Re-Degree My Cams from 264's - 272's?

[PredatorSniper]

I bought my 92 GSX and it has HKS 264s in the car. The car already has adjustable cam gears and I assume they have been degreed. Question is, when I go to the 272s, can I just bolt them in or will i have to degree them?

 

[synthetek]

look at your cam gears, if the markings are at 0 then they are not degreed.

 

[YZFR1]

, can I just bolt them in or will i have to degree them?

The best way to answer your question is to do some research on the kind of cams you are looking at and try and find out if it is common or not for the particular cams be out of specs.

Any good cams for the most part will be within specs without degreeing, like my gsc s2's were spot on even though i had plenty of machine work done, i've also heard of some regrinds being off by as much as 8 degrees. So, it just depends on what you are getting.

 

[PredatorSniper]

They have been degreed, so when I go to the new HKS 272 can I leave the cam gears alone or do I have to degree specifically for the 272's?

 

[Boostdriven]

How much adjustment is there on your 264s ?

If you don't have the tools to degree the new cams I would say set the cam gears to 0. If the cams are close to where they need to be you should see somewhere between 11-14 inches of vacuum at idle (1000) rpms. If you see less then 10 or more then 15 I would say you should get them degreed.

There is fairly simple way of doing it yourself, all you need is a dial indicator, you can do this with out a degree wheel. Make sure you have a cam card for those 272s because you will need to know where to set those cams.

When you get the cams in and set to 0 start the car and let it warm up for a bit, once the car is idling around 1000 rpms check your vacuum and see what numbers your seeing. You might need to change some numbers in your VE table at idle to get the car to idle correctly.

So let's say your vacuum at idle is 8 inches which is a little low or 16 inches which I think is a little high. While your engines is still warm take your valve cover off and set your engines to TDC on cylinder #1 with both intake and exhaust valves closed. You will use your timing marks on the timing belt cover to degree your cams. As you know there are marks on the timing cover 10....5....0 or T for TDC. You will have to make a new mark on your cover with a pencil or a marker. Add a new mark after 0 at a estimated 5 degree mark. I'm sure you can eye ball that same size gap as it is between 10-5 and 5-0 so your new mark will be 0-5, 5 being ATDC. When you look at the cam card for those cams you will see the degree #s at which each cam will open and close. Doing little bit of research on line this is what I found for hks 272s.

272 Intake Max Valve Lift - 10.3mm (0.4055")
Intake Valve timing at 1mm (0.0394")
Valve opens at 6 deg BTDC
Valve closes at 32 deg ABDC
Valve Centerline 103 deg
Duration at 1mm lift 218 degrees

272 Exhaust Max Valve Lift - 9.8mm (0.3858")
Exhaust Valve timing at 1mm (0.0394")
Valve opens at 36 deg BBDC
Vavle closes at 2 deg ATDC
Vavle Centerline 107 deg
Duration at 1mm lift 218 degrees

So once you have your engine set to TDC and the valve cover off the engine, set your dial indicator on top of the exhaust valve retainer of cylinder #1. If you look at the cam specs you can see the your exhaust valve should still be a little bit open since it has a 1mm lift at 2 degrees ATDC. Once the dial indicator is set, turn the engine clockwise to the new estimated 2 degree mark on the timing cover. Loosen up the bolts on the cam gear and move it clockwise causing the exhaust valves to close 100% double check to make sure the crank didn't move and its still at your new mark of 2 degrees ATDC. Now set your dial indicator to 0 and take your exhaust cam and slowly start turning counter clockwise (backwards) causing the exhaust valves to open back up, watch your dial indicator and stop turning the cam once it reads .040 or 1mm. Tighten up the cam gear bolts. At this point you have set the closing point of your exhaust cam which is 2 degrees ATDC at 1mm lift which means that if the cam has 218 degrees of duration at 1mm lift it will begin to open and will be at 1mm lift at 36 degrees BBDC 2+180+36=218

Same process applies to setting up your intake cam. According to the cam card, the intake cam should be at 6 degrees BTDC at 1mm lift. Set the timing mark on the crank pulley to 6 degrees BTDC, basically just before the 5 degree mark on the timing cover. Loosen up the cam gear bolts on the intake cam, turn the intake cam counter clockwise (backwards) making sure that intake valves on cylinder #1 are 100% closed. Double check to make sure the crank didn't move and still is on the 6 degrees BTDC mark. Place the dial indicator on top of the retainer of one of the intake valves on cylinder #1 and set it to 0. Now turn the cam clockwise causing the valves to open and watch the dial indicator. Stop turning the cam as the dial indicator reaches .040 or 1mm, tighten up the cam gear bolts. At this point you have set the opening point of 1mm lift at 6 degrees BTDC. If the intake cam has 218 degrees of duration that means 218-180-6=32 which is where the cam card shows for the intake cam to close or have 1mm lift about to close.

