Scratch/bashing a 702

[landman]

While adding pieces to the manifolds, I narrowed the valve covers by one saw kerf. Hardly noticeable but it does slim them down. Then I filled the ribs to get a smooth surface.

Remade the heads to obtain the taller profile of the originals.

The I;1 has 5 frost plugs on each side of the block. Made some using 4mm rings. 3, or even 2 mm would have been better, but this is the smallest I could find short of cutting some very small tubing.

Edited October 25, 2020 by landman

[landman]

Part of the "chunky" problem is visible in post 324. The runners don't rise high enough above the collector. Back to the drawing board.

[kilrathy10]

Man....As far as I can see, you're doing a wonderful job on this thing....I think you'll be just fine.....This thing looks really good....

[landman]

Remembered the stash of short tubings I got the other day. Cut some of that up and made what I think are more realistic frost plugs.

Also cut off all the ports off the exhaust manifolds and reconfigured them so the entire port is above the collector.

Edited October 25, 2020 by landman

[landman]

Here's a recap. Redid the exhaust manifolds using smaller material. They are better but not as slim as the 1:1s.But they'll do for now. After all, it IS a prototype. Prototypes get modified.

Spent most of the weekend trying to make flanges on the intake manifolds. Here are the results.

Posed it next to the CAT 1106 for size reference. I still think it looks too wide at the top compared to the actual engine which appears narrower and taller. Maybe once the pan is installed...

Someone suggested I cast this. I feel it isn't an accurate enough replica for that, however, we'll see. But then, I may select the best of something and cast the others off it for consistency. Hope you guys are enjoying this as much as I am. I will take a short break and go back to the Caddy for a bit.

Edited October 25, 2020 by landman

[Superpeterbilt]

I am definitly enjoying watching this. Im currently scratchbuilding an engine for the first time myself. Its something that Ive always been intimidated by, but now that Im doing it, its very rewarding. I second the suggestion that you cast this. Even if its not entirely accurate, its better than starting from scratch. I would buy a few of them because it looks good to me.

[landman]

The carbs were Strombergs WW, anyone know if they are reproduced? Anything similar?

Edited October 25, 2020 by landman

[tbill]

Pat, that's pretty sweet. I have no doubt you will keep improving on it until it's perfect, great work so far.

[landman]

Rummaging through the junk engine parts to find stuff suitable for the font cover, water pump, fuel pump etc..

Edited October 25, 2020 by landman

[Chariots of Fire]

Just a thought on those 5 plugs. If you wrap some spool wire around a piece of small brass or aluminum tubing 2-3 times and then cut the wrappings you end up with nice small rings. Just trim the ends and squeeze them together. You can do any size you want.

[landman]

Just a thought on those 5 plugs. If you wrap some spool wire around a piece of small brass or aluminum tubing 2-3 times and then cut the wrappings you end up with nice small rings. Just trim the ends and squeeze them together. You can do any size you want.

Now why didn't I think of that.

[gatorincebu]

Like WOW! You have grabbed my attention with this thread. I nver realized the made a 12 cylinder gas motor. Duh??? lol

Be Well

Gator

[MeatMan]

Wow Pat, I just started a CBP on the Mad Max movie Fury Road and decided to build one of the cars that has the 702! Although the promo states that it's powered by two V6's back to back my research found that the thing has in fact a 702! I plan on pairing a couple of Chevy 409's as a start and fill in the holes in the block. I hope you don't mind if I pirate some of your ideas. Yours looks simply fantastic!

[landman]

No sweat Dennis, none of this is copyrighted.

[Rob Hall]

What an interesting engine..seems like lots of potential for hot rod and unusual builds..

[landman]

What an interesting engine..seems like lots of potential for hot rod and unusual builds..

Several hot rods have been made as wells an outstanding custom roadster.Just google GMC twin six 702 images.

[dptydawg]

Pat it looks like you are making good progress on the intake manifolds. its amazing the amount of time that scratch building can soak up. Great job on the 702 so far.

Carl

[landman]

Pat it looks like you are making good progress on the intake manifolds. its amazing the amount of time that scratch building can soak up. Great job on the 702 so far.

Carl

I bought some smaller square tubing the other day. I may try another one with that to see.

[landman]

Several hot rods have been made as wells an outstanding custom roadster.Just google GMC twin six 702 images.

That custom roadster is the Blastolene B-702: http://www.randygrubb.com/the-b702/

[kilrathy10]

Goodness, Gracious.....What an undertaking....Looks just beautiful, to me.....

[landman]

I had trouble visualizing the front of the water pump casting from the angled view in the exploded diagram so I asked for an end on picture from Thunder V12 which they provided. I then reduced it to the size needed and cut out a base from sheet styrene.

Then using bits I found the other day, I set out making the shape of the casting. The cover in the third photo will serve to make the bottom part.

Edited October 25, 2020 by landman

[Superpeterbilt]

Great work.

[Tesla]

Pat, your level of detailing is incredible...looks great

[mustang1989]

Wow!

[landman]

Front casting is taking shape. Also made up a fuel pump out of scrap bits.

Edited October 25, 2020 by landman