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Discussion Starter #1 (Edited)
old intake spec 14/42
old exhaust spec 48/12
26* of overlap
intake duration is 236*
exhaust duration is 240*
intake installed centerline of 104*ATDC
exhaust installed centerline of 108* BTDC


new intake spec 18/38
new exhaust spec 46/14
32* of overlap
intake duration is 236*
exhaust duration is 240*
intake installed centerline of 100*ATDC
exhaust installed centerline of 106* BTDC

I've got the new grind 37g in my recent build.

Notice the 4* advance shift in the intake timing, plus I installed the Woods 2* advance cam key on advice given here. This is 6* advanced on the intake timing over the original grind. Notice the exhaust timing is back to the original numbers.

So, in essence the valve timing is this now:
overlap and duration same
with 2* cam key advanced intake spec 20/36
with 2* cam key advanced exhaust spec 48/12
intake installed centerline = 98* ATDC
Exhaust installed centerline = 108* BTDC

So, fess up! %[email protected] With the new 37 intake timing, I really didn't need the 2* cam key installed in advance. What I really needed to do is put the cam key in as 2* retard. That should put the intake events back to where the original grind was when used with the 2* advance cam key but it puts the exhaust events to 4* advanced from where the original grind was. Which is probably not ideal either because the late exhaust closing could possibly cause reversion back up the intake.

overlap and duration same
with 2* cam key retarded intake spec 16/40
with 2* cam key retarded exhaust spec 44/16
intake installed centerline = 102* ATDC
Exhaust installed centerline = 104* BTDC

I keep reading here that a few degrees of cam timing make a big difference on performance.... well dang! if that's true, no wonder my build is making torque but not near the hp on the top end that it should. The cam grind changes and the advance key are working AGAINST me. Don't you think?

Please explain where I'm wrong on this, if I am...... and which direction you would go to correct it.
 

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Totenkopf said:
old intake spec 14/42
old exhaust spec 48/12
26* of overlap
intake duration is 236*
exhaust duration is 240*
intake installed centerline of 104*ATDC
exhaust installed centerline of 108* BTDC


new intake spec 18/38
new exhaust spec 46/14
32* of overlap
intake duration is 236*
exhaust duration is 240*
intake installed centerline of 100*ATDC
exhaust installed centerline of 106* BTDC

I've got the new grind 37g in my recent build.

Notice the 4* advance shift in the intake timing, plus I installed the Woods 2* advance cam key on advice given here. This is 6* advanced on the intake timing over the original grind. Notice the exhaust timing is back to the original numbers.

So, in essence the valve timing is this now:
overlap and duration same
with 2* cam key advanced intake spec 20/36
with 2* cam key advanced exhaust spec 48/12
intake installed centerline = 98* ATDC
Exhaust installed centerline = 108* BTDC

So, fess up! %[email protected] With the new 37 intake timing, I really didn't need the 2* cam key installed in advance. What I really needed to do is put the cam key in as 2* retard. That should put the intake events back to where the original grind was when used with the 2* advance cam key but it puts the exhaust events to 4* advanced from where the original grind was. Which is probably not ideal either because the late exhaust closing could possibly cause reversion back up the intake.

overlap and duration same
with 2* cam key retarded intake spec 16/40
with 2* cam key retarded exhaust spec 44/16
intake installed centerline = 102* ATDC
Exhaust installed centerline = 104* BTDC

I keep reading here that a few degrees of cam timing make a big difference on performance.... well dang! if that's true, no wonder my build is making torque but not near the hp on the top end that it should. The cam grind changes and the advance key are working AGAINST me. Don't you think?

Please explain where I'm wrong on this, if I am...... and which direction you would go to correct it.
The TW5 cam has the 2* advance built into it also......put a std key in and forget the anvance or retard .Yes 6* will work aginst you.
 

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Discussion Starter #3
hdmd88 said:
The TW5 cam has the 2* advance built into it also......put a std key in and forget the anvance or retard .Yes 6* will work aginst you.
Doc,
Thanks for replying!

Are you okay with the 4* advance on the intake valve timing with the new 37 grind? That is still +2* over the original recipe that you have had so much success with.

