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Supercharged GM 3800 with no power and "dug dug" sound

I have a '95 Riviera that was run low on oil by the previous little old lady owner because of a leaky oil sending unit. I’ve changed a bad coil and the supercharger gasket and a new set of OEM rod and main bearings – the crank nose is a little chewed up and the first 2 rod journals as well. But would the bouncing crank take away the engine power and give it the “dug dug” sound under a load - it idles and revs great! ??? BTW, it is an OBD1 with an OBD2 connector because of it being built in the transitional year.


If the journals are chewed up - don’t get too far away from home. Those new bearings are more than likely trashed already.

Considering the situation and history of the car, the first things I would do is pull the spark plugs and run a compression test. If the compression is good (don’t bet the farm on that) then I would connect a vacuum gauge. A vacuum gauge is cheap, easy to use, and can tell you many things very quickly.

There’s not enough info known about the car to get real specific but considering the crankshaft problem, and if the compression turns out to be not so good, it may simply be time for another engine. The 3.8 is easy to locate so that shouldn’t be a problem.

Thanks for your thoughts…I try to keep it under 2000RPM’s and not too far away from hom. It just sounds soos good idling and revving. I have been looking for a front crank sleeve as a quick fix. Any thoughts on that.
Thanks again.

A Speedi-Sleeve as they’re called is an acceptable fix for the crankshaft nose and can certainly prevent oil leakage from the front seal.

If it will make you feel any better, Ford even recalled their Ford GTs (the 150 grand exotic car) for rear main seal leakage due to a poor surface on the crankshaft journal. (I don’t think Ford was behind the engine construction very much but they’re liable, so…
This involved dropping the entire engine/transaxle assembly out of the vehicle (costly to Ford even under warranty) and that was their solution for it - install a Speedi-Sleeve.

Acceptable on an everyday old car but if I was rich enough to give 150-200 grand for one of those things and was told a 3 dollar Speedi-Sleeve was the proper fix Ford would be in court and buying that car back.
If the seal surface is not smooth enough then what about the bearing journals… :slight_smile:

Just a thought… are you sure that the supercharger is filled with oil and of the proper type?

Thanks…one of the first things I suspected was the SC…the gasket had 2 cracks in it. It was disassembled, cleaned and the coupler and gasket and oils were changed. The SC goes into a by-pass mode when not under a load – mebe I should look into that again. The plugs are clean since then and after the center coil was changed.
Any and all suggestions are welcomed! I had a vin C 1988 Olds with less HP and I know how that felt and sounded under acceleration - this is nothing like that and it is supposed to be 225HP compared to 160??


Yeah, it should get up and move… Supercharged Rivs could roast the fronts all day long.