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Cam Phasing - An Easier Way

7K views 25 replies 7 participants last post by  eschaider 
#1 ·
ModMotors bring a variety of new challenges to the engine builder. One of the more painful is cam phasing. I have followed the tried and true path most of us have or are following in our engine builds. During this death by a thousand cuts, it occurred to me there was an easier route available to us that I have never heard anyone suggest - so I am going to.

This approach uses a homemade fixture and an Excel Spreadsheet to dramatically shortcut the entire process. To start out, you will need to fabricate a fixture to hold two dial indicators simultaneously and a TDC tool to make finding TDC easy and accurate, and that's about it.

This is what the homemade fixture for the dial indicators looks like. This is the front view;

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And this is the back view;

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The split collet gizmos for locating the dial indicators are Starrett items and, as you might guess, come at a relatively dear price of $25 to $30 each, depending on where you buy them.

The fixture itself is very simple. It bolts to the head at the cam cover attaching screw holes. I used two chunks of aluminum for the indicator mounts and sized them to place the indicator probes just above the valve stem on the tip of the cam follower. To make angle selection easy, I used a small stud and wing nut to snug the fixture down so it would not move around during cam phasing.

The next homemade tool you will need is a ModMotor-specific TDC tool long enough to stand above the sparkplug well when installed in the head. I took a spark plug, removed the porcelain, and machined an aluminum shaft to push in and protrude into the chamber an inch or so to stop the piston before it reaches TDC. This is what it looks like;

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When you install it in the head, this is what It looks like;

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This makes it very easy to install and remove the TDC tool whenever you need to check your TDC mark on the degree wheel.

I like the Jomar-style degree wheels. Mine is a 40-year-old version. The Jomar approach to degree wheels uses a collet held to the snout of the crank by the crank stud. The collet has a jam nut to lock the degree wheel wherever you wish. I built a homemade TDC pointer gizmo out of a dial indicator swivel clamp, two lengths of mild steel rod, and a $1.50 block of optically clear plastic from Tap Plastics. This is what the pieces look like;

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And this is what it looks like on the engine block;

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OK, now to the fun part. There is a downloadable XL spreadsheet at the end of this post that I built to take the burden of doing all the math off your shoulders as you are trying to phase your cams. The spreadsheet has one worksheet for the passenger side cams and one worksheet for the driver's Side cams. Start with the driver's side. It will make your life easier. Use cylinder #6 for phasing. Again it will make the job easier. This is the Driver's Side Cam Phasing Worksheet;

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The only numbers you need to enter are the 0.050" before max lift crank position number and the 0.050" after max lift crank position number. The spreadsheet does the rest for you. The spreadsheet will also accommodate the now unavailable Cloyes 9-Way secondary sprockets if you are fortunate enough to have them.

Let's put some numbers in. You only enter data into the yellow cells; all the green cells are calculated for you. The first thing we want to do is put the cams in straight up with all the 9 ways, and the hex adjust set to 0. When everything is set to zero, and the pre and post-max lift points are entered in crank degrees, this is what we get;

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Remember you only enter the data into the four yellow cells. The spreadsheet will calculate the individual lobe centerlines for both the intake and the exhaust, along with the lobe separation angle (LSA) and how much the cams are advanced or retarded, in this case, 0.75˚ retarded.

Let's say that I wanted the engine for a street-use vehicle, so I am going to look for somewhere between zero and -10˚ of overlap so my idle bypass still works reasonably well. Using Mark Olson's great CamCharting tool, we find the following phasing will provide a -3.5˚ overlap target.

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Marks CamChart tool confirms an LSA of 114˚ advanced 2˚ will provide -3.5˚ of overlap and open the intake valve at exactly TDC.

Soooo, what do we do now?

Time for the Cam Phasing Worksheet. We already know the cams are at a 109.25˚ LSA with everything set at 0. We want to be at an LSA of 114˚ so let's do this,

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By installing the Cloyes 9-Way intake sprocket in the 4˚ retard position, we can open up the LSA from 109.25˚ to 111.25˚. Cloyes only provides +/- 4˚ of freedom with their sprockets, which means we are still 2.75˚ from our 114˚ LSA target.

