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Discussion Starter #1
Hello All: It's bob again:
I would like to know why my GTO runs so great at 22 degrees BTDC. Intial Timing. Idle rpm's 700
1. Total Timing kicks in at 2800 rpms at 34 degrees ????
2. I have a MSD electronic system. 6AL model.
3. Stock Distrubutor with just a rotor and magnictic pickup.
4. Engine 400cu with Hooker Header's and Elderbrock manifold.
5. Elderbrock carburator model 1460 600cfm
6. No cam
7. Runs like shit at 14 degrees BTDC.
8. Runs better at 18 degrees BTDC
9. Runs much better at 20 degress BTDC
10. Runs like a Jet at 22 degrees BTDC
11. Engine sounds so smooth and Idel's great.
12. Start's right up when Hot. Engine running much cooler.
13. I just don't understand???? I believe I should not be at 22 degress at base timing??????? No pinging at all. Engine rmp's at 4000. No pinging???
What's with this engine?????
Curious minds would like to know???
Have a great day, Bob :)
 

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Have you verified the timing mark is accurate and actually represents TDC? Have you tried another timing light to make sure the readings are the same? My neighbor had a Harbor Freight timing light with adjustable dial. The sticker with the increments came loose and gave false readings so you can't always trust the readings. There have been multiple times in the past where I had to set timing bu ear because the balancer mark was not correct....mostly on small block Chevy engines...

Sent from my SM-G930V using Tapatalk
 

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Did you Un hook the vac advance? 22 degrees sounds about right when the vacuum advance is hooked up. And that would be about 12 degrees without vac advance. And as far as the 34 total that is also about perfect. Now keep in mind that the vacuum goes away under throttle, so all numbers you mentioned sound good if you had your vac advance hooked up.
 

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Discussion Starter #4
Hello My65Goat:
I got no vaccum advance. MSD Ignition system. No vaccum line going to the Distrubutor. Just Distrubutor cap. Read my post closely....
Got me... Timing Light OK.... Got new Balancer, but could it be off??????? Will ask #3 mechanic about that. It seems to run like it did before, before the new timing cover with the new balancer????? Dame engine is running like a F16 Jet.... LOL I will talk to my #3 mechanic about this. I'll have him work my Timing light. It's a high end one with all the toy's on it...... I just got a Devil Engine.... Kick's ass right now. Up's and goes in 3rd gear at 70 mph. Right up to 100mph.... No pinging?????? It's MAGIC.... LOL I have a HT400 Trans.
Anyone out there got any Idea's why this engine runs great at 22 degress at Base timing????
Bob :)
 

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Beast - Cams ?? Cam timing / degreed ?

With regards to timing, you already answered your question - you have no vacuum advance and total timing is 34* which is pretty much what most say is about right. So as MyGoat65 said, you are right where you should be ~22* at idle & 34* total timing by 2800. (Congrats!)

You may want to read Lars' How to Set Timing document.....

So in summary, you don't have an anomaly and you are running the standard timing.
 

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Forget factory specs when you've made changes to other things - they're meaningless. Don't let the specs play mind games with you and make you feel like you must be "wrong" because your car is different.

You're doing fine. First order of business is to find out how much total at WOT your engine likes, and at 34 degrees it sounds like you're probably right on the money. Most engines usually LIKE a lot of advance at idle no-load conditions, but as they move off of idle and start to see some load, not as much. That's one of the functions of the vacuum advance mechanism that a lot of people don't realize. At idle/no load your engine is making lots of vacuum so the diaphragm is adding a lot of advance. However, as soon as you add throttle/load and vacuum starts to drop, it has the effect of actually pulling advance OUT of the engine which is exactly what needs to happen under those conditions in order to stay out of detonation. Then as RPM increases, the mechanical advance starts to add it back in.

As long as it's not hard to start, doesn't overheat, runs like a healthy Pontiac should, and doesn't ping/rattle under load - you're fine. Don't sweat it.

