Why doesn't the 928 need new lifters with a cam change?
03-03-2008, 03:13 PM
#16
Rennlist Member
Thanks for chiming in Jim. I'll probably email you as I get closer to the install.
There is a local cam grinder here, Delta Camshaft, that's been around for awhile. I was going to bring in my DEVEK B1's and have the grinds plotted. Louie had suggested that I have the exhaust cam modified to help out with the fact that I'm running these with an A/T. Once I get to that point I'll send you an email.
On the wipe test you said you use "prussian blue", I'm not familiar with this. Is this the similar to machinests dye, that brush-on purple stuff? On the wipe test are you looking for a particular contact pattern, or just maximum contact across the width of the lobe face?
Thanks again everyone for your comments so far.
What I'm hearing then is that the lifter crowns are untypically hard and so they don't wear as easily as other manufacturer's. Since they aren't wearing, the lifters are close enough to spec regardless of being used that it's all the same to the camshaft.
I'm still going with new, but I do think its interesting that there have been so many cam swaps and the lifters haven't seemed to be an issue.
There is a local cam grinder here, Delta Camshaft, that's been around for awhile. I was going to bring in my DEVEK B1's and have the grinds plotted. Louie had suggested that I have the exhaust cam modified to help out with the fact that I'm running these with an A/T. Once I get to that point I'll send you an email.
On the wipe test you said you use "prussian blue", I'm not familiar with this. Is this the similar to machinests dye, that brush-on purple stuff? On the wipe test are you looking for a particular contact pattern, or just maximum contact across the width of the lobe face?
Thanks again everyone for your comments so far.
What I'm hearing then is that the lifter crowns are untypically hard and so they don't wear as easily as other manufacturer's. Since they aren't wearing, the lifters are close enough to spec regardless of being used that it's all the same to the camshaft.
I'm still going with new, but I do think its interesting that there have been so many cam swaps and the lifters haven't seemed to be an issue.
Prussian blue is machinist's dye.
If you have contact completely across the lifter face, the cam & lifters will wear out within 1000 miles. Mike's correct (as usual), the cam lobes should be tapered so the lifter & cam rotate together rather than grind each other to dust.
Hammer
03-03-2008, 03:41 PM
#17
Rennlist Member
Thread Starter
Hammer wrote:
Delta did my cams (to Phil Threshie's specs).
If you have contact completely across the lifter face, the cam & lifters will wear out within 1000 miles.
03-03-2008, 03:43 PM
#18
Rennlist Member
Does anyone have proof that the lifters can pump up enough to adapt to a cam with some of the base circle taken off for greater effective lift? We were talking about .5mm, and i would love to hear if anyone has done this
back on topic. Interesting. So, if i measure the cam lobs, there will be some difference across it in dimension? how much. the concept sounds right, that way the lifter is always spinning and the cam doesnt have full contact on it, but i have a hard time picturing it. so those things must be rippin around at 6000rpm. I would think that they are not in much contack, just by the forces and speed of the cam lobs. But, if one side hits first and there is any friction, (and non holding it in place ) it would spin.
I would like to see that high speed video. anyone got a link?
By the way, I've changed out cams many times and havent had a problem yet.
MK
back on topic. Interesting. So, if i measure the cam lobs, there will be some difference across it in dimension? how much. the concept sounds right, that way the lifter is always spinning and the cam doesnt have full contact on it, but i have a hard time picturing it. so those things must be rippin around at 6000rpm. I would think that they are not in much contack, just by the forces and speed of the cam lobs. But, if one side hits first and there is any friction, (and non holding it in place ) it would spin.
I would like to see that high speed video. anyone got a link?
By the way, I've changed out cams many times and havent had a problem yet.
MK
Delta did my cams (to Phil Threshie's specs).
Prussian blue is machinist's dye.
If you have contact completely across the lifter face, the cam & lifters will wear out within 1000 miles. Mike's correct (as usual), the cam lobes should be tapered so the lifter & cam rotate together rather than grind each other to dust.
Hammer
Prussian blue is machinist's dye.
If you have contact completely across the lifter face, the cam & lifters will wear out within 1000 miles. Mike's correct (as usual), the cam lobes should be tapered so the lifter & cam rotate together rather than grind each other to dust.
Hammer
03-03-2008, 04:13 PM
#19
Three Wheelin'
Mark, the lifters have 3mm of plunger travel. I've been told that a normal installation has them nearly fully compressed so that would allow for a regrind.