If you use another Cloyes 9-Way adjustable sprocket on the exhaust cam, it will not change the exhaust phasing, but it will change the secondary drive chain phasing with respect to the intake cam. This time though, the changes are counterintuitive. Installing the sprocket in a retarded position on the exhaust actually advances the intake cam and vice versa if you use the advance settings.

Let's take the Exhaust 9-Way and advance it 4˚, which is the equivalent of retarding the intake 4˚ and increasing the LSA by 2˚. This is what it will look like;

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Now we are at a 113.25˚ LSA. Because of the indexing limits on the 9-Ways of +/- 4˚, this is as close as we are going to get to a 114˚ LSA. We are still confronted with the fact the cams are retarded 4.75˚. To fix this, we need to advance both cams by 4.75˚. The Cloyes Hex-Adjust range of adjustment, as specified by Cloyes, is +/- 4˚; however, most Cloyes timing sets can sneak up on a +/- 5˚ adjustment range. Let's set our Hex-Adjust all the way toward its advance limit of 5˚. When we do that, the Cam Phasing Worksheet will look like this;

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Now we have the cams at a 113.25˚ centerline with a 0.25˚ advance. We wanted a 2˚ advance, but that was not in the offing because of the Hex-Adjust design. Cloyes elected to make the range of adjustment on the Hex-Adjust +/- 4˚. To reach our 2˚ advance target, we would need an additional 4˚ increase in the range of advance from +/- 5˚ to +/- 7˚.

A crank sprocket has 21 teeth on it which means each tooth is the equivalent of 360/21 or 17.14˚ of crank rotation. To avoid getting caught without enough adjustment range, the hex-adjust would need to have a range of +/- 8.57˚ or one-half of the angular displacement in each direction of a single tooth on the crank sprocket. Because 8.57˚ is a clumsy number to work with, the range ought to be set at +/- 9˚ or a little more than twice what Cloyes has provided.

Currently, there is no clean fix for the reduced range of adjustment with the Cloyes hardware, and like the example above, the enthusiast would have to settle for close to but not precisely what was he was looking for. To be fair, this shortcoming does not usually manifest itself but can, as it did here. Whether or not it will affect your install depends on how the cams were ground and where you elect to install them. All things being equal, the Cloyes package is still the best available for our engines today - even if some parts are hard to come by.

Most significantly, from an effort on the builder's part perspective, the entire cam phasing process has required only two measurements. The first was the initial look-see with the cams installed at zero on all the hardware to get your starting point. The second and last install was to set the cams as close as physically possible to your target phasing and then confirm their phasing with one last measurement. You follow this process once for each bank, and you are done. When you compare this to the hours of repeatedly installing, measuring, making calculation mistakes on paper, reinstalling, and remeasuring to achieve the same result - this is clearly the much easier way to get the job done.


Note: This file has been previously downloaded 25 times. If you downloaded it before Friday, July 26, 2019, Please download it one more time. This version of the file has updates and is configured to behave like a template giving you a tablet-of-paper sort of experience. When you save each new model, you will be asked to give it a new file name to distinguish it from the earlier files you saved and not overwrite them.
 

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#3 ·
This type of information sharing is how these websites can lighten the load on all of us, Robert. If we share the success stories we each experience at different times in our builds, everyone wins. And it should go without saying that there is usually more than one way to do many of the things which means just because someone already threw a good idea up on the site, there is no reason someone else cannot add to the treasure trove with yet another perspective.
 
#6 ·
Thanks for the props Jonathan. The pain and suffering associated with the usual approach has had me thinking of this for some time now. I put it to work last weekend and it was a breadth of fresh air. The process went from tedious and aggravating to well under an hour start to finish. I should have timed it just to have the numbers but it was stunningly easy.

One of the important things to remember to do is use square keys that have an intimate fit with the various cams and gears. If you don't the process is still doable you just need to maintain a tension on the chain drives like they see with the engine running. If the keys are allowed to wander in the keyways and gears the phasing job becomes more tedious.

