Another SJ410 question

Post by **notajp** » Thu Mar 31, 2005 1:49 pm

Well, I've gotten my block and other parts back from the machine shop, my re-ring kit is ordered, and I am now going thru all the parts that were in the back of the truck to figure out if I have all the pieces I need, and where I have more than one, decide which to use. Which brings up my problem: I found two each of the crank and cam belt sprockets. However, there are two different sizes of each! I assume that one set came from the original motor and the other from the "new" motor that was disassembled to a short block. Since I didn't take any of this apart, I don't know which sprockets to use. Unless Suzuki used two different length cam belts in the 410 motor (which I really doubt), I'm guessing I would need to use either the larger crank sprocket with the smaller cam sprocket, or the small crank sprocket with the large cam sprocket. The only thing I can think of is that at some point during the build run of the SJ410, for some unknown reason Suzuki decided to change the sprocket sizes. Any ideas what I should do here? I'm worried that if I use the wrong sprockets it could throw off the cam timing. I have the factory service manual, but it has been no help with this problem. :cry:

Post by **Podge** » Thu Mar 31, 2005 2:11 pm

There was 2x different belts run in the SJ410. Gates P/No. T028 (84X 19mm) in SJ410 type 1/2 (81-11/84). Some application books list this as being a metal dash type. The other is T070 (88X 19Mmm) in SJ410 type 3/4/5 (11/84-87) and Maruti MG410 (90-99). This is listed as being a plastic dash model in some application books.

Post by **christover1** » Thu Mar 31, 2005 3:59 pm

keep it simple, cam has to go round once for crank to go round twice. (one pwer one exhaust)
therefore cam sprocket = 2 x the teeth on the crank sprocket
usually 20:40 or 18:36 a matching set is very important,
nearly got that wrong myself
I think belts are close enough the same, there is plenty of adjustment?????

christover

Post by **Podge** » Thu Mar 31, 2005 5:11 pm

It does matter a whole lot when the 2x belts have different teeth, for starters. Think about it.

Post by **notajp** » Thu Mar 31, 2005 5:23 pm

So I guess it may not matter which of the two pair of sprockets I use, as long as I maintain the 2-1 ratio between the cam and the crank sprockets. I'd still like to know why the two different setups in the first place. I figure there has to be some reason Suzuki changed horses in mid-stream with this, but I sure can't think of a good reason. BTW, I also noticed that one of the two cam sprockets has two keyways. Haven't figured that one out yet either. Never seen that on a Samurai motor........

Post by **christover1** » Thu Mar 31, 2005 10:09 pm

Podge wrote:It does matter a whole lot when the 2x belts have different teeth, for starters. Think about it.

ok I thunk about it, but need you to explain, please.
Obviously the shorter belt goes round the smaller cogs/sprockets.
Are the teeth different shapes?
The length only has to fit in the existing space with the correct tension.?
I give up, why?

Post by **christover1** » Thu Mar 31, 2005 10:16 pm

notajp wrote:So I guess it may not matter which of the two pair of sprockets I use, as long as I maintain the 2-1 ratio between the cam and the crank sprockets. I'd still like to know why the two different setups in the first place. I figure there has to be some reason Suzuki changed horses in mid-stream with this, but I sure can't think of a good reason. BTW, I also noticed that one of the two cam sprockets has two keyways. Haven't figured that one out yet either. Never seen that on a Samurai motor........

Thats what I believe, I cannot think of any reasons why it matters which set you use...I discovered the difference when bolting a 2nd hand head onto my 1.o litre block....Only lucky I noticed the difference. I never discovered why they changed them, either.. both my cam belts were the same size (dont actually know what size) from both engines, one had 20 40 the other 18 36...it worked fine.
2 keyways is from when same sprocket has a different use in another engine, I think.
I've seen this in 1300, not in 1.0 litres, tho.
christover

Post by **Podge** » Thu Mar 31, 2005 10:46 pm

I put the 2x belts side by side this afternoon and there wasn't enough difference in the teeth to worry about but what there is a difference in is the length of the two belts. Despite what the books have listed in size there was a good 25mm difference in length. No amount of adjusting is going to take up that much tension. Do you still have the belt that came off the engine? If so look for the OE P/No (which will be a 10x digit number) and pass it on, I can usually cross reference the part number with the aftermarket part. It will be really difficult to get an OE belt in the states. The numbers are usually worn off but you can only try.

Post by **christover1** » Thu Mar 31, 2005 10:54 pm

nah I converted my car to 1.3, all the 1.0 litre stuff is dead and buried.
but shorter belt fer smaller sprockets makes sense....
christover

Post by **notajp** » Fri Apr 01, 2005 10:59 am

Actually, I think he was referring to me. The only belt I have is an OE Suzuki part # 12761-73000. Unfortunately I don't have a clue which motor this belt is from, the original 85 motor, or the replacement. I may have to wait and see what the belt that comes with my engine kit is. Is there any way to decipher any numbers that may be on the block to determine what year the replacement motor is?

John

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