[Equus]

Ok- Last night with vacuum gauge and timing light-
Refitted the holley and checked idle mixture with vacuum gauge

Using laser thermometer #4 177degrees
#3 150 degrees
Using vacuum gauge to set timing temperatures dropped down to 120-130 degrees.
Check timing with timing light it showed base timing of 42 BTDC ! WTF !
(Had been set at 10BTDC with the same timing light)
Pulled 4 degrees out of it and went for a drive - WOW car felt good and strong and no hint of pinging .
it was cold last night and i need to drive it in hotter conditions to fine tune it with possibly a different timing light.

thanks for your help
Rob

 

[CrackrStang71]

What were your other header temps??? Last time my header temps were 150, I had a massive vacuums leak at the intake gaskets or a bad spark plug. Usually I see them from 400-600 degrees.

 

[Equus]

What were your other header temps??? Last time my header temps were 150, I had a massive vacuums leak at the intake gaskets or a bad spark plug. Usually I see them from 400-600 degrees.

Once engine was running well they where all withing 10-20 degrees of each other 100-120 degrees Celsius (ceramic coated headers)
Just a cheap laser thermometer- to many variables to be very accurate. Only that the advancing the timing - definately dropped the exhaust temps..

Rob

 

[sportsroof69]

How old is your balancer? Could the ring have possibly slipped, and the timing marks are off now?

 

[Equus]

How old is your balancer? Could the ring have possibly slipped, and the timing marks are off now?

New harmonic balancer- not sure how to verify the correct positioning of the timing pointer?

When installed cam and timing gear TDC was verified. Initially we did set the timing for max vacuum then pulled it back 4 degrees with the timing light for safety.( that is when we saw the 42BTDC) !

If it is not pinging under load and runs very well

can leave it alone ?


Rob

 

[Lee12609]

set #1 to TDC manually and see where your pointer and marks are to determine if your balancer has slipped.

if its running good and no pinging leave it be.

 

[Blue Blood]

If you think you're off 30 degrees advance there's no way I'd let it go without trying to figure out what's going on. Just my $.02.

 

[lemonshindig]

set #1 to TDC manually and see where your pointer and marks are to determine if your balancer has slipped.

if its running good and no pinging leave it be.

Yep. Do this.

 

[theman1990]

I once had an injector stuck open and it did the exact same thing, cherrrrrry red... This was on a FoMoCo 306 with a B-cam and at idle.

 

[sportsroof69]

set #1 to TDC manually and see where your pointer and marks are to determine if your balancer has slipped.

if its running good and no pinging leave it be.

This should be the first step.


Remeber that an engine CAN detonate without you hearing it. You need to know for sure that the information you are seeing is correct.

 

[Woodchuck]

How about THIS for a first step..... what does the plug say?

 

[Equus]

Ok now I am confused.
Went for another drive in hot weather and loading up the motor . No pinging that I could hear.
Borrowed another timing light- still showing 38 btc at idle.The car is easy to start hot or cold. I have tried the pick up on other leads and they where sparking.I am running a cam with the HO firing order but I made the requisite changes for this. The dizzy is a Mallory unilite which was on the car. I had it regraphed to the cam and compression specs and re-installed.
Pulled #1 spark plug verified tdc was lined up with the 0 mark on the harmonic balancer. Sparkplug was nice and grey/white with out black deposits.

If the new balancer has slipped ,would it not line up to something other than 0 tdc?

I am at the limit of my backyard mechanic knowledge

Can the valve timing be out and cause this ? The cam was installed dot to dot with the new timing gear and chain.
Now as far as I can tell the car is running very well. I am just baffled by this timing issue. :shrug:
Cheers
Rob

 

[Woodchuck]

Couple questions.....

Did you remember to use a shaft key on the new balancer when you installed it?

Does your balancer have 2 scales for different timing pointer locations?