Be sure to download the new version of the Cam Phasing Workbook I posted and discard the original if you downloaded it already. It had some development construct artifacts that I forgot to remove from the software. The Rev 1.1 version of the software is clean.
 
#5 ·
If you were one of the 9 members that downloaded a copy of the original Cam Phasing Master Workbook before the date of this post please download it one more time. The original which you first downloaded still had some development constructs in it. The current version is properly configured. The correct version of the tool is Rev 1.1 and the heading at the top of each page has been renamed from Worksheet to Workbook. you will find the Revision number in both the file name and also the banner at the top of each page.

The Revision 1.1 copy of the tool will open as a read only file. Do not be concerned by this. I did this to allow you to save individual copies of each cam phasing event as an individual file so you would have a cookie crumbs sort of trail to follow if you ever needed to. Additionally by requiring a save of each new file under it's own name you maintain the integrity of your template for future use. Each file you save under a project specific name is editable and resaveable under that same name. Even though you can use the same name I would encourage you to use names that you add revision numbers to inorder to leave yourself that cookie crumb trail to backtrack with just in case you ever need to.

My sincere apologies for the misconfigured original. Please download the replacement. Everything still works as indicated in the writeup in my post #1 above.
 
#7 ·
This is fantastic Ed. I (as I’m sure many others) are blessed to have you here (and a number of other members as well) on Modfords. The time and effort you continue to put in and the work and fruits you share with everyone is priceless in this hobby. I am getting my ducks in a row but will definitely be putting this method to use within hopefully a few months. I will be sure to start a build thread when I finally start putting the collection of parts and pieces together I have been collecting. It’s stuff like this and build threads like Jrgoffins and the countless other members who have documented the ups and downs when building these motors that keeps me coming back daily to check on anything new. I truly wish we just still had the traffic we used to have here before the facespace or mybook thing took over. I don’t use those and probably never will do I’ll continue to check on things here and add what ever I can when the time comes.
Thank you and everyone else who still shows up and contributes to our great hobby!

Ken
 
#8 ·
This is fantastic Ed. I (as I'm sure many others) are blessed to have you here (and a number of other members as well) on Modfords. The time and effort you continue to put in and the work and fruits you share with everyone is priceless in this hobby. I am getting my ducks in a row but will definitely be putting this method to use within hopefully a few months. I will be sure to start a build thread when I finally start putting the collection of parts and pieces together I have been collecting. It's stuff like this and build threads like Jrgoffins and the countless other members who have documented the ups and downs when building these motors that keeps me coming back daily to check on anything new. I truly wish we just still had the traffic we used to have here before the facespace or mybook thing took over. I don't use those and probably never will do I'll continue to check on things here and add what ever I can when the time comes.
Thank you and everyone else who still shows up and contributes to our great hobby!

Ken
Thanks for the props, Ken. I think you will enjoy using the Workbook. It substantially reduces the PITA grief normally associated with the job.

A lot of the original guys from the site have sold their cars and bought newer rides to replace them so we don't see much of that crowd any more. Others that like the jousting and back and forth of the social media scene find those communities a better fit. Most of the guys still around here tend to be more of the hands on type of enthusiasts (like you) with both race track operation and street use for that special attitude adjustment time you can only find in one of these type of vehicles.
 
#10 ·
Wow! What can I say, Ed . . . THANK YOU just doesn't seem to be enough. I am new to the Mod motor so I need to re-read this a few times before the impact of your method sinks in. I hope I can make contributions in the future.
All the very best.
Glad to be able to help saltfever.

Where in NorCal are you located, I'm a little South of SJ in Gilroy.
 
#12 ·
C heads will not have any fitment issues. The OEM main caps are more than fine, save your money and put it elsewhere in the build. Also, OEM primary chains are fine. The chains you will want to upgrade are the secondary chains. You can purchase them from Accufab.
 
#13 ·
Everything Russ said is spot on saltfever.

Ford and the aftermarket do make two different primary chains for 4.6L engines. One chain is for the 03/04 SVT Cobra and the other is for everything else. The Cobra chain is referred to as a fine finish chain but beyond chain finish it is constructed differently. Here are pictures of the two side by side,

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The chain on the right is the proletariat grocery getter model. The chain on the left is the fine finish 03/04 SVT Cobra chain. The two should be distinguished by the vehicle vin code. The Cobra code is VIN Y. Be sure to do a visual check before you leave the store.

