Camshaft Top End Rattle

[mlinder]

Don, is that 104 intake 106 exhaust?

How did you arrive at those? Just curious, it's very close to what my head guy has told me to set them to (though I'm using the 550 exhaust cam.)

 

[Suzuki_Don]

Don, is that 104 intake 106 exhaust?

How did you arrive at those? Just curious, it's very close to what my head guy has told me to set them to (though I'm using the 550 exhaust cam.)

It is actually 105 intake and 106.625 exhaust. I found I did have the data at work.

I was aiming at 104:106 or 105:107 as suggested by RAPIDRAY, lower numerical figures for more torque.

I could not get these exact figures as you would probably know if you've done cam degreeing before that once the cam sprocket bolts are loosened the camshaft will slip into a different position as dictated by the spring pressure and valve buckets & shims. I was shooting for 105:107, but I ended up with 105:106.625, it was close enough for me.

An interesting fact is the cam timing on the 650 cams in standard trim actually has the numbers reversed.

Going off Suzukis cam timing figures in the manual the lobe centres are EX - 103 and IN - 106.

When I checked the standard 650 cams in my motor before slotting the cam sprockets, i.e. standard timing - I found they were EX - 103 and IN - 108.

As you will see these standard figures are back to front to the way Suzuki cams are usually ground and timed. Normally the EX is the larger number and IN the smaller number, but on the 650 cams it was the other way round. Don't know why, anyway I timed mine in the more standard way as I said previously looking for 105:107 intake and exhaust respectively.

BTW is there any reason why you are using the 550 exhaust cam?

Hope this helps and not too confusing.

 

[Nessism]

ED: As you will have now realised I have fitted the valves back into the cylinder head, so am not keen to pull them all out again to check if the contact area is the same on all valves, but I assume it is. Is there any advantage (the hot rodders like them this way) or disadvantage (the manual says not to do it) of the contact area on the valve being towards the outside circumference of the valve head.

With the seat at the outside edge of the valve it increases the effective diameter of the valve. I'm not sure what the downside is other than maybe a ridge on the seat could form the valve pounds in, and the valve can sink. I'd just go with it since everything is assembled now.

 

[Suzuki_Don]

With the seat at the outside edge of the valve it increases the effective diameter of the valve. I'm not sure what the downside is other than maybe a ridge on the seat could form the valve pounds in, and the valve can sink. I'd just go with it since everything is assembled now.

Thanks Ed.

 

[BadBillyB]

Billy, I have degreed the cams in previously, 104 & 106 I think from memory. I am at work now so don't have the details with me. So I just reinstalled them as per the timing marks on arrow 2 and arrow 3 with 19 pins in between. MLINDER is right. I will get you a pic when I get home tonight.

TEAMDAR commented that putting a thicker base gasket on would advance the cam timing, so how much would .010" advance the timing and would the numbers be higher or lower, closer or further apart.

Hey, alright....I am probably wrong this time, my old eyes dont see detail very good.....I think you will find the cam timing is only advanced 1 or 2 crankshaft degrees with the taller base gasket. The intake timing will be a smaller number (TDC to max lift) and the exhaust number will be a larger number (max lift to TDC) .......I'm not a street tuner but that seems like a lot of advace for an intake cam.....Now we are talking 102/108 I/E.....Billy

 

[TeamDar]

Don, see if the noise goes away. If it does then take the time to degree the cams again. Dar

 

[Suzuki_Don]

Hey, alright....I am probably wrong this time, my old eyes dont see detail very good.....I think you will find the cam timing is only advanced 1 or 2 crankshaft degrees with the taller base gasket. The intake timing will be a smaller number (TDC to max lift) and the exhaust number will be a larger number (max lift to TDC) .......I'm not a street tuner but that seems like a lot of advace for an intake cam.....Now we are talking 102/108 I/E.....Billy

Thanks Billy, I never could really visualise stuff with camshafts, always got confused when there were changes in the motor and people said that one cam advances and the other cam retards, yet to my way of thinking both cams are being pulled the same way by the chain off the crank sprocket and I would think that both cams are being advanced seeing as they are both moving either forward or backward by the same amount if you can see what I mean.

