I was driving around for a while with low compression on one of the cylinders, had no idea that the other one was bad too. Car has 199K on it Many thanks for any insight into how this happened and how to prevent in future.
Engine came back from a rebuild at the machine shop with the parts that failed - what could have caused this? (2 Viewers)
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Rheinmetall
Piston seizure or piston broken? What was the cause of the damage? We will help you to correctly diagnose damage in day-to-day repair shop activities and prevent expensive consequential damage.
www.ms-motorservice.com
this might help.
Kinda hard to tell but it looks like the left piston has a broken ring and the right piston has a section of the piston broken out? I see a lot of carbon build up in that oil scraper ring, could be insufficient oil changes, poor oil quality, running hot / overheating, or a combination of those.
What did the shop say? What about the condition of the cylinders and the rest of the engine? Are you getting this rebuilt?
- Thread starter
- #3
Hi, Thanks for this. There was a problem with the mixture due to the carb float not floating. So it could be that. Both pistons had a section of the cylinder broken off. The engine is back now after a complete re-build and I'm going to try and put it in myself over the next few days,Rheinmetall
Piston seizure or piston broken? What was the cause of the damage? We will help you to correctly diagnose damage in day-to-day repair shop activities and prevent expensive consequential damage.
this might help.
Kinda hard to tell but it looks like the left piston has a broken ring and the right piston has a section of the piston broken out? I see a lot of carbon build up in that oil scraper ring, could be insufficient oil changes, poor oil quality, running hot / overheating, or a combination of those.
What did the shop say? What about the condition of the cylinders and the rest of the engine? Are you getting this rebuilt?
micruz60
Unleaded Regular
Do you know which pistons these are- 3 + 4 ? are closest to the center of the inline 6 and could have been ‘washed’ by excess fuel draining from the carburetor.
- Thread starter
- #5
the 6th piston was the one getting <50 compression that prompted me to take the engine out and bring it in for a rebuild. it was confirmed as one of these two that were damaged. Can't remember which the other one was
The piston on the left has a severely occluded oil control ring. Incorrect oil and/or poor maintenance certainly contributed.
- Thread starter
- #8
always used 10W-30 and changed every 3K miles, might have gotten low once, but it always went through a lot of oil. I always had a suspicion the rings were worn as oil used to gum up the air filter. IIRC I got it at 179K miles and a couple of years ago. I used to regularly have to remove and clean the spark plugs otherwise they'd get dirty . Hopefully that's behind me and I can look forward to a new set of problems now.
in Kennett Sq PA ,
your in the 20W-50 Viscosity Range of your owners manual and FSM chart .....
10W-30 is too thin , especially in spring , summer and early autumn driving conditions
- Thread starter
- #10
Thanks - should I use the 10W-30 I already have and change it out in the spring or just use 20W-50 when I fill it once I get the engine in?
im south of you near DC , it's oddly warm today ? 46'' F now exactly ...
my personal recipe has always been 2 qts. 10W-30 + 6qts. 20W-50 in the winter months , however i use and have always used FULLY SYNTHETIC Valvoline and MOBILE 1 , since 1990 first car 12/78 FJ40LV-KCJA usa spec. 2F
mid-spring , summer , early autumn , FULL ON Valvoline 20W-50 API Certified full synthetic is my choice , based on a pile of personal and professional R and D time digging hard into this topic :
- i will ALWAYS mention that VALVOLINE is the ONLY 20W-50 full synthetic , that does NOT contain the super high-additional levels of ZINC. Rich or ZDDP additives , because these ZINC PHOSPHATES , WILL Trash ANY TOYOTA Catalytic Converters , FJ40 ones , FJ60 , FJ62 , FJ80 etc ......
below is the 3FE FJ62 owners manual Motor Oil Viscosity Chart , keep in mind it was written and published for conventional motor oils long before fully SYNTHETIC motor oil was the now Norm. ......... at least now the Norm. for those who know and understand the rocket science on this topic is real , similar to the VIKINGS discovering America Verses , say the world is flat and shell Rotella 15W-40 conventional DIESEL motor oil is some how going to protect internal Land Cruiser engine moving metallurgy on metallurgy parts better from normal use age and time wear and tear factor ......
