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Timing Issue--new crate 383--timing mark is far past end of timing tab

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Brentmc

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Discussion starter · #1 ·
I'm looking for someone who might have some wisdom on what this problem might be. Here are the motor specs:

Blueprint crate 383 with 7 miles on it (block decodes to a 1987 Camaro)
Brand new 8" professional products 80003 balancer
8" GM timing tab
MSD Ready to Run HEI distributor
MSD Blaster 3 coil
Aftermarket aluminum 1-piece timing cover
700R4 Transmission

I am unable to get the timing set right--for it to run "right", the timing needs to be advanced far (6 to 8 degrees) past the right end of the timing tab.

The shop confirmed TDC and it matches "zero/TDC" on the timing tab. The balancer is brand new.

The shop confirmed that the wires are right and distributor is not a tooth off.

I confirmed that I have the correct 8" timing tab and the tab is installed in the only location (2 o'clock-ish) that matches up to the balancer.

We can time this using vacuum but I would really like to time it exactly using the numbers on the balancer/tab.

Any ideas of what could be causing this issue? I researched all over the net and both the shop and I are confused as to what the problem could be.
 
#2 ·
I assume you caught what I always forget....pulled the hose off the vacuum advance can and plugged it.
 
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#4 ·
It is not uncommon for non-stock engines to need timing beyond the tab. You need a dial back timing light or just the timing tape installed on your harmonic balancer.
 
owns 1969 Chevrolet Camaro
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Discussion starter · #5 ·
To add one more data point...the distributor on the motor (MSD 8360) sat unused in the motor for 1 year. could this have caused issues with the advance springs, plate or bushings?

Could this be a distributor problem?

....at TDC on timing tab when not running....then requires 28+ degrees at idle to run right....?
 
Discussion starter · #6 ·
TJS69 said:
It is not uncommon for non-stock engines to need timing beyond the tab. You need a dial back timing light or just the timing tape installed on your harmonic balancer.
Click to expand...

I do have timing marks on the balancer...the timing is up in the high 20 degrees at 800 RPM idle to get it to run fairly well...

Could this be a distributor problem?
 
#7 ·
TJS69 said:
It is not uncommon for non-stock engines to need timing beyond the tab. You need a dial back timing light or just the timing tape installed on your harmonic balancer.
Click to expand...
I am off the timing tab and my intial is 14 to 15 * at 850 rpm total 36 at 3000rpm , I don't know about hi 20's but what the total at 3000 , and my dizzy sat for 10 yrs in my drag motor ,works fine in this motor, MSD no vacuum advance ..can't remember the part #...What springs do you have on the weight's ,lite springs my have excessive timing in at 800rpm,again check your total advance at 3000 to 4000 ...I am no expert just a lunkhead...monday humor....
 
#9 ·
Are you sure your timing light is attached to the No. 1 cylinder spark plug wire, and the distributor is firing the #1 cylinder at TDC on the compression stroke ?
 
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Discussion starter · #10 ·
BPOS said:
Was the cam degreed? Figuring out some of the aftermarket timing sets is harder than Chinese algebra.
Click to expand...
It was degreed and dyno'd by the builder (he used a different distributor)

Here is some more info I realized:

The distributor sat in the motor for 10 months without being fired.

Older (2009 and back) MSD 8360's are known to have corrosion issues due to having non-vented caps and bare metal plates.

I'm wondering if the following theory is possible:

The weights in distributor became corroded and now stick in "advanced" position. When the motor idles, the weights automatically advance the timing causing an at-idle timing of 10+ degrees too much???

The questions I have about this theory though are:

If the advanced timing at idle is caused by stuck weights, why will the car not run properly when I manually reduce the idle back to 12 to 14 degrees?

And shouldn't it run crappy at idle if it is advanced to 28 degrees due to stuck weights vice it running fairly well at that 28 degrees?

All advice and comments are welcome--this is driving me crazy.
 
#12 ·
I know that there are at least two different timing tabs.They changed some time in the late sixties or early seveties.Make sure you have the one that corosponds with the balancer you have.I bet that's the problem.
 
