Well, the time has come to address the power production of the Boneyard Buick. We have performed the typical bolt-ons and, since we do not want to push a 130,000-mile motor too far, the Turbo 6 will be freshened prior to making some more substantial power mods. Before jumping headlong into bolting on a huge turbo, front-mount intercooler and installing a high-boost chip, a performance enthusiast should have a detailed battle plan before making the first move. Some of the more important factors are: intended usage of the vehicle, budget of the build-up and expectations (e.g. power output, e.t. performance, reliability and downtime). Set goals for the project based on these issues. For the Boneyard Buick, we want 50-state legality, daily driver reliability and 11-second capability. The T-Type is a daily driver that is a 90-percent street and 10-percent strip proposition. Therefore, legality and reliability outweigh the need for 11-second timeslips. For instance, when it comes to turbo selection, responsiveness is more important than high flow figures. From a budgetary standpoint, we are taking the middle road, but will detail the strictly budget and high-performance options as the project moves along.
It is always good to know the limitations of the powerplant when laying down the groundwork for any project, as this knowledge will save time and keep one from spending money on unneeded or over-engineered (for that application) parts. To better fathom what our buildup will encompass and to further expand our Buick database, we quizzed Buick tuner Lou Czarnota of Lou's Auto Service in Lake Forest, Calif. on the weaknesses of the Turbo 6 powerplant.
According to Czarnota, the V6 suffers from a weak bottom-end because there is no reinforcement between the main caps and the pan rail. So for high-performance applications, a Loveridge girdle is recommended (see sidebar). For applications running less than 20 psi, the stock set-up will suffice. The Buick engine block tends to develop cracks in the main webs where the cap joins the block. This area should be checked when the engine is disassembled. The thin-wall block design can also be a weakness when things are pushed too far. It is wise to remember that the V6 block was originally designed to support 150 hp in carbureted form. It is true that the nickel content of the turbo block was increased and the head bolt threads were countersunk deeper in the block for added head bolt reinforcement but these design upgrades are still less than ideal, considering the extreme potential of a turbocharged EFI-equipped V6.
One can opt for an aftermarket Stage II block, but beware that only the early models were off-center and only the early off-center blocks will work with stock upper-end hardware. The blocks are rare treasures, as Czarnota recently sold an early Stage II block for $2,800 and we're talking about a bare bones block. Czarnota said that a virgin early Stage II block could easily fetch $3,500 to $4,500.
Our block was deburred and the cylinders were bored to .030 inches over with a torque plate using a 625 Sunnen stone to a 320-grit finish. The cylinder walls were then finished via a plateau honing procedure using a fine brush to give the rings an easy start on life and reduce piston/piston ring friction. Close attention should be paid to the base of the main caps; this area is known for casting flashes. Slag is also inherent in the heads. Be sure the pickup tube and block feed holes are cleared out. The head-mounting surface on the block must be machined to a high standard, quality fasteners should be used and a high-performance gasket incorporated into the process. The engine builder should also closely adhere to the gasket manufacturer's recommendations regarding the torquing of the heads. For high-boost applications (20 psi and up) Czarnota recommends Fel Pro Wire-Loc head gaskets but warns that the receiver groove must be precise and should be performed on a Bridgeport mill by a competent machinist to exact specs. If you are unable to get the receiver grooves executed correctly, you are better off running stock gaskets.
Reliability is often where budget impacts the project. You can go overkill with engine internals and wind up with a thin wallet. Crower offers a package that includes a crank, rods and pistons-which is an excellent one-stop shopping opportunity for higher dollar, more extreme build-ups. Billet cranks, forged pistons and upgraded rods can also be purchased separately. TRW pistons deliver forged aluminum performance at a more cost-effective price. For applications where boost will be cranked past 20 psi, Czarnota prefers JE pistons. It seems that 20 psi is the magic number, as block reinforcement and the use of other upgraded engine internals are needed at this point.
Since our goals are much more modest than the typical Buick racer, we have tailored a plan of action that will result in a stout short block at an affordable price. We have refurbished the stock crank, which will swing a stock rod and TRW piston combination. Czarnota employed JE wrist pins because they are light, strong and any reduction in rotating mass is always a good thing. It should be noted that TRW pistons are only offered in .030-inch overbore sizes, while JE's can be ordered for any size overbore. When it comes to ring gaps, Czarnota likes to run .018-inch on the top ring and .016-inch on the bottom ring. This is a closer tolerance than the manufacturer's spec of .020-inch, but Czarnota cited superior sealing and no leakdown problems, even at higher boost levels, as major benefits.
The crankshaft is a point of contention, as it can hinder performance in high-output build-ups. The Buick crank is an even-fire design where the crank journals are situated in a split-pin configuration, which by virtue of its design is weaker than a common-journal crank found in other engines, including the venerable small-block Chevy.
Picture a common journal set-up, as two circles of the same size are transposed over one another. Each circle represents a rod location. A split-pin configuration is attained by moving the same two circles so that they intersect each other. The common ground shared by each circle represents its attachment to the shaft. The split-pin has much less material in the shaft attachment area, which accounts for its weakness. Czarnota does not recommend regrinding a stock crank past .010-inch. If a crank needs more machining work than this, a cherry, new stock cast crankshaft should be used.
In Turbo 6 applications, steel main caps are used on the center mains only because that is where most of the load is absorbed. With the previously mentioned need for reinforcement in the bottom-end, the use of steel main caps and quality fasteners, such as ARP hardware, is good insurance, especially if the engine is expected to produce more than casual street performance.
Our crank will be secured by Pro Gram Engineering steel main caps and ARP fasteners will be used exclusively on the caps and connecting rods. A Fel Pro neoprene main seal (PN BS40613) will be used in place of the inferior stock rope-style seal. We have also upgraded to a Cloyes double roller timing chain (PN 9-3100) and have added a high-flow Melling oil pump (PN K-201PHV).
Going into the planning portion of the build-up, we wanted to turn the boost up to 18-20 psi. We forgot to mention that we plan to upgrade the turbo. What many enthusiasts fail to realize is that it is air volume, not boost pressure, that results in added thrust when the hammer is dropped. It is likely that our Limit Engineering turbo will flow more air at 15 psi than our stocker did and, therefore, make more power. The key is to tabulate all of the factors of the build-up, pick the best parts one can afford, keep things reliable and let the chips fall where they may when it comes to power and quarter-mile performance.
At this point, the short block has been 95-percent assembled. In the next installment we will catch up with our heads, which are at BPE Racing Heads, and lay the groundwork for the rest of the engine build-up series. Stay tuned.