Recently I've been helping my father resurrect an old honda that's been sitting dead in his garage for the last year or so. It had a blown head gasket, and we were debating whether it was even worth fixing (89 accord SEI).
As a fun project, we decided to get it running again...and during the process I made the bad decision of trying to clean the carbon off the cylinders (150k miles worth). I later learned that doing so could break pieces of it off which can score the cylinder bore upon restart...so to correct my error I added some MMO to each cylinder before we departed for an out of state wedding. (Car was sitting without a cylinder head during this time).
Fast forward a week, and all of the carbon that I had failed to remove with a manual scrub brush and some carb cleaner (pretty much all of it
), was now either already detached from the pistons, or so soft that the swipe of a finger would remove it. I then took my oil extractor to suck the remaining MMO and carbon off the pistons. The pistons were left looking brand spanking new...not a single piece of carbon remained. I did do a nice once over with some high pressure carb cleaner to clear the rings, then coated the bore with engine oil before we put the head back on.
Car runs great...good power, etc etc.
Anyways, I'd just thought I'd share my experience with MMO. There are probably numerous products that would accomplish the same thing with the allotted time, but MMO worked in this instance just fine. Had I performed this procedure with the engine still assembled, I'm reasonably certain that virtually all of the carbon would have been blown out the exhaust upon the first start...it was that soft. I was actually astonished how easily it lifted off, especially considering it was as hard as stone before the soak (scrubbing with a plastic brush did nothing). I had to use a brass brush to remove the carbon from the cylinder head, as soaking that in mmo wasn't feasible. It took lots of scrabing and tons of carb cleaner to get it all off...the MMO soak was far easier, just took more time.
I've got some MMO in the sump of his camry in the hopes it can take care of a little varnish. I'll post back with results in a couple months. Sadly, I didn't snap any pictures of the pistons before and after. There was a lot of cussing and finger busting going on during the work, and stopping to take pictures wasn't exactly on our to do list.
As a fun project, we decided to get it running again...and during the process I made the bad decision of trying to clean the carbon off the cylinders (150k miles worth). I later learned that doing so could break pieces of it off which can score the cylinder bore upon restart...so to correct my error I added some MMO to each cylinder before we departed for an out of state wedding. (Car was sitting without a cylinder head during this time).
Fast forward a week, and all of the carbon that I had failed to remove with a manual scrub brush and some carb cleaner (pretty much all of it
), was now either already detached from the pistons, or so soft that the swipe of a finger would remove it. I then took my oil extractor to suck the remaining MMO and carbon off the pistons. The pistons were left looking brand spanking new...not a single piece of carbon remained. I did do a nice once over with some high pressure carb cleaner to clear the rings, then coated the bore with engine oil before we put the head back on. Car runs great...good power, etc etc.
Anyways, I'd just thought I'd share my experience with MMO. There are probably numerous products that would accomplish the same thing with the allotted time, but MMO worked in this instance just fine. Had I performed this procedure with the engine still assembled, I'm reasonably certain that virtually all of the carbon would have been blown out the exhaust upon the first start...it was that soft. I was actually astonished how easily it lifted off, especially considering it was as hard as stone before the soak (scrubbing with a plastic brush did nothing). I had to use a brass brush to remove the carbon from the cylinder head, as soaking that in mmo wasn't feasible. It took lots of scrabing and tons of carb cleaner to get it all off...the MMO soak was far easier, just took more time.
I've got some MMO in the sump of his camry in the hopes it can take care of a little varnish. I'll post back with results in a couple months. Sadly, I didn't snap any pictures of the pistons before and after. There was a lot of cussing and finger busting going on during the work, and stopping to take pictures wasn't exactly on our to do list
.
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