Bear
 

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Discussion Starter #8
1968 engine timing issues

Hello Goat Roper: The 1968 GTO has a 1968 engine. 400cu.
Read the spec. in first post... I think I posted in wrong area...
Thank you all for the input.
I'm a proud owner of one wild running Jet Engine 1968 GTO. She is screaming.
I don't think I should go any higher than 22 degrees at bast timing. My engine is so smooth at Idel you can put a glass of water on the air cleaner and not spill a drop.... My #3 mechanic saw it today and we checked out my timing light. Everything OK.... I'm going to run the 1/4 mile at 8 sec. at 170 mph. LOL LOL
You all have a great week. Tks
Bobby :)
 

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Forget factory specs when you've made changes to other things - they're meaningless. Don't let the specs play mind games with you and make you feel like you must be "wrong" because your car is different.

You're doing fine. First order of business is to find out how much total at WOT your engine likes, and at 34 degrees it sounds like you're probably right on the money. Most engines usually LIKE a lot of advance at idle no-load conditions, but as they move off of idle and start to see some load, not as much. That's one of the functions of the vacuum advance mechanism that a lot of people don't realize. At idle/no load your engine is making lots of vacuum so the diaphragm is adding a lot of advance. However, as soon as you add throttle/load and vacuum starts to drop, it has the effect of actually pulling advance OUT of the engine which is exactly what needs to happen under those conditions in order to stay out of detonation. Then as RPM increases, the mechanical advance starts to add it back in.

As long as it's not hard to start, doesn't overheat, runs like a healthy Pontiac should, and doesn't ping/rattle under load - you're fine. Don't sweat it.

Bear
This^^^. I secretly think you are less than a true 22 initial, due to markings, parts, etc. I can tell you, my GTO's would not crank over with that much advance unless the spark was disabled. Waaaay too much, if accurate. You should run a vacuum advance, though, for better power, better economy, and lower engine temperatures. Win-win-win.
 

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Discussion Starter #10
1968 engine timing issues

To: GeeTeeohguy

I just got this car running great, and you want me to set it up with a Vaccumm Advance system. Why do so many people like the MSD ignition system.

Your car is a different animal than mine so I'm assuming the timing would be different. Like everyone says let your engine tell you when she is happy. I will double check now the Balancer to top dead center. Timing light is ok. I got new everything on the car. Don't those MSD ignition system kind of help the timing???????? Have a great day,
Bobby :)
 

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Racing only distributor in a street engine, common issue, NO vacuum advance to help idle quality. Now, if 14 were used as an initial timing, AND, a CORRECTLY SET UP VACUUM ADVANCE with 8 degrees of crankshaft timing set into it, run on full manifold vacuum, the initial would be reasonable, and the idle timing would be at the 22 it has always wanted to have, even dead stock. The nice thing is, there would be an adjustable option to add whatever degrees needed to match the 22/24 idle degrees, no matter the initial you want to use.

Examples: 14 initial, 8 vacuum, 22 idle, 12 initial, 10 vacuum, 22 idle, and, on, and, on.

Now, just how to set up the timing stop on a vacuum advance? Two different ways, set distance and adjustable, ask for the vacuum advance pictures package, NO COST, NO ADS, just how to do it right, and inexpensively. You have NOTHING to lose by looking.

[email protected]
 

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He says in his initial post that it is a stock distributor with a "msd" pick up.....that's why I thought that he didn't Un hook vacuum advance.

If it is a stock distributor with a "msd" conversion, then it has a vacuum advance. If it doesn't have a vacuum advance then it has a hole in the side of distributor where it was......

Better ask mechanic #4 ....
 

