JoeinCA Posted October 17, 2009 Share Posted October 17, 2009 Okay. An overview of the situation... I have a 355 1988 chevy engine that I built 6 years ago, and put about 4,000 miles on in my k2500 pickup. I lost the rear transmission seal on the Getrag 5 speed coming out of wyoming, towing and hauling way more weight than reasonable people would think to be safe.. Not noticing that the synchros were gone until Nevada severely shortened the life of the transmission.. to about 501 more miles. Luckily we only had to travel 500.9 more miles. The engine did not seem to mind much. I stored the engine for the next 5 years in my garage. This is a quality engine: Gm Performance parts TBI heads. Mild cam aimed for low end torque ( i cannot for the life of me remember the specs.) Holley 750 vac. secondary with adjust-a-jet on the main metering block. MSD HEI distributor (Brand new yesterday) Garbage weiand intake manifold.... So, the engine is installed in the z, the dizzy gets bent in the process, fails completely after about an hour of total run time. First start fails, engine fills with water, oil pan everything, until pushing its mocha frothy mobil 1 goodness out of the rtv at the back of the valley... My friend was filling the engine at the same time we were going for the first start, so when the water kept dropping, he kept filling. Anyhow, the engine tried to start, and failed with a loud pop and puff of smoke from the valve cover. Fast forward a week, new manifold, same Weiand Garbage, have to over torque manifold to get the damn intake runners to stop sucking air. ( I use fel-pro gaskets) The engine runs great, but is burning some oil. and leaking a bit from a sensor. A few runs around town over the course of a week and It needs over 2 quarts! I never had a drop in oil pressure below 20 psi at idle engine hot, and have between 45-60 psi cruising. I have had 2 plugs oil foul, on #3 and #7. #7 has stopped fouling with replacement of the distributor and the spark plug wire. #3 cylinder has 11 bar of compression, or about 160 psi. #7 has about 11 bar, as does #6. Cylinder # 3 puts wet clean oil on the compression adapter. I have checked the timing with a light, I dont know exactly where to set it. I have an 02 sensor on the passenger side exhaust. There have been no signs of fouling on that bank of cylinders, plug mixture readings have looked a little lean on #8, but good on 2, 4, and 6. I get 940 mv at part throttle cruise, and large drops between shifts, down to about 300 mv. I am at approximately a 67 size jet on my main circuit. I did a test run before i began writing this, and all is not well. The popping in the exhaust is still happening on decel. I tried a 3/4 throttle acceleration, and chirped into 2nd, then throttled down quickly into 4th gear to resume cruising. The engine would not return to idle, and kicking the throttle would not allow the engine to return to idle. Throttle response was also akin to having a major vacuum leak, laggy and lean. I shut the ignition off, and the engine continued to diesel a bit. I restarted the engine, and it continued to run as though there was a vacuum leak. So I shut it off again, and had much worse dieseling, followed by a large fairly audible blast of smoke from under the hood. I coasted for a while, and then started the engine again, and the high idle/vacuum leak problem was gone. This is the second or third time this has happened. I need some help here. What is causing this? Timing way out? Blown rings on #3 causing the engine to diesel on on the oil and carbon coal in the cylinder? Bent or sticking valve? Santa claus? I'm supposed to be halfway to San Diego... this time last week. Joe Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted October 18, 2009 Share Posted October 18, 2009 I guess you could be sucking oil past the intake gasket from the lifter valley area. Other than that I think you're headed towards a tear down. Quote Link to comment Share on other sites More sharing options...
bschiltz Posted October 19, 2009 Share Posted October 19, 2009 Did your engine ever overheat when you were towing? If something is warped (block, heads) that might explain the over-torquing the manifold to get a good seal and the leaks. Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted October 20, 2009 Share Posted October 20, 2009 Are you mixing fluids (still)? I don't think you could ever pull that much oil from the lifter valley now that I think about it because the intake is higher than where I would picture oil flow being. But I was also thinking you could have messed up some valve seals. If not a valve seal then I think you have something wrong with the bottom end. And I agree with bschlitz thinking that you might have warped heads too. Quote Link to comment Share on other sites More sharing options...
JoeinCA Posted October 27, 2009 Author Share Posted October 27, 2009 280zwitha383 was right. There was a leak at the intake gasket, caused mainly by the garbage weiand manifold. I modified a dz302 manifold i had sitting around, and then used crummy gaskets... so after the 9 hour trip to san diego, the gaskets became oil soaked and subsequently allowed a vacuum leak again. One more go with new fel-pro gaskets seems to have fixed it. Now i just have to remember to retighten the manifold periodically for the next month or so. Now a mystery intermittent grinding noise.. probably the starter pinion gear clearance... or a clutch problem. And a leaky fuel tank... and new door locks. and the list goes on. So, thanks for the input guys. Joe Quote Link to comment Share on other sites More sharing options...
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