Measured/Degreed my jwt cams

[Kfred]

I set all valve clearances in the .010"-.012" range.

I found Jwt s1 cams are fairly small compared to other "272" duration cams on the market.

Because most import cams are measured at 1mm lift, i used this so i could compare. At 1mm lift the jwt cams have a duration of ~222*, which is pretty much equivalent to kelford stage 1 (256/264) cams.

Using .001" of lift I was able to get data that corresponds to the cam-card.
MIy results:
IVO 12*btdc
IVC 80*abdc
EVO 70*bbdc
EVC 22*atdc

This gives: Your shaft has an Overlap of 34.00 degrees and has in Intake Duration of 272.00 degrees. The Exhaust Duration is 272.00 degrees. The Inlet Cam has an Installed Centerline of 124.00 degrees ATDC. The exhaust cam has an Installed Centerline of 114.00 degrees BTDC.

Jwt Says:
IVO 15btdc
IVC 77abdc
EVO 72bbdc
EVC 20atdc

This gives: Your shaft has an Overlap of 35.00 degrees and has in Intake Duration of 272.00 degrees. The Exhaust Duration is 272.00 degrees. The Inlet Cam has an Installed Centerline of 121.00 degrees ATDC. The exhaust cam has an Installed Centerline of 116.00 degrees BTDC.

Both of my cams are retarded 2-3*, which i expected since my head was decked. So, I plan on leaving the intake cam where its at, and advance the exhaust cam 5*to bring it 2-3* advanced more than drop in. This will lower the overlap from 35 to 29* and hopefully help my lowend-midrange out. For high boost applications jwt recommends you retard the intake 2.5* and advance the exhaust 2.5*, the above will put me where i need to be.

[adamky]

Very interesting. So, I wonder if cams should be degreed at .001 lift instead of .050"? I degreed mine at .050, but you're making me want to check them again at .001".

[Walperstyle]

Very noobish question: but this is regarding the 272's correct?

I have yet to do anything with my Crower 280s, but 272 is a good starting point.

[adamky]

Very interesting. So, I wonder if cams should be degreed at .001 lift instead of .050"? I degreed mine at .050, but you're making me want to check them again at .001".

Looking at the info again, it's obvious that you are supposed to degree the cams using .001" lift. Which means I need to re-degree mine.

[Kfred]

If the cam card lists valve timing events, try to use this data to degree the cams. For instance kelford list valve events at 1mm lift, use this data and adjust the cam gears until you get as close to the events as possible.

The jwt cam gives valve timing events, but doesn't say what lift they were measured at. After a lot of measuring, i figured out that the adv duration and events were measured at a very low lift. and .001 gave me the proper duration.

If the card doesn't give valve events, but gives lift at tdc you can use this to degree the cams. (kelford gives these specs as well)

Centerlines should be a last resort to dial in the cams.

Ideally you should use the cam gears to get the cam as close to the card as possible. Changes should be made on the dyno, because what works for one setup won't work for another. My car is definitely going on the dyno to dial in the cams (some day).

[turbonola]

where do you dyno at? corr?

[Kfred]

where do you dyno at? corr?

Probably not. Jay is a cool guy, but thats a good drive for me to either location.

I have a friend that works at a honda shop in the Prairieville/BR area that can rent me a mustang dyno for $50/hr. If they are booked i'd go to TPS (total performance solutions), a mustang shop.

[turbonola]

oh ok

[ILuvS13s]

Ok I want to clear up a few things before this post gets out of hand. I do not want to disprove anything, I just want to make sure we get information that is linier and not subjective to incorrect interpretation.

First off you said

Because most import cams are measured at 1mm lift, i used this so i could compare. At 1mm lift the jwt cams have a duration of ~222*, which is pretty much equivalent to kelford stage 1 (256/264) cams

This is true. Most import cams do say to degree using 1mm of lift. The JWT cam card, however, states 222* lift @ .050 not 1mm, and .050" = 1.27mm Now the differences will be miscule.. so give or take a couple of degree or so. .27mm from 1mm is just not alot.

Using .001" of lift I was able to get data that corresponds to the cam-card.

Did you use 1mm or .001" ? The main reason I ask is because most dial gauges sold degree kits in the US are in inches. The industry standard for initial valve opening is read @ .050". This being said Imported cams usually say to take the measurement @ 1mm of lift, as you stated. Now here's the problem I see. 1mm = .03937" which can be rounded up to .040"

If you took your measurements, in fact, at .001 inches instead of .040 inches, then I beleive that your readings are correct, but the relation to TDC on the cam card is not.

*edited for misunderstanding the intent of original post*

[Kfred]

This is true. Most import cams do say to degree using 1mm of lift. The JWT cam card, however, states 222* lift @ .050 not 1mm, and 1mm = 1.27mm Now the differences will be miscule.. so give or take a couple of degree or so. .27mm is just not alot.

Now it is intriguing that the readings that you got were pretty much on point, and I cannot argue with that fact. So if you can please respond to this so we can figure out what is going on here, I'd be elated.

I think you mean .050"=1.27mm, and this .27mm does change the valve events and duration noticeably.

I am an engineer and I am always very specific on which units I use. I am very aware that 1mm = .03937", and this is what i used to get my 222deg of duration at 1mm lift figure. I tried to get the dial guage as close to .0394 as possible. At .050" lift my duration measured was quite less than 222, it was around 213-215. This is pretty much the same duration that adam measured at .050" lift with his jwt cams.

I found tdc using a piston stop and the dial indicator method and they were both spot on. If you enter the the valve events on the cam card into a calculator you can obviously see that the valve events were recorded at the lift that the advertised duration was measured at.

