Roller lifter pre-load on a Windsor?

wrogers55 · #1 (**permalink**) 04-29-2012, 08:45 PM

Just changed the cam and roller lifters, Comp Cams, in my 418. This is a retro fit roller motor.

Have a lot of different numbers on the pre-load for the hydraulic roller lifters. Everything from a quarter turn to a full turn on the poly-lock nut. I also have a Ford manual and it say .030 to 0.045 thousands down on the plunger. I know that 2 flats on the nut is about 120 degrees and is .030 to .035, which is where I just set them.

So am I OK or do I need to redo? Any expert help before I button this up. Intake is still off so everything is easy....now.

Thanks,

Rick Parker · #2 (**permalink**) 04-29-2012, 11:18 PM

Are the rockers on 3/8-24 studs? 3/4 turn after rolling the pushrod between fingers and snuging the poly lock until they will not spin between fingers any longer, this is also done while valve is fully closed and roller is on the heel of the lobe. Do it in firing order, and intake then exhaust of the same cylinder.

Rick

Gaz64 · #3 (**permalink**) 04-30-2012, 02:54 AM

Wayne,

As Rick has asked, what rocker stud thread pitch have you got?

My maths says 2 flats is not enough. On a 24 tpi stud and rocker ratios in the 1.5 - 1.7 zone, 1 turn on the pozi-lock nut equals roughly 66 -70 thou, 2 flats gives you 22 -23 plunger depression.

I'd say you're ok to leave them where you have them, some people run anywhere between near zero preload to 3/4 turn.
With that in mind, you're just short of the mid-point.

RICK LAKE · #4 (**permalink**) 04-30-2012, 04:27 AM

Wrogers55 W if you are going to race this motor or 7,000 rpms and bounce it off a rev limiter then you would want no more than 1/4 turn pass contact of the 3 parts. Reason for this is lifter pump up and you don't want Mr. valve to make contact with Mr. Piston. The deeper your adjustment goes the better possiblity of a hit with a miss shift or rev limiter hit. Mine are .015" with a dial indicator on the plunger of the lifter. Have you checked the rocker postion on the top of the valves? Want to make sure that the roller stays as close to the center of the valve stem as possible. This is a good test for making sure you have the correct pushrod length also. Good luck Rick L. Ps if you are not going to high rpm the motor up to 1 turn is the normal. I would stay with 1/4 and if you hear noise from the rocker than tighten to a 1/2 turn. Be sure it's the pushrods maken noise and not the lifters or the retainer plates or bars.

mreid · #5 (**permalink**) 04-30-2012, 07:08 AM

Start with 1/4 turn. Put the engine at TDC on cylinder #1 and adjust both intake and exhaust, turn the engine 90 degrees and adjust both for the next cylinder in the firing order (#3), and continue 90 degree rotations, adjusting both valves in the cylinder until you run the firing order. Review your geometry and kame sure the rocker tip is relatively centered on the valve stem. Now drive the car how you will run it normally. If they need more adjustment, simply add another 1/4 or 1/2 turn without rotating the engine. Each time you make a change review the geometry.

blykins · #6 (**permalink**) 04-30-2012, 02:02 PM

Different lifters require a different amount of preload. Do you know which lifters you have? If not, I'd shoot for about 1/2 turn and go from there.

As for setting the valves, set the intake when the exhaust valve is starting to open on that cylinder. Set the exhaust when the intake valve is starting to close. This makes sure that the lifter is setting on the heel of the lobe, which may not be possible with any other methods and cams with larger amounts of overlap.

wrogers55 · #7 (**permalink**) 04-30-2012, 03:53 PM

Brent's comments on setting methods and big overlap cams is starting to worry me. It's a big cam.

So, here is what I did to set the preload....and I do have time to redo!

1. went to #1, turn crank clockwise
2. exhaust vale opens and closes
3. intake opens and just as it closes completely (intake off easy to see) I stop
3. put the ratchet on the crank bolt at 12 o'clock and continue to turn it clockwise to 5 o'clock.
4. set the lash on both intake and exhaust.
5. continue to the next cylinder and do the same, and so on.

