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Hi,
The BRICKBOARD has plenty in sentences and between the lines information if you read carefully over the experiences of the many owners.
Good questions and statements entertain us.
That is interesting that you think the adjustment is not in the path between crankshaft and the cam.
The adjustment is punching inward on the entire belt so it’s adjusting both at the same time.
The crankshaft is pulling the belt around. The real slack, for lack of a better term, it is on the adjusters side.
So in a sense, it’s averaging the belt back to a mid point but since the belt has a finite length it all averages out.
Yes, the belt can have stretch between each tooth on the belt.
That the accumulation is also a wear factor.
To tell the truth, not all or every tooth will stretch or wear the same amount either.
Even a new belt comes with built-in manufacturing tolerances, as nothing is perfect, if you look close enough.
Even in the last year of the 240, the 1993 belt got a rounded tooth profile and sprockets and I assume the 900s.
Does it help anything? I don’t know, maybe, a smoother and quieter running wear in factor?
So here I am, just as guilty as you about over thinking things in the details!
Changing the seals on all three shafts and the timing belt is wise enough.
The top seal should get less oil up there but the head is hotter on the seal so they do go first.
The others will follow and it’s usually the crankshafts seal(s). Front and rear.
There’s a lot more oil down there in the pan than up in the head. I don’t think an intermediate seal has ever leaked on me but I change it.
You can only Wipe down things underneath the car periodically. It a variable time line on those.
To explain laws in averages this is an entertaining story.
If you have ever owned a bicycle or especially a motorcycle you will know that chains do not wear evenly.
You have to find the tightest or least amount of free play in between the sprockets and adjust that out to just so tight but not too tight.
In this case the sprocket wear in out of round too.
Each and every pin and roller gives a little wear. The side plates of a chain don’t give much so the length stays finite.
On a bicycle chain you use a gage that measures between a certain number of teeth and you check around the chain. If you find an short length out of tolerance it is recommended to replace the chain.
You can do that with human powered devices.
Motorcycles have engine pluses that can set up harmonics between worn sprockets and a stretched chain This can cause them to snap.
We are talking about an excessively worn drive train here. My story.
I did that on my first motorcycle, in my youth, only once! I was 17 or 18 years stupid.
When it happened I had ridden about 200 miles, back up to my home town above Memphis.
The temperature when leaving Memphis was just below 40 degrees in late afternoon.
I was going up to a shop to get service done the next day in Nashville and visit a Grandma.
I don’t have any idea how cold it got but it didn’t snow.
On into the night the chain broke near the end of my trip.
I didn’t know how cold I was until I walked back to get the chain out the road.
My legs were numb and heavy.
It felt like pins were in them when I walked.
Hypothermia wasn’t a word I used before or felt in my life before.
Running around in town was always just chilly to this daring boy.
But apparently it had closed in on me.
Any way, I had to put my spare repair link with another master link.
I owned a chain breaker tool so I was prepared for a long trips as I did ride a lot.
No cars in my life’s budget.
Only, I didn’t plan on me being so cold. I barely hold could align the ends of the chain together.
The shakes had started while I was warming up from my walking and a few minutes in the store as he was closing.
Luckily country store was right there and he left a light on for me.
The next day I went to the shop. The mechanic there working on my bike, came out to the front as asked who owns a black and white Sprint motorcycle.
I acknowledge him from a distance by waving.
He then rolled the smaller sprocket, off the engine, across the floor towards me.
It rolled like a coin on the concrete.
He said he was amazed that I drove it 40 miles to the HD shop.
The Work Order must have had my address and so I guess I needed to be embarrassed.
He talked to me that and he was truly in wonderment.
I just said, “Well it did ratchet or slip a little bit getting here!
He just stood there squinting in 1968.
I Didn’t tell him how the chain broke the night before.
He meant to insult me as old timers did back then.
Yep, he was probably in his mid to late forties! (:) (:)
But was not so injured as I was the poor boy paying a bill.
I got more into doing my own work later after the Navy.
Especially after I bought a brand new F-100 truck in 1974.
A Big mistake for many reasons.
I still have it too, parked up on stands for reasons of silliness.
My brain has definitely earned some singe marks through the years but the Ford and a Harley Davidson woke me up.
The Volvos stopped my buying cycle as they advertised.
I have saved as many as I could so I would never but a new vehicle ever again.
I learned to follow recommendations in service manuals. Volvo used to recommend 30,000 for chain timing belts on these car early on.
I have pushed them to 60,000 and only had one break in forty years during acquiring my six cars.
So here a recommendation … don’t keep six cars at a time or everything you ever bought in your lifetime unless it worthwhile. I valued everything as a habit.
50,000 on T- belts and 5,000 mile oil changes.
It makes it easier to remember.
It’s Something about being handy and the fives helps my brain “grip” reality better. (:)
Enjoy forums with caution as I didn’t have them back when.
Phil
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