"DZ" grease pencil mark

[Mike S]

 Here is one picture sent to me. It was taken in '68, notice the 'MO' on the head. As Bryon noted it was easy to spot a DZ motor. I am sure we can spot a DZ motor easy enough but maybe the person who had to pull many motor’s off the racks for in-line builds in a fast paced environment was not as knowledgeable about what to look for so a hand written block code would have made it easier and less prone to error and time wasted to get the correct one.
 It's great having CRG back up to have discussions like these. 

Mike

[bcmiller]

I asked Jerry M. specifically about DZs and head markings he has seen and he said

“Any that I've seen are badly faded and a lot of the orange paint is gone from the head.”

[X33RS]

Here is one picture sent to me. It was taken in '68, notice the 'MO' on the head. As Bryon noted it was easy to spot a DZ motor. I am sure we can spot a DZ motor easy enough but maybe the person who had to pull many motor’s off the racks for in-line builds in a fast paced environment was not as knowledgeable about what to look for so a hand written block code would have made it easier and less prone to error and time wasted to get the correct one.
 It's great having CRG back up to have discussions like these. 

Mike

That's interesting.  Notice on a 68 it's on the passenger side because the alternator is opposite??   Reversed on 69.   That tells me these engines were fully dressed so they were making their notations where they would be visible....   Do you guys come to that conclusion or am I way off base?

[bcmiller]

Like I said, that’s not the norm.

Remember “the engine was sprayed with cheapest orange enamel available in bulk that month”.  Maybe that month it was thinner than normal?

One picture does not make it clear cut.

[Mike S]

 My thinking is it was written the the head after it was assembled (not dressed) and painted but before it went on the inventory rack. Just speculation.

Mike

[bcmiller]

Possible.

But more likely it was for the engine plant assembly use. Double hump heads were available with both 1.94/1.50 valves and 2.02/1.60 valves. The DZ or MO notations were probably for engine assembly use.

I will see if I can get JohnZ to chime in.

[bcmiller]

There are potentially two different things we are taking about.

1. What was done at the engine assembly plant. The yellow markings on the block (such as 302) were put there to help the workers know which rotating assembly to install in the block. There were markings on the heads too, probably to help determine which heads to put on the block. The 302s got the heads with 2.02/1.60 valves. Whether this was done with grease pencil or a paint pen, I don’t know. But these markings were painted over.

Jerry has seen many original cars and I quoted what he said above.

2. What was done at the vehicle assembly plant. Could some engines have gotten a code written on the head with a grease pencil? Possibly, but it’s not the norm. By 69, big blocks had an broadcast code sticker on the valve cover. I can’t say for small blocks. Flint and Tonawanda might have had different policies.

Try an experiment. Grease pencil a marking on the head of a freshly painted engine and see how long it lasts. I don’t think it was done that way, but give it a try. Probably won’t last through many heat cycles on the front of a head. 

It’s graffiti. Like some restored cars with grease pencil markings for paint code on the firewall. Cars got them, but they were covered over by the firewall blackout paint. Grease pencil markings behind the rear seat generally survived, for obvious reasons.

[KurtS]

2 different markings. Both done by the engine plant.

- Side of the block, upside down to know what parts to load. Was painted over.

- End of head, broadcast code to help ID the block without looking at the pad. Used by both the engine and vehicle plants. I see them more in 67/8, but that's may be because the alternator is in the way in 69 or due the use of stickers.

[bcmiller]

Thanks Kurt. Doesn’t look like much paint on that head in the area with the letters. Was originally under the paint?

And this has broadened into a larger topic, but original question was for a DZ engine. 

[KurtS]

No, it's clearly on top. I've seen it on many engines and JohnZ has talked about it.

[X33RS]

Great discussion.  I don't mind what it's been morphed into.  I think it's helping to possibly understand, and I love the pictures.

I could possibly see the need for the engine code to be written on the head for the line workers as demonstrated on that 68 photo.  I can only imagine after doing the same thing day in and day out that all these engines just start to look the same after a while.  An easier way to identify to lessen mistakes does make sense.

But as Kurt mentioned, he's seen more on 67-68.  I've never seen stickers used on the small block stuff.   So what changed to not see the hand written marks as often (or not at all) on 69 SBC's???  Other than the alternator location obviously. 

[william]

Here's a pic that has been around for decades. It's an engine bay photo taken at delivery. Enlarge it and it does appear there is something written on the end of the head.

There is a similar photo of an L48 engine in a Nova SS. Nothing visible on the cylinder head.

If this was done [probably] it was hardly visible. Did they always do it? Probably not.

[X33RS]

I'll have to get my wife involved, I can't enlarge it anymore than what it is.  But I appreciate the pic Bill.  As it is though, I think I do see something there.

[KurtS]

On 69+ engines, the alternator would be in the way if they put it on the right side (like 67-68). So much harder to see in a fully dressed engine.

[firstgenaddict]

Here is the best I could get in photoshop... I enlarged and then manipulated hue saturation and lightness...