rpsmith79 Posted June 17, 2012 Report Share Posted June 17, 2012 Today i have been trying to diagnose my recent engine problems, so i did a compression test, but the results are all really low across all cylinders 100, 100, 105, 105 What does this mean, i know they should be around the 160-170 mark, they are all close, but all really low The only thing i can think that would cause this is incorrect timing, either that or simultaneous failures across all cylinders (which is highly unlikely) Any other ideas welcomed Link to comment Share on other sites More sharing options...
GreyRacer Posted June 17, 2012 Report Share Posted June 17, 2012 (edited) I'm not an engineer but how about a cylinder head gasket that is too thick? Feel free to shoot me down if it's a crap idea. Edited June 17, 2012 by GreyRacer Link to comment Share on other sites More sharing options...
Dorris Posted June 17, 2012 Report Share Posted June 17, 2012 (edited) If I’m right you are running that standard head gasket you got off me plus you’ve had the head skimmed. Have you tried a few drops of oil down your bores when you did the compression test, its either going to be ring/bore or cam/valve issue, what state where your bores and pistons in? Dorris Edited June 17, 2012 by Dorris Link to comment Share on other sites More sharing options...
rpsmith79 Posted June 17, 2012 Author Report Share Posted June 17, 2012 I put oil down one of the bores and it made no difference And yes i'm running a standard head gasket on a skimmed head The bores were honed and new rings were fitted Link to comment Share on other sites More sharing options...
_Chris_ Posted June 17, 2012 Report Share Posted June 17, 2012 What are your symptoms ? Did they appear suddenly, or get gradually worse ? If suddenly, did something happen at the same time (e.g. overheating) or was there maintenance just before (e.g. new cambelt) ? Initial thoughts are: 1. Incorrect results - faulty tester / should have been done with wide open throttle and about 5 engine cycles. Battery should have been turning over at a good cranking speed. 2. Slightly bent valves after cam belt failure or cam belt timing out causing interference. Or burnt valves after running with very retarded ignition timing. 3. Damaged pistons / rings likely after overheating. p.s. after reading other replies, looks likely it's not piston/ring issue. Link to comment Share on other sites More sharing options...
rpsmith79 Posted June 17, 2012 Author Report Share Posted June 17, 2012 What are your symptoms ? Did they appear suddenly, or get gradually worse ? If suddenly, did something happen at the same time (e.g. overheating) or was there maintenance just before (e.g. new cambelt) ? Initial thoughts are: 1. Incorrect results - faulty tester / should have been done with wide open throttle and about 5 engine cycles. Battery should have been turning over at a good cranking speed. 2. Slightly bent valves after cam belt failure or cam belt timing out causing interference. Or burnt valves after running with very retarded ignition timing. 3. Damaged pistons / rings likely after overheating. Could be onto something here, i was running at 0 degrees for the first few hundred miles due to a mix up when initially setting the timing A bit of background info, this was a reconditioned engine that was fitted at the tail end of last year, it was running fine but has now developed a rattle at high revs, and does seem to be lacking in power, previously it had been running fine Link to comment Share on other sites More sharing options...
_Chris_ Posted June 17, 2012 Report Share Posted June 17, 2012 10 degrees retarded and light throttle probably wouldn't be enough. I was thinking more the forgetting to lock the dizzy and then full throttle keeping the car running at -40 or so. Normally low compression would show worst symptoms at idle / low RPM. What sort of rattle ? Does it change with throttle position ? Can you post a recording / video ? Link to comment Share on other sites More sharing options...
rpsmith79 Posted June 17, 2012 Author Report Share Posted June 17, 2012 The rattle is only when on throttle, and a brief rattle on cold start Link to comment Share on other sites More sharing options...
princy Posted June 17, 2012 Report Share Posted June 17, 2012 Valve timing okay? Link to comment Share on other sites More sharing options...
rpsmith79 Posted June 17, 2012 Author Report Share Posted June 17, 2012 Valve timing okay? That is what i am thinking, Dom is coming over tomorrow to have a look Link to comment Share on other sites More sharing options...
leigh_boy Posted June 17, 2012 Report Share Posted June 17, 2012 check clearances Link to comment Share on other sites More sharing options...
_Chris_ Posted June 17, 2012 Report Share Posted June 17, 2012 The rattle is only when on throttle, and a brief rattle on cold start Possibly big ends or piston slap, but could be other things. If you get loud rattle for a couple of seconds on cold start before oil pressure gets up I'd say big ends. Did the engine get run short of oil ? Link to comment Share on other sites More sharing options...
izzzzythedog Posted June 17, 2012 Report Share Posted June 17, 2012 ok my imput is this ,,, are you sure the readings are right ? skimmed head means more compression , gasket well your gunna notice its uber thick to reduce it that much , seems to me the reading could be wrong given its across the entire range and the engines running ok , can you borrow another gauge from somewhere Link to comment Share on other sites More sharing options...
rpsmith79 Posted June 17, 2012 Author Report Share Posted June 17, 2012 Yeah, i really need to check with a different gauge i think But as said, it all started with hearing the rattle and feeling of slight loss of power, and then checking the compression is the first and easiest thing to do Link to comment Share on other sites More sharing options...
Hou Posted June 18, 2012 Report Share Posted June 18, 2012 Sorry to say it but sounds like a big end issue to me. My starlet did it, rattle on startup and at about 2500-300rpm but sounded like the top end. It sounded like I had left a spanner on the rocker cover lol. Used oil and was down on power. Went with Steve (silversurfer) to go get him a new engine for his 140 (death rattle) and one for mine (got one with 29k miles on), turned out to be great timing as mine gave way on the way home Link to comment Share on other sites More sharing options...
rpsmith79 Posted June 18, 2012 Author Report Share Posted June 18, 2012 I hope not Hou I had another good listen to it today after work, and i'm 90% sure it's coming from the top end But i think i may have sourced myself a spare engine, just need to wait till it's available and figure out how/where i'm going to fit it Link to comment Share on other sites More sharing options...
Hou Posted June 18, 2012 Report Share Posted June 18, 2012 I was certain mine was top end too, took it toyota who reckoned it was piston gudgeon pins, all I know is that when it let go you could limp it home but plumes of smoke out of the back and it was knocking it's ass off Link to comment Share on other sites More sharing options...
Sherv Posted June 19, 2012 Report Share Posted June 19, 2012 Sorry to hear this Rich.. Link to comment Share on other sites More sharing options...
rpsmith79 Posted June 20, 2012 Author Report Share Posted June 20, 2012 Looks like the engine is goosed, Dom reckons bottom end has gone I have got an engine lined up, but it won't be available for a few weeks at least, then the fun of fitting it Link to comment Share on other sites More sharing options...
Biggy Posted June 20, 2012 Report Share Posted June 20, 2012 Looks like the engine is goosed, Dom reckons bottom end has gone I have got an engine lined up, but it won't be available for a few weeks at least, then the fun of fitting it get bek to fit it ,does them in his sleep now.. Link to comment Share on other sites More sharing options...
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