Discussion starter · #13 ·
daves69 said:
I know that there are at least two different timing tabs.They changed some time in the late sixties or early seveties.Make sure you have the one that corosponds with the balancer you have.I bet that's the problem.
Click to expand...
There are 3 positions for the tab and 3 sizes of tabs. I triple-checked that I have the right tab in the right position...I was worried about that too. I have an 8" tab at 1:30. The block is a 1987 Camaro 5.7L block.

Anyone have any idea of it could be sticking mechanical advance weights doing this?

The shop is trying to find the problem but is having no luck and I am stuck at work...
 
#15 ·
To check TDC on the tab. pull #1 spark plug, put your finger over the hole, when u feel pessure its coming up on the compression stroke.
juse a scew driver or better still a bit of mig wire, and feel the piston come up to the top.
mark on the tab where the piston stops moving up, and mark where the piston feels to move down
1/2 way between these 2 marks is TDC or damn so close doesnt matter

It is not uncommon for non-stock engines to need timing beyond the tab.
Click to expand...
Yeah because modern dizzies are intially set up for post pionts/ poluution stuff/ ported VA....When the timing is set at the top of the range/degrees, the dizzy has not been modded to be able to drop the intial back in a range so as not to screw up starter motors and stuff...
When this is done, easy starting, and with the correct speced VA for the engine installed on manifold vac, it is actuated fully, adding to the intial idle advance...
ie intial of say 8 deg... a VA all in at say 10 degs gives idial advance of 18 degs.
 
Discussion starter · #16 ·
Thanks for all the input so far. Here is where it stands:

The shop confirmed that TDC and the Zero on the timing tab are correctly aligned (with the engine off).

Confirmed that the plug wires are correctly installed.

Confirmed that the distributor is not 180 off or one tooth off

Balancer is brand new and has not slipped

Timing tab is matched to the balancer.

Timing tab is installed correctly and in the right location

Vacuum line removed and plugged.

Distributor worked fine on previous motor.

So.....the shop took the car out and advanced the timing until it pinged under acceleration and then backed it off 2 degrees. They say it runs strong at that setting. They are ready to give it back to me.

The timing (at idle) reflected on the balancer/tab at idle is now at 30 degrees. The shop says this is "exactly 16 degrees more than it actually is".

The shop says that they checked for stuck distributor weights and that was not an issue (I will check again once I get it back too)

Any ideas here? It is a brand new motor. The differences between the motor the builder dyno'ed and how it is set up now is the: carb, balancer, timing cover/tab and the distributor. (I changed the cover to an aftermarket aluminum but did confirm that it is an exact match to the one from the factory). Everything else is the same.

So, what could be happening? I appreciate any ideas or input
 
#17 ·
As I understand the chronology, you changed balancers after getting the engine back from the shop. Have you compared the two balancers to see if the keyway is in the same position relative to the TDC mark on both?
 
Discussion starter · #18 ·
Mkelcy said:
As I understand the chronology, you changed balancers after getting the engine back from the shop. Have you compared the two balancers to see if the keyway is in the same position relative to the TDC mark on both?
Click to expand...
The current balancer is the only balancer that I have had on it. It is the recommended balancer for the motor.

The motor is a Blueprint 383 motor....
 
#19 ·
As Mike has mentioned and others, there are two different timing scales in relationship 2 the key way. One of them is inline with 2° and the other is inline with 10°. The 2° is for pre 1969 engines. The 10° is for 1969 and later engines. There was also a setup in the late 70's that had the timing tab located at the 12 o'clock position, where you checked the timing from behind the water pump.

With all that said, if your TDC has been confirmed... you have the correct balancer and timing tab.
 
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#20 ·
Brentmc said:
The differences between the motor the builder dyno'ed and how it is set up now is the: carb, balancer, timing cover/tab and the distributor. (I changed the cover to an aftermarket aluminum but did confirm that it is an exact match to the one from the factory). Everything else is the same.
Click to expand...

Brentmc said:
The current balancer is the only balancer that I have had on it. It is the recommended balancer for the motor.
Click to expand...
The quote above is what threw me.

Anyway, how did the shop confirm that the TDC shown by the balancer and timing tab is precisely TDC? Did they pull a head or use a piston stop in the spark plug hole? How do they know that the timing is 16 degress less than shown by the timing tab?
 
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dave ray
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