I figured the advertised duration were taken at .000" lift, or some .00x" lift where x is an integer. Only .001" gave me the advertised duration and really close valve timing events, especially since i was expecting them to be retarded a few degrees due to my milled head.

[Kfred]

You are using too many blanket statements. We should measure our cams at .001", we should measure our cams at .0394", and we should measure our cams at .050"....

If you have kelford cams it would be absolutely ignorant not to measure your valve timing events at 1mm (.0394") and degree the cam accordingly. Then once you adjust your cams, measure your valve lift at tdc and make sure they agree with the cam card. Kelford has a great cam card.

Brian crower lists valve timing events, but doesn't list what lift they are taken at. If I had to guess i'd say they are at .050" lift, but i'm not sure.

[ILuvS13s]

A simple typo im sorry. I was just making sure that you were taking those measurements at 1mm lift. thats all. Some people dont take into consideration the metric to std conversions necessary. Also BC takes their lift measurements at .050" I beleive. This is why I degreed my BC V2s @ .050". I will call them today to see where they actually took their valve events from.

As I said I was not trying to disprove you, but trying to add information and make sure our facts cooincide, which I obviously did quite poorly due to my typo. I will edit that later when I get back from work.

The reason I am so interested in this, is that I have a How To to edit once a solid conclusion is drawn. Thanks for all the info man.

[ILuvS13s]

Ok so I talked to Dustin @ Brian Crower today. I asked him at what lift, at least on the BC cams, that they are using to get their valve timings. He said take them at .050".

I have never seen any cam company specify valve events at .001" of lift. Maybe someone should call JWT and ask them why they did so. After all, as I stated before, the industry standard measures valve movement starting at .050", this is a fact.. not a blanket statement. The only reason I suggest otherwise is for imported cams which specify to measure lift at 1mm.. which can equate to roughly .040" instead of the traditional .050".

Also I found out that the BC cam cards with the ka24de cams where indeed wrong. Dustin said the guy that took the measurements did them with the wrong gears. They have corrected the issue.

I am going to make a new post dedicated to passing around the correct cam card. So look for that in the KA-T Basic forum.

**edit** - viewtopic.php?t=48531

[ILuvS13s]

One thing I've noticed about the JWT cam card. It says that the intake is supposed to open ATDC not BTDC like you have listed KFred. The Exhaust is supposed to close BTDC not ATDC like you also has listed.

Our engines spin clockwise, so there is no way the IVO should be mistaken as BTDC when the number taken is on the left side of TDC.

There is one problem that I cant shake about the JWT cam card. The timing events that it lists do seem to be taken at low lift. You were correct in this KFred. This is the only way you can get numbers like that. But here's the problem I have. Since the cam card lists IVO as ATDC that number should have been negative and the same goes for EVC. So the numbers on the cam card should look like this.

-12 atdc
77 bbdc

72abdc
-20 btdc



But if you plug them in as such, you get a number that is WAYYY skewed. The numbers would have to be entered as positive to get the correct results. Which you did. The results that are listed on the cam card put the duration @ 272. These numbers are correct for finding the total lift of the cam. These, however, are NOT the correct timing numbers used to measure when the valves begin to open and close.

The numbers on the cam card were taken at .001" lift and SHOULD HAVE to be listed as IVO BTDC and EVO ATDC on the cam card, to be correct. Just like you have listed KFred. They are not. The numbers listed on the cam card were not taken at either .050" or 1mm lift, that is true. The numbers on the card, when the math is done, do not show duration @ .050 lift either. It, once again, shows total lift.

If I do the math on the new correct BC cam card, the numbers come out perfectly to spec.

Your cam has an Overlap of -11.00 degrees and has in Intake Duration of 226.00 degrees.
The Exhaust Duration is 226.00 degrees.
The Inlet Cam has an Installed Centerline of 121.00 degrees ATDC.
The exhaust cam has an Installed Centerline of 116.00 degrees BTDC.



Kelford lists their 272 cams as such.

IVO 6 BTDC
IVC 46 ABDC
EVO 52 BBDC
EVO 0 BTDC

If you do the math on those events, the math come out perfectly.

Your cam has an Overlap of 6.00 degrees and has in Intake Duration of 232.00 degrees.
The Exhaust Duration is 232.00 degrees.
The Inlet Cam has an Installed Centerline of 110.00 degrees ATDC.
The exhaust cam has an Installed Centerline of 116.00 degrees BTDC



My conclusion: The JWT cam card is incorrect for the following reasons. The valve openings listed were taken at .001" which shows the total lift of the cam, not the valve opening points. The cam card also lists the incorrect openings in relation to TDC.

The timing events listed on the JWT cam card should have been written for .050" lift. When the math is done on the card, this should show the duration at .050" lift; like is specified (222 DUR @ .050" lift). This is not the case, however. There is no way to find DUR @ .050" lift with the numbers that JWT has listed on that cam card. Can you find them on your own? Yes and you did that, but thats not the point. I am a little bothered though that you got 222* DUR @ .3937" lift instead of the specified .050" lift on the JWT cam card.

The numbers on the cam card are simply incorrect. Correct for finding total lift, but not for finding when the valves actually start to open.

So KFred you are correct. But the cam card as it is, is not.

[Kfred]

I talked to jwt this morning and they said the valve events measured are at a very low lift, but they didn't know what lift off hand. One of the engineers said it is probably around .001" but he couldn't give me the exact figure.

He did give me one very important piece of information though, he said that the cam has a perfectly symmetrical lobe. This means using the centerline method on these cams will work. He recommended I measure the cams at a few different lifts and make sure I get the same centerlines (i did this already) and adjust them until I get the desired centerlines.

Don't let the diagram shown fool you. That is just the way most companies do their card. American engines spin CW, and go look at their cam card diagrams, same thing.