absolutely not true.. rpm's have near the same impact on sludge accumulation as the low temps you speak of. It has to do with the oils flow rate too..(as with thinner/hotter oils.. the faster it can flow.. the more it can keep contaminants in suspension and run a cleaner path to some degree).. which is affected by viscosity as you mention above in relation to heat.. which inevtiabley means that it can occur in both scenario's. Not to mention that Mobile 1's comparable grading system to regular crude will give you thinner oil viscosities by nature. But yes.. even though I didn't imply it in the above.. improper warm up as well as too light a throttle caused a double whammy in that scenario. Thicker oil at low flow. Although.. I can only assume that operating temps were likely decent enough by the end of the 7 mile journey into town on his Chevy smog motor running its overly hot factory t-stat(those Vortecs can run at WELL over 200 degree temps). In other words.. you have some viscosity/flow similarities when running an insufficiently warmed up engine using 10w30 at normal rpm's(think about the number of folks who turn the key and drive shorter distances to work every day).. as you would with consistently running 60w racing oils at sufficient temps at extremely low rpm's. Rpm helps move oil/fling it around and ultimately keeps surfaces cleaner. Hot oils at lower viscosities and higher flows help in that same respect. All I can tell you from experience is that even a couple minutes of 6,500 rpm duty heats up the oil temps faster than you may realize. Granted, it may not get all the way up to 180+.. but it will easily see 150 and the pan will get fairly warm to the touch. I would highly doubt that even in the scenario above.. you could lay your hand on his oil pan after 15 minutes of idling and racing around cones. I've seen it firsthand with tuning and running stuff on the dyno's many times. High rpm, high pressure, and friction does that to oil. Anyhow.. that's all the debate time I have right now so I'll leave you with that for now.
What does all this pissing match have to do with the original posters question? You guys need to give it a rest, or swap phone numbers.
If low RPM were a issue my 83 year old mom's '03 Grand Marquis should be loaded with sludge, as she just putters around town with engine reaching full operating temp maybe 50% of the time(seven miles is a major trip for her)... When I changed the oil last fall, I did look through the oil fill in the valve cover, top of head is still clean and could could pass for a new engine... I generally use Motorcraft Semi Synthetic in her engine, though it's seen some Castrol Syn Blend as well... You have your proof and I have mine, we'll leave it at that...
says the king himself. lol and I'm certainly not adverse to staying on topic.. but let's just keep in mind that if all posts had to stay extremely specific to the threads title?.. there'd only be about 11 legitimate posts a day around here.
alright heres the deal. family schtuff has required my finds be allocated elswhere. (typical i know) so since i wont have the funds necessary to devote to a 347, im just going to rebuild the roller block with ported gt40 heads and bore it to 30 over for fresh cylinder walls. i was hoping to gather all the 347 info for this thread so that people could uyse it in the future, but i figure there is enough of that info on the net. sorry, dudes. as for oil, i just use castrol gtx lol
If you really want to save cash, take a close look at the cylinder walls in your roller block. If you can see the cross hatch pattern in the walls, then leave it be and replace the heads. Also pull the bearing caps and inspect the bearings and journals, if the bearings are not worn into the copper and the journals aren't scratched, just replace the bearings with a fresh set. Next, replace the oil pump and pump drive (use a HD pump drive, no matter what) You can do all this without removing the pistons from the bores if you like. I've done a few like this and they all run good as new afterwards, this is basically what's called an overhaul, (vs a rebuild) You can do this and replace the heads for as little as $500.
the cross hatch is still there, but there is some vertical wear lines. i figured i would just have a shop bore it 30 over to get rid of imperfections and have a fresh cylinder wall (also, i kind of knicked one of the cylinder walls at the very bottom when removing one of the pistons. will that pose a problem? careless of me). i was looking at the bearings and some of them had some bluing. a buddy of mine said that might indicate overheating? it was definitely a high mileage engine. possibly with an oil delivery problem. i am going to port and polish the heads with a friend of mine. i cant wait to get this build going!!! next ill have to mess with the rear end. the open diff is driving crazy! but one thing at a time haha thanks res-evil. its nothing serious, just life expenses
Can you clean up the scratches with a honing ? If they're not deep, they're not going to hurt anything after honing. What do the crank journals look like ? As for the nick at the bottom, take a drill and a porting bit and smooth off the rough/sharp edges to eliminate any chance of a crack starting there later. The bore bottoms are notched anyway for a stroker, so just the presence of that nick doesn't hurt anything. If you decide not to bore, clean the pistons, including the ring lands, then rering them. To clean the ring lands, take one of the old rings and break it, then use it as a scraper to scrape the carbon out of the ring lands. The lands need to be clean so the new rings will move freely in them. You will also need to clean the block. Do this with it on the stand, take it outside, use a pressure washer if you've got one. Spray carb cleaner works good, as does Easy-Off oven cleaner. Run the pressure washer into the oil passages, verify that they're clear of any blockage. Do not spray the oven cleaner on the cam bearings. Rinse it thoroughly after the oven cleaner. Blow dry the block when you're done, then spray the machined surfaces with WD40 to keep em from rusting. When I do one this way, I'll go thru a case of carb cleaner.
after looking at it more closely, i notice that the cylinder walls are pretty worn. im hoping i dont have to bore it; but as it looks currently, honing may not be enough. the knick isnt that bad at all. so that shouldnt be a problem. as for the machining and block prep. i think i have a shop do that. have them tank it and all that stuff.
Have you considered sleeving the bad cylinder and boring to the desired spec? A lot cheaper than a new engine, and a lot safer than taking another .10 from the cylinders. Ask the shop if they can do it, and what the charges are.
