I just received these lifters from Summit for my engine build. I put two in to check for push rod length and set lash 1/8 turn past zero. I noticed they compressed quite a lot before moving the valve. Seemed like way too much for a limited travel lifter. After placing a dial indicator on the push rod side of the rocker, I was able to compress the plunger .140" by hand. I then did the same exercise with a stock lifter and found it had similar travel! I'm wondering if Comp mis-labeled this set. Has anyone else checked travel on the 875 lifters? How much should they have?

 

You got the "R" series, IIRC are the 875's. Might want to check with Comp on plunger travel but what may be going on is your new lifters most likely are not pumped up so the lifter would easily go down under the spring pressure....unless you are also using a light spring to check PR length.

In looking at 850's and 875's on Summit site, there is a difference between what he cup end looks like (clip)...assuming the pictures are accurate to the part # shown

875's: http://www.summitracing.com/parts/cca-875-16
850's: http://www.summitracing.com/parts/cca-850-16

I ran the R's without any problem years ago. Don't lash them ANY FURTHER than 1/8 turn. The spec is zero to 1/8th turn MAX

Back when there was a debate over 875 failure because of a "new" type clip that held them together...I suspect many of the claimed problems was install error of over lash

 

Has anyone measured the travel on the 875's? I've found on other sites that some claim .050".

 

I never measured mine when I had them but other reports travel between stock and the 875's to be:

"Standard hydraulic liftrers have about 0.125" plunger travel. The limited, short or reduced travel lifters have 0.060" plunger travel. When the short or reduced travel lifters are set at 0.001" to 0.005" preload they cannot pump up and float the valves because they have no where to pump up to. "

If your 875's plunger travel is .140 as you note....that would suggest they are standard and not short travel 875's...so maybe they were mis-boxed

I would think if you contacted Comp they would swap them over to 875's if in fact they were mis boxed as the shorter travel lifters should not have that much travel

 

Thanks for the info. I did some more digging was able to get a few more facts. After talking to Comp, the only difference between the regular 850 and the limited travel 875 is the retaining clip. The 875 clip pushes the plunger down 0.050" while the 850 clip doesn't load the plunger at all. While that may be somewhat helpful at high RPM, this is not really a short travel lifter in my opinion. I ended up returning these and ordered a set of the 15850 race lifters. Those are supposed to be a true short travel design with ~0.050" total. We'll soon see if that's true.

 

Just got the 15850s. All I can say is wow, what a difference! The quality is incredible. I measured the travel and it's .050" total. These are definitely worth the extra coin.