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 60 degrees of initial advance??
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65Poncho
Tribal Scout

8 Posts

Posted - 31 Mar 2017 :  4:00:43 PM  Show Profile  Reply with Quote
Getting my car running after years of sitting. Rebuilt carb. She idles fine. Pushes you back in your seat. Timing was where I left it years ago.

Then I checked the timing. With vacuum advance plugged, she showed 60 degrees advanced at idle! Huh? Used a different timing light. Same thing. No knocking during idle or driving. I turned the distributor to take out some advance. It immediately ran worse. Couldn't get down to the teens or it would die. I raised RPMs and it added another 5-10 degrees. Hmm... Got a piston stop out and confirmed the dampner hasn't shifted (in fact I'm not sure there's rubber in the old school one I have from '65). So TDC on the timing tape is still TDC for #1 piston.

What am I missing?

65 GTO with 400. 6X heads. 770cfm Holley. Pertronix HEI. MSD. Only 1,000 miles on the build, but she has sat for years at a time - 14 years total.

Phil
The Great White Buffalo

USA
7146 Posts

Posted - 31 Mar 2017 :  9:45:51 PM  Show Profile  Reply with Quote
Are you 100% certain you're on the number 1 plug wire?

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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GtoGuy32
Cochise

USA
836 Posts

Posted - 31 Mar 2017 :  10:34:57 PM  Show Profile  Reply with Quote
Make sure you don't have any vacuum leaks.

Also agree you might be off a plug wire.

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Blued and Painted
Chief PONTIAC

USA
3331 Posts

Posted - 01 Apr 2017 :  11:52:11 AM  Show Profile  Reply with Quote
The balancer ring may have spun.
Mechanically check #1 or 6 piston TDC thru spark lug hole, then check balancer mark.


Bull Nose Formula, 461, TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 01 Apr 2017 11:54:13 AM
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65Poncho
Tribal Scout

8 Posts

Posted - 01 Apr 2017 :  12:33:50 PM  Show Profile  Reply with Quote
Thanks for the replies guys.

I don't think the balancer has spun because I confirmed TDC with a piston stop on the #1 cylinder. Also, not sure my dampner even has rubber in it. Can someone confirm that? It's the '65 two piece unit. It's been 15 years. I can't remember.

Wondering about vacuum leaks. Can't hear any, but will check with propane or starter fluid. But 60 degrees advanced at idle?

Plug order on cap is right. 1,2,3,4... Just kidding. 18436572 counterclockwise.

I know my light is on #1 wire. Driver side at the front closest to radiator. Two different guns got same reading.

I pulled distributor last night. Put #1 piston 12 degrees before TDC on the compression stroke, then took off the cap. Rotor was past #1 terminal. I think this confirms that indeed it has a LOT of initial advance.

I can play with weights and springs, but what has me stumped is why would it like 60 degrees? Something doesn't make sense.

If cam and crank gear were out of whack it wouldn't want THAT much advance would it? Timing chain and engine build only has about 1,000 miles on it. Also, why would it run reasonably well if cam and crank were way off.

I really appreciate all ideas and help.
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tjs44
Cochise

USA
373 Posts

Posted - 01 Apr 2017 :  6:30:55 PM  Show Profile  Reply with Quote
I cant believe it will start with 60 init!Tom
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GtoGuy32
Cochise

USA
836 Posts

Posted - 01 Apr 2017 :  9:11:03 PM  Show Profile  Reply with Quote
So, you are not the only person to have experienced 60 degrees initial:

http://www.hotrodders.com/forum/60-degree-initial-timing-help-112896.html

"yea, ive never heard of 60 degree initial timing either..... anyways, thanks for the help guys, the problem has been solved. In my infinite wisdom , I think that when I attached the timing light onto plug wire #1 it was touching #2 as well because when I went back today I was able to set it at 18 degrees...... lesson learned, pay attention and dont rush."
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Admin
Ye Olde Webmaster

838 Posts

Posted - 02 Apr 2017 :  07:26:23 AM  Show Profile  Reply with Quote
60 degrees advance is bizarre to me.

