BARACU Posted October 18, 2001 Share Posted October 18, 2001 I've been reading and searching on this board for a few weeks, hoping to find a solution to a smoking problem at start up.'77 z engine, bored .020" with flattop pistons, slightly hotter streetcam,Clifford 4V intake with Holley 390 carb,headers and 2 1/2" exhaust.Engine has 4000miles on it and just started with blue smoke at start up. never while running. Compression either hot or cold is 225-230lbs on all cylinders, initial compression stroke is 125 on all cylinders.head was redone at rebuild with new valves,and seals...guides checked out Ok. About a month ago, I found a broken guide on #3 exhaust and thought that was the problem. Head was pulled and redone all new guides and seals were installed, Head was checked and had 0 leakdown. Reinstalled head and still had same problem. Leakdown test, with Snap On dual gauge tester, on cold engine showed 0 leakdown on 4 cylinders and 1/2lb on two cylinders. Carb was rebuilt and checked for leakage,PCV cleaned and checked,no sign of coolant in oil or vice-versa,brake fluid not being sucked into intake, intake shows no sign of oil contamination. Ignition checked, wires metered.Running 20-50 Castrol oil...no usage Everything appears to be perfect in this engine. Yet, it still smokes at startup. I'm pretty much out of ideas.Hopefully someone can help. Sorry for the length. Thanks in advance! Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted October 18, 2001 Share Posted October 18, 2001 blue on startup is typically valve guides and/or valve seals, but seeing as you've done both already it's hard to say..... [ October 17, 2001: Message edited by: Ross C ] Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 19, 2001 Share Posted October 19, 2001 BLUE SMOKE: BLUE SMOKE IS MOST ALWAYS OIL BURNING. LATE MODELCHEVY V8 AND V6(INCLUDING MY OWN ASTRO V6) HAD A SIMILAR PROBLEM-BLUE SMOKE AT STARTING. THE MODIFICATION WAS NEW DESIGN VALVE GUIDE SEAL. CHECK YOUR SEALS REAL GOOD AND ALSO CHECK VALVE GUIDE TO VALVE CLEARNACE. YOU CAN VERIFY THE PROBLEM BY PUTTING IN ENGINE OIL DYE IN THE MOTOR OIL. THIS DYE IS VISIBLE WITH UV LIGHT. RUN THE DYE IN ENGINE AND DO SEVERAL START UPS. THEN PULL THE INTAKE AND CHECK BACK SIDE OF INTAKE VALVE(ONLY INTAKE SIDE SUCKS). IT SURE SHOW SLIGHT TRACE OF DYE BUT NO LARGE AMOUNTS. ALSO LOOK FOR POSSIBLE LOOSE VALVE GUIDES. GOOD LUCK, SUNNY Quote Link to comment Share on other sites More sharing options...
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