BTW, that is a good thing for the lifters to be nearly collapsed, it keeps them from collapsing under racing conditions and slapping the valvetrain to death. I've modified domestic hydraulic lifters before to restrict movement to a minumum and treat it like a mechanical tappet during assembly. The only reason for alot of plunger travel is to allow loose manufacturing tolerences, especially in a pushrod engine.
Hammer, thanks for the props but it was Sterling who pointed out the lobe taper. I've also measured taper across the lobe face, something like 2 thou or so across the lobe face IIRC. That would make sense since the lifters are convex.
That prussian blue is the most concentrated stuff ever, especially the real Dykem brand. If you're not careful with it you can wind up making everything in your shop blue. A machine shop practical joke is to put a dab of it under the handle of someone's toolbox, if not noticed within seconds it will be everywhere!
BTW, that is a good thing for the lifters to be nearly collapsed, it keeps them from collapsing under racing conditions and slapping the valvetrain to death. I've modified domestic hydraulic lifters before to restrict movement to a minumum and treat it like a mechanical tappet during assembly. The only reason for alot of plunger travel is to allow loose manufacturing tolerences, especially in a pushrod engine.
Hammer, thanks for the props but it was Sterling who pointed out the lobe taper. I've also measured taper across the lobe face, something like 2 thou or so across the lobe face IIRC. That would make sense since the lifters are convex.
That prussian blue is the most concentrated stuff ever, especially the real Dykem brand. If you're not careful with it you can wind up making everything in your shop blue. A machine shop practical joke is to put a dab of it under the handle of someone's toolbox, if not noticed within seconds it will be everywhere!
03-03-2008, 04:52 PM
#20
Does more lift for the same duration and separation ONLY move the power range up a few 100 or several 100 rpms? Does it add power elsewhere? Or always take it away?
03-03-2008, 05:37 PM
#21
Rennlist Member
Also interesting. thanks.
When i was at Road america. I started my car after it had been shipped 2000miles on a truck, and it made a bunch of noise, I mean, LOUD tappet /lifter noise. i thought the car had something broken. but, i figured it out that it was a every other revolution frequency, so it was a cam or valve issue. i drove it to tech, warmed it up and for 5 min, it was REALLY making a racket. I thought my expensive weenked of racing at Road america was done before it started.
But, as i drove back from tech, the noise went away and was normal again.
My theory is that the car was on the truck and being vibrated for 24hours , pulled all the oil out of the lifters and a couple of them didnt pump up for a while. this means to me that they are not flat to the cams and need to be pumped up a bit. how much? i dont know, but i wonder what that space was to make that kind of racket!!
do you guys think taking .5mm off the 85 4 valve cams is worth it for the coming Renlist 6.5 liter engine? Goal is to make near 400rwhp with stock stuff
mk
When i was at Road america. I started my car after it had been shipped 2000miles on a truck, and it made a bunch of noise, I mean, LOUD tappet /lifter noise. i thought the car had something broken. but, i figured it out that it was a every other revolution frequency, so it was a cam or valve issue. i drove it to tech, warmed it up and for 5 min, it was REALLY making a racket. I thought my expensive weenked of racing at Road america was done before it started.
But, as i drove back from tech, the noise went away and was normal again.
My theory is that the car was on the truck and being vibrated for 24hours , pulled all the oil out of the lifters and a couple of them didnt pump up for a while. this means to me that they are not flat to the cams and need to be pumped up a bit. how much? i dont know, but i wonder what that space was to make that kind of racket!!
do you guys think taking .5mm off the 85 4 valve cams is worth it for the coming Renlist 6.5 liter engine? Goal is to make near 400rwhp with stock stuff
mk
Mark, the lifters have 3mm of plunger travel. I've been told that a normal installation has them nearly fully compressed so that would allow for a regrind.
BTW, that is a good thing for the lifters to be nearly collapsed, it keeps them from collapsing under racing conditions and slapping the valvetrain to death. I've modified domestic hydraulic lifters before to restrict movement to a minumum and treat it like a mechanical tappet during assembly. The only reason for alot of plunger travel is to allow loose manufacturing tolerences, especially in a pushrod engine.
Hammer, thanks for the props but it was Sterling who pointed out the lobe taper. I've also measured taper across the lobe face, something like 2 thou or so across the lobe face IIRC. That would make sense since the lifters are convex.
