Shimming Hydraulic Flat Tappet Lifters

Tom Turner · 05-17-2017, 02:07 PM

What advantage do Short Travel Roller Lifters they have over the GM Roller Lifters?

About 30HP, Maybe more depending on your tenacity.

Coleydog · 05-19-2017, 05:16 PM

What they're saying, no loss of lift or duration with shimming. Now, just use a solid lifter
Mike

ss3011 · 05-19-2017, 06:44 PM

Converting from a hydraulic lifter to a solid sounds good , but how does that work ? Wouldn't you have to develop a new camshaft ? Wouldn't you lose some lift due to whatever valve lash you use ? Are there some stocker profiles out there that are solid but are designed for very tight lash , say under .012" . Just asking , I am interested !

Alan Nyhus · 05-20-2017, 08:36 AM

Quote:

Originally Posted by ss3011

Converting from a hydraulic lifter to a solid sounds good , but how does that work ? Wouldn't you have to develop a new camshaft ?

It depends on the lobe, of course. The acceleration ramps are theoretically different on a hydraulic vs. a solid profile. Many lobes will accept either style lifter with no issues.

Quote:

Originally Posted by ss3011

Wouldn't you lose some lift due to whatever valve lash you use ?

Yes, you do. Since the lash isn't figured into the checking clearance (zero) a solid lifter combo is in the same boat already. On a 'hydraulic cam' that's been switched to solid lifters, .002-.003 lash (hot) is pretty normal.

Quote:

Originally Posted by ss3011

Are there some stocker profiles out there that are solid but are designed for very tight lash , say under .012" . Just asking , I am interested !

Most solid lifter stocker cams that I'm around use lash figures in that neighborhood already.

Hope this helps.

-Al

ss3011 · 05-20-2017, 10:51 AM

So I guess the point is , is the benefit of a solid lifter worth the loss of whatever valve lift you would lose because of lash .

killintime6968 · 05-20-2017, 12:22 PM

Who makes the best solid lifter for a bigblock chev. Would you use anything different if converting from hydraulic lifters.

Bruce Cameron
1968 Nova 396 E/S

Greg Reimer 7376 · 05-29-2017, 03:41 PM

Some of you guys are experimenting with things in an attempt to try things, and asking good questions. Some of the results reported in this thread rise up some other good questions as well. If some of you report large HP and MPH gains just by changing lifters to a non-hydraulic type, something must be going on here. Topping out the travel on a hydraulic lifter plus a little for lash(.002-.004), prevent the lifter from pumping up, thereby extending the theoretical RPM range of the engine, but what if the trend to stiff valve springs, low pressure oil pumps, and lightweight oil is resulting in a hydraulic lifter steadily collapsing as engine RPM increases going down the track? That would result in cam lift and duration steadily decreasing while on the back half of a run.The change to a solid lifter would prevent this, thereby maintaining valve train activity during the whole run,and resulting in ET reduction and MPH gain, in effect, more peak horsepower. That kind of lifter collapse would probably not result in audible valve noise because the lifters would quickly pump back up while slowing down and driving back on the return road. You would'nt probably hear it over the sound of uncorked headers either.If you switch from hydraulic to solid lifters,you would have to recheck your total valve lift as well, since the more accurate valve train activity might result in a change. Also, if the solid lifter was somehow shorter that the hydraulic, it would result in a change in the effective height of the valve train. Shorter or longer push rods might be necessary to restore proper lift. It would be easier to check lift because you wouldn't have hydraulic lifters trying to squash down under load at max lift anyway. One of those variables that's impossible to measure while an engine is running and the car is going down the track.

05-17-2017, 02:07 PM	#1
Tom Turner Member Join Date: Jan 2005 Location: Lake Tapps, Washington Posts: 137 Likes: 0 Liked 0 Times in 0 Posts	Re: Shimming Hydraulic Flat Tappet Lifters What advantage do Short Travel Roller Lifters they have over the GM Roller Lifters? About 30HP, Maybe more depending on your tenacity.

05-19-2017, 05:16 PM	#2
Coleydog Senior Member Join Date: Jul 2014 Posts: 569 Likes: 36 Liked 53 Times in 38 Posts	Re: Shimming Hydraulic Flat Tappet Lifters What they're saying, no loss of lift or duration with shimming. Now, just use a solid lifter Mike

05-19-2017, 06:44 PM	#3
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 909 Likes: 70 Liked 239 Times in 114 Posts	Re: Shimming Hydraulic Flat Tappet Lifters Converting from a hydraulic lifter to a solid sounds good , but how does that work ? Wouldn't you have to develop a new camshaft ? Wouldn't you lose some lift due to whatever valve lash you use ? Are there some stocker profiles out there that are solid but are designed for very tight lash , say under .012" . Just asking , I am interested !

05-20-2017, 10:51 AM	#5
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 909 Likes: 70 Liked 239 Times in 114 Posts	Re: Shimming Hydraulic Flat Tappet Lifters So I guess the point is , is the benefit of a solid lifter worth the loss of whatever valve lift you would lose because of lash .

05-20-2017, 12:22 PM	#6
killintime6968 Member Join Date: Oct 2009 Location: Whitecourt,Alberta,Canada Posts: 236 Likes: 4,630 Liked 91 Times in 29 Posts	Re: Shimming Hydraulic Flat Tappet Lifters Who makes the best solid lifter for a bigblock chev. Would you use anything different if converting from hydraulic lifters. Bruce Cameron 1968 Nova 396 E/S

05-29-2017, 03:41 PM	#7
Greg Reimer 7376 VIP Member Join Date: Nov 2008 Location: Glendora,Calif. Posts: 1,135 Likes: 172 Liked 704 Times in 218 Posts	Re: Shimming Hydraulic Flat Tappet Lifters Some of you guys are experimenting with things in an attempt to try things, and asking good questions. Some of the results reported in this thread rise up some other good questions as well. If some of you report large HP and MPH gains just by changing lifters to a non-hydraulic type, something must be going on here. Topping out the travel on a hydraulic lifter plus a little for lash(.002-.004), prevent the lifter from pumping up, thereby extending the theoretical RPM range of the engine, but what if the trend to stiff valve springs, low pressure oil pumps, and lightweight oil is resulting in a hydraulic lifter steadily collapsing as engine RPM increases going down the track? That would result in cam lift and duration steadily decreasing while on the back half of a run.The change to a solid lifter would prevent this, thereby maintaining valve train activity during the whole run,and resulting in ET reduction and MPH gain, in effect, more peak horsepower. That kind of lifter collapse would probably not result in audible valve noise because the lifters would quickly pump back up while slowing down and driving back on the return road. You would'nt probably hear it over the sound of uncorked headers either.If you switch from hydraulic to solid lifters,you would have to recheck your total valve lift as well, since the more accurate valve train activity might result in a change. Also, if the solid lifter was somehow shorter that the hydraulic, it would result in a change in the effective height of the valve train. Shorter or longer push rods might be necessary to restore proper lift. It would be easier to check lift because you wouldn't have hydraulic lifters trying to squash down under load at max lift anyway. One of those variables that's impossible to measure while an engine is running and the car is going down the track.