But if my figures are truly going to be 102 and 108 then i can see a reason to degree the cams again. OH!! how I hate setting up that degree wheel and pointer on the crankshaft. Probably better to do it now while the generator cover is off.

I will set the shim clearances first and then check the lobe centres again after that.

If the lobe centres are at 102 and 108 is there any chance the valves will hit the piston or each other. I have read that the lower the numbers the closer things run to each other.

 

[Suzuki_Don]

Don, see if the noise goes away. If it does then take the time to degree the cams again. Dar

Thanks Dar for raising this little issue, better to check it now before the motor is completely back together and deciding to do it then.

What are your suggestions on lobe centre settings for a street motor. Stock except for a 4 into 1 and fairly restrictive silencer.

 

[TeamDar]

I like the 104-105 intake and the 105-106 exhaust. That will give you good mid-range where you will spend most of your time on a street bike. I think your timing will only be off about a degree at the crank. That is figuring about a 3" diameter cam sprocket with a circumference of 9.420". For every .026" in base gasket thickness difference the timing would change 1 degree at the cam or 2 degrees at the crank. Since you only changed .010" then it would be about 1/2 that or 1 degree at the crank. Dar

 

[Suzuki_Don]

I like the 104-105 intake and the 105-106 exhaust. That will give you good mid-range where you will spend most of your time on a street bike. I think your timing will only be off about a degree at the crank. That is figuring about a 3" diameter cam sprocket with a circumference of 9.420". For every .026" in base gasket thickness difference the timing would change 1 degree at the cam or 2 degrees at the crank. Since you only changed .010" then it would be about 1/2 that or 1 degree at the crank. Dar

OK thanks for that. I will report back when I have checked the lobe centres on my motor again.

 

[Nessism]

Don,

Noticed the 550 takes a 116 link cam chain while the 650 takes a 120 link chain. Which one did you use?

Edit: just noticed the 650E uses the same 116 link chain as the 550. Thought I was on to something but no. It's the 650G that takes a 120 link chain.

 

[BadBillyB]

But if my figures are truly going to be 102 and 108 then i can see a reason to degree the cams again. OH!! how I hate setting up that degree wheel and pointer on the crankshaft. Probably better to do it now while the generator cover is off.

I will set the shim clearances first and then check the lobe centres again after that.

If the lobe centres are at 102 and 108 is there any chance the valves will hit the piston or each other. I have read that the lower the numbers the closer things run to each other.

Hey Don, yeah I hear you. At least you will be more proficient at degreeing cams when you get done and like you said your already there, might as well. I use an aluminum 10" degree wheel and just super glue it to the left end of the crank with 0 somewhere near the top. Fasten the pointer wire nearby and find absolute TDC with a homemade piston stop. After setting the lobe centers, I just knock the degree wheel off the crank with my hand.

If both cams are advanced the same amount (which they were) the valve to valve clearance stays the same, but the intake valve to piston clearance is closer. Since you have stock cams, theres lots of clearance there anyway. It's refreshing to see someone so thorough and clean with their engine build......Billy

 

[Suzuki_Don]

Don,

Noticed the 550 takes a 116 link cam chain while the 650 takes a 120 link chain. Which one did you use?

Edit: just noticed the 650E uses the same 116 link chain as the 550. Thought I was on to something but no. It's the 650G that takes a 120 link chain.

Yes Ed they have the 34 tooth camshaft sprockets and 17 tooth crank sprocket as opposed to the 550 and 650e which have the 30 tooth cam sprockets and 15 tooth crank.

Thanks for still working at it on my behalf though.

 

[Suzuki_Don]

Hey Don, yeah I hear you. At least you will be more proficient at degreeing cams when you get done and like you said your already there, might as well. I use an aluminum 10" degree wheel and just super glue it to the left end of the crank with 0 somewhere near the top. Fasten the pointer wire nearby and find absolute TDC with a homemade piston stop. After setting the lobe centers, I just knock the degree wheel off the crank with my hand.