That prussian blue is the most concentrated stuff ever, especially the real Dykem brand. If you're not careful with it you can wind up making everything in your shop blue. A machine shop practical joke is to put a dab of it under the handle of someone's toolbox, if not noticed within seconds it will be everywhere!
BTW, that is a good thing for the lifters to be nearly collapsed, it keeps them from collapsing under racing conditions and slapping the valvetrain to death. I've modified domestic hydraulic lifters before to restrict movement to a minumum and treat it like a mechanical tappet during assembly. The only reason for alot of plunger travel is to allow loose manufacturing tolerences, especially in a pushrod engine.
Hammer, thanks for the props but it was Sterling who pointed out the lobe taper. I've also measured taper across the lobe face, something like 2 thou or so across the lobe face IIRC. That would make sense since the lifters are convex.
That prussian blue is the most concentrated stuff ever, especially the real Dykem brand. If you're not careful with it you can wind up making everything in your shop blue. A machine shop practical joke is to put a dab of it under the handle of someone's toolbox, if not noticed within seconds it will be everywhere!
03-03-2008, 05:55 PM
#22
Rennlist Member
Adam, I had Racer Brown Cams double check my cams when I recieved them (due to Phil Threshies reputation) & he said no worries.
Hammer
03-03-2008, 05:59 PM
#23
Rennlist Member
Does anyone have proof that the lifters can pump up enough to adapt to a cam with some of the base circle taken off for greater effective lift? We were talking about .5mm, and i would love to hear if anyone has done this
back on topic. Interesting. So, if i measure the cam lobs, there will be some difference across it in dimension? how much. the concept sounds right, that way the lifter is always spinning and the cam doesnt have full contact on it, but i have a hard time picturing it. so those things must be rippin around at 6000rpm. I would think that they are not in much contack, just by the forces and speed of the cam lobs. But, if one side hits first and there is any friction, (and non holding it in place ) it would spin.
I would like to see that high speed video. anyone got a link?
By the way, I've changed out cams many times and havent had a problem yet.
MK
back on topic. Interesting. So, if i measure the cam lobs, there will be some difference across it in dimension? how much. the concept sounds right, that way the lifter is always spinning and the cam doesnt have full contact on it, but i have a hard time picturing it. so those things must be rippin around at 6000rpm. I would think that they are not in much contack, just by the forces and speed of the cam lobs. But, if one side hits first and there is any friction, (and non holding it in place ) it would spin.
I would like to see that high speed video. anyone got a link?
By the way, I've changed out cams many times and havent had a problem yet.
MK
Here's the link,
http://h=nda-portal.com/honda-videos.php?video_id=459
Ooops, it doesn't seem to work anymore, anyone else have a more recent link?
Hammer
03-03-2008, 06:21 PM
#24
Three Wheelin'
Is this it?:
http://www.youtube.com/watch?v=sEf8va1S7Sw
The video has appeared all over the place but I don't think it's origin is known.
http://www.youtube.com/watch?v=sEf8va1S7Sw
The video has appeared all over the place but I don't think it's origin is known.
03-03-2008, 06:54 PM
#25
Rennlist Member
the tech spec booklet defines the max/min range for the distance from the top of the valve stem to the top of the head surface. This defines operating range of the lifter's plunger. This implies that you can machine down the cam base, if you have room, and the lifters will be fine.
03-03-2008, 07:06 PM
#26
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Is this it?:
http://www.youtube.com/watch?v=sEf8va1S7Sw
The video has appeared all over the place but I don't think it's origin is known.
http://www.youtube.com/watch?v=sEf8va1S7Sw
The video has appeared all over the place but I don't think it's origin is known.
www.youtube.com/watch?v=_REQ1PUM0rY&NR=1
10-25-2022, 10:45 PM
#28
Nordschleife Master
Hi Ted - sounds like you've got a 16V car?
Definitely start a new thread and post a pic - there are plenty of experienced and helpful sets of eyes on the forum, and you've added your post to the end of a very old thread where it maybe won't get the attention you need.
Your best bet is probably (depending on which 16V model) a used cam from Mark at 928intl, but I'll leave it up to better experts than me to weigh in with whether there are other viable options
Definitely start a new thread and post a pic - there are plenty of experienced and helpful sets of eyes on the forum, and you've added your post to the end of a very old thread where it maybe won't get the attention you need.
Your best bet is probably (depending on which 16V model) a used cam from Mark at 928intl, but I'll leave it up to better experts than me to weigh in with whether there are other viable options