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Hello All: It's bob again:
I would like to know why my GTO runs so great at 22 degrees BTDC. Intial Timing. Idle rpm's 700
1. Total Timing kicks in at 2800 rpms at 34 degrees ????
2. I have a MSD electronic system. 6AL model.
3. Stock Distrubutor with just a rotor and magnictic pickup.
4. Engine 400cu with Hooker Header's and Elderbrock manifold.
5. Elderbrock carburator model 1460 600cfm
6. No cam
7. Runs like shit at 14 degrees BTDC.
8. Runs better at 18 degrees BTDC
9. Runs much better at 20 degress BTDC
10. Runs like a Jet at 22 degrees BTDC
11. Engine sounds so smooth and Idel's great.
12. Start's right up when Hot. Engine running much cooler.
13. I just don't understand???? I believe I should not be at 22 degress at base timing??????? No pinging at all. Engine rmp's at 4000. No pinging???
What's with this engine?????
Curious minds would like to know???
Have a great day, Bob :)
number 3. " stock distributor with just a rotor and magnetic pickup"
 

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Discussion Starter #14
1968 engine timing issues

Hello Guys: You got me all confused??? Is my GTO not set up right???
Do I need a vaccum advance or not. I bought the car this way? Seems to run ok???????? I thought the Idea with a MSD ignition system was that you don't need vaccum advance or points????? I'm confused... Only thing I seem to have here in Florida when I'm at a red light for awhile and the engine get's up to 200 degrees. Gas gets hot and she kind of stumbles in 3rd gear when I give her the gas. As soon as the temp comes down to 180 degrees she runs great. I think she would like a set of colder spark plugs. I got one new big radiator in her, and that has really helped alot. I think some times you all are to technical for the average JOE..... LOL Keep up the good work. I read these posts a lot. Is 22 degress intial timing ok????? I'm back to my first question????
Thank you, Bobby :)
 

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22 degrees is right on target, it matters HOW you get to it. OP, what pickup is in the distributor, whom did it?

And, ANY stock GM point distributor can be set up with no vacuum advance, not hard to do. I delete the VA on EFI-HEI units I convert, no issues, as they are also locked out on the mechanical advance as well, for the EFI computer to set the timing.

We do not know much about this engine, need more info to properly advise, like how many degrees of cam duration, compression ratio, more.

READ "6. No cam", at that 18 deg/BTDC initial, it should be fairly unhappy starting, especially hot. It sounds like it isn't.

If the engine is cast iron block and heads, 180 deg/F is just right. There are a lot of other things that can make the temps rise under certain conditions, fan, shroud, pulley ratio, thermostat, and in a Pontiac, the restrictors/diverters at the water pump, and more. Simply hanging a giant radiator on an engine may well not work as it should if other things are not right.
 

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I'm not trying to confuse you Bob. I just don't think that it is 22 degrees. And I'm not the only one.
Now, you say stock distributor with rotor and magnetic pick up, that's what leads me to believe that it is 22 degrees with vacuum advance, which is pretty good. And 34 total is also pretty good.

Here's the bottom line.....If it's running great and starting great....then it's great, but as others have said vacuum advance is good for a street car.

200° is fine, 180 at cruise is even better. I wouldn't touch a thing. Drive it and enjoy it.
 

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Discussion Starter #17
1968 engine timing issues

Hello Dave and MyGoat: As to Dave question about the radiator. I left out that it also has a 7 blade flex fan, high end water pump, and shroud. Just did my Sunday mourning 110 mile ride, and she ran at 170 degrees on the highway at 60 mph. Also I put in her a 160 degree termostate. Radiator is rated for 700hp. To all that read this. When I bought the car it ran very Hot here in Florida would get up to 230 degrees just sitting at a red light. Then run hot moving at 40 mph. Run around 200 degrees all the time or more. I did not like that. So what I put in the car really, really stopped the heating problem I drive the car everyday to the golf course, and never get over 190 degrees at a long stop light anymore.