A bit more trivia that is helpful is discriminating between the two. If you look in the picture the fine finish chain has 8 links and the proletariat chain has 9. The fine finish chain groups its links in pairs of two and the proletariat chain sometimes does and other times does not. Even though the fine finish chain has one less link it is the stronger chain. My guess, and it's only a guess, is that the links may be made of a higher strength steel and possibly are thicker. Without measuring the two side by side, link thickness is hard to tell from the picture but does appear to favor the fine finish chain.
 
#18 ·
Everything Russ said is spot on saltfever.

Ford and the aftermarket do make two different primary chains for 4.6L engines. One chain is for the 03/04 SVT Cobra and the other is for everything else. The Cobra chain is referred to as a fine finish chain but beyond chain finish it is constructed differently. Here are pictures of the two side by side,

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The chain on the right is the proletariat grocery getter model. The chain on the left is the fine finish 03/04 SVT Cobra chain. The two should be distinguished by the vehicle vin code. The Cobra code is VIN Y. Be sure to do a visual check before you leave the store.

A bit more trivia that is helpful is discriminating between the two. If you look in the picture the fine finish chain has 8 links and the proletariat chain has 9. The fine finish chain groups its links in pairs of two and the proletariat chain sometimes does and other times does not. Even though the fine finish chain has one less link it is the stronger chain. My guess, and it's only a guess, is that the links may be made of a higher strength steel and possibly are thicker. Without measuring the two side by side, link thickness is hard to tell from the picture but does appear to favor the fine finish chain.

Ed
Does anyone have a part number that is verified for the polished chains? I looked on the Advance Auto parts site and their photo of the Cobra VIN Y chain looks to be but not sure if it is what I will receive. Their PN is A5100324084OEA. All others look to be the standard 4V Ford replacement 5W7Z-6268-AA. Thanks.
 
#19 ·
Accufab is trustworthy.

Not always the least expensive but always the right stuff at a reasonable price. You should not have any doubts about what they say or sell. Quality people, quality operation, quality parts.
 
#20 · (Edited)
Accufab is trustworthy.

Not always the least expensive but always the right stuff at a reasonable price. You should not have any doubts about what they say or sell. Quality people, quality operation, quality parts.

Ed
Ed, Dhenderson,

These look to be the correct chain to me.

https://accufabracing.com/ford-mod-motor/4.6l-timing-chains-ford

Also, on RockAuto Cloyes Part No. C387 or Melling 387 look to be correct as well. Fraction of the price from Accufab. I have attached a photo.

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#21 ·
Robert,

The chains you have found at RockAuto have (for the most part) the correct image in the picture. They are not organized by Ford VIN number. Most resellers use VIN number for positive identification.

That said the Cloyes picture seems correct although they do not make the VIN number association. The Cloyes picture seems to show the outer face of the chain as not having the same fine finish that OEM Ford chains for the engine have - something to be cautious about. The other place the fine finish was originally used was on the face of the plates to make for a more supple chain as it rounds the gears, in particular the 21 tooth crank gear.

The Melling chain (again if the picture is correct) has square cut load bearing links w/o a visible fine finish, anywhere. Once again the picture may not reflect the part they ship but why play high stakes poker when you don't have to.

dhenderson,

The chain you have found carries the important VIN Y designation so I would expect it to be the correct chain. The only way to be certain however, is to see it with your own eyes.

For both of you guys I would ask the question why have you decided not to use Ford OEM parts from Ford for your engines? You can order them from Tasca and know the stuff is right. The guy to talk to over there is Steve Powell. Steve will provide you with the lowest price on OEM parts you are likely to be able to find anywhere, especially if you tell him you are from ModFords. If you are shy Steve knows me well, just tell him I sent you. This is Steve's phone number 401.709.7845‬. That number goes directly to Steve.
 