Is the 2* retard option I mentioned with the cam key too risky because of the late exhaust closing? or is there something else in the timing that I haven't caught onto yet?

I'm also curious about the increase in overlap to 32* and it's affect on the build. Any thoughts?

Would switching to another cam be advised at this point since the 37 grind has changed?

You mention the TW-5G having the advance built in..... but how about the TW-6G with my build?

I would rule out the TW-5G because of the lift.
TW-5G
Intake 17/37 234* Duration .575" Lift
Exhaust 39/15 234* Duration .575" Lift

This cam looks interesting to me......... is it now the better choice over the new 37?
TW-6G
Intake 20/40 240* Duration .510" Lift
Exhaust 42/18 240* Duration .510" Lift
 

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Totenkopf said:
old intake spec 14/42
old exhaust spec 48/12
26* of overlap
intake duration is 236*
exhaust duration is 240*
intake installed centerline of 104*ATDC
exhaust installed centerline of 108* BTDC


new intake spec 18/38
new exhaust spec 46/14
32* of overlap
intake duration is 236*
exhaust duration is 240*
intake installed centerline of 100*ATDC
exhaust installed centerline of 106* BTDC

I've got the new grind 37g in my recent build.

Notice the 4* advance shift in the intake timing, plus I installed the Woods 2* advance cam key on advice given here. This is 6* advanced on the intake timing over the original grind. Notice the exhaust timing is back to the original numbers.

So, in essence the valve timing is this now:
overlap and duration same
with 2* cam key advanced intake spec 20/36
with 2* cam key advanced exhaust spec 48/12
intake installed centerline = 98* ATDC
Exhaust installed centerline = 108* BTDC

So, fess up! %[email protected] With the new 37 intake timing, I really didn't need the 2* cam key installed in advance. What I really needed to do is put the cam key in as 2* retard. That should put the intake events back to where the original grind was when used with the 2* advance cam key but it puts the exhaust events to 4* advanced from where the original grind was. Which is probably not ideal either because the late exhaust closing could possibly cause reversion back up the intake.

overlap and duration same
with 2* cam key retarded intake spec 16/40
with 2* cam key retarded exhaust spec 44/16
intake installed centerline = 102* ATDC
Exhaust installed centerline = 104* BTDC

I keep reading here that a few degrees of cam timing make a big difference on performance.... well dang! if that's true, no wonder my build is making torque but not near the hp on the top end that it should. The cam grind changes and the advance key are working AGAINST me. Don't you think?

Please explain where I'm wrong on this, if I am...... and which direction you would go to correct it.
How can you tell if you have the old or new grind?
 

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Thanks for the update on the grind , I'm still saving for the 37G and think this is great news .
 

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Discussion Starter #8
Measuring them, that would be the best way.

Otto had a 2005 Andrews catalog laying around last weekend at his shop when I noticed it. I figure the change had to be in 2004 to make it in that catalog, although I have a question into Andrews tech service right now to see if there is any identifying marks and what the shipping dates to their distributors were. I bought this cam set from Drag 6 weeks ago, I would bet that it is the new grind based solely on the logic of the events timing with the evidence we have.
 

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Toten, If you just bought the cam new, there should be a cam card in the box with it that gives the specs. Then you would know for sure...
 

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Discussion Starter #10
adlerx said:
Toten, If you just bought the cam new, there should be a cam card in the box with it that gives the specs. Then you would know for sure...
Went and looked in the box, no cam card but there was a tag giving the production date, 5-17-05. There was also the installation instructions, that had all of the cam specs of their TC88 products. This lists the new grind valve timing; 18/38 46/14 for the 37g.

I'm positive it's the new grind. In any case, towards the end of the coming week, Otto is going to install the new Dakota Kid reworked TB/intake manifold, he'll remove the advance cam key and probably reverse it to 2* retarded and he's going back into the clutch. I noticed it beginning to slip again in 3rd and 4th gear, the other day. Then we will bring the bike to the dyno and we will re-tune it, this time with Otto running the dyno.
 

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Well, isn't this just spiffy.
Andrews changes the grind and doesn't change the designation at all, so I (like you) put in a 2 degree advance key for SIX degrees of advance.
Crap. :(
 

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I'm confused now. Does this new grind mean that you don't need an advance key now to move the powerband down like the old grind?
 

