QuestionThis is in answer to the question I asked before about engine looseing power. Ran compression cold 90 psi, with oil squirted in 110 psi. ran engine till loose of power, compression 65 psi
with oil squirted in 110 psi. Does this mean what you thought, that the rings might be stuck because they don't expand when it gets hot? Does engine need to be taken apart and replace the rings and hone cylinder out? Piston is stamped .010 now. last owner said engine was overhauled in about 1998. When I seated the valves there was not much carbon present, cleaned what was there. Would this also cause to backfire through carb sometimes when it gets hot?
Before it starts to loose power it sounds like a blown head gasket (a high pitch sound). It cuts about 150' x 200' area before it starts to get hot. This engine is on a cub cadet 1000, 1975.
AnswerHello Again Rich:
Actually, when you Performed the Valve Job; you Should Not have De-Carbon the Piston at All. Even the Smallest Particle of Carbon Dust can Do a Lot of Damage to the Rings in a Short Time. If the Piston has a Heavy Carbon Problem, then you are Left with No Choice but to Remove the Carbon in Chunks with a Chisel. From your Description it Sounds like the Rings are Worn Out or Stuck. This will Also Cause the Backfire you have Experienced. When I Build an Engine, I Usually Check the Piston Clearance Before Making a Decision. If the Piston Clearance is too Great, then a New Piston is Required and then I Suggest a Short Block. However, from the Way you have Written to me, I Feel you will have No Problems Overhauling this Engine. Remember to Keep All Parts As Clean as Possible and Use White Lith Grease for Assembly of the Parts. Remember to De-Glaze the Cylinder and Check the Ring End Gap. The Ring End Gap Should be No More Than .020in.. Check this Gap at the Same Places In the Cylinder that you Checked the Piston Clearance. I Disassemble the Engine and Clean All the Parts (This includes Bead Blasting the Block, the Head/s and the Nuts and Bolts). Now Check the Piston to Cylinder Clearance. This is the Gap Between the Piston and Cylinder Wall. Do the Check at the Bottom, Middle and 1/2" from the Top of the Cylinder. The Specifications Should be in the Catalog at this Site Addy; http://faqs.custhelp.com/cgi-bin/faqs.cfg/php/enduser/std_adp.php?p_faqid=1487 . The Following is a Basic Instruction File for Examining the Inside of a Small Engine and will Assist you in having Access to the Governor, Oil Pump (if Applicable) Cam and Crankshaft Gear. Any Input is Appreciated. **This is a Simple Process. Drain the Oil and Remove the Engine to the Work Bench with the Oil Pan Facing Up. I have a Wooden Rest that was Especially Made to Hold the Engine when in this Position. Using Fine Sand Paper, Remove ALL the Rust and Debris from the Crankshaft. Remove the Oil Pan Bolts. After All the Oil Pan Bolts are Removed; Tap Lightly on the Sides of the Oil Pan to Loosen it from the Dowel Pins. When the Oil Pan is Removed, you can See the Governor Resting on Top of the Cam Gear. ****If Required: Lift Off and Replace with a New Governor. Check the Engine Block for Debris from the Old Governor and Wipe the Inside of the Block With a Rag, Until Clean. Set the Governor Shaft So it will be Resting on the Governor whine the Oil Pan is Replaced and Carefully Replace the Oil Pan. If the Crankshaft Seal Was Not Leaking, then Leave it Alone. It Should be OK. You can Easily Replace it While Mounted on the Machine if Required Later. Make Sure the Governor Stays in Contact with the Governor Shaft while Replacing the Oil Pan. Re - Mount the Engine to the Machine. Refill With Oil. Your Internal Governor May Differ.** If you Hit a Snag or this Does Not Correct the Problem, I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Thanks.
Respectfully
John