#23 ·
. . . You can order them from Tasca and know the stuff is right. The guy to talk to over there is Steve Powell. Steve will provide you with the lowest price on OEM parts you are likely to be able to find anywhere, especially if you tell him you are from ModFords. If you are shy Steve knows me well, just tell him I sent you. This is Steve's phone number 401.709.7845‬. That number goes directly to Steve.
Thanks for that info, Ed. Up till now I hadn't found a good, repeatable contact for 4.6 stuff. MMR & Accufab seem like sources for custom fab parts but many times OEM Ford parts can't be beat.
 
#24 ·
They are supposed to be a better cam follower, Kirk. That said there are lots of guys who run their engines at 8500 to 9000 rpm using the original cam follower. If I had all my other parts covered and there was $600 burning a hole in my pocket I might consider spending it on those pieces - but probably not.

A number of years ago the Ford / Riley team, using Roush-Yates Modmotor powered Daytona Prototype cars appeared for the 50th running of the Rolex 24 Hour race at Daytona. No one paid any attention to the effort. Part of that was probably because R-Y had published some power figures for the engines that were not all that impressive. In fact a baseline Coyote engine today comes off the showroom floor with more horsepower. IMO R-Y was sand bagging but who knows, that was a half dozen years or so ago.. The race was widely expected to be won by a BMW or GM LS powered car.

For those unfamiliar with Daytona Prototype cars, IMSA, the sanctioning body describes them as the fastest and most technologically advanced sports cars in North America, the Daytona Prototype cars are specifically designed and engineered for the race track. DP cars use a tube chassis built to international specifications, powered by engines from mainstream automotive manufacturers.

By the time qualifying was over, the R-Y powered cars had nailed down the top qualifying spots - they were fast and it wasn't a flash in the pan sort of performance. By the end of the race, the R-Y cars had finished 1-2-3, sort of reminiscent of LeMans and Shelby decades earlier. I vaguely remember a comment someone made about the R-Y powered cars. While I can't recall the exact words anymore, the essence of the comment went something along the lines of, racing against them was like racing against an F-1 powered car or words to that effect.

By the time a pushrod engine had peaked in its power curve the R-Y powered cars supposedly still had another 2000/2500 usable rpm left. This went on for hours, 24 hours! I could be wrong but I don't believe those fancy $600 cam followers existed yet! I think it is perhaps less a matter of do you need them and more a matter of a do you have a $600 wad of money burning a hole in your pocket. There is plenty of other important engine stuff to flatten your wallet without resorting to those.

For those inquiring minds, this was a Roush-Yates ad for the engines back then (check out the R-Y advertised power rating);

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and this is what the cars they went into looked like;

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Interesting times, impressive DNA ...
 
#25 ·
Ed I checked the online auto parts store because you said: "The question about the primary chain selection is answered by the fact they are available over the counter at virtually all Auto Parts stores. You want to get the fine finish chain that is used on the 03/04 SVT Cobras. That chain is identified in the parts catalogs as being for the VIN Y vehicle code cars, which are by default the 03/04 SVT "The chains Ford sells now for the 04 Cobra is 5W7Z-6268-AA which is the stronger chain design but without the polished finish. I was specifically looking for the polished chains. However if they are no longer available from anyone I will just buy the Ford OEM chains. They are $54 each from Tasca, much cheaper than the Accufab primary chains, which appear identical to the oem. If the Accufab's are better please correct me.
 
#26 ·
Your instincts were on target, the Ford driven aftermarket however, has made finding certain parts tougher than in the past. The fine finish is good to have if you can find it. In general the chain suppliers stop providing a part when the market or the manufacturer discourages it. The most important consideration is the link construction / arrangement. The VIN Y chains have the configuration you want. Sometmes the online auto parts stores find a way to sell them very inexpensively, sometimes not. Steve at Tasca will provide you the chains as inexpensively as just about anywhere and they are OEM quality. I would not give a second thought to looking elsewhere if Steve has the original component available.

The Accufab primary chains are necessarily sourced from the same chain vendors as everyone else. The market for this stuff is pretty smalll, which means the same chains. Go for the less expensive OEM chain from Steve at Tasca.
 
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