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mq sd33 comp. probs.
Posted: Mon Mar 01, 2004 8:02 pm
by shorty.mqute
guys, havin some probs at the moment, i have just replaced pistons and rings in my shorty, but she is still running lower comp. than it should be.
in the manual it quotes 2452kpa as minimum pressure, but with a cold comp test im getting about 2100 to 2600 kpa on the gauge, when i warm ythe engine for 10 minutes first the comp figures drop by bout 100-200kpa....
could this be to do with valves not closinfg properly or the tappets being badly addjusted....
or could the rings just not have seated proprely.
it also blows alot of gray/white smoke
any help much appreciated
cheers batesy
Posted: Mon Mar 01, 2004 9:51 pm
by ShortyMQ
Does the motor run smoothly or is it a bit chaffy(charfy) sounding
Posted: Mon Mar 01, 2004 10:47 pm
by V8Patrol
you replaced the pistons and rings........
what did you do to the bores ?????
Posted: Tue Mar 02, 2004 8:45 pm
by shorty.mqute
V8Patrol wrote:you replaced the pistons and rings........
what did you do to the bores ?????
i honed the bores slightly to ruffen them up a bit
and yeah it runs fairly smooth, idles good, but gets a bit ruff when you accel.
cheers
Posted: Tue Mar 02, 2004 8:52 pm
by DR Frankenstine
shorty.mqute wrote:V8Patrol wrote:you replaced the pistons and rings........
what did you do to the bores ?????
i honed the bores slightly to ruffen them up a bit
and yeah it runs fairly smooth, idles good, but gets a bit ruff when you accel.
cheers
sounds like valves.
1...warm the motor up
2...do a comp test
3...put a tablespoon of oil in each pot
4...re-comp test
if the compression comes up you probably have oval pots
if it doesn't you have burnt valves or you're tappets are to tight and you,re valves arn't closing properly
Posted: Tue Mar 02, 2004 9:05 pm
by shorty.mqute
DR Frankenstine wrote:shorty.mqute wrote:V8Patrol wrote:you replaced the pistons and rings........
what did you do to the bores ?????
i honed the bores slightly to ruffen them up a bit
and yeah it runs fairly smooth, idles good, but gets a bit ruff when you accel.
cheers
sounds like valves.
1...warm the motor up
2...do a comp test
3...put a tablespoon of oil in each pot
4...re-comp test
if the compression comes up you probably have oval pots
if it doesn't you have burnt valves or you're tappets are to tight and you,re valves arn't closing properly
by oval pots do you mean out of shape cyclinders?
cheers for your help
Posted: Tue Mar 02, 2004 9:56 pm
by DR Frankenstine
shorty.mqute wrote:DR Frankenstine wrote:shorty.mqute wrote:V8Patrol wrote:you replaced the pistons and rings........
what did you do to the bores ?????
i honed the bores slightly to ruffen them up a bit
and yeah it runs fairly smooth, idles good, but gets a bit ruff when you accel.
cheers
sounds like valves.
1...warm the motor up
2...do a comp test
3...put a tablespoon of oil in each pot
4...re-comp test
if the compression comes up you probably have oval pots
if it doesn't you have burnt valves or you're tappets are to tight and you,re valves arn't closing properly
by oval pots do you mean out of shape cyclinders?
cheers for your help
yep
Posted: Wed Mar 03, 2004 11:10 am
by V8Patrol
sounds to me like worn bores.....
was there a lip at the top of the bores before /after you honed them?
One of the reasons diesels are so expensive to rebuild is the block.... well the bores more accurately, if they aint right then its time to fit new cylinder sleves.