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Cat Converters are a LOT cheaper than engines.
- Thread starter
- #14
Thanks for this - I'll start following this regime
I've never understood fully the two upper rows on the viscosity vs temp graph in the FSM. Is it just to give an option for the warmest temps/seasons (20W/50 or 10W-50)?im south of you near DC , it's oddly warm today ? 46'' F now exactly ...
my personal recipe has always been 2 qts. 10W-30 + 6qts. 20W-50 in the winter months , however i use and have always used FULLY SYNTHETIC Valvoline and MOBILE 1 , since 1990 first car 12/78 FJ40LV-KCJA usa spec. 2F
mid-spring , summer , early autumn , FULL ON Valvoline 20W-50 API Certified full synthetic is my choice , based on a pile of personal and professional R and D time digging hard into this topic :
- i will ALWAYS mention that VALVOLINE is the ONLY 20W-50 full synthetic , that does NOT contain the super high-additional levels of ZINC. Rich or ZDDP additives , because these ZINC PHOSPHATES , WILL Trash ANY TOYOTA Catalytic Converters , FJ40 ones , FJ60 , FJ62 , FJ80 etc ......
below is the 3FE FJ62 owners manual Motor Oil Viscosity Chart , keep in mind it was written and published for conventional motor oils long before fully SYNTHETIC motor oil was the now Norm. ......... at least now the Norm. for those who know and understand the rocket science on this topic is real , similar to the VIKINGS discovering America Verses , say the world is flat and shell Rotella 15W-40 conventional DIESEL motor oil is some how going to protect internal Land Cruiser engine moving metallurgy on metallurgy parts better from normal use age and time wear and tear factor ......
.
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The thicker the motor oils ffilm in mil's is , the greater it protects the 2 metallurgy surfaces that it is designed to do ...
motor oils primary number 1 mission is cooling , reduce heat from friction of metal contact to contact while moving also against each other , hence less breakdown and loss of metal over time , so this = tight clearances and tight like new tolerances m same as plasti-guage when you install new rod and main bearings
the thinner the viscosity , less oil film mil's , heat thermal is UP HIGHER , and now metallurgy wear and tear is going on FAST
think of drilling a hole in a frame rail , u keep drill bit COOL using OIL right ? this = long sharp bit life and even nice hole in metal too , NO BLUING of either bit top or frame rail ....
u use water or say WD-40 as a lube oil drilling same as above , it WILL SMOKE OFF FAST and blue drill bit tip and metal frame hole too ...
and drill bit tip gets DULL fast and can snap and break too
does this exacting details same as inside a engine theory applied here make better sense ?
the oem FSM viscosity chart is saying use the THICKEST possible motor oil for the greatest protection and anti-wear factor possible , as it relates to your outside climate temperature range it spells out ..
its a bit of give and take and achieving a optimum balance to keep the highest possible protection level you can
here is DC east coast today in January its currently 46' F , unusually warm fot this time of year ?
but , is it now with hotter and hotter winters globally , as the earth continues to get hooter each cycle around the sun ?
i am now today at its 10W40 ish range , closer to 20W-50 , .....
matt
This is another thread that's turning into an oil symposium, but I have to add:
The above oil viscosity/temp chart is for SF/CC oil which was the spec for 1980-1988 vehicles so it would apply if you're running a dino SF rated oil. SF oil hasn't been produced in 25 years.
Toyota specs a 0w20 from my 2023 V6 Tacoma which I'm forced to use due to warranty reasons, but it is spec'd for high temps due to its modern formulation, part of it being a FULL SYNTHETIC oil, plus it (the TGMO) has very high levels of Moly, which is an expensive superior substitute for ZDDP (zinc).
Run whatever you want, but rebuilding these 2F engines isn't cheap. If you want to protect it the best you can, best is a high-zddp oil, changed often.
A BREAK-IN oil, specifically formulated for break-in, is a MUST, and it should be changed very soon after first fire. Your engine builder should give proper break in procedure.
but I have to add:The above oil viscosity/temp chart is for SF/CC oil which was the spec for 1980-1988 vehicles so it would apply if you're running a dino SF rated oil. SF oil hasn't been produced in 25 years.