Finding TDC on #1 cylinder can't be found using a stop. It's better to use a finger in the spark plug hole that pops when compression gets close to TDC on #1. Then the crank needs to be rotated by hand using a socket and long bar to move it to 0 on the tab.

When dialing in a camshaft using a wheel on the front of the engine the stop is used to note the position when moving the crank clockwise and then rotating it the opposite direction to get the opposing marks (numbers on the wheel) and dividing the two to locate TDC. A different procedure.

The other thing is to forget the vacuum canister all together when setting up initial timing. The vacuum port needs to be plugged. Set the timing per the stock engine specs and test it with the light. Then plug in the vacuum advance between the vacuum port and the canister and take the total vacuum at idle. What is it?

Which vacuum source are you running off of? Manifold or Carb? There's a difference on how timing is set. More later....

"Dedicated to keeping the classic Pontiac engine alive."

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Blued and Painted
Chief PONTIAC

USA
3331 Posts

Posted - 02 Apr 2017 :  12:16:58 PM  Show Profile  Reply with Quote
the posts on the distributor cap are 45 degrees apart. And 90 degrees of crank rotation. So 90 degrees minus 15x2 initial is 60 degrees crankshaft
So move the timing light lead from wire to wire until running timing, is on the timing cover scale.

cylinders # 2 and #1 could be switched and the engine would be skipping.


Bull Nose Formula, 461, TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 02 Apr 2017 12:28:19 PM
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cortcomp
Coyote

USA
5219 Posts

Posted - 03 Apr 2017 :  09:32:06 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I had a similar issue that, IIRC, turned out to be the comp timing set was made incorrectly and the cam was either advanced or retarded like 12 or 16 degrees. Motor was haunted.
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65Poncho
Tribal Scout

8 Posts

Posted - 06 Apr 2017 :  08:58:16 AM  Show Profile  Reply with Quote
Thanks for all the input. Still trying to figure this out.

Pulled and went through the distributor. It is a Pertronix HEI unit. Weights felt a little "grabby." Cleaned them up. Put the quickest opening copper springs in. Turned vacuum advance down to 12. Confirmed with mityvac it does open with vacuum.

Put it back in. Checked and double checked order. #1 piston was confirmed to be 12 degrees before TDC on compression stroke. Pointed rotor at #1 . Wouldn't start. Turned dist both directions all the way. Wouldn't start. (Sigh)

Pulled the dist, advanced it about 45 degrees and put it back in. Started right up! Put the light on it. 50 degrees. Take timing out, she stumbles. Add it, she likes it. Can only turn it to 60 so I do.

Switched timing light to #6 wire. (I want this to be operator error more than anyone) It also reads 60 degrees! (Again, the tape is the right tape. TDC has been confirmed with a piston stop (turning both ways and splitting the dif of the two readings).

Idles smooth. Starts up first turn of the key. Will push you back in your seat. ???

Questions:

Can someone tell me how to shim my distributor? Currently it just sits down on the block.

How do you tune your timing without a timing tape? Advance it until you hear spark knock then dial it back?

Guess I'll check for vacuum leaks. That sounds fun. I've watched some YouTube videos. Neither propane or starting fluid sound overly safe. : )

And now, the SUPER dumb questions because I feel like I'm losing my mind with this. When looking at the crank pully, it turns clockwise, right? So timing tape should wrap around it clockwise, right? Rotor spins counterclockwise, right? Twisting distributor clockwise advances timing, right? How far do I need to separate my plug wires (they are newer, performance oriented wires) to make sure none are cross sparking? They can touch, right? I've tried to keep 5 and 7 apart as best I can.

