Lately there has been some discussion regarding the clutch for the 3.4 DOHC engine conversion. When Dwain Their did his he used the GM flywheel for a 3.4 but a heavy duty clutch (Center Force Dual Friction for a 2.8. Everything bolted together real nice.
On the motor mounts Dwain used the motor mounts from the 3.4 running the right side (passenger) through the motor mount. There is limited amount of twisting this way.
The cradle had to be modified for the motor mounts by adding a couple on it for the motor mounts.
On the exhaust, Dwain's son made up a set of headers out of stainless steel. The biggest hassel was getting plates. They still have the original set that were put together for test purposes.
There was a problem in the speedo conversion, but that was fixed by one of the electronic engineers in the club.
Also, he had to put a rubber piece over the back the engine to keep water out of the spark plug holes.
The most important thing about the conversion is you have to get the whole engine and wireing harness and computer. You have to get it all.
From: Frank Martin
Here is what I have learned about his swap from talking to him:
The dog bone, is on the OTHER side of the engine. He took the mount that the dog bone attaches to and put it on the front engine compartment wall, so the dog bone is in the "stock" 3.4 location (not the stock Fiero location).
The heads/intake runners are HUGE. They take up almost the whole engine compartment from the front wirewall to the back. In the other direction (side-to-side), they don't stick out much farther on the left (driver's) side, but they do stick out more to the right. There is ONE problem with that though... it doesn't clear the passenger-side decklid torsion rod/mount. He had to cut it out, and uses a stick on the other side to prop the decklid open.
He used all of the accessories and their mounts from the 3.4. (They looked smaller to me, but you really can't see them very well around the intake.) You definately won't be able to get to the accessories from the top either. (Of course you really can't get to them from the top on the 2.8 anyway.) He used the stock air cleaner housing, and I think even the stock air intake tube from the air cleaner to the engine.
He guesses it makes close to 250hp due to less restrictive exhaust than the stock Lumina exhaust. He also estimates that he can do 0-60 in about 5 seconds. The engine redlines at 7000 RPM, so I'm sure that top speed is quite a bit higher.
The only other thing non-stock is that he's running a performance chip and 160-degree thermostat. (Either ADS or HyperTech...I forget which) He also has hood vents from a turbocharged Sunbird (the opposite of the Trans Am vents, the vents point up and toward the rear of the car to draw air out, rather than to force it in), and reports no cooling problems.
His total cost for the conversion was around $2200. However, he only paid $800 (wholesale price from a friendly salvage yard) for the engine with less than 10Kmi on it.
BTW, he also mentioned that the new in-the-crate price for a new 3.4 TDC without accessories/computer/etc is about $4500.
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