Toyota specs a 0w20 from my 2023 V6 Tacoma which I'm forced to use due to warranty reasons, but it is spec'd for high temps due to its modern formulation, part of it being a FULL SYNTHETIC oil, plus it (the TGMO) has very high levels of Moly, which is an expensive superior substitute for ZDDP (zinc).
Run whatever you want, but rebuilding these 2F engines isn't cheap. If you want to protect it the best you can, best is a high-zddp oil, changed often.
A BREAK-IN oil, specifically formulated for break-in, is a MUST, and it should be changed very soon after first fire. Your engine builder should give proper break in procedure.
- Thread starter
- #18
you think using 10W-30 is what trashed the pistons? getting some other advice that I can't really understand. Asked the shop that rebuilt it just now and they recommended lucas hot rod 20W-50 for a break in - what do you think please? Anything else I need to do once I get it all back together?im south of you near DC , it's oddly warm today ? 46'' F now exactly ...
my personal recipe has always been 2 qts. 10W-30 + 6qts. 20W-50 in the winter months , however i use and have always used FULLY SYNTHETIC Valvoline and MOBILE 1 , since 1990 first car 12/78 FJ40LV-KCJA usa spec. 2F
mid-spring , summer , early autumn , FULL ON Valvoline 20W-50 API Certified full synthetic is my choice , based on a pile of personal and professional R and D time digging hard into this topic :
- i will ALWAYS mention that VALVOLINE is the ONLY 20W-50 full synthetic , that does NOT contain the super high-additional levels of ZINC. Rich or ZDDP additives , because these ZINC PHOSPHATES , WILL Trash ANY TOYOTA Catalytic Converters , FJ40 ones , FJ60 , FJ62 , FJ80 etc ......
below is the 3FE FJ62 owners manual Motor Oil Viscosity Chart , keep in mind it was written and published for conventional motor oils long before fully SYNTHETIC motor oil was the now Norm. ......... at least now the Norm. for those who know and understand the rocket science on this topic is real , similar to the VIKINGS discovering America Verses , say the world is flat and shell Rotella 15W-40 conventional DIESEL motor oil is some how going to protect internal Land Cruiser engine moving metallurgy on metallurgy parts better from normal use age and time wear and tear factor ......
.
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no ,
i did not say or imply that in any way ....... did i ?
this relates to the oil viscosity topic we entered into the discussion , and i mention more then once , the whole broad brush oil viscosity tech tooic , is a longer term wear and tear factor topic as in 10K + chunks of miles ......
if u ran 5W-30 conventual cheap store brand Safeway motor oil , that was API certified , in the ARAZONA desert summer time , all summer and HOT spring and HOT fall , i bet there would be a serious issue verifiable that would occur ...!
- i saw this during my time at the dealership ship service dept. running thin cheap oil , in the inline 6 cylinder Toyota engines that had a variable viscosity chart ....
possibly if NO motor oil was in the engine , that will cause your pistons and other catastrophic internal engine failure to occur you have going on here ,,,
you have a much larger , and muti-topics at play here , to cause this damage .......
are we clear on this now ?
if your pistons look like this , your cylinder walls inside , must be VERY damaged also , Correct ?
post photos here inside each cylinder that has a damaged trashed piston please ....
thanks
matt
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- Thread starter
- #20
They've been bored out now, and I can't find the pictures I took, but before I took the block in for machining I gambled that it was the head and had that done. There was no obvious damage to the cylinder walls that I could see when I took it off. I took a pic and sent it to a guy - he couldn't see anything glaring - I might even have posted them here. seems a long time ago now.
Only clue I had that there was anything wrong was low compression on one cylinder and my uneducated, inexperienced gut feeling that it was a rings/pistons issue. Once I got the head back on and that didn't change the compression then it came time to get the block in and that's how the damage was discovered.
I can't really pinpoint any time when the performance changed since I got the vehicle or when this might have happened.
Appreciate your advice as I know very little about engines and am learning as I go
