PhaTTy Posted April 5, 2003 Share Posted April 5, 2003 Well.. ran last night for 30 mins or so and ran fine.. went to start up today and knocking.. Changed sparkplugs, checked for cylinder full of gas and none were.. Unplugged the injectors 1-by-1 while running and nothing stopped the knocking.. I also noticed I had lost around 300-400rpm at idle when this started today when I started the car. Any ideas at all? If I have to do major work on the engine, should I try to fix the 2.8 N/A or go with a 350? I am about fed up with all the troubles this has been giving me so far. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 6, 2003 Share Posted April 6, 2003 Alright now, you are going to start the car, get out and lift the hood, try to locate the area of this knock (is it really a knock?), come back in and tell us all about it! Quote Link to comment Share on other sites More sharing options...
PhaTTy Posted April 6, 2003 Author Share Posted April 6, 2003 my dad which is a professional mechanic checked and said it is definitely a knock as far as we can tell. He said it is coming from the inner engine. But the stange thing is with the injectors being unplugged 1-by-1 it still makes the sound so it seems like it is something in the head but I cannot pinpoint it.. Should I try putting the P79 head back on it.. Right now it is a P90 head which is making the noise, which I picked up from salvage. The P79 was working fine before so I may just try that. Let me know what you think. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted April 6, 2003 Share Posted April 6, 2003 Phatty; I cannot diagnose an inside engine knock from here. But you say you swapped heads and that may be it. Right offhand all I can think of is a near zero quench area (as a result of the swap)..... or piston slap. The thing that makes it even touchier is that I don't know exactly what has been going on since you put the other head on and first started it up. You say it just started knocking like it came out of nowhere, and that is not too likely unless whatever it is happened when you last shut it off, and that is streching it a bit but.....things happen! How do we know that the installed head is not a higher compression one that has already hurt the engine? Check the timing at the crankshaft and maby retard the spark a few degrees. You have to either take action now or stop driving it now, one or the other! Knock?.....Whatever. Listen to your dad, he's a mechanic. And, no wonder you are seeking help.....LOL. But someone will come in here and do better than I most likely, just be patient. PS: Because of what you say abouit pulling the injectors and still hearing the knock, I put my money on a small screw, washer, pebble, peice of gasket or whatever happily covering the top of one of your pistons with indentations. Pull the head! Quote Link to comment Share on other sites More sharing options...
PhaTTy Posted April 6, 2003 Author Share Posted April 6, 2003 I will probably do that.. Will be pulling the valve cover tomorrow to see if we can notice anything else, if not, then the head is coming off. Quote Link to comment Share on other sites More sharing options...
A. G. Olphart Posted April 13, 2003 Share Posted April 13, 2003 Well PhaTTY, what was the problem when you got the head pulled? My old Datsun pickup (L20b) died recently after similar symptoms. It made it 25 miles to its' permanent resting place, the last few miles within a huge cloud of smoke. A friend who deals in used engines told me that a loose valve seat insert can drop overnight if the engine happens to shut down with that valve open... the insert contracts as it cools, and OOPs. Next morning there is a terrible clatter every time the valve doesn't close... and the piston comes to visit. My experience supports this theory (no post mortem done to prove it) as a holed piston wouldn't do much to keep crankcase oil out of the combustion chamber. Quote Link to comment Share on other sites More sharing options...
PhaTTy Posted April 13, 2003 Author Share Posted April 13, 2003 the problem was a lash pad had come loose on one of the valves. No damage is evident so we will are going to adjust the valves and put it back into place and see how it goes. Quote Link to comment Share on other sites More sharing options...
denny411 Posted April 13, 2003 Share Posted April 13, 2003 glad to hear it was nothing major. Do you have any idea how the pad came out? It seems odd to me. Quote Link to comment Share on other sites More sharing options...
PhaTTy Posted April 14, 2003 Author Share Posted April 14, 2003 no idea at all.. guessing maybe it was about to come out when the head was put on as I did not inspect it in that much detail. I am guessing the valves may have been out of adjustment or something.. it still seems sort of weird to me but hopefully we will be able to get it all back together once I get some time off in the next few days. Thanks for the suggestions / comments to all! Quote Link to comment Share on other sites More sharing options...
Synlubes Posted April 14, 2003 Share Posted April 14, 2003 Rule # 1 Check it and then Check it again ! Quote Link to comment Share on other sites More sharing options...
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