I'll try to make this a short story.

I was running my engine trying to get the timing curve dialed in (mostly idling, with occasional sustained revs to 3K RPM), but I was running it without the blower belt on because my idler/tension pulley is over at the welders getting unfubared from the previous owner. I felt some unusual heat and when I looked down the headers were getting red hot.

1) Could this be because the engine was starving for fuel/air? The blower was freewheeling and so allowing air to pass, and its my understanding from the manual that in the event you lose a blower belt it's safe to drive it home that way. In fact I have once before about 2 years ago, I lost the belt and drove it home about 5 miles.

I dont suspect a timing issue as it's sitting at about 0* static (which is kind of low now that I think about it) and I haven't noticed any problems in this regard on test cruises around the neighborhood.

2) Odds that I hurt anything?

 

I'll be honest I don't know anything about blowers, but I know when my timing is that low my headers glow red hot from hot exhaust gasses.

 

Yes I see from the archives that I need to get some initial into it before I proceed. I have been trying to work it from mech advance back (the Lars way) but my mech adv is not working right. I got new springs and weights today, but lost an e-clip. ZZiingggg..clatter, clatter.

Seems a pretty big split about whether its indicative of too rich/lean, but I would say I am rich because of the exhaust smell. Let me ask what might seem like a silly carb question. The idle setting has nothing to do with how much fuel is provided at any other setting besides idle, that is based on the jet size only, correct?

I am just surprised that this didn't show up before now, Ive got maybe an hour on the engine, this is why I suspected a prob caused by not having the belt on the blower.

 

First off, I wouldn't try any tuning on a blower motor without the...well..blower. Yeah you can limp home without a belt but you really can't dial anything in without it.
I don't think you have near enough timing in it. And you're right about the idle mix adjustment.

From the BDS website:
Q. Why are my headers red hot?
A. Exhaust pipes get red hot for two basic reasons. Either the ignition timing is incorrect or the engine is running extremely lean. There are other causes but these are the two most common, ignition timing is extremely critical. Blown motors love advance. Without enough initial timing advance, blown motors will run hot and the exhaust pipes will glow in the dark. Blown motors should run as little as 16 degrees or as much as 26 degrees initial advance with the total advance of about 32-36 degrees at 2500 RPM to 3000 RPM. Specific timing requirements depend on compression, blower drive ratio, engine load, camshaft, and fuel octane.

 

Well yes, that sensible of course but I was trying various things to try to get the weights to quit hanging. They are coming in slightly late and all at once, vs a smooth advance. Hopefully the new weights and springs will take care of this, but Lars' advice to use the gold springs seems to put about as heavy as a spring back in there as is coming out. The silver ones look much more appropriate, or even the black ones, but I am sure he's worlds ahead of me on this matter so I'll start with the gold. Soon as I get to the e-clip store. I suppose I can work on the "air in the brake system" problem until I get my idler back from the welders tomorrow.

The reason I asked about the idle mix is that it was running well, but I think I backed all 4 screws out an additional turn in the mistaken belief that this would help keep the engine cool from by keeping extra fuel on the pistons. If this only matters at idle then Ill lean it back out to 1.5 turns like it was when I took it apart, and let the jets and the power valve handle the rest.

Is it possible to get that much idle advance when setting from total timing (36*) backwards? I guess thats where the heavier springs would come in?

 

Depends on how much mechanical advance is in your dist. Get your advance all in as quickly as possible and see where it is.
Are you running a vacuum advance?
My setup now is 22* initial. Manifold vacuum advance pulls in another 12* for an idle timing of 34*. Throttle response is instant, runs cool and idles perfectly.

Every setup wants something a little different. If you don't want to run a vacuum can on the dist. you may want to run a locked out dist. I know that some blower guys do it with good results.

 

I use 12 degree's initial and 34 total and have no problems with detonation. Look into a color tune. Its a spark plug where you can watch the combustion color inside the cylinder. You will be able to jet your carbs for optimal air fuel ratio. Its like a old fashioned oxygen sensor.

 

I have vacuum advance, but I cant tell you the size right off hand. What would determine the amount of mechanical advance in the dist? Set at manufacture? What is a locked out out dist? No vac advance?

Yea, hey I remember those from the way back machine. Ill have to look for one.

 

I have vacuum advance, but I cant tell you the size right off hand. What would determine the amount of mechanical advance in the dist? Set at manufacture? What is a locked out out dist? No vac advance?

Best way is with a dial back timing light. Rev your motor till advance is all in, turn the dial to zero the timing marks, subtract the initial and that's the mech advance amount.
A locked out dist. is simply one that the mech. advance has been disabled or "locked" and the timing is set to the max number from idle to wot.

