Hot Rods Another metal casting adventure...in honour of Mr Mcgurk

So my last adventure was to make adapters to transition from Chevy 250/292 intake port to GMC 270/302 port. It turned out good but I was adapting a Weber DCOE triple carb intake and the Weber carbs are about $500.00 US each so I am looking for a more reasonable , cost effective(cheap) route to follow. I looked at old pics of GMC manifolds and McGurk was a popular manifold of the day. The McGurk manifold has runners that are separate from the "log" so I thought I could attempt that. I found that plastic plumbing elbows are roughly the shape and size I wanted so I started with that. I made some flanges with MDF and made a core mold from plumbing pipe. The castings turned out OK but I'm getting what look like pinholes and pimples on the exterior of the castings. I was thinking I was having a gassing problem but when I sand down the castings the pock marks go away. So I think I'm having a sand issue , not a gas bubble issue. Maybe a more experienced metal caster will chime in. Anyway, I got three useable castings for the runners and now I have to make a pattern for a "log" and top.

 

I assume it's the sand also. Maybe moisture? (IDK)

You likely already look at YouTube casting vids..."green sand" is something you can buy or make yourself.

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Lookin' good there!
She'll be well fed.

 

Suggestions to reduce gassing: Allow molds to dry for one hour before pouring. Poke small vent holes through the mold with TIG wire or equal to aid venting. Avoid holding the aluminum at melt temperature too long.

 

I'm using petrobond sand so it shouldn't have moisture in it but I will try letting it dry out next pour.

 

Are you sealing the mold with a wash? We used an alcohol based wash and after painting, you would light it to burn off the residual alky! The ones that made the cut sure look Great. Keep posting, this is good stuff.

 

Pin holes or no pin holes, that is some neat stuff right there. Well done!

 

The next step is to make patterns for the top and log part of the manifold. I used whatever leftover lumber bits I had lying around. Some pine , MDF and two old yardsticks, I think they are maple. I coated the moulds with fibreglass resin and sanded them to 400 grit. I tried casting the top and had some issues but my proof of concept says that this will work. I need to get some more petrobond as I kinda ran a little lean in some areas and had a couple minor collapses but as an exercise it worked out ok.

 

Neat!

 

I finished the "log" and top and then Bippity Boppity Boo....

Whenever I post any progress on anything on the weekend or near a holiday it gets buried pretty fast ,I hope it will get some views. I'm pretty happy with this one!....Geez that sounded pretty needy huh?

 

thats some nice work and an eye candy engine

 

Great work!

 

Nice work!

 

Great Work, Jethro! Merry Christmas to You and your Family.

 

Great work. Wish I had that talent. I might. Lol

 

Thanks catdad! Same wishes to you and yours!

 

Very Nice!

 

I don’t like it! But, I Love it!


Sent from my iPhone using The H.A.M.B. mobile app

 

That is absolutely awesome. Would love to have the ability to do this for my 250.

Sent from my moto z3 using The H.A.M.B. mobile app

 

That is excellent! Is this for the A?

 

Hey Duke....it's been a while! How've you been?
Yeah, going in the model A. since we can go fenderless now and I found a real vintage mill I can be like you and BCT and make a traditional car

 

Things are going well. Still working on the A. Other projects keep getting in the way. Spent the afternoon fixing a 34 ford frame, instead of the A.

 

that(those) are WONDERFUL!!

 

I love making stuff out of plastic plumbing pipe. It's easy to work with and cheap enough that I don't worry too much if I scrap a part.
Great job with the casting!

 

Very impressive. Came out great. Do have a lot of experience casting before you started with your adapters?

 

Love it when Jethro posts a how-to piece!

 

Very impressive, I love the design and the resulting intake system!!!

 

Actually , I only started doing sand casting this year. Up until then I had done a little(very little) lost foam casting. I have spent quite a bit of time reading backyard metal casting articles and watching Youtube videos. I'm a trial and error (lots of error) kind of guy. The nice thing about having failures in aluminum is they can go right back into the pot. You lose a little each pour but you can recycle your mistakes . If you have basic woodworking skills and can visualize a negative space you can make basic patterns for casting.

 

I find your creativity astounding.... every single time.

 

^^^^^^me too!