BlueStag Posted June 10, 2014 Share Posted June 10, 2014 The engine: an 2.6L with twin SUs. It was rebuilt about 15 years ago, but the car was up on blocks for a decade. It has been running for the last three years, in my Triumph Stag. This is a warm climate, so I tend to not use a LOT of choke to start it: when I do, liquid gas shoots out the tail pipe and I have to back thru the cloud of it as I pull down the drive way. Yesterday and today, first time, when starting from stone cold, there is an alarming heavy metalic thunk coming from the engine. Very disconcerting. It goes away quickly enough. I have oil and oil pressure. I THINK that when I start it tomorrow, if I choke it a bit more, it might not do it. Or it will throw a rod. Which would be a bummer. I suppose I could pull the engine. I'd like that about as much as having my teeth pulled out with a pair of pliers. The front carb has a tendency to have its jet stick if the choke is pulled very far out, and then half the engine will be running quite rich compared to the back half when I attempt to release the choke. Which is the second reason that I try to start the car with the minimum choke that I can. Anyone got a Turbo engine they want to give me? I don't need a starter or an alternator, but if you have a spare exhaust system that a muffler man can cut up to fit my car, that would be a bonus..... Quote Link to comment Share on other sites More sharing options...
BlueStag Posted June 11, 2014 Author Share Posted June 11, 2014 Wow. No takers? No symptoms this morning. The only difference is that I gassed up yesterday. Quote Link to comment Share on other sites More sharing options...
NewZed Posted June 11, 2014 Share Posted June 11, 2014 I THINK that when I start it tomorrow, if I choke it a bit more, it might not do it. Anyone got a Turbo engine they want to give me? Probably waiting to see what happened this morning. Did it thunk? Metallic is usually clang or clank, not thunk. So that part was a little confusing. Free turbo engines...I'll take one too. Quote Link to comment Share on other sites More sharing options...
BlueStag Posted June 11, 2014 Author Share Posted June 11, 2014 Probably waiting to see what happened this morning. Did it thunk? Metallic is usually clang or clank, not thunk. So that part was a little confusing. Free turbo engines...I'll take one too. No, me first. No noise this morning. I gave it a bit more choke than the previous two days. And watched the oil pressure very closely. It responded immediately. You could call it a clank if you like. Quote Link to comment Share on other sites More sharing options...
NewZed Posted June 11, 2014 Share Posted June 11, 2014 This is a warm climate, so I tend to not use a LOT of choke to start it: when I do, liquid gas shoots out the tail pipe and I have to back thru the cloud of it as I pull down the drive way. Yesterday and today, first time, when starting from stone cold, there is an alarming heavy metalic thunk coming from the engine. Very disconcerting. It goes away quickly enough. I have oil and oil pressure. Gasoline in the oil? I filled a crankcase full of gasoline once with a borrowed carburetor that had had the float bowl needle removed. Small block chevy so no external leakage was evident. Quote Link to comment Share on other sites More sharing options...
johnc Posted June 12, 2014 Share Posted June 12, 2014 Could be too much liquid fuel in the combustion chamber causing a mild hydroloc. If you have fuel running out the tailpipe you have serious carb problem. Could also be a bad thrust bearing. Try starting in neutral with the clutch out and then starting it in gear with the clutch in. See if there is a difference in the noise. Quote Link to comment Share on other sites More sharing options...
BlueStag Posted June 12, 2014 Author Share Posted June 12, 2014 Could be too much liquid fuel in the combustion chamber causing a mild hydroloc. If you have fuel running out the tailpipe you have serious carb problem. Could also be a bad thrust bearing. Try starting in neutral with the clutch out and then starting it in gear with the clutch in. See if there is a difference in the noise. It's an automatic. Yes, my carbs could be funky. Possibly the floats need adjustment. I was also thinking that I was running on the last of the gas, and there was water in it, and when I topped up, the water was not getting to the engine or was diluted. Quote Link to comment Share on other sites More sharing options...
BlueStag Posted June 12, 2014 Author Share Posted June 12, 2014 Just got back from my speed shop (Tyerman's in Burbank, CA, for those three of you that are near by. They really are excellent.) I took it in for an oil change, dreading shavings or a thrust washer. No signs of bum bearings. Joel, the owner insisted that if I had a bad rod bearing, that it would not go quiet after a few seconds of running. He thinks the most likely culprit is either my bendix drive or my flex plate. He says he has seen flex plates crack and give just this sort of transient, death rattle noise. The pisser is that it may be impossible to pull the tranny without pulling the engine. It is very tight in there. But it beats the hell out of a new engine, if that is what it is. Quote Link to comment Share on other sites More sharing options...
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