If both cams are advanced the same amount (which they were) the valve to valve clearance stays the same, but the intake valve to piston clearance is closer. Since you have stock cams, theres lots of clearance there anyway. It's refreshing to see someone so thorough and clean with their engine build......Billy

Thanks for the compliment Billy. Just an 'ol amateur home made mechanic doing the best I can with a little help from my friends (you guys).

 

[Suzuki_Don]

A bit more progress tonight.

First the picture that Billy wanted of the ends of the camshafts.

Degree Wheel set up on one side of the motor.

TDC on other side of motor.

Metal plate set up for magnetic dial gauge.

.

 

[Suzuki_Don]

Decided to go outside and do a bit more.

I set up the dial gauge and took readings off the degree wheel at .050" going down and then back up again. The readings that I got for the intake lobe on #1 cylinder was 3? after TDC and closing at 27? after BDC. So I came up with 102? lobe centre on the intake cam. A bit out from where it should be I would say.

Is .050" OK to do the readings at, or is .040" better.

Does someone want to check my calculations to make sure they are correct. Thanks.

I will do the exhaust tomorrow night hopefully.

 

[BadBillyB]

I set up the dial gauge and took readings off the degree wheel at .050" going down and then back up again. The readings that I got for the intake lobe on #1 cylinder was 3? after TDC and closing at 27? after BDC. So I came up with 102? lobe centre on the intake cam. A bit out from where it should be I would say.

Is .050" OK to do the readings at, or is .040" better.

Does someone want to check my calculations to make sure they are correct. Thanks.

I will do the exhaust tomorrow night hopefully.

Hey Don, you sure do work fast, keeps me interested. I did check your math and you forgot to add 3 degrees to the 102 (1/2 total duration).....I came up with 105 centerline for the intake. Heres my math
177 + 27=204(total duration)
divide by 2= 102
count 102degrees from the 3atdc
= 105 lobe center
Doesn't really matter .040" or .050" thats kind of splitting hairs.....Billy

 

[BadBillyB]

Forgot to mention there is another way to do this and I prefer it with performance cams.

Find max lift with the dial indicator
Zero indicator
Turn motor backwards a bit, then forward and stop at .050" before max lift
Mark degree wheel
Roll motor past max lift stopping at .050" after
Mark wheel
1/2 way between the marks is your lobe center

Billy

 

[Suzuki_Don]

Well Billy if your maths is correct and I believe it is as I'm only a learner on this cam degreeing thing then 105? is the same as my original cam timing for the intake. So I should not have to alter anything. I have done cam timing previously only by following a formula, i.e. 5 + 180 + 35 / 2 = 110 - 5 = 105? and so on. I now understand what is actually happening in practical terms. Thanks Billy.

I will check the exhaust when I get home tonight.

BTW here are the numbers from the initial cam degreeing exercise when I slotted the sprockets.

FINAL CAM SPECIFICATIONS: (Using Dial Gauge Method – measured @ 0.030”)

EXHAUST CAM:

Opens: 35.25? BBDC
Closes: 2? ATDC
35.25? + 2? + 180? = 217.25? DURATION
217.25? / 2 = 108.625? - 2? = 106.625? LOBE CENTER

INTAKE CAM:

Opens: 5? BTDC
Closes: 35? ABDC
5? + 35? + 180? = 220? DURATION
220? / 2 = 110? - 5? = 105? LOBE CENTER

 

[BadBillyB]

Hey Don, thanks for the pic from the right side showing the camshaft cut outs to cylinder head relationship. Just making sure there is no gross error. I forgot to ask you if you used a piston stop tool to find TDC. They are easy to make with an old spark plug. I also see now where the confusion is. The formula used to find the lobe center is based on whether the intake opens before or after TDC. This is directly related to what number lift you measure at. .030", .040", .050" .....In some cases you add the small number and in other cases you subtract the small number....Thats why I prefer the alternate method I described in my earlier post. Theres less room for error. Anyway heres a nice page to use for a guide.....Billy http://www.webcamshafts.com/pages/degreeing.html