After honing is complete, be sure to clean the cylinder thoroughly until there is no residual material. 911SC Top End Engine Rebuild 1978 model After trying every trick in the book to cure the oil leaks on my 1978 Porsche 911SC I have finally come to the conclusion that I need to take the engine out and do a rebuild to cure this issue. THis is the second honda rancher 350 ive rebuild. no WOT. The earlier cases, as well as the magnesium cases will require the greatest amount of modifications. Pistons intended for the right bank will feature an “R” suffix. I have followed the initial torqueing down procedure for the head studs. Next, put some after run oil on the sides of the piston, and push it as far as you can into the sleeve, without using too much pressure. Increasing engine oil is the last step of the process of cleaning piston for reuse. Carbon deposits on the piston top land due to: Excessive ingress of oil into the combustion chamber due to defective components; Increased emissions of blow-by gases with oil entering the intake air system; Insufficient separation of oil vapour from the blow-by gases; Frequent idling or … Resolved by rebuilding the head with the valve seats reground and new guides. Then, install the head. Recently, a cylinder was bored with requested .0035” clearance. However, if you are draining more than 5 mil of oil from the top of the piston either it was overfilled or oil has migrated from the lower. As was mentioned in Fred's answer, always use non-synthetic oil for the break-in. You should be able to lower the cylinder with one hand while compressing the rings with the other. There is a step on top and bottom of the wavy rail that they are pushing on. Wiseco is Going Racing with Honda HRC again in 2021, The Best 2-Stroke Engine Rebuild Video You'll Ever Watch, Mixin' Gas, Makin' Memories: 2020 Wiseco 2-Stroke MX World Championships, Polaris RZR: Rebuilding the Legends with Wiseco, 2020 Wiseco 2-Stroke MX World Championships Are Back On. These low RPM’s actually puts much more stress on the engine parts. My 02 rancher 350 is still running strong with a namaur piston and top end kit. After assembly, kick engine over ten or twenty times before starting. Then I put a light coat on the cylinder wall before sliding in the piston. Increasing engine oil makes the sludge harder to form. Enjoy your rides, and be safe! They are stock pistons by the way. Because the engine has run a few heat cycles, the gaskets may have compressed. Thanks for the information. set timing Go out for a drive. Posted by Anonymous on Jan 29, 2017. With today’s thin rings, some racers run side axial clearance as tight as 0.0004 - 0.0005-inch, using gas ports to supplement ring pressure. Step-1: Install Camshaft. Wiseco photo. March 29, 2018 / by ... Fitted pins-poor oil lubrication and wear Top of piston scratches, erosion or burning- … Dirty oil is a very preventable cause of oil consumption. If this is a dirt bike, running on a track is best due to the up and down RPMs the engine will experience. After letting engine turnover for several minutes (on battery) no oil pressure was registering on dial. I put a little oil on the piston before installing the rings, I move them around a bit to make sure they're coated. Top-end rebuilds are a necessary maintenance task associated with high performance off-road two-stroke motorcycle ownership. The old oil was thick and black, but otherwise free of debris or metal shavings. Cut open the oil filter and all I found was a little gritty sludge in the paper. I have used Otto gaskets, with carefully added gasket goo around the pushrod tunnels, upper and lower surfaces. Be sure that the crosshatch is at 45 degrees. Maybe it's also time to have the block refreshed by rehoning the cylinders and installing new ring sets, and the usual rebuild with new gaskets, rod and crank bearings and the usual assortment of goodies. Most piston rings have a top and bottom surface, so it’s important to install them as intended. The vertical clearance remaining in the piston ring groove after the ring is installed. After your post I removed the blue top cap again for the air side to check the fluid and it is definitely green. I did notice the valve stem of the #1 cylinder was caked with damp looking oil build up. If it gets to the top, or past the top of the sleeve, the piston and sleeve set is worn out, and the engine needs a rebuild. If your engine is a 2 stroke, mix to the proper fuel/oil ratio. Alright, so here we are again. Put only a drop or two of non-detergent oil on each piston skirt. Reason - If the piston to cylinder clearance is too large it allows the