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| Timing Set Oiling/Oil Slinger/Redesigned Front Crankshaft Seal/Vibration Damper Groove Questions https://slantsix.org/forum/viewtopic.php?f=19&t=66729 |
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| Author: | Sonic Purity [ Wed Aug 17, 2022 11:47 am ] |
| Post subject: | Timing Set Oiling/Oil Slinger/Redesigned Front Crankshaft Seal/Vibration Damper Groove Questions |
Your favorite(?) over-thinker/under-doer/over-typer is back with more questions. Intro/current status of my van’s engine Vibration damper on my ’81 hydraulic lifter 225 has been pulled. No grooving, which is good, but there’s a question on that below. Very obvious from the dried-up oil spray pattern behind the damper that the front crankshaft seal was leaking. Further verified once the old seal was removed from the timing cover: old seal slides easily on and off the crankshaft. New one (not yet lubed) resists even starting. No oil slinger, being an ’81. I’ve spent the last several days reading 30+ existing posts here about oil slingers and timing set oiling. This post is meant to be a summary of salient points + some questions i have which were unanswered by any posts i found. Question 1: Will adding an oil slinger to a newer engine which never had one deprive the new seal design of enough oil that it will groove the vibration damper shaft more or faster? This post from Craig in 2004 states in part: Quote: Studying my factory service manuals, 1975 or so states something special about one half of the front main bearing having a chamfer for timing chain oiling. A couple years later the manuals change to saying something about the front cam gear having something for timing chain oiling. Not enough info there to know exactly what it is for either bearing. I've posted here a couple years ago about these bearing mods and timing chain oiling but never got any definite answers about the subject. My ’81 Truck factory service manual says nothing whatsoever about timing chain/sprocket oiling that i can find. In this post Slant Six Dan explains: Quote: The slinger was discontinued in the early '70s when the front seal was redesigned. I’ve found no information on the nature of the front seal redesign. Guessing mostly better (in theory) oil control, so they could delete the slinger and save $. True? Other reasons for the change? Reason for my question: i’ve read (here is one example) about many grooved vibration damper shafts needing a micro sleeve to fix. I’m wondering whether the new seal was designed to be bathed in oil due to the lack of a slinger, which oil bathing might be necessary to minimize cutting one or more grooves in the vibration damper shaft. Does this theory make any sense at all? I love the idea of adding an oil slinger to reduce the amount of oil control the front seal has to do and may do so even if a groove gets cut faster, but i’m wondering what it is about some rubber front crankshaft seals and some vibration damper shafts leads to grooving. Anyone know? General consensus i have read in posts here: All Slant 6es benefit from having an oil slinger installed. Opinions vary on how essential/important it is. Question 2: How did Chrysler intend timing set oiling to work over the years, and what are today’s best practices for engines old through new, assembled and working (like mine) and being built? I’ve read in many posts (like this one from Charrlie S) about the chamfer on the #1 main bearing shell, and that it was deleted at a certain point (when?) which may or may not correspond to the oil slinger deletion. My engine likely doesn’t have this, and it’s assembled and working so i won’t be adding it. Once the chamfer was deleted, how did Chrysler intend that the timing set be oiled? In terms of mods/improvements, Doc has several: Drill hole in oil gallery plug: Quote: One other "trick" I have used is to drill a small hole in the front oil gallery plug in order to provide a stream of pressurized oil right onto the chain and gears. Keep this hole small, .020 is all you need. I use a larger drill to go most of the way thru the plug from the back side the "poke thru" at an angle with the small drill, from the front. DD Question 3: Can or Should this be done on a late hydraulic lifter engine that’s fully assembled (other than the timing cover is off and timing sprockets and chain are out)? Add cam sprocket oil passage Quote: Oil bleeds-out of the front cam bearing and builds some pressure behind the top timing sprocket. Drill a small hole from the inner edge of the "cup", on the back of the sprocket, to the front face of the sprocket. This directs some of that oil out to the front of the sprocket where it can be thrown around. Doing this also reduces the chance that pressure behind the top sprocket will push the sprocket / cam assembly forward. Some top sprockets already have this feature but add it if a passage is not there. Basically, this is just another way to get more oil onto the sprocket teeth and chain. DD Original post has a nice photo. What is not addressed: Drill straight through? At an angle? Thanks for any information! |
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| Author: | Rick Covalt [ Wed Aug 17, 2022 1:34 pm ] |
| Post subject: | Re: Timing Set Oiling/Oil Slinger/Redesigned Front Crankshaft Seal/Vibration Damper Groove Questions |
Just going from personal experience. I am not sure any of my engines have oil slingers in them. Pretty sure my race engine does not. I have never had front seal leaks as a problemon any of my slant 6 engines. Along the timing cover to pan interface? Yes for sure. 
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| Author: | Charrlie_S [ Wed Aug 17, 2022 2:43 pm ] |
| Post subject: | Re: Timing Set Oiling/Oil Slinger/Redesigned Front Crankshaft Seal/Vibration Damper Groove Questions |
All of the engines I assemble have the chamfer on the bearing and a slinger. That said I wouldn't remove the timing cover (and open a can of worms) just to do that. To add the chamfer, to the bearing, requires dropping the oil pan (another can of worms). If the motor is OK, why bother. If it ain't broke, don't fix it. |
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| Author: | Sonic Purity [ Wed Aug 17, 2022 8:56 pm ] |
| Post subject: | Re: Timing Set Oiling/Oil Slinger/Redesigned Front Crankshaft Seal/Vibration Damper Groove Questions |
Figured this one out myself later in the day: Sonic Purity wrote: Quote: Drill a small hole from the inner edge of the "cup", on the back of the sprocket, to the front face of the sprocket. This directs some of that oil out to the front of the sprocket where it can be thrown around. Doing this also reduces the chance that pressure behind the top sprocket will push the sprocket / cam assembly forward. Some top sprockets already have this feature but add it if a passage is not there. What is not addressed: Drill straight through? At an angle? The worn part in the van has a 1/4" hole drilled at approximately a 45° angle: Attachment: angled oil hole SL6.jpg [ 23.94 KiB | Viewed 675 times ] I realized that the big locator slot in many of the new cam sprockets including the one i have serves the same function of letting oil flow, so for me no drilling needed. ***** Still wondering how the front crankshaft oil seal can cut grooves in the vibration damper and whether adding an oil slinger might exacerbate that. And whether Chrysler designed sufficient oil flow for the timing set or whether DD’s oil gallery hole drilling is needed/advisable. |
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