LT1-7

Andrew, see you saturday then. I'm going to start around 3pm but lets make it 4pm to be safe. I should have the turbos hooked back up but I still can't let it idle for too long w/o a cooling system

jimlab

Yep, it's pretty ragged, which is a bit surprising for the specs you posted. Wingsfan is right, though. An LSA in the 114+ range would have been a better choice.

1point3liter

Looking good. I can't wait till it's on the road.

I pulled my engine and are about to put in a set of rods, pistons, and a different cam in preperation for a turbo. I'm pretty sure I'm going to use a single t-76 but I keep toying with the idea of twins.

wingsfan

Bryan, go with twins. As you know twins are my first choice, I just don't think they'll fit. But if you work out the kinks first...

jimlab

You know, that 9.7:1 Motown 454 is sounding better and better all the time...

wingsfan

Shouldn't you finish your current project and decide it's not good enough before you do a complete platform redesign?

jimlab

What platform redesign? I'm just talking about replacing the short block.

wingsfan

Just looking at the specs on the crate motor you'd have to take a performance hit over your current motor (~50HP). Of course, knowing you there's no way you'd leave it alone and use the base crate motor.

I have no knowledge of the Motown 454. Are the mounts the same as your LT-1? Would your sheet metal intake work on it? What would you stand to gain (other than displacement and a lower CR for boost applications) by going with it?

LT1-7

Jim, wouldn't it be easier to just change out your pistons? I know you have a bad *** bottom end, why go out a replace it with a crate?

jimlab

A short block comes without cylinder heads or valvetrain. It's just the block, pistons, rods, and crankshaft.

LT1 = SBC as far as dimensions, bolt patterns, and many parts. I have what are basically converted SBC heads. The only question would be whether I'd need a different flywheel for the two-piece rear main seal.

You pretty much nailed it. Another 60 cubes and compression low enough to reach or exceed 1,000 horsepower on pump gas on boost.

jimlab

Several reasons...

My custom JE pistons were made to match the deck height, bore, and stroke of my block, and 4.04" is an odd size, so replacing them would mean another set of custom pistons, and I'd probably have a little trouble selling these. They really should stay with the block they're in, since that's what they were made for, and don't forget the cost of the coatings.

However, even if I did get new pistons, I don't have the compression height for the dish I'd need to lower the compression ratio significantly. As you can see in the picture below, with a 6.0" rod and 3.875" stroke, the wrist pin intrudes into the oil control ring. That's a 5cc "dish" (valve reliefs), BTW. I don't have the material to get a 20+cc dish out of these pistons or a new set that would work with my current rods and crankshaft. I've already talked to JE about it. They don't recommend it, and they won't make me a set of pistons with those specs.



The alternative would be to run shorter rods, but my crankshaft was clearanced for the 6.0" rods. I'd have to pull the crankshaft, send it back to Crower, and have it clearanced for 5.85" rods to be able to fit a piston in the block with the compression height to handle a 20cc (or whatever) dish. At that point, I'm "tossing" a set of extremely expensive rods, I'd have to buy new rods and pistons, and my crankshaft has to be modified, which means a complete teardown and rebuild.

I could keep the rods and lose the crank instead, but I'd lose all the displacement I worked to get. To keep the rods, I'd have to go with a 3.48" stroke (356 CID) crankshaft, because even dropping to a 3.75" stroke (385 CID) wouldn't make enough difference with the 6.0" rods to buy me the increase in compression height that I'd need. Obviously I'd need a new set of pistons also. Better to lose the rods than to scrap the ultralight crankshaft and lose 40 cubic inches.

Bottom line, I'd be better off selling my short block as a package to someone (or parting it out) than taking either of the possible options. If you subtract the cost of a new set of custom pistons (~$850), a set of Oliver billet rods (~$1,200), and the cost of machining the crank and having the engine rebuilt (~$600-800) from the cost of the Motown 454 short block (~$4,700), you end up with about an $1,850 difference. Doesn't it make more sense to just unbolt my heads and gain another 60 cubic inches, especially when I could easily sell my short block or part out my components for more than enough to cover the cost of the new one?

wingsfan

But then you'd have to get another engraved cover plate for your throttle body.