I'm sure that's not the best way to degree the cams and having the engine out of the car with a degree wheel would be much better but I've done this on several cars with great success. Hope this helps you out.

 

[PredatorSniper]

How much adjustment is there on your 264s ?

If you don't have the tools to degree the new cams I would say set the cam gears to 0. If the cams are close to where they need to be you should see somewhere between 11-14 inches of vacuum at idle (1000) rpms. If you see less then 10 or more then 15 I would say you should get them degreed.

There is fairly simple way of doing it yourself, all you need is a dial indicator, you can do this with out a degree wheel. Make sure you have a cam card for those 272s because you will need to know where to set those cams.

When you get the cams in and set to 0 start the car and let it warm up for a bit, once the car is idling around 1000 rpms check your vacuum and see what numbers your seeing. You might need to change some numbers in your VE table at idle to get the car to idle correctly.

So let's say your vacuum at idle is 8 inches which is a little low or 16 inches which I think is a little high. While your engines is still warm take your valve cover off and set your engines to TDC on cylinder #1 with both intake and exhaust valves closed. You will use your timing marks on the timing belt cover to degree your cams. As you know there are marks on the timing cover 10....5....0 or T for TDC. You will have to make a new mark on your cover with a pencil or a marker. Add a new mark after 0 at a estimated 5 degree mark. I'm sure you can eye ball that same size gap as it is between 10-5 and 5-0 so your new mark will be 0-5, 5 being ATDC. When you look at the cam card for those cams you will see the degree #s at which each cam will open and close. Doing little bit of research on line this is what I found for hks 272s.

272 Intake Max Valve Lift - 10.3mm (0.4055")
Intake Valve timing at 1mm (0.0394")
Valve opens at 6 deg BTDC
Valve closes at 32 deg ABDC
Valve Centerline 103 deg
Duration at 1mm lift 218 degrees

272 Exhaust Max Valve Lift - 9.8mm (0.3858")
Exhaust Valve timing at 1mm (0.0394")
Valve opens at 36 deg BBDC
Vavle closes at 2 deg ATDC
Vavle Centerline 107 deg
Duration at 1mm lift 218 degrees

So once you have your engine set to TDC and the valve cover off the engine, set your dial indicator on top of the exhaust valve retainer of cylinder #1. If you look at the cam specs you can see the your exhaust valve should still be a little bit open since it has a 1mm lift at 2 degrees ATDC. Once the dial indicator is set, turn the engine clockwise to the new estimated 2 degree mark on the timing cover. Loosen up the bolts on the cam gear and move it clockwise causing the exhaust valves to close 100% double check to make sure the crank didn't move and its still at your new mark of 2 degrees ATDC. Now set your dial indicator to 0 and take your exhaust cam and slowly start turning counter clockwise (backwards) causing the exhaust valves to open back up, watch your dial indicator and stop turning the cam once it reads .040 or 1mm. Tighten up the cam gear bolts. At this point you have set the closing point of your exhaust cam which is 2 degrees ATDC at 1mm lift which means that if the cam has 218 degrees of duration at 1mm lift it will begin to open and will be at 1mm lift at 36 degrees BBDC 2+180+36=218

Same process applies to setting up your intake cam. According to the cam card, the intake cam should be at 6 degrees BTDC at 1mm lift. Set the timing mark on the crank pulley to 6 degrees BTDC, basically just before the 5 degree mark on the timing cover. Loosen up the cam gear bolts on the intake cam, turn the intake cam counter clockwise (backwards) making sure that intake valves on cylinder #1 are 100% closed. Double check to make sure the crank didn't move and still is on the 6 degrees BTDC mark. Place the dial indicator on top of the retainer of one of the intake valves on cylinder #1 and set it to 0. Now turn the cam clockwise causing the valves to open and watch the dial indicator. Stop turning the cam as the dial indicator reaches .040 or 1mm, tighten up the cam gear bolts. At this point you have set the opening point of 1mm lift at 6 degrees BTDC. If the intake cam has 218 degrees of duration that means 218-180-6=32 which is where the cam card shows for the intake cam to close or have 1mm lift about to close.