I like MyGoat answer that if it's running and not getting Hot, and start's right up. It is fine. Please understand I do NOT have a Vaccum advance. Just the Distrubutor, rotor, and the magnitic pick up in the Distrubutor. All this run by a MSD model 6AL box. what ever you call it. Blaster 2 coil. 8mm spark plug wires. R43S plugs. Would like to find some colder plugs. Car ran so strong this mourning running at 170 degrees.... It just loves the highway. Open up the 4 barrell and right up to 90 to 100mph... I get scared at 100 mph. With this 50 year old car afraid the front windsheild will fly off. LOL LOL I'm going to leave it at 22 degrees base timing. Been at that setting now for 500 miles... Engine didn't blow up. Engine is stock 400cu,stock cam, and just headers, and a high rise manifold, with a simple Elderbrock 600cfm carburator. With one big F%^$ Radiator. LOL LOL You all have a great week. Also Thank you for the help...
Bobby :)
 

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The reason for the engine wanting to run 180 deg/F is combustion chamber temperature efficiency. If that same engine had aluminum heads, to keep the same efficiency, I would go for a 192 to 195 deg/F thermostat. Sounds like the cooling system is working well. If you are not aware4 of this as of yet about Pontiac engines, they use a setup at the water pump that other engines do not use, inserts to direct and control flow behind the water pump. If left out, worn out, heating issues can easily ensue.

The ONLY reason to run any engine hotter than their old skool efficiency is if the design has evolved into a full-on emissions setup, that needs higher chamber temps to help burn off more fuel residues.

I am well aware you have no vacuum advance, it was removed from the stock distributor. If it runs as you like nopw, keep it as is. I think it could run even better, with a correctly set up vacuum advance enhanced distributor.
 

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Hello All: It's bob again:
I would like to know why my GTO runs so great at 22 degrees BTDC. Intial Timing. Idle rpm's 700
1. Total Timing kicks in at 2800 rpms at 34 degrees ????
2. I have a MSD electronic system. 6AL model.
3. Stock Distrubutor with just a rotor and magnictic pickup.
4. Engine 400cu with Hooker Header's and Elderbrock manifold.
5. Elderbrock carburator model 1460 600cfm
6. No cam
7. Runs like shit at 14 degrees BTDC.
8. Runs better at 18 degrees BTDC
9. Runs much better at 20 degress BTDC
10. Runs like a Jet at 22 degrees BTDC
11. Engine sounds so smooth and Idel's great.
12. Start's right up when Hot. Engine running much cooler.
13. I just don't understand???? I believe I should not be at 22 degress at base timing??????? No pinging at all. Engine rmp's at 4000. No pinging???
What's with this engine?????
Curious minds would like to know???
Have a great day, Bob :)
I would replace the 25% CFM you lost with a 800 CFM carb.
My engine seems to like the 195 thermostat and runs best at this temp.
Stock size radiator and clearance done on the plates.
If I run it hard it goes up to 205 but cools quickly once I let off.
Normal running temp is 190.
 

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Discussion Starter #20
1968 engine timing issues

Hello Goat, and Dave: Like to know where you two guys live. I don't think either of you live here in Florida. The weather here this summer has hit 100 degrees easy.
Humidity off the carts. Very hot out side for these old engines. I had a new timing cover put on with a high flow water pump, and I know about the spacer was put it correctly. Bought the system from Butler Eng. I only buy the best for the car. As far as a bigger carb. sounds good, but I'm 66 years old, and it looks just like it came off the assembly line. Mint. I really baby this car except when I clean her out for my Sunday rides. The engine is the stock engine. Cast Iron heads, and all stock in side. I had the mechanic #3 check compression, and all is ok. I pulled the spark plugs just to see how they were burning the fuel. All still looked good after 1500 miles with a light brown color. No build up so I believe no oil is leaking by the rings, and the new carburator is working great. We did put a spacer between the carb and the manifold to help with the heat down here in Florida. I'm surprise we didn't have any other member's on this site sign in and say. Yes, Florida is very HOT. LOL LOL Any other information you got I surely would love. Have a safe ride, and a great week. Bobby :)
 
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