 

OK, so here is where I am at.

I put the gold springs in (which are the heaviest), and set the initial timing for 12 w/vac disconnected.

Idle at about 900. I put the mixture screws at one turn out, which the car seemed to like since that picked the idle up about 150 RPM (they were at 1.5).

I left 12 dialed on the gun so my balancer read 0 and revved it up. It comes in smoother now, not all at once, but still a bit jerky. I read 30 on the balancer, so 12+30=42 total. (Oh by the way the vac can says 10, I dont know if that means 10* or half of that, based on something I was reading this morning, but again its not hooked up during this test.)

The pipes seem to be running at about 250* but quickly move up to 300-350*, even 400* on cylinders 4 and 6 when I begin revving the engine. I dont know whats a normal hooker header pipe temp is, but that still seems to be a bit high. I dont know what temperature glowing red is, and I didnt see any indication of glowing ( I dimmed the garage lights).

The blower is still freewheeling, but Im not sure it does much of anything at idle anyway. I know thats not helping matters, but I wont get my idler back until tomorrow and would like to make some progress on this before that.

Whats the consensus, besides 42* being too high?

What is normal operating temp for a hooker header, anyone want to go shoot a temp gun at a normally running car?

The best info I could find on the temp of glowing steel is from wikipedia:

"Iron or steel, when heated to above 900 °F (480 °C), glows with a red color"

 

If you could limit the amount of mech. advance and put it towards the initial I think you'd be better off all around.
What distributor do you have?

 

I am supposing that its just a stock HEI. I did some quick look shopping at summit, and thier lowest priced one is set at 11* at 1500, and they have a performance one that comes with replaceable bushings to set the max adv and spring sets to set the rate. Hate to buy a new distributer over this, but I might end up doing that. It says that you need an ignition box with their perofrmance one, so Im assuming my current MSD-6 would work.

What do you think about the exhaust temps?

Im pulling the wheels off now and putting speed bleeders in to try and chase my brake air around for a while. I sense an impending purchaase in that dept too......

 

You might just tinker with the one you have. Here's a good link to dialing in a HEI.
http://www.73-87.com/7387garage/drivetrain/hei.htm
Those exhaust temps don't seem too high to me.

 

No more than 36 degrees total advance with a blower under boost. 35 is usually the safe upper limit. You have to make sure it doesn't detonate. I hope you are running forged pistons. What is your boost pressure? What is your compression ratio?

 

Purpose built blower motor. All forged internals, 4 Bolt, O-ringed, low CR ~8.3. Boost remains to be seen with the move from 355 to 383 CI. Some here say that I wont even be able to make boost with the bigger cam and more displacement, but that remains to be seen, Im not buying into that yet. Part of my upgrade was a BIG boost gauge that I can see while looking out the windshield. Because yes, thats what happened to the 355. Too much boost, detonated the top edge off a (forged) piston @ 10 PSI. But as it turned out that motor had other issues that contributed....

 

What kind of blower is this?

 

Interesting, but I dont know what I can do about the dist putting in 30* mech. That part seems pretty fixed. I must not have a stock dist here ?

I thought that vac adv was pretty much not used in the calculations since especially in my case, there wont be any vac at WOT?. If Ive got to include vac advance then , uh, I dont know how this would ever work?

I know without even looking at the tach that my mech is starting to come in way later then 800 RPM with the gold springs. Sounds about 1800. I suppose that changing to one of the softer ones will move it earlier. No extensive testing this afternoon because of the whole "no blower belt" thing. Just wanted to get in the "no glowing pipes" neighborhood. Hopefully Ill get my idler back in the morning as promised.

And not to belabor the point, but you think 300-400* is okay? I have no concept of how hot they should be. Pretty damn hot I guess, since we've all seen what bumping up against just a sidepipe does to a person's leg. The sidepipes must be 200* themselves.

 

b&m 144

 

I have a Weiand 144 you should be able to get 8 pounds out of it, max. That will be about your max boost without blowing the blower up, due to excessive blower rpm. You must have already changed the pulley to get 10 pounds on a 350 c.u.

 

Same thing. I dunno, its whatever was on there when I got it. There are other pulleys and such in the box of parts, but Ive never explored. I was making 7-8 until I put on a fresh belt and then I saw 10 for about 2 weeks until it broke kicking it up over a bridge across the bay here. I'll be happy with 6-7. I really dont think that the extra cam and CI is going to suck it up, but what the hell do I know? There are much more knowledgable people than me on this board.