I recently discovered that several of my Honda OHC engines are in fact equipped with timing belts, one is a on a tiller and it was a rental unit before I bought it and was rode hard and put away wet. I probably put 20 hrs a year on that tiller and would say it has very high hours. It has a timing belt, as well as my brand new 4 cycle mantis tiller (why I waited so long to buy a mantis is beyond me), I also have a 2003 Honda harmony push mower and a 2003 pressure washer with honda motors that have timing belts. I don’t know how this never came to my attention sooner, somehow I have missed this fact over the years until I read the manual for my new mantis.
From what I can tell the belts are in a sort of oil bath but I might be wrong about this, Now I know that a tiller or pressure washer or generator will never have the hours on it a car does, but why have we not tried the same technology in a car or truck? I figure its just not feasible, as most small engines run at a fixed rpm and do not run in below zero weather, however I find this technology interesting and think its worth discussion.
A car that has 250k miles, with a 60mph average speed over those miles will have over 4100 hours on it, now I figure that average speed is much lower but I am sure there are generators with over 10k hours on them with the original timing belt, any input?
I didn’t realize that Honda made overhead cam small engines–I had assumed that these engines were overhead valve engines. Perhaps these small engines are not interference engines.
I hope your Mantis tiller works out well for you. I bought a small tiller that has a 2 stroke engine and until last year was always difficult to start. Often, I would resort to squirting carburetor cleaner directly into the air intake on the carburetor. A friend suggested that I try this premixed non-ethanol fuel and that seems to have solved the starting problem with my tiller. However, it did create another problem: the 50:1 premix at $5 a liter is so expensive that I had to give up something. I had to give up booze for myself so that I could afford non-alcohol fuel for my tiller. Ironic, isn’t it?
I believe they are non interference engines, it appears that the timing belt is also the vehicle that moves oil to the top of the motor for the cam and valves, though im not sure.
When I bought the mantis I paid a 100 dollar premium for the 4 cycle engine. I read many complaints about the echo sourced 2 cycle being hard to start which I found odd since I have an echo blower and weed eater and they start fairly well. The Honda powered mantis starts fairly easily, the bigger reason I bought the 4 cycle is for the increased power and torque, and the biggest reason I bought it was for the quieter operation, I find 2 strokes get on my nerves after a while even when wearing hearing protection.
Do you like your tiller? I love the mantis, its like a chainsaw for the dirt, it was pricey for what it is but I hope it lasts because it should get alot of hours on it. I finally bought it after an hour using the stirrup hoe, I did in 10 minutes with the mantis what took me an hour with the hoe.
Final note, you can get ethanol free fuel at some country mark gas stations here in Indiana, its worth a look. The nearest one to me is about 30 miles. I plan to start using ethanol free fuel in my small engine powered equipment minus my zero turn mower. The Z turn uses to much fuel to haul in from another county.
I don’t think it’s the speed that puts the most stress on timing belts. I think acceleration probably puts more stress on timing belts than a constantly maintained high speed, say 80 MPH. Then there is the jolt the belt takes every time the transmission shifts gears.
So the question arises as to what happens when that belt does go south. Trash the engine on the way out or an engine diassembly at a minimum just to change a belt?
“[I]t appears that the timing belt is also the vehicle that moves oil to the top of the motor for the cam and valves, though im not sure.”
Really good question. Also, what lubes the rockers on the small OHV engines? I’ve seen reference to Briggs “DuraLube™ Splash Lubrication System” but how the heck do you splash oil to the top of the cylinder?
Notice, there is only one cam! It works both intake and exhaust valves.
I’ve seen reference to “oil mist” getting up to the rockers of early OHV motorcycles (Norton). I’m guessing that’s what’s used on small OHV engines that don’t have oil pumps.
I don’t really think it matters if the engine’s an interference or not, @WheresRick. Consider the “blue book” value of a decade-ish old lawnmower. With a repair rates of $30/hr or more, internal engine work = buy a new one.////////
This is why I’m sold on flatheads for 4-stroke small engines. Splash-lube design means It’s a PITA to lube an OHV. A flattie is more repairable when a head gasket job requires loosening/tightening 8 bolts and not messing with the intake or exhaust. Not only is it non-interference, you can actually have a valve spring fail and be back in buisiness in under an hour of labor. Given that mowers max out at ~3000 RPM, you gain little from the better breathing of OHV.
@WheresRick
Great discussion. Love small old motors .
One thing though. A car with 250 k miles on it with an average speed of 60 mph must have been used by a manic. the average car, if there is one, should have an average speed well less then 40 mph and would have many more hours on it. Just an observation cause my tractors all had hour meters which I like much better for maintenance. One hour for them is based on one hour operating at their recommended operating rpm…slightly 2000 over to 2500 rpm. Lawn mowers, trimmers generators etc. often operate at one rpm. So seasonal service or time works best including valve train maintenance.
@Caddyman
I have a four stroke Merc with the power head made by that highly reputable US manufacturer, Tohatsu.
I inherited a 1998ish Honda lawn tractor with two cylinder liquid cooled engine. It too has a timing belt I have never touched nor really anything else but the fluid. It musters on.
A bit off topic but in the mid 1980’s I wanted to turn a 15’ by 40’ grass area into a garden. I borrowed a name brand new rototiller from a friend which just bounced off the sod. I resigned myself to pick and shovel followed by the chiropractor. I was in a rural area on my delivery route with an Econoline 350. I noticed a yard sale with a rototiller in the driveway. It was old and a bit rusty. It had no brand name but looked about 1950’s. The engine was a Techumsa (sp). No clue as to the hp. It had the old school rope with t-handle that wrapped around a pulley for starting. It started on the first pull and sounded great. I had no problem paying the asking price of $30. It had no problem with the sod and if I let it go would have dug to China until it ran out of fuel. I changed the oil and replaced the sparkplug a year later. I used this old gal for almost 10 years with no problems. I moved to a house where it was not needed and gave it to a friend. He was still using it in 2013! I remember when things were made to last.
@sgtrock I’m sure that tiller was made to last, and priced accordingly. Most people used hand tools for working their gardens. Tillers were a luxury. Tecumseh is an old brand that started out making compressors for AC and refrigeration, which they still do. Later they bought a small engine maker and sold those for decades before selling off that part of the business a few years ago to a company that shut the operation down. Hard to compete in that business with so many bigger companies worldwide. The company was named after Tecumseh, Michigan, where it was founded, with the town named after the famous Shawnee chief.
the average car, if there is one, should have an average speed well less then 40 mph and would have many more hours on it. Just an observation cause my tractors all had hour meters which I like much better for maintenance. One hour for them is based on one hour operating at their recommended operating rpm…slightly 2000 over to 2500 rpm. Lawn mowers, trimmers generators etc. often operate at one rpm. So seasonal service or time works best including valve train maintenance.