Guest docmiller13 Posted March 8, 2011 Share Posted March 8, 2011 (edited) I have a 27 pontiac that used to sit in a museum for 20 years...got her running a couple weeks ago but notice a slapping sound in the upper part of the motor. Had a local mechanic look at it and said it could be a normal noise but wasn't sure. It does smoke a bit after starting and doesn't have alot of top end speed. Smoke goes away a little after it warms.Another said the cams could have rusted and thru running the motor the sounds may go away. So, what to do ? thanks Edited March 8, 2011 by docmiller13 (see edit history) Link to comment Share on other sites More sharing options...
Owen_Dyneto Posted March 8, 2011 Share Posted March 8, 2011 If it diminished as the engine warmed up, could be piston slap. If so, it's not the worst engine problem for a rarely-used car, but if it is and you want to fix short of a rebore and new pistons, the old art of knurling the skirts can postpone the inevitable. Some frown on knurling but I've used it myself and if you understand that it's more of temporary fix than a permanent solution, it has it's place. Link to comment Share on other sites More sharing options...
Rusty_OToole Posted March 8, 2011 Share Posted March 8, 2011 I have a collection of old MoToR magazines from the thirties, the American garage trade magazine. There were ads for piston skirt expanders, knurlers, and patent valve stem seals on nearly every page.Knurling or expanding the pistons was a very common part of an overhaul. I expect it would be as permanent as anything is on such an old engine. If "temporary" means 20000 or 30000 miles and you drive 1000 miles a year it could be considered permanent.The noise could also be a loose wrist pin. If so the noise should go away or diminish if you disconnect the spark plug. An old trick was to give each wrist pin a 1/4 turn at overhaul time to put a fresh wear surface to work.Could be a sticky valve, worn timing chain slapping its cover, or several other things. It would be best to figure out what exactly the trouble is. It does not sound normal and is not likely to get better by itself and it could develop into a serious problem if not attended to. Link to comment Share on other sites More sharing options...
Guest docmiller13 Posted March 8, 2011 Share Posted March 8, 2011 (edited) The engine smokes as well..gets better a little when it warms up....hmmm....so, your saying basically could be piston slap because the rings are shot....or a bad wrist pin possibly...so sounds like I need to pull the oil pan and pull the pistons out and check the rings and wrist pin bearings...any suggestions on where I can find rings for the 27 ?...thanks Edited March 8, 2011 by docmiller13 (see edit history) Link to comment Share on other sites More sharing options...
keiser31 Posted March 8, 2011 Share Posted March 8, 2011 The engine smokes as well..gets better a little when it warms up....hmmm....so, your saying basically could be piston slap because the rings are shot....or a bad wrist pin possibly...so sounds like I need to pull the oil pan and pull the pistons out and check the rings and wrist pin bearings...any suggestions on where I can find rings for the 27 ?...thanksTry Egge MachineEGGE Machine Company - Parts and Services for Nostalgic Motors Link to comment Share on other sites More sharing options...
Larry Schramm Posted March 8, 2011 Share Posted March 8, 2011 I agree with the above. Noises generally do not get better with age. Link to comment Share on other sites More sharing options...
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