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Discussion Starter #13
hdmarsh77 said:
I'm confused now. Does this new grind mean that you don't need an advance key now to move the powerband down like the old grind?
Correct. In fact, it's 4 deg advanced by itself on the intake now in the new grind, which may be more than what some folks want.

I'm going to try the 2* cam key in retard and see what the motor performance is like. If I'm not happy with it, I may have to search out another cam grind. potential Bummer! but we are hopeful it will meet our expectations.
 

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Looks as though the TW 26 changed too , moving up 200 rpm . from another post :
GRIND/OPEN/CLOSE/DURATION/LIFT/LIFT TDC
26(Old)
Intake/09/37/226/.490/.129
Exhaust/43/04/220/.490/.112

GRIND/OPEN/CLOSE/DURATION/LIFT/LIFT TDC
26(NEW)
Intake/11/35/226/.490/.129
Exhaust/41/09/230/.490/.112

The new grind should get "on the cam" approx. 200 rpms later than the old grind. It also moves the overlap to 20 instead of 13.
 

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Totenkopf said:
Correct. In fact, it's 4 deg advanced by itself on the intake now in the new grind, which may be more than what some folks want.

I'm going to try the 2* cam key in retard and see what the motor performance is like. If I'm not happy with it, I may have to search out another cam grind. potential Bummer! but we are hopeful it will meet our expectations.

Thanks T.

So, what you're saying is that the power may come on too soon now for some? Maybe those with lighter bikes that don't need to power so far down? Or is there another reason the 4 degrees is too much for some?

What about a bagger? How would it work(the new grind) as is?
 

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Discussion Starter #16
hdmarsh77 said:
Thanks T.

So, what you're saying is that the power may come on too soon now for some? Maybe those with lighter bikes that don't need to power so far down? Or is there another reason the 4 degrees is too much for some?

What about a bagger? How would it work(the new grind) as is?
It all depends on your riding style. I can say with the 2* cam key in, it pulls very hard from the mid to upper 2k's to 4K rpm. She noses over after that. From your response, you pretty well understand how this may not be the panacea cam for everyone. For a heavy bagger that does not ever drag race, my combination may be perfect for them. For some one like me with a bike that can be heavy or can be somewhat trimmed down, I want it all, call it a balanced approach, grunt on the bottom end and still pull hard on the top. For a light bike that never is ridden two up and the rider wants to street race, there are probably far better cam choices out there for that application.

We will find out more when we make the changes I've described. I'm looking for the broadest torque curve that should extend up to about 5000rpm, that will deliver close to 100hp at 5800rpm or so.

We will see what happens next.
 

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Discussion Starter #17
Well, this is interesting.........

Ralph at Andrews Tech Service just emailed me back and says the 37g has always been........

18/38, 46/14 never changed it.

hmmmm.......... :wacko:

Says that those other numbers could be a misprint from one of their distributors or something like that. Anybody got an older Andrews catalog?

Still going to take out the cam key and will discuss further on whether to retard the timing 2* or leave it straight up.
 

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Totenkopf said:
Well, this is interesting.........

Ralph at Andrews Tech Service just emailed me back and says the 37g has always been........

18/38, 46/14 never changed it.

hmmmm.......... :wacko:

Says that those other numbers could be a misprint from one of their distributors or something like that. Anybody got an older Andrews catalog?

Still going to take out the cam key and will discuss further on whether to retard the timing 2* or leave it straight up.
He's full of $hit, I was looking at an andrews catalog for 2003 at my local dealer on Saturday and the #'s for the 37B were different than what they currently are.
 

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bedemonster said:
He's full of $hit, I was looking at an andrews catalog for 2003 at my local dealer on Saturday and the #'s for the 37B were different than what they currently are.
The chain driven 37B used to be:
Andrews TW37B Y 14 42 48 12 as per the not up to date www.nightrider.com page.
37G as far as I could find evidence was never changed since introduction. I venture a guess here that Andrews changed the 37B to 37G specs when they introduced the latter one a few years back. So both parties are right due to a lack of clarity what the actual question was....

Just my 0.02cts
 
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