The International Cessna^® 170 Association

Hope someone has a reference to resolve this question:

Continental Illustrated Parts List specifies 637269 for the lifter hydraulic unit. Superior lists SA646846. In all other cases I've seen, the SA part #. tracks the Continental #. Is this an exception, or has the original part been superceded? I tried tcmlink.com without success. Neither Superior nor Premium Airparts list the original number. Preferred Airparts lists both, but only show one of each in stock.

Thanks, Miles

cessna170bdriver wrote:Hope someone has a reference to resolve this question:

Continental Illustrated Parts List specifies 637269 for the lifter hydraulic unit. Superior lists SA646846. In all other cases I've seen, the SA part #. tracks the Continental #. Is this an exception, or has the original part been superceded? I tried tcmlink.com without success. Neither Superior nor Premium Airparts list the original number. Preferred Airparts lists both, but only show one of each in stock.

Thanks, Miles

Miles,

My Cotinental Motors Service parts Catalog (form X-30014) list a completely different number for the Unit, Lifter Hydraulic. On page 12 figure 6 illistration #3 is listed as 533399. I looked in the index of part number in the back of my manual and the highest number listed is 636683. The date on inside cover of my manual is November1969. I hope this does not muddy up the water for you.

This is from the for what it is worth department, be sure you use the snap rings that hold the whole Lifter Assembly together. This is the voice of a bad experience speaking.

According to the TCM Current Publications Listing on their website http://www.tcmlink.com/powerstore/showi ... tegoryID=8# , the most current issue of the parts book X-30014 is November 1981, which is the one I have. TCM no longer gives carte blance access to all of their service bulletins, so I can't determine for sure if 637269 has been superceded. Evidently is was superceded once; it could have happened again.

I've been through the lifter snap ring snafu before, but in reverse. The first time I overhauled this engine, I went by the book and inserted the snap rings per the assembly drawing. The problem was, the lifters were the old style, without the retaining groove. The snap rings all eventually showed up in the suction screen. On the Swift forum, there is an article that says that these snap rings only serve to prevent the hydraulic unit and pusrod socket from being drawn out with the removal of a push rod.

Miles

cessna170bdriver wrote: On the Swift forum, there is an article that says that these snap rings only serve to prevent the hydraulic unit and pusrod socket from being drawn out with the removal of a push rod.

Miles

Miles here is a picture of a lifter body that did not have a snap ring installed allowing the piston to fall out and wedge between the lifter body and the pushrod tube retainer. When the lifter body gets into this condition you have no choice but to split the case haves again.

Reminds me of that time I found a piece of the bottom end (flange) of a lifter body in the suction screen... Kinda ruins your whole day. It makes me wonder why this series of engines has the flange on the cam end of the lifter bodies. Others I have seen are the same diameter all the way down, and can be removed without splitting the case. With the right style of push rod tube, you don't even have to pull the cylinder.

Miles

cessna170bdriver wrote:Reminds me of that time I found a piece of the bottom end (flange) of a lifter body in the suction screen... Kinda ruins your whole day. It makes me wonder why this series of engines has the flange on the cam end of the lifter bodies. Others I have seen are the same diameter all the way down, and can be removed without splitting the case. With the right style of push rod tube, you don't even have to pull the cylinder.

Miles

Amen to ruining your whole day, it's more like several days.

The mushroom fange on the bottom of the lifter body must influence the duration of the valve timing and probably the cam grind.

cessna170bdriver wrote:Reminds me of that time I found a piece of the bottom end (flange) of a lifter body in the suction screen... Kinda ruins your whole day. It makes me wonder why this series of engines has the flange on the cam end of the lifter bodies. Others I have seen are the same diameter all the way down, and can be removed without splitting the case. With the right style of push rod tube, you don't even have to pull the cylinder.

Miles

For a comparison of TCM vs LYC hydraulic lifters and valve systems see:
http://www.prime-mover.org/Engines/Marvel/tbo3.html

cessna170bdriver wrote:Hope someone has a reference to resolve this question:

Continental Illustrated Parts List specifies 637269 for the lifter hydraulic unit. Superior lists SA646846. In all other cases I've seen, the SA part #. tracks the Continental #. Is this an exception, or has the original part been superceded? I tried tcmlink.com without success. Neither Superior nor Premium Airparts list the original number. Preferred Airparts lists both, but only show one of each in stock.

Thanks, Miles

So... does anyone have a definitive answer for my original question?

Miles

gahorn wrote:

cessna170bdriver wrote:Reminds me of that time I found a piece of the bottom end (flange) of a lifter body in the suction screen... Kinda ruins your whole day. It makes me wonder why this series of engines has the flange on the cam end of the lifter bodies. Others I have seen are the same diameter all the way down, and can be removed without splitting the case. With the right style of push rod tube, you don't even have to pull the cylinder.

Miles

For a comparison of TCM vs LYC hydraulic lifters and valve systems see:
http://www.prime-mover.org/Engines/Marvel/tbo3.html

Especially notice the pic in Fig. 6.

The mushroom vs straight lifter body doesn't seem to be a TCM vs LYC issue. There are examples of both type lifters in both type engines.

Miles