Discussion
Car has just had a full rebuild. started smoking after about 100 miles on tickover. didnt look blue but didnt look white either.
tickover was very lumpy but i think thats because its badly shimmed.
oil pressure has dropped way below what it should sit at.
the guy who rebuilt blamed the head, as he only changed the valve seals on it.
i took head off to check it & had it tested & new seals onagain just to make sure.
heads fine valve seats are fine.
so only other option is rings or turbo.
doesnt smoke on boost & compression is way down so i think its the rings.
the bores are smooth but i dont think they have been honed.
i dont know what grade of stone to use to hone it.
can the rings be fitted upside down?
tickover was very lumpy but i think thats because its badly shimmed.
oil pressure has dropped way below what it should sit at.
the guy who rebuilt blamed the head, as he only changed the valve seals on it.
i took head off to check it & had it tested & new seals onagain just to make sure.
heads fine valve seats are fine.
so only other option is rings or turbo.
doesnt smoke on boost & compression is way down so i think its the rings.
the bores are smooth but i dont think they have been honed.
i dont know what grade of stone to use to hone it.
can the rings be fitted upside down?
scott9951 said:
Car has just had a full rebuild. started smoking after about 100 miles on tickover. didnt look blue but didnt look white either.
tickover was very lumpy but i think thats because its badly shimmed.
oil pressure has dropped way below what it should sit at.
so only other option is rings or turbo.
doesnt smoke on boost & compression is way down so i think its the rings.
the bores are smooth but i dont think they have been honed.
i dont know what grade of stone to use to hone it.
can the rings be fitted upside down?
Some rings are marked to show the topside but only if they have to fit a certain way up. If the rings weren't seated then you'd be boosting into the sump. What is the engines compression ratio and what cylinder pressures have you recorded? Low oil pressure suggests shells, maybe they picked up some dirt? You may have broken 1 ring but would have had to have abused the engine to do so? How has the car been driven since the engine work, tell the truth tickover was very lumpy but i think thats because its badly shimmed.
oil pressure has dropped way below what it should sit at.
so only other option is rings or turbo.
doesnt smoke on boost & compression is way down so i think its the rings.
the bores are smooth but i dont think they have been honed.
i dont know what grade of stone to use to hone it.
can the rings be fitted upside down?
Boosted.
i have only drove the car 180 miles & 100 of that was on the motorway doing about 60 mph with no boost. the other 80 were stop start miles with no boost again. the oil pressure for the 1st 150 miles was perfect
compression should be 150 psi
compression readings are
1 110psi wet 147 psi
2 145psi wet 180 psi
3 100psi wet 152 psi
4 150psi 150 psi
compression should be 150 psi
compression readings are
1 110psi wet 147 psi
2 145psi wet 180 psi
3 100psi wet 152 psi
4 150psi 150 psi
Scott,
180 miles is not really enough to bed in the rings ……………. Especially if they are moly chrome AND you are using a quality oil………………if the rings are chilled iron and not chromed then I would expect them to bed in within 500 miles ………. Chrome rings take significantly longer, depending on the quality of the honing and bore.
Many other factors come into play here …………. Was this a re-bore ? or is it just a bore clean up with the hone ? If it’s the latter, then what was the bore wear ? ….. any more then 3 thou ovality will give you problems as this is difficult to hone out. Another question to ask is to what tolerance were the bores honed ? On a worn bore, not only do the bores wear oval, but also the wear is vastly different between the top and the bottom. On my current rebuild I have had the bores taken out to +20 & honed to within 1 thou over the entire bore length and the forged pistons are fitted with chilled iron moly chrome rings ……… I will expect this one to bed in within 5K miles before I touch the rollers ………….
On a rebuilt engine I usually change the oil after 30minutes run time, then again at about 500 miles, then again at 3K………………….. the first two oil changes are done using an oil of (how do we say this ) lesser quality ……….. good quality synthetics are far to slippy and protect moving components really well and that does not promote a good bedding in regime.
However, the lack of oil pressure is worrying ………….. what is the engine and what oil are you using ?
Ian
180 miles is not really enough to bed in the rings ……………. Especially if they are moly chrome AND you are using a quality oil………………if the rings are chilled iron and not chromed then I would expect them to bed in within 500 miles ………. Chrome rings take significantly longer, depending on the quality of the honing and bore.
Many other factors come into play here …………. Was this a re-bore ? or is it just a bore clean up with the hone ? If it’s the latter, then what was the bore wear ? ….. any more then 3 thou ovality will give you problems as this is difficult to hone out. Another question to ask is to what tolerance were the bores honed ? On a worn bore, not only do the bores wear oval, but also the wear is vastly different between the top and the bottom. On my current rebuild I have had the bores taken out to +20 & honed to within 1 thou over the entire bore length and the forged pistons are fitted with chilled iron moly chrome rings ……… I will expect this one to bed in within 5K miles before I touch the rollers ………….
On a rebuilt engine I usually change the oil after 30minutes run time, then again at about 500 miles, then again at 3K………………….. the first two oil changes are done using an oil of (how do we say this ) lesser quality ……….. good quality synthetics are far to slippy and protect moving components really well and that does not promote a good bedding in regime.
However, the lack of oil pressure is worrying ………….. what is the engine and what oil are you using ?
Ian
the engine had been rebuilt b4 i got it but had no head. so i supplied a head & got it running.
it ran fine then transplanted it into another car.
started it up & ran fine until you touched the accelerator then it throught out oil & water via the exhaust.
so then it got stripped down & rebuilt.
i dont think he honed the bores this time as they looked very good & still do.
the engine is a fiat 1372 turbo from a punto gt.
the engine was running very lumpy & pouring smoke out on tickover then oil pressure went way to low.
the guy who did it blamed the head as i supplied that, thats why i had it checked out. theres nothing left to blame now just rings. the compression was 2 bad just to need running in
it ran fine then transplanted it into another car.
started it up & ran fine until you touched the accelerator then it throught out oil & water via the exhaust.
so then it got stripped down & rebuilt.
i dont think he honed the bores this time as they looked very good & still do.
the engine is a fiat 1372 turbo from a punto gt.
the engine was running very lumpy & pouring smoke out on tickover then oil pressure went way to low.
the guy who did it blamed the head as i supplied that, thats why i had it checked out. theres nothing left to blame now just rings. the compression was 2 bad just to need running in
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