I really appreciate the help guys.
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65Poncho
Tribal Scout

8 Posts

Posted - 06 Apr 2017 :  09:01:42 AM  Show Profile  Reply with Quote
Should have noted that the timing was checked with vacuum advance disconnected and plugged.
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65Poncho
Tribal Scout

8 Posts

Posted - 06 Apr 2017 :  11:08:26 AM  Show Profile  Reply with Quote
Hmmm.... Now I'm thinking about my distributor gear. I'm running a mild flat tappet cam. But I have a hi flow oil pump. I have a bronze distributor gear on there. I think I swapped it out for some reason. And I think I remember (it's been 15 years) someone telling me I better get that off of there for some reason.

What gear should I be using? Stock steel or aftermarket bronze? Now that I think about it, that gear may be worn. When I was looking at it the other day, the teeth looked thinner along the outside edge. Is my hi flow pump chewing it up? Could that be affecting my timing?
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Admin
Ye Olde Webmaster

838 Posts

Posted - 06 Apr 2017 :  11:33:27 AM  Show Profile  Reply with Quote
When you look at your timing tab the degrees show advance number as they approach zero which is supposed to equate to zero TDC on the piston. Many times it's a theoretical zero because the crank is off, or the keyway etc...but for all intents and purposes it is zero TDC.

Any timing tape purchased must be correct for the size of the damper on your Pontiac. Don't buy one for a Chevy...no good at all. The correct tape will show degrees coming from 6 o'clock to 12 o'clock.

Being a little old fashioned, I made my own tape. I found the circumference and worked backwards mathematically to find diameter and then marked 36 degrees on it. Noted the location on the damper. All circles as you know have 360 degrees.

If you break the damper down into quarters, 90. 180, 270 and 360 (which is also 0) degrees like a compass from the grove on the damper a mark at 270 degrees (9 o'clock) will be 90 degrees advance, space the distance evenly between 270 and 360 and you have 315 degrees. This equates to 45 degrees advance on your distributor. With vacuum advance in play plus mechanical at an rpm that weights are fully open, 45 degrees should be it, no more than that under part throttle--cruising speed on the highway.

+++
I have to ask, has you engine ever had a cam swap? Or perhaps a new timing chain and gear? I still find your case to be quite weird.

Another question: Did you buy the Petronix HEI new? Many years ago I had a fellow work on my HEI, he worked on the curve and unfortunately mixed Chevy parts with my Pontiac on reassembly. Engine wouldn't start. I took it back to him. He pulled it apart and saw his mistake and put the correct pieces parts back into it. I did not see him do this. However, when I put the HEI back into the engine it fired right up. Sometime after that, I purchased my own Sun Distributor machine and spent considerable time messing with several junk yard distributors to figure things out. I think there could be something amiss with your HEI. What? I don't know.

I can only suggest that somebody, a friend local to you, who also owns a traditional Pontiac, temporarily loan you his HEI to try on your car. If it fires up like it should with normal Pontiac timing specs--you will know if it's the distributor. If not, then it is something at the crank.

A gasket between the bottom of your distributor and the engine block will bring up the position of the distributor ever so slightly so wear on the gear isn't so likely. Fel-Pro has them. They aren't much thicker than 2 business cards stacked together.

"Dedicated to keeping the classic Pontiac engine alive."

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Phil
The Great White Buffalo

USA
7146 Posts

Posted - 06 Apr 2017 :  12:03:04 PM  Show Profile  Reply with Quote
Why are you running a bronze gear on that FT cam?

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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65Poncho
Tribal Scout

8 Posts

Posted - 06 Apr 2017 :  12:34:09 PM  Show Profile  Reply with Quote
I don't know. I think I may have thought they were better 15 years ago when I built the motor. Or I was planning for a roller setup and then ended up going flat tappet. I'm assuming I should change it out for a stocker or a steel replacement?
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65Poncho
Tribal Scout

8 Posts

Posted - 07 Apr 2017 :  09:55:19 AM  Show Profile  Reply with Quote
Phil, I swapped out the distributor gear to a stocker. Didn't change anything on the timing as you would expect. Indeed I was chewing up that bronze gear given the hi-flow pump.

Bill, how'd you make your timing tape? I'm going to extend the numbers on mine so I can continue to tune. I played with it a little yesterday and she runs better than she ever has before. Not scary fast, but smile inducing!