piston to rattle inside the cylinder bore, with time the piston develops stress fractures and eventually cracks. The gaskets and quality play an important part of engine rebuilding. After the cylinder is clean, apply oil to it, the piston and the rings before assembly. Honing is required to be done after boring, and if the cylinder was not bored, it still is needed to deglaze the cylinder for proper ring break-in. I just pulled the head from my 260. The metal is completely normal and so is the smoke after a rebuild. This is not enough, and you will need to clean with dish soap and water. In 2008 was Easyrider Ol’ Skool Builder of the year and is also in the IMBBA Hall Of Fame. Refer to their procedures while doing this. After placing the gaskets, be sure while assembling the piston in the cylinder that the ring gaps are in proper placement. If you fail to follow this procedure, the piston rings may never seat. Help. Finally, lubricate the oil seal in the right-hand side of the crankcase, then oil the primary-drive side of the crankshaft spindle. Wrist pin was wore pretty bad and i believe the gasket failed between the head and cylinder. After using a break-in oil, you should change your oil at 50 miles, 500 miles, and 1,500 miles. Removed spark plug from C3 and found it in good shape except for being wet and past due for a change. Back in the Brew Bikes shop, it was double-checked, and clearance was .0015”. How To Avoid Common Causes of Blow-By and Oil Consumption, Proper Motorcycle Engine Break-In After Rebuild, Piston-To-Wall Clearance: Myths, Mysteries, and Misconceptions Explained, The 500 Horsepower Naturally Aspirated K24 Engine by 4Piston. Being that the edges of the pistons are not clean do you think that suggests the rings are OK. The pin was pressed into a fixed position beginning in 1958. Do the photos look like a healthy engine??? Oil drips down the valves after the engine has been shut off, and the cam leaves the valves open for the oil to slide on to the pistons. Now wait a few minutes until the engine is slightly warm to the touch, repeat #2, letting the engine get slightly hotter. Sign up for a new account in our community. When complete, it looked like it was tighter. I mean it is a possibility though. Typically, it would be a combonation of possible bad rings and definately bad valve guides/seals. Next, warm up the engine for a couple minutes as you did in the other procedures. This does not include the cost of tools, most of which are pretty basic. The metal comes from the parts wearing in and some metal comes off and ends up in the filter. In English this would be oil that can by wiped off to expose the piston top below. The cylinder pressure from 50 to 75 percent and eventually to 100 percent load will place additional pressure on the back side of the rings which will quickly establish the proper wear pattern for seating. Use the proper engine oil and fill to the proper level. Assume tappet cover seals are leaking a bit as top of cover is clean. We want to help as many people as we can avoid that feeling. Change the oil, and filter, at 1/2 the normal time, then use as normal. I did not really notice the other stems. Everything was clean as well as checking ring gaps for proper tolerance. Afterwards, take it easy on the engine for the next 1000 miles. Check your engine manual for proper placement of the piston gaps. Same thing would happen with a new bike. Let it cool again till it is slightly warm to the touch. I always recomend the oil filter be changed after the first days run, That gets the dirt out that will collect when doing the rebuild, and not to idle it. He slipped the piston through the cylinder a few times and said, "It's okay." But that's more than what should be there. Without good cylinder to ring contact the piston will continue to expand in the bore. I got the piston rings seated in the cylinder, but when it came to pushing the cylinder to seat it on the engine case, I had a lot of difficulty and had to tap it with a rubber mallet to move it at all. Start by removing the bar, air filter cover, starter, and engine cover. Most companies give the head nut torque rating with the washers, nuts and studs being clean and dry. #1 before rebuild – 117psi #2 before rebuild – 97psi #3 before rebuild – 140psi #4 before rebuild – 140psi Results for cold and dry are listed below. Oil drips down the valves after the engine has been shut off, and the cam leaves the valves open for the oil to slide on to the pistons. 421 applications through 1966 's okay. bolts at the proper position on the piston the will! 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