I'm sure that's not the best way to degree the cams and having the engine out of the car with a degree wheel would be much better but I've done this on several cars with great success. Hope this helps you out.

I bought these cams used but with low miles. Do I need the cam card specific to this batch of HKS 272s or do all HKS 272 have the same cam card?

 

[Boostdriven]

I bought these cams used but with low miles. Do I need the cam card specific to this batch of HKS 272s or do all HKS 272 have the same cam card?

I'm not sure if there are different hks272s, I would imagine that they are all the same but regardless if they are the same or not when you use that method of degreeing cams you are setting up one point of the cam and the other point of the cam is determined by the cam size itself.
Where the intake valve opens and where the exhaust valve closes determines the overlap and overlap is where piston and valves come close to each other. In the case where the intake valve is to advanced or the exhaust valve to retarded you run a higher risk of hitting the valves with a piston. Using this method sets up your overlap for you because you set when the exhaust will close and where the intake will begin to open.

I would say its safe to use those cam specs for those 272s you got.

 

[Zack Huffman]

The best way to answer your question is to do some research on the kind of cams you are looking at and try and find out if it is common or not for the particular cams be out of specs.

Any good cams for the most part will be within specs without degreeing, like my gsc s2's were spot on even though i had plenty of machine work done, i've also heard of some regrinds being off by as much as 8 degrees. So, it just depends on what you are getting.

This is pretty good advice. Just imagine if one cylinder is off by 8 degrees and the next one on that cam is off by 8 in the other direction. -But there is more to consider than just the cam manufacturer's QC tolerance. For most quality cams, it's not going to be off so much that it really matters, especially if you tune your cam positions for your own desires and not just try to match the cam card on cylinder #1.

They have been degreed, so when I go to the new HKS 272 can I leave the cam gears alone or do I have to degree specifically for the 272's?

You should really consider redoing it.

...
I'm sure that's not the best way to degree the cams and having the engine out of the car with a degree wheel would be much better but I've done this on several cars with great success. Hope this helps you out.

That's pretty good. The only thing I'd like to add to that is to double check that you really do have the piston actually at TDC, the stock rubber dampers on these cars like to separate and move around. Also, using this method, it would be important to get the dial indicator perfectly in line with the valve's shaft for accuracy of measurement, otherwise the event on the other side of the lobe wouldn't occur where you thought.

I bought these cams used but with low miles. Do I need the cam card specific to this batch of HKS 272s or do all HKS 272 have the same cam card?

They have the same card. It's up to you to try to make your particular shafts meet all the specs on it or not.

 

[AllanL]

these might help as well...

Effect Of Changes In Cam Timing And Lobe Separation Angle

http://www.dsmtuners.com/forums/art...ing-dummies-understanding-what-happening.html

cheers!

 

[AllanL]

any updates on this?

i'm interested and curious as well.

let us know...

 

[PredatorSniper]

any updates on this?

i'm interested and curious as well.

let us know...

I sold my 264's so I will be installing the new ones this weekend

 

[YZFR1]

When you go to degree the new cams, it might be very hard if not almost impossible to setup for zero lash without having to use solid lifters. I was able to remove lifters to install different washers without taking cams out but if you have some nice titanium retainers they might get scuffed up.

What i would recommend doing if you don't have solid lifters is to setup for negative lash. This is where your valve is slightly open, just barely. Don't worry about the cam timing on the cam card, concentrate on the Centerline @ Peak Lift. The centrline is going to tell you how much advanced/retarted your cams are from the cam card.

For example, on my cams the centrline on intake is 107 and exhaust is 113. What that means is that the intake is advanced 3 degrees from the factory (110*-107*) and exhaust is retarded 3 degrees (110*-113*) also from the factory. If you come up with different numbers you would know how much advanced/retarted you are form the cam card.