Yes to cam swap. Yes to new timing set. The only thing stock on it is the crank. Degreed the cam in myself. I remember a builder who sold me some parts talking about advancing or retarding the cam itself to get a few more HP (there was talk of a offset crank key I believe), but I can't remember if I did anything about that. I guess I could degree the cam to really nail down valve events relative to crank degrees, but the BIG question I have is, can you change the cam to crank relationship (by cam install or slipped tooth) enough to need 60 degrees of advance at idle and still have decent performance? I can do a burnout. I can chirp the tires in all four gears.

Pertronix HEI is new. Just got a recurve kit and it came with the same weights and base plates as what was on it. An MSD box is in the mix so maybe there's something there? But 60 degrees?

This weekend I'm going to check for vacuum leaks. Hope I find one. It would be awesome to have an explanation for this timing stuff. And it would be even more awesome if there was a lot of untapped HP still left in my setup!
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cortcomp
Coyote

USA
5219 Posts

Posted - 07 Apr 2017 :  10:01:28 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
If i had to shoot from the hip here, i'd have to guess your timing tape has to be off. Dead on at 0, but off a ton at 60. If it's running that well, i just can't imagine you being that far off on cam timing. Then again, if i hadn't seen it myself, i'd think it was impossible.
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cortcomp
Coyote

USA
5219 Posts

Posted - 07 Apr 2017 :  10:07:19 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
Just saw the part about the MSD box. Take it out of the loop, run everything straight and normal and THEN see where you're at.
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Bill Boyle
Horse Feathers (Charter Member)

USA
4615 Posts

Posted - 07 Apr 2017 :  12:39:52 PM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
cortcomp stated: "Just saw the part about the MSD box. Take it out of the loop, run everything straight and normal and THEN see where you're at."

I concur.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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65Poncho
Tribal Scout

8 Posts

Posted - 07 Apr 2017 :  3:52:06 PM  Show Profile  Reply with Quote
That's a great idea. I'll do that and report back.
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GtoGuy32
Cochise

USA
836 Posts

Posted - 07 Apr 2017 :  9:32:30 PM  Show Profile  Reply with Quote
I have heard of the cam keyway slot being cut wrong (some degrees off). Just hear this recently about an old school Lunati cam.
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Phil
The Great White Buffalo

USA
7146 Posts

Posted - 08 Apr 2017 :  12:00:46 PM  Show Profile  Reply with Quote
I hadn't noticed the msd box either. Although I haven't run one in years, I seem to remember that a timing light doesn't work with them due to the multiple spark discharge (which makes sense). I also seem to remember having to disconnect it in order to adjust/set initial timing.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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Djustice
Tribal Scout

Norway
6 Posts

Posted - 04 May 2017 :  07:13:53 AM  Show Profile  Visit Djustice's Homepage  Reply with Quote
I was also puzzled by my timing when i first got my car i had about 50 degrees @ idle.
Just for assurance i pulled the harmonic balancer it had not slipped the elastometer, however....


Edited by - Djustice on 04 May 2017 07:28:11 AM
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Bill Boyle
Horse Feathers (Charter Member)

USA
4615 Posts

Posted - 04 May 2017 :  08:16:46 AM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
Oops, that one has seen better days! Anyone need a paper weight?

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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cortcomp
Coyote

USA
5219 Posts

Posted - 04 May 2017 :  08:58:49 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
Just put the new seal sleeve on and run it, right?
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Djustice
Tribal Scout

Norway
6 Posts

Posted - 04 May 2017 :  10:07:09 AM  Show Profile  Visit Djustice's Homepage  Reply with Quote
quote:
Originally posted by cortcomp

Just put the new seal sleeve on and run it, right?



Lol nah, i got a powerbond balancer , think it was 1056 SS it was SFI 18.1 atleast, and a new Snout seal for the timingcover. TDC seems to be within 1-2 degrees using a small screwdriver in sparkplug hole nr.1 watching it rise and fall past TDC mark on damper, as i rotate the engine
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