plug.

John

 

[Lee_in_KC]

This @#$%&! hotrod is going to put me in the looney bin!!

Before pulling the motor I got under the car and pulled the flexplate cover off to see what I could see. Coolant had been dripping from the vents in the bottom of the cover such that there was a 6" puddle of coolant on the garage floor. I have had coolant in the motor for about two weeks. During the three run-ups trying to deal with the timing I left the radiator cap off to ensure all the air was out of the system, so it never pressurized. The coolant leak was from static pressure. I could not see any obvious source behind the flexplate, but it was difficult to see anything at all, so I decided the motor had to come out.

There is absolutely no sign of a leak at the back of the block. The freeze plugs were well installed using sealant. No sign of a crack anywhere. Back of the block was completely dry, with no residual coolant or oil.

So I'm trying figure out where coolant might be coming from. I knew I had a small leak from the back of the water pump, probably due to a bad gasket (since confirmed). I'm wondering if coolant from that leak was running down the front of the block, down along the oil pan rail to the back of the motor, then dripping down into the flexplate cover. The front of the car is on jack stands and the motor was sitting at about 10* degrees nose up, so it would be easy for the coolant to run to the back of the block.

My biggest concern was if a freeze plug at the back of the block were not properly installed, it could blow out when I'm out driving and I may or may not realize it in time to save the motor. I'm now confident that won't happen, so pulling the motor was justified as far as I'm concerned.

Now back to the timing issue. As I reassemble the motor and put it back in, I'm going to double check everything again. If it still wants to idle at 30*, so be it!! I'll drive it like that (carefully) and see what happens.

 

[2old2fast]

I have to ask , I've done it , is yours a dial-back timing light ??
dave
Did you put a little silicone around the water ports of your intake gaskts. ?








.

 

[Lee_in_KC]

Not a dial-back. No silicone on the gasket. Fel-pro instructions specifically said no silicone or gasket sealer on the "Print-o-seal" gaskets.

 

[one finger john]

Pressurize the coolant system (water would be o.k) and see where it leaks. If you could put the engine on a stand, attach the radiator, take off the flywheel and add 20 lbs. of coolant pressure to see where it is leaking (with 20 lbs. it should squirt right out) and there you are. Radiator can handle 20 lbs. easy.

John

 

[HenrysT]

You can also get an old bike tube (or new one) cut it in half and put one end on the inlet and the other on the outlet, hose clamp it and pressurize it to 20lb.

 

[railroad]

Lee,
If you have not pulled the engine yet, I would pressurize it while still in the car. Hopefully the leak will be somewhere accessible. I hope you do not have problems with the fel pro print o seal gaskets. The small block Ford guys had to learn to avoid them, me included. I used them on a crate engine and never could get the car tuned where I thought it should be, computer EFI. After pulling the intake, the gaskets around the water ports had literally melted. Fel Pro, does make a gasket with a metal layer that is much better. Hope you have good luck.

 

[fletcherson]

As others said, I would pressurize the coolant prior to pulling the engine, sounds logical about coolant running back and dripping out of the inspection pan. It could be a head or intake gasket too, a little air pressure will tell the tale. I don't like those print o seal gaskets. I have had them fail. I like the standard gaskets and always use silicone, always. I install parts with new gaskets and silicone, snug them, let them sit for a while to cure the sealant, then tighten. No leaks. Just my preference based on my experience. If you happen to have a intake gasket leak, that could also explain some of your tuning trouble. If the leak turns out to be seepage around a freeze plug or similar, the copper or aluminum powder that you add to the radiator works. I know many will have negative things to say about such products, I don't use many such products, but I used to re core radiators professionally, and we always put it in them after a re core, I have been told that some manufacturers use it on new cars. If it's a gasket, fix it.

 

[Gerry]

Great thread, lots of good stuff from the guys on here. And you are correct, a lot of manufactures did put in leak sealer's (Barrs) from new.