Hot Rod Forum banner
1 - 15 of 15 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
Hi guys,

I just got my new '47 Buick Super streetrod and it has a crate 502 chevy engine. All I got with the car was 4 pages detailing the customisations made to the car, but no details on the engine other than its a "crate 502".

615283
615284


I've pulled the numbers off the block (14096859) and the casting date (C313) and from what I can tell its a 502 GEN V - but I need help confirming that.

615281
615282


Also, where can I go to get the stock timing specs? The Chevy site seems to just list the details for the current engines.
 

·
Registered
Joined
·
2,804 Posts
Just to be clear, it says 10 degrees initial and 32 degrees total by 4K rpm, so it assumes 22 degrees mechanical from the distributor they supply.

I’ve only worked on SBC engines, but it seems that is a really mild timing curve. With aluminum heads and reasonable compression I think you could use more like 14 degrees initial, and 36 total by about 2500 rpm and you would feel a seat-of-the-pants power increase.

Bruce
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #4 ·
The referenced document above is for the ZZ(or Ramjet)502/502.

The block casting number by the distributor on my engine is 14096859 and from what I can see on this page it looks like its a GEN V HO 502 engine which is 461hp - but I'm not positive. The Date Casting number shows C313 - so I'm guessing that's March 31st possibly 1993 or 2003?

This document for a 502HO looks to be the correct document on the Chevrolet website, but how can I confirm this isnt for a newer version of the 502HO engine? https://www.chevrolet.com/content/d...nes/01-images/502ho-crate-engine-12568778.pdf
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #5 ·
Just to be clear, it says 10 degrees initial and 32 degrees total by 4K rpm, so it assumes 22 degrees mechanical from the distributor they supply.

I’ve only worked on SBC engines, but it seems that is a really mild timing curve. With aluminum heads and reasonable compression I think you could use more like 14 degrees initial, and 36 total by about 2500 rpm and you would feel a seat-of-the-pants power increase.

Bruce
thanks Bruce. It looks like the stock HEI distributor, but will have to see if I can get a part number off it to confirm. Either way, looks like both engines have the same initial/total timing specs.

I'm confused by this statment in the guide as it seems to suggest not to use the vacuum advance on the distributor. Mine is connected?

"The HEI vacuum advance canister should remain disconnected. This engine is designed to operate using only the internal centrifugal advance to achieve the correct timing curve"
 

·
Registered
Joined
·
2,804 Posts
I agree that the statement about the mechanical advance is confusing. I assume it means that the total timing figure (32 degrees) is with mechanical advance disconnected.

I don't see why you would leave it disconnected during normal driving. A vacuum advance is for economy, and doesn't really do much for engine performance otherwise. The only issue might be if the total (initial + centrifugal + vacuum) went too high during cruise and the engine started pinging during light throttle. That might lead you to using an adjustable advance so you could set the max a little lower, but I would still use it.

Bruce
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #8 ·
I don't know anything about 502's, but that is a beautiful old Buick. I love me some old Buicks. I'll bet that thing floats like a cloud down the road.
I love the old Buicks... particularly 40's/50's and 60's cars... I also have a '55 Special, '57 Super, '57 Century, and a '66 Wildcat Custom Convertible.... beautiful cars!
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #9 ·
I agree that the statement about the mechanical advance is confusing. I assume it means that the total timing figure (32 degrees) is with mechanical advance disconnected.

I don't see why you would leave it disconnected during normal driving. A vacuum advance is for economy, and doesn't really do much for engine performance otherwise. The only issue might be if the total (initial + centrifugal + vacuum) went too high during cruise and the engine started pinging during light throttle. That might lead you to using an adjustable advance so you could set the max a little lower, but I would still use it.

Bruce
Great, thanks for the help! Will be out playing with her today so all going well she should be well tuned by the end of the day!
 

·
Registered
Joined
·
1,198 Posts
I love the old Buicks... particularly 40's/50's and 60's cars... I also have a '55 Special, '57 Super, '57 Century, and a '66 Wildcat Custom Convertible.... beautiful cars!
Yeah, me too. That is a nice Buick collection you have. My Dad was a huge Buick guy. I remember well in 1957 when he brought home a new red and white 1957 Buick Special. I remember the Wonder Bar radio station selector. It also had an adjustable speed warning device. My Dad called it a fishwife. I remember steering it sitting in his lap. I also remember a year or so later waking up and there was a 3' diameter tree laying across the roof. Totaled it! Replaced with a '59 white Buick. Don't remember what model. The best one he had when I was 16. A '66 GS. A dark blue green with black vinyl top, black interior and redline tiger paws. That thing would run!
 

·
Registered
Joined
·
2,270 Posts
thanks Bruce. It looks like the stock HEI distributor, but will have to see if I can get a part number off it to confirm. Either way, looks like both engines have the same initial/total timing specs.

I'm confused by this statment in the guide as it seems to suggest not to use the vacuum advance on the distributor. Mine is connected?

"The HEI vacuum advance canister should remain disconnected. This engine is designed to operate using only the internal centrifugal advance to achieve the correct timing curve"
I think the statement is pretty clear , leave it disconnected ,period !
 

·
Registered
Joined
·
5,982 Posts
Those stupid timing specs were used to protect the factory from warranty claims. If they thought you exceeded them there was no warranty when the motor was new.
Easy out for them.
Doesn’t matter now.
If you didn’t buy it new it’s just like any used motor. Set the timing curve any way you like.
 

·
Registered
Joined
·
2,270 Posts
Those stupid timing specs were used to protect the factory from warranty claims. If they thought you exceeded them there was no warranty when the motor was new.
Easy out for them.
Doesn’t matter now.
If you didn’t buy it new it’s just like any used motor. Set the timing curve any way you like.
I agree , but without careful documented testing with an AFR meter & a knock sensor , all we can do is speculate , that's WAG in layman's terms ..
 

·
Registered
34 Ford, 502 BBC 6 speed Tremec
Joined
·
166 Posts
These are he specs that came with my ZZ 502 Deluxe motor. =

Timing Information Set initial spark timing at 10º before top dead center (BTDC) at 650 rpm with the vacuum advance line to the distributor disconnected and plugged. This setting will produce 32º of total advance at wide-open throttle (WOT). The HEI vacuum advance canister should remain disconnected. This engine is designed to operate using only the internal centrifugal advance to achieve the correct timing curve. The HEI distributor supplied with the ZZ502 deluxe engine has mechanical centrifugal spark advance with the following curves:

Im not sure that I get the full 32 degrees total advance i know it comes very close, I do have it set at 10 degrees at Idle rpm. It always starts right up and accelerates good. I do not use the vacuum advance just as instructed.
 

·
'23 T-Bucket Pickup
Joined
·
1,863 Posts
Hi guys,

I just got my new '47 Buick Super streetrod and it has a crate 502 chevy engine. All I got with the car was 4 pages detailing the customisations made to the car, but no details on the engine other than its a "crate 502".

View attachment 615283 View attachment 615284

I've pulled the numbers off the block (14096859) and the casting date (C313) and from what I can tell its a 502 GEN V - but I need help confirming that.

View attachment 615281 View attachment 615282

Also, where can I go to get the stock timing specs? The Chevy site seems to just list the details for the current engines.
Personally I’d think that with a HEI distributor that totally timing would be in by 2500 rpm. At any rate, if it was mine I’d hook up the vacuum to ported advance NOT manifold vacuum and set the timing for 32 degrees total and not worry about what the advance is at idle. But then , it’s not mine. Just my preference from personal experience.
 
1 - 15 of 15 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top