Are you considering a boosted application now, or do you just want that flexibility if that's the route you choose to take later?

Or are you just afflicted win tinkerers disease (as I am, and I think I already know the answer to that)?

One of the problems with my current setup is that I like to tinker with the car more than I like to drive it. And since it doesn't break every other week any more...it needs more power until it does.

I would have guessed that with all of the pain and suffering associated with your current motor/project you'd want to see that through to the end.

Really on the street 650hp is going to be no different than 1000hp. You won't be able to hook either up at any legal speeds, and once you're spinning your wheels that's it. Not that 1000hp wouldn't be cool. I certainly wouldn't turn it down

jimlab

RaceLogic...

LT1-7

Ahh, I see what you mean Jim. I went through the same problem with my setup remember? It does sound like you've more than thought about it though, you want to share a secret with us

jimlab

Sure. Shafiroff Racing Engines now has a 472 CID small block available...

LT1-7

OK, I pretty much just got all the piping for the downpipes down but now I'm very unhappy. The positioning of the turbos just bothers me so much. I thought I would be able to put that aside and concentrate on getting the car running but I can't. Just ordered some more flanges and going to route the turbos way different. Anyone have any ideas on where I should place them? I was thinking right next to each other with the exhaust pointing towards the back

wingsfan

John, Ed and I were talking about that on our drive back. Just flip the orientation of the drivers side turbo 180º and then "Y" your downpipes together and route them along the passenger side of the block.

Your space limitations pretty much ensure that you're going to have a sub-optimal routing, but you could probably run two 3" downpipes and Y them to a single 3" pipe all the way to the catback.

LT1-7

That was what i was going to do but it still is going to hang out the front too much. If you look at the space between the turbos and the balancer, i have about ' of room. i was thinking of lifting the turbos higher and sit them sorta on top of the balancer. i think i screwed myself when i started to use such big radius mandrel bends. i wonder how much room i'll save using the cut andd weld method like you did?

LT1-7

Found some old flanges so I wanted to see what I could come up with. What do you guys think? I'm open to any suggestions.

1point3liter

I'm glad I've decided to stick with a single turbo. That's a lot of plumbing. lol

Do you still have enough room for a downpipe on the drivers side around the steering shaft. I imagine you've thought of this and now that the manifolds come up and forward it isn't an issue.

I'd try and do something similar on the passanger side. Maybe make the charge tubes go out and around the front of the car to an intercooler. Have it flow vertically from bottom to top and have a single charge pipe route to the throttle body.

What kind of motor mounts are you using? Are you concerned with the right manifold hitting the strut tower when engine torques? There's not much clearance.

LT1-7

I just might have room to route the driver side dp under the balancer, that's if I can get a tight enough bend after the turbo. I'll just have to work on it and see what I can come up with.

Solid motor mounts are currentlly being made to fit with the messed up cradle I bought from Granny's. A solid tranny mount is also on its way from Summit Racing. So to answer your question, no I'm not concerned about the exhaust hitting.

Here are some pics, some progress but not much. Hoping to get the passenger side done by saturday and have the car driving at least on my street by tuesday.

SyderJL

john that looks like it will make routing a lot easier!

PM if you want some help.

Justus

LT1-7

Justus, looks like it's gonna be alot easier to do things now. I big problem I have now is that the alternator absolutly will not fit now. I'm thinking of selling it and mounting the stock LT1 alternator I have lying around in the garage. Only problem is now I'd have to make a custom alt. mount. Doesn't sound like fun. I'll be working on the car tuesday around 2:30- dark if you want to come by.

jimlab

John, what is the "bar" across the top of the Opti-spark distributor where the water pump would be?

LT1-7

That would be the start of my remote electric water pump. Remember how I wanted you to make me flanges to weld some -16AN fitting on? Well, I've decided to make an actual housing and run in and out lines to it. I made this thinking the turbos would hit the stock wp, but now I've changed the whole design so I'm still thinking if I should go through with it.

That reminds me, do you still have that Meziere pump you weren't gonna use?