I marked the cam base circle centers with a felt tip before I put it in and this method brought those marks close to the roller.

So, I thought I was OK......maybe not. I'm not looking to invent a new way to do this and this may not be new anyway, but now I'm a bit worried.

Brent, lifters are Comp Cam rollers #851 and this is a retro fit motor with a spider and dog bones to hold the lifters in place.

In case it's important: Duration at .006 tappet lift Intake=299 Exhaust=305
Duration at .050 on the cam card = intake 248, exhaust 254
I installed it at 106 Intake centerline.

Guess there is more than one way to skin a cat, just hope mine is skinned!

Thanks for the help.

blykins · #8 (**permalink**) 04-30-2012, 04:15 PM

The jist of it is that you want to make absolutely sure that the lifter you're working on is on the heel of the lobe. Now if you can guarantee that you're fine, but I rarely see a scenario when you can set both valves at the same time when that piston is at tdc.

I've seen that method vary by a decent amount on a solid cam compared to the Evo/ivc method. It's not that critical in a hydraulic cam engine but the same theory applies. Your cam has a good bit of overlap and there's more of a chance that both valves are not closed at tdc.

olddog · #9 (**permalink**) 05-01-2012, 04:12 PM

This piston comes to TDC two times.

One time it is the transition from the exhaust to the intake stroke, and both valves are slightly open.

The other time is the transition from the compression to the power stroke, and both valves are closed. You would have to turn the crank ~45 deg either direction to get a valve to start opening (actual numbers will vary depending on duration). This is approximately the position the original poster described.

I'm no expert, but I do not see anything wrong with this method. If there is, please explain it, as I would like to know too.

blykins · #10 (**permalink**) 05-01-2012, 04:25 PM

As I said, if you can guarantee that the lifters are on the heel, it's perfectly fine.

However, I have used the TDC method and the EVO method on a solid cam engine before for comparison, and got about .002" difference. With the EVO method, I can guarantee that the lifter is on the heel of the lobe.

With the EVO/IVC method, you set the intake valve when the exhaust valve is opening. When the exhaust valve is starting to open, you've had a power cycle and you're starting to push the exhaust out. There is no feasible way that the intake valve could be open at this point. On the flip side, you set the exhaust valve when the intake valve is starting to close. When the intake valve is starting to close, you're somewhere in the compression stroke. The cam dictates at what point that intake valve starts to close relative to the piston on this stroke. However, it's not possible that the exhaust valve could be open at this point.

If you look at that transition from the compression stroke to the power stroke that you were referring to, depending on the cam, it's possible that the intake valve could still be off the seat, even by a minute amount, due to the IVC event (the same principle that gives us the DCR relationships), especially with 82° of overlap, which Wayne's cam has. The other transition from the exhaust to the intake stroke will absolutely almost guarantee that one or both valves will be open. If you happen to try to adjust the valves there, you will get a discrepancy.

Also, with the EVO/IVC method, you can literally hop through the entire bank of cylinders in just a couple of minutes if you pay attention. While you're watching one exhaust valve starting to open so that you can set the intake on one cylinder, you can keep your eye on the intake valve starting to close on another cylinder, so you can hop right to that exhaust valve. It takes no time at all.

RET_COP · #11 (**permalink**) 05-01-2012, 04:31 PM

Comp Cams Retro roller lifters 8931-16 SBF and many others of the like call for .050-to .100 preload. It also states in the paperwork that I received 1 turn after 0 lash. 7/16-20 on a 1.6 scorpion rocker= .020 for every quarter turn. I measured this at the lifter. This paperwork is 2 months old. I set mine at 3/4 turn after 0 lash for .060 preload. Everything is working very well. Thread count, rocker ratios play the biggest part and to a very small extent the make of the rocker. Not all ratios have the same distances between fulcrum and roller tip and fulcrum and pushrod cup. The industry has no standard and that goes for heads and stud placement. It's a long story.

madmaxx · #12 (**permalink**) 05-01-2012, 06:02 PM

Correct me if I am wrong, the whole purpose of hydraulic lifters is to accomadate wear. As long as when the cam is on the heal the lifter is not bottomed out or on the top you should be ok. With that being said I would lean towards closer to the top in case a lifter pumps up, valve floats etc. I would go 1/4 turn after lash is taken up.

olddog · #13 (**permalink**) 05-01-2012, 09:12 PM

Quote:

Originally Posted by blykins

As I said, if you can guarantee that the lifters are on the heel, it's perfectly fine.

