BobsZTwins Posted June 20, 2003 Share Posted June 20, 2003 I've got a noticeable skip and an occasional puff of blue out the tailpipe of my Stage II Scarab motor. It's the single turbo chevy 350 rated at 425hp. I've tried all the usual: new plugs, wires, cap, rotor. Checked compression, it's around 135 except one's down at 125, not too far off. Plug threads are oily but plugs aren't fouling. No telltale sounds but I do have a bad hesitation when I romp on the gas, no problem if I ease down to the floor. That sounds like an accelerator pump. But it's certainly down on power. Any suggestions? Anyone know of a GOOD engine builder/rebuilder in the Jacksonville, FL area? I really want to get the car screaming again! Thanks!! Quote Link to comment Share on other sites More sharing options...
Guest the_dj Posted June 20, 2003 Share Posted June 20, 2003 Sweet I didn't know anyone else on here had a turbo'd 350. Quote Link to comment Share on other sites More sharing options...
dmyntti Posted June 20, 2003 Share Posted June 20, 2003 The blue puffs out of the pipes sounds like valve seals. You may just need to have the cylinder heads rebuilt. The miss and lack of power could be anything. I would probably start by looking at the carb. Turbos with carbs can be very difficult to set up. I assume the turbo is blowing through the carb. If so make sure the fuel bowl vent is seeing the pressurized air or you will have a problem running lean. Also check the fuel pressure because the carb will need more fuel pressure as the boost goes up. Just a few thoughts. Quote Link to comment Share on other sites More sharing options...
Guest Potent68 Posted June 20, 2003 Share Posted June 20, 2003 The valve seals definitely sound like a suspect here. What happens, in case you don't know, is as your vehicle sits overnight for example, the oil leaks past them, into your cylinders, so you get that initial blue puff on startup. When they get a little worse, people behind you will notice a little blue puff after sitting, idleing at a stop light. My old Nova was worn down enough that if I let it sit overnight it wouldnt' puff blue, only because my rings were so bad the oil in the cylinders would leak past them, back into the crankcase. As far as the hesitation, I'd also say accelerator pump, however, I've never attempted to tune a turbo, so I'm really no help there. Good luck. Tom Quote Link to comment Share on other sites More sharing options...
BobsZTwins Posted June 21, 2003 Author Share Posted June 21, 2003 Thanks for the feedback, I have to agree about the valve seats/seals. Especially on the right side where the turbo sits right next to the valve cover. I'm sure residual heat after shutdown shortens the life of the seals. The system is a pull thru and I know I'm getting plenty of fuel pressure, I just rebuilt the elec pump and tested flow at the carb. But the bogging must be the accel pump. I think I'm gonna put it in the shop next week, I wanna feel the full pull of 425hp again! Thanks! Quote Link to comment Share on other sites More sharing options...
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