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Adam

Well Known Member
Can you guys tell me what you are seeing on a Dry Tappet Clearance for XP Engine Roller Lifter. I think the book calls for .28 to .80. My reason for asking is that all my clearances all all higher but similary the same.
 
I needed to use the -31 pushrods to get the required clearances switching to roller tappets (had -35 pushrods before for non-rollers). I believe the clearance is something like .028-.080 (as you mentioned)? I have the "official" clearance tolerances at the hangar in my notes. This was with a Superior case, cam and roller tappets.

Sounds good that they are all the same. I think you'll just need to get the pushrods that will be in the heart of the range (.054) gap. I would give them a call and ask. They are great people and very friendly. Dave
 
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Thanks for the info but what I found is that my engine was built in 2005 with the old style of roller lifter and the clearance is .28 to .210. My issue was that when I check all my clearances, about .124 witch was a concern based on the original info I got which called for .28 to .80.
 
Really

You don't really mean .28 to .80 do ya? I am thinking .0.28" to 0.080". and whats with the .124 to .280. I am not a Superior mechanic... (no wait, I did not mean it like THAT) but I think everyone on this thread needs to be clear of the problem. (Wait, I mean: needs to understand the problem). I need coffee.
 
Superior Dry Tappet Clearance

.8" sounds WAY too much to me. That is over 3/4".

I looked in my manual.

From the March 2005 Overhaul Manual Table 72-00-11.1 page 2.

Following is a Copy / Paste:

Description of Limit Minimum (in.) Maximum (in.)

Dry Tappet Clearance 0.0280 0.0800


My memory tells me that Lycomng is the same.


Just checked, there is a newer version of the manual out dated 2007 and it can be downloaded here. It is the same table and values in the newer manual.
 
The Lycoming tool

IMG_0002_zps8f3c22fa.jpg


I bought this Tuesday at the Lycoming School I scanned it "flat" and printed it then stood the tool on edge with the printed image backing it so it is almost unreadable but in the middle it says:

LYCOMING
ST-23

In accordance with their standard abbreviations that probably means Lycoming Service Tool 23

And on the thin and thick ends it says:

".028" and ".080"

respectively

The instructor made a point of emphasizing the "DRY". The hydraulic unit should be removed cleaned in mineral spirits and not lubricated before reinstallation and completing this check to determine if you need a different dash number (length) push rod to adjust the gap. This requires the removal of the rocker, push rod and tube for access but it as fairly easy and the little cap/interface and then the hydraulic unit are easily fished out with a piece of formed safety wire for cleaning.

Bob Axsom
 
2004 Overhaul Manual

The spec in the 2004 Superior Overhaul Manual is .028 to .080. As a side note the first generation Superior roller lifters (up to late 2007 or 2008) are not removable from the engine without splitting the case.

Andy
 
H-m-m-m-m

andyrv said:
The spec in the 2004 Superior Overhaul Manual is .028 to .080. As a side note the first generation Superior roller lifters (up to late 2007 or 2008) are not removable from the engine without splitting the case.

Andy
Click to expand...

That makes it a little harder to do a valid random test.

Bob Axsom
 
Just to be clear for engines built before 2008 with Roller Tappets have a clearance of .28 to 210 as information sent to me by Superior Air Parts.
 
Just to be clear for engines built before 2008 with Roller Tappets have a clearance of .28 to 210 as information sent to me by Superior Air Parts.
 
Adam said:
Just to be clear for engines built before 2008 with Roller Tappets have a clearance of .28 to 210 as information sent to me by Superior Air Parts.
Click to expand...

Must be a typo, never seen a hyd lifter that can accomodate a 1/4" gap!
 
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