However, I have used the TDC method and the EVO method on a solid cam engine before for comparison, and got about .002" difference. With the EVO method, I can guarantee that the lifter is on the heel of the lobe.

With the EVO/IVC method, you set the intake valve when the exhaust valve is opening. When the exhaust valve is starting to open, you've had a power cycle and you're starting to push the exhaust out. There is no feasible way that the intake valve could be open at this point. On the flip side, you set the exhaust valve when the intake valve is starting to close. When the intake valve is starting to close, you're somewhere in the compression stroke. The cam dictates at what point that intake valve starts to close relative to the piston on this stroke. However, it's not possible that the exhaust valve could be open at this point.

If you look at that transition from the compression stroke to the power stroke that you were referring to, depending on the cam, it's possible that the intake valve could still be off the seat, even by a minute amount, due to the IVC event (the same principle that gives us the DCR relationships), especially with 82° of overlap, which Wayne's cam has. The other transition from the exhaust to the intake stroke will absolutely almost guarantee that one or both valves will be open. If you happen to try to adjust the valves there, you will get a discrepancy.

Also, with the EVO/IVC method, you can literally hop through the entire bank of cylinders in just a couple of minutes if you pay attention. While you're watching one exhaust valve starting to open so that you can set the intake on one cylinder, you can keep your eye on the intake valve starting to close on another cylinder, so you can hop right to that exhaust valve. It takes no time at all.

Thank you for the explanation. I understand now.

I was thinking it would take over 360 duration on the intake for the valve not to be seated at TDC on compression stroke. However I forgot that the 0.006 inch lift duration does not include all of the ramp. With Wayne's 5 O'clock method he was close to TDC but not exactly. Actually quite a bit of error possible. Now I see your concern.

wrogers55 · #14 (**permalink**) 05-01-2012, 09:48 PM

OK thanks to everyone for ALL the wisdom and discussion on what seemed to be a really simple process....until you get into the type of cams with lots of overlap we tend to use in these cars.

I went back over it with Brent's EVO/IVC and got it all set. Put them all at a quarter turn, and then cinched up the lock screw and gave the whole thing another hand whack to cinch up the nut. Didn't move much at all, but it's tight now.

Didn't seem to change anything from the previous way I had them set, but a few thousands up or down a ramp would really be difficult to tell by sight I guess. Thanks Brent and everyone else, once again.

Really good discussion and help and it was greatly appreciated. I'll sleep good tonight.

Anxious to light this on off again in a couple of days.

blykins · #15 (**permalink**) 05-02-2012, 02:47 AM

"Didn't seem to change anything from the previous way I had them set, but a few thousands up or down a ramp would really be difficult to tell by sight I guess."

Exactly...on a hydraulic cam, a few thousandths isn't going to hurt anyone, especially when you can jump from 1/4 turn preload to a 3/4 turn preload and vice versa.

Where it does matter is on a solid cam, and a few thou lash could actually change some engine parameters.

Glad you got her buttoned up Wayne.....let us know how it runs when you light a fire in it.

mdross1 · #16 (**permalink**) 05-02-2012, 03:34 AM

Have always run my motors to near valve float and a few times nosed it over.A long time ago was taught to adjust them till they no longer tick in most cases about .020 off lifter plunger seat,which with 24 threads per inch is about a quarter turn.It's called insurance.As with so many other engine issues your bound to get a lot of opinions.Good Luck and have fun.Remember experience is always the best teacher, I would run yours the way they are set.