 

[rickgto]

First of all never connect the pcv to the rear "unless" you're running a carb with a 4 corner idle a/f adjustment. It will lean the rear cyls. And depending on what cam you put in there (specs) 38* at idle including vac advance isn't excessive. By that I mean a fair cam (2teens to 220's @ .050 or bigger) on a short LSA (110 or less) and intake centerline 106 or less. And yes, a rich mix will for sure glow headers. Lean will usually glow an inch or two from the head. Rich will glow the header a foot or so but normally only under power, not at idle. Move your pcv to the front, and no matter what the books say, adjust your idle a/f screws to where the engine wants them to be no matter if they're not the same side to side.

 

[Equus]

Did you remember to use a shaft key on the new balancer when you installed it?
Yes ,
key on crank to keyway on new harmonic balancer.

Does your balancer have 2 scales for different timing pointer locations?
Good question !!

Rob

 

[Equus]

First of all never connect the pcv to the rear "unless" you're running a carb with a 4 corner idle a/f adjustment. It will lean the rear cyls. And depending on what cam you put in there (specs) 38* at idle including vac advance isn't excessive. By that I mean a fair cam (2teens to 220's @ .050 or bigger) on a short LSA (110 or less) and intake centerline 106 or less. And yes, a rich mix will for sure glow headers. Lean will usually glow an inch or two from the head. Rich will glow the header a foot or so but normally only under power, not at idle. Move your pcv to the front, and no matter what the books say, adjust your idle a/f screws to where the engine wants them to be no matter if they're not the same side to side.

Hi,
fixed all the PCV and brake vacuum lines. Cam specs are as follows :

• Advertised Duration (Int/Exh): 256/262
• Duration @ .050 (Int/Exh): 213/219
• Gross Valve Lift (Int/Exh): .483/.499
• LSA/ICL: 112/108
• Valve Lash (Int/Exh): Hyd/Hyd
• RPM Range: 1000-5500

Idle and timing has been all adjusted by using a vacuum gauge .
Rob

 

[sportsroof69]

Can the valve timing be out and cause this ? The cam was installed dot to dot with the new timing gear and chain.
Now as far as I can tell the car is running very well. I am just baffled by this timing issue. :shrug:
Cheers
Rob

no. cam timing, and ignition timing are two completely separate things.

 

[SWPruett]

At the risk of opening a HUGE can of worms, is your distributor running with ported or manifold vacuum to the advance can?

 

[Equus]

At the risk of opening a HUGE can of worms, is your distributor running with ported or manifold vacuum to the advance can?

No vacuum advance - Mechanical only

Rob

 

[GolfBoy]

Ok now I am confused.
Went for another drive in hot weather and loading up the motor . No pinging that I could hear.
Borrowed another timing light- still showing 38 btc at idle.The car is easy to start hot or cold. I have tried the pick up on other leads and they where sparking.I am running a cam with the HO firing order but I made the requisite changes for this. The dizzy is a Mallory unilite which was on the car. I had it regraphed to the cam and compression specs and re-installed.
Pulled #1 spark plug verified tdc was lined up with the 0 mark on the harmonic balancer. Sparkplug was nice and grey/white with out black deposits.

If the new balancer has slipped ,would it not line up to something other than 0 tdc?

I am at the limit of my backyard mechanic knowledge

Can the valve timing be out and cause this ? The cam was installed dot to dot with the new timing gear and chain.
Now as far as I can tell the car is running very well. I am just baffled by this timing issue. :shrug:
Cheers
Rob

My guess is that your vacuum advance isn't working. Timing will be perfect at idle, but will not move when you accelerate or drive at speed, then it will be VERY retarded, causing unspent fuel to be pushed out the exhaust making the manifold (or header) glow red.

Easy check: Put on the timing light, with the vacuum line attached and rev the car while watching the timing mark. If the mark doesn't move, bad vacuum. Replace the vacuum advance dashpot ($25 fix) and about 15 minutes work (two screws and a small cotter pin).

If your distributor doesn't have vacuum advance (mechanical), then I can't help you other than suggest replacing the distributor.