Gary Hart's 1951 GMC Half Ton - now with Teaser video!

[TheSilverBuick]

Hey Gary! I'm interested in seeing more of that intake manifold setup you got there! I like the style, I'm thinking of going downwards with the exhaust and upwards with the intake on mine (and be no where near as beautiful as yours!).

Welcome to Bangshift!

[67pete300]

Awesome!

[Huskinhano]

Wow! I love following along on project like this where there is a lot of custom made parts and just not a "catalog" build picking already match parts for a final build. One question about the EFI. How do you handle the injectors and firing them with just 3 intake ports. Are you planning to run 3 injectors doing double duty? Love the engine turned plate that the coil packs are mounted on.

[dieselgeek]

One question about the EFI. How do you handle the injectors and firing them with just 3 intake ports. Are you planning to run 3 injectors doing double duty? Love the engine turned plate that the coil packs are mounted on.

great question. Shared intake ports and port EFI can be a huge pain in the butt. He's running six injectors, which will be fired in groups of three (2 banks of injectors). If distribution becomes a problem, we'll fire them sequentially (using the MS3x CPU upgrade), timing the injector opening with the corresponding intake valve opening. Upgrading from his MS2 to MS3x is a few extra bucks and hour or two of wiring. We'd need a cam speed sensor, which is easy to do inside the old distributor with a pertronix module, or even points.

For starters, we're going to see how it does on bank fire injection first. With the injectors a little bit upstream, I don't expect us to need the sequential.

[TheSilverBuick]

On the inliners forum, a gut there with an EFI'd turbo chevy 250 ran into issues with afr's and fuel distribution with the shared ports (lump ports). He went to an individual runner head and it cleaned it up. I wonder how the sequential will work with the shared ports.

[dieselgeek]

On the inliners forum, a gut there with an EFI'd turbo chevy 250 ran into issues with afr's and fuel distribution with the shared ports (lump ports). He went to an individual runner head and it cleaned it up. I wonder how the sequential will work with the shared ports.

It's said that sequential injection is the only proper way to do shared port EFI. That's how the guys with the Salt Cat did it on their shared port XXO engine (inline 8 buick like Dr. Mike's) and they had a lot fewer problems than we had on the #1950 Buick, same engine.

The idea is to inject the fuel in the column of air that's headed for a specific cylinder, and not to overlap them. The salt cat guys said it was super easy to set up and gave them no problems at all. Versus what we went through on the #1950 - different sized injectors, 12 of them? spraying all over trying to optimize distribution, which was only good at WOT. We'd have put ms3x on the buick if it had been available at the time, I think. May still try that in the future.

[Huskinhano]

One question about the EFI. How do you handle the injectors and firing them with just 3 intake ports. Are you planning to run 3 injectors doing double duty? Love the engine turned plate that the coil packs are mounted on.

great question. Shared intake ports and port EFI can be a huge pain in the butt. He's running six injectors, which will be fired in groups of three (2 banks of injectors). If distribution becomes a problem, we'll fire them sequentially (using the MS3x CPU upgrade), timing the injector opening with the corresponding intake valve opening. Upgrading from his MS2 to MS3x is a few extra bucks and hour or two of wiring. We'd need a cam speed sensor, which is easy to do inside the old distributor with a pertronix module, or even points.

For starters, we're going to see how it does on bank fire injection first. With the injectors a little bit upstream, I don't expect us to need the sequential.

I was going to ask if you were going to run 6 injectors but I thought there wouldn't be enough room. I find this a real inrtersting post. So what's up with the 50 Buick? Any progress you can post on that?

[DanStokes]

Scott - I'll demonstrate my ignorance and ask the Dumb Guy question - Why not TBI? Is fuel distribution the issue? Seems like with that log manifold that the mixture would be pretty homogenous, especially under pressure. Maybe not - I don't know. That's why we have you in the world.

So, what's the pros and cons?

Dan

[dieselgeek]

Scott - I'll demonstrate my ignorance and ask the Dumb Guy question - Why not TBI? Is fuel distribution the issue? Seems like with that log manifold that the mixture would be pretty homogenous, especially under pressure. Maybe not - I don't know. That's why we have you in the world.

So, what's the pros and cons?

Dan

We considered that, but using anybody's OEM TBI unit would probably not meet the fuel demands of the turbo setup. (Some will argue this, I know). Anyways, injecting upstream similar to what they did on the Spectre Maverick *IS* a good way to do it IMO. just not using an OEM TBI, but still adding the fuel well upstream and running a wet manifold.

It may end up that way, who knows. Gary welded stainless for a living - he can fab this stuff up in his sleep. He uses one of those old school scratch-start welders too. Very cool.

[SuperBuickGuy]

Scott, you mentioned a LSR 50 Buick... out of complete and idle curiosity, do you know Les Liggett?