This month we're going to step back from some of the "big stuff" that's going into the construction of the C5 Shark and take a breather of sorts. That's not to say nothing is happening on the project. Instead we're going to focus on one relatively small, but absolutely necessary, bit of work on the GM Performance Parts LS1, then take a gander at two readers' LS1-powered Sharks-one completed and the other still in its own "Construction Zone."
As I mentioned last month, we've heard from several readers regarding the "backwards" positioning of the LS1's thermostat housing in four of the photos in the March installment. I also mentioned last month that we had a fix for this problem, which will be the main thrust this month.
The thermostat housing on an LS1 mounts on the front of the water pump and, in stock configuration, points outward at roughly a 45-degree angle, on a horizontal plane. That works fine in C5s and late F-bodies (Camaros and Firebirds), and not at all in the narrow confines of a '63-82 Corvette frame, at least when the LS1 is situated in the original positioning for the stock, original drivetrain. (I went into some detail last month about why we opted to replicate factory engineering rather than set the engine where it fit best-or easiest.)
The talented crew at Bow Tie Overdrives has done a great job thus far on the C5 Shark project. But, while it may seem like a minor task, the revisions to the thermostat housing fall a little out of their realm, and once again fall right into street rod territory. Ergo, we took the thermostat and its housing, an aluminum casting, to a street rod fabricator, Barry White's Street Rod Repair Company.
The best known car to roll out of the SRRC shop is Richard Berg's "Impact," an entirely hand-formed, all-steel, '33 Ford roadster-with an F-body LS1 and 4L60E for propulsion. Among the honors this street rod has been accorded is one of the most exalted-America's Most Beautiful Roadster at the 2001 Grand National (nee Oakland) Roadster Show. Yeah, the car is that good. Anyway, to make the LS1 fit under the hood sides of the '33 roadster its thermostat had to be modified, and ended up being pointed straight ahead. You may be thinking that a show car doesn't need to be truly functional, and in some instances you'd be correct. But Mr. Berg is a firm believer in driving his toy, to the tune of nearly 3,600 miles, in between shows in the past year and he has experienced absolutely ZERO problems with the roadster.
If it works on Impact, it certainly oughta work on the C5 Shark.
What has to be done is to take the thermostat itself out of the housing, cut the housing apart (where you cut is critical!), reposition the radiator hose-end of the housing, and TIG weld the thing back together with the hose-end pointing straight forward. The housing is an aluminum casting, with a nice finish to it. It is, however, an inexpensive casting, and is fairly porous. Aluminum is not the easiest metal to weld under the best circumstances, to weld a porous and fairly thin aluminum casting requires a high level of skill, and TIG welding, while not the simplest process, gives a very high measure of control.
On a recent Saturday morning we headed over to SRRC with one LS1 thermostat assembly, as well as cameras and film to record the procedure while fabricator Chad Vogele did the deed. Rather than blather on and on, we'll let the photos tell the story. And while this may seem like a fairly minor task, it's an important step ahead on the C5 Shark's road to completion.
Our Way Ain't The Only Way
This whole thing about swapping the Gen III (LS1/LS6) into early Corvettes is in its infancy. The engine has been in production for just 5 years, appearing for the first time in the '97 C5 and a year later (and in very slightly revised form) in Camaros and Firebirds. We're not exactly talking huge volumes of vehicles or across-the-board applications.