I have a ‘67 L71 whose original engine has been out of the car since 1968. I just did a complete rebuild on the engine and as part of that work the machine shop hot tanked the block and repainted it and all other factory painted parts with typical engine paint.

The vehicle this engine is going back into has 45,000 miles on it. While I was pretty meticulous with specifying rebuild parts etc in hindsight I probably should not have done a complete repaint of the block & heads. What I’m hoping to do is make the new shiny orange paint on this freshly beefed up engine look like it has been in the car forever and look like the engine has 45,000 miles on it too.

That said short of chemically stripping are there any ways to make new engine paint look old and heat distressed? Weird situation and question and I’m not sure I’ll go through with it.....just wondering if there is a way to make new paint look old (some sort of caustic spray on chemical/cleaner, etc).

 

I've had to do this more than a couple times:

Get another brand of Chevy orange paint that doesn't quite match and blend over the base. Wad up a dirty shop wrag and dab the paint while it's still wet.

Blow some overspray on the intake and bypass hose/clamps. They were on when the block was painted.

You need to strip the sides of the block, put on the exhaust manifolds and reshoot the engine. They were on when the block was painted so they should have overspray on them and the block should be bare underneath. Hopefully you didn't have them or the bolts blasted so they are nice and rusty.

Look for an oil fill cap, some valve covers and an oil pan that have a nice patina. I can help you with an original oil cap.

Replace all the fasteners with used bolts off a donor motor.

Matt finish clear is your friend.

Battery acid and salt water are both great for aging new plated parts.

A good way to simulate sticky grunge is with the black soot that streams from an acetylene torch before you turn on the oxygen. You can create a nice layer of dirt misting clear paint and using the exhaust port on a shop vac to disburse the dust inside onto the clear.

There's a lot of technique to this and the guys who are good at it don't share their secrets. If you tell anybody any of this I'll have to kill ya

 

Thanks for all this info. Very interesting.

 

You're welcome. Appearance is more a consequence of storage conditions and age than miles. You can help things along as I mentioned above, but as long as the paint is applied as it was at the factory (overspray and proper components in place when it is painted), it will get a nice patina pretty quickly with use. The real work is creating the "look" with accessories, hardware and the rest of the engine bay.

Here's one I built from flea market table parts in an engine compartment that had been media blasted. Part of the illusion are the intentional obvious deviations from factory (aftermarket radiator cap/air filter/hoses/clamps and the oil change sticker added to shroud). These draw the eye away from looking at what I don't want people to see and create the impression of a survivor. Visible reproduction/restoration parts are a huge no-no. There's not a single part from the original motor but it looks like it's never been out of the car. The biggest challenge for me is getting myself to age a high dollar NOS part when I can't find a suitable used original...

 

You are very talented, do you have a pic of the right side of the motor?

 

Thank you. Here's a picture of the other side. The car has its NCRS Regional Top Flight; very few originality deducts (the K&N filter is for driving).



And a couple with the filter housing off:

 

Very nice.

 

Thank you. It's mighty tough to find the used original pieces to put together a date code correct L71 that looks like it's never been out of the car (Original owner put in an L88).

 

Another painting detail-
The Tonawanda decal was on the valve cover before the engine was painted. A tape/film protecting it from over spray was removed after painting. Like the block behind the exhaust manifolds, slightly pulling back the decal with a fingernail will reveal a bare steel valve cove beneath the decal.