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Hello all, I have an 87 na that blew a couple months back. I’ve got a built s4 TII engine (Bridgeport, oversized dowels, etc.) that I bought a while back with the intention of continuing to gather the rest of the drivetrain while I drive the na. With the car stuck right now though I’m just thinking of the consequences of mating the TII engine to the na trans. Done a lot of research and I know the na trans doesn’t handle much power and the gearing is different so it won’t be ideal but I just hate to see that car sitting while I try to find a TII trans (haven’t even seen overpriced ones in my area). My main concern is damage to the engine. The rotors are the same weight so I’m thinking there won’t be a weight difference if I use na flywheel and clutch. I won’t be trying to push a lot of power until I get the trans and diff. I’m not a hooligan so I won’t be doing burnouts or drifting it (yet lol)
1. Is there a chance for damage to engine because I’m using na drivetrain?
2. if not do y’all see na drivetrain lasting at all or it’s not even worth it?
any advice appreciated thank you
If it's naturally aspirated or low boost and you aren't clutch dumping or big loaded 3rd gear pulls it should last a while.
3rd is most likely to spread and damage gear teeth under "normal" operation but if you have enough clutch to can break just about any part of those boxes.
3rd is weakest, 2nd is next weakest, next is the transfer gear on the input shaft.
The largest weakness in the transmission is the bolts for the retainer plate like to back out. I have taken to replacing them with much longer, serrated-head bolts (I think I settled on M8x30) torqued to about 40 ft-lb, with Loctite. When these bolts back out, the mainshaft can rack back and forth, constrained only by 1st gear grinding against the main plate, which sends all sorts of aluminum dust flowing through the oil and bearings. When the mainshaft racks back and forth, the gears have less contact laterally, and the transmission can pop out of gear, both of which are no fun. If the shifter **** moves back and forth on and off throttle when in gear (not 4th or Reverse) then those bolts are loose. The **** will move up to about 3/4" when it is really bad.
If it's naturally aspirated or low boost and you aren't clutch dumping or big loaded 3rd gear pulls it should last a while.
3rd is most likely to spread and damage gear teeth under "normal" operation but if you have enough clutch to can break just about any part of those boxes.
ok cool so the transmission could break (hopefully not) but the engine will be fine?
