oil pressure drop
Thread Starter
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6th Gear
Joined: Aug 2009
Posts: 10
Likes: 0
From: East Texas
Thanks, Ron
I did a compression check and had 84% leakage on the front cylinder and 92% on the rear. Removed the pushrods and the leakage dropped to 7% and 8%. Apparently the pushrods were too tight. I had only backed them off 1/4 turn from snug. I figure I'll back them off 1 full turn next time. What do you suggest? Aluminum pushrods and solid lifters. I made a intake test plate similar to Cotten's and found no intake leaks. Apparently my own ignorance cooked my pipe. I hate it when that happens.
I'll be inspecting the check ***** today. Verified timing gears alignment. Points plate about 2 degrees off, so I corrected that.
There was a little more metallic shimmer than I want to see in the oil when I drained it. Hopefully that will go away.
What exactly is supposed to hold the breather screen and separator in place? When I pulled the timing cover they were just laying on the bottom. I can wedge them in, but don't expect them to stay. The pics in my manual are vague.
Which brings up another question. What are the best manual(s) for the pan? I'm using the H-D Panhead Service Manual 1948-1957.
I'm learning I have a lot to learn...
I did a compression check and had 84% leakage on the front cylinder and 92% on the rear. Removed the pushrods and the leakage dropped to 7% and 8%. Apparently the pushrods were too tight. I had only backed them off 1/4 turn from snug. I figure I'll back them off 1 full turn next time. What do you suggest? Aluminum pushrods and solid lifters. I made a intake test plate similar to Cotten's and found no intake leaks. Apparently my own ignorance cooked my pipe. I hate it when that happens.
I'll be inspecting the check ***** today. Verified timing gears alignment. Points plate about 2 degrees off, so I corrected that.
There was a little more metallic shimmer than I want to see in the oil when I drained it. Hopefully that will go away.
What exactly is supposed to hold the breather screen and separator in place? When I pulled the timing cover they were just laying on the bottom. I can wedge them in, but don't expect them to stay. The pics in my manual are vague.
Which brings up another question. What are the best manual(s) for the pan? I'm using the H-D Panhead Service Manual 1948-1957.
I'm learning I have a lot to learn...
Advanced
Joined: Feb 2009
Posts: 57
Likes: 18
From: Fresno. CA.
Re: Low oil pressure & lean front jug
Clymer makes a fairly good service manual for 48-65 Pans, and you can get one from J&P cycles for $33.99 (pt.# 160-038) . I'm rather fond of aluminum pushrods & solid lifters myself, others will say to go with hydraulic lifters, it all comes down to how you're going to ride the bike.
Yes, solid lifters do make noise, but I've found through the years that it makes for easier pushrod adjustment & a more positive valve train.
When tightening the pushrods with solid lifters you want to have a cold engine, take the plugs out & slowly push the kicker by hand, starting with the front exhaust pushrod & make sure that the lifter is at it's lowest point.
Then adjust the pushrod until you can just barely spin the pushrod with your fingers, tighten the locknut & recheck the spin, repeat the procedure for the other three pushrods & you'll be done.
The oil separator & breather screen can be a bit of a pain at times, and yes, sometimes you have to play with them to get them to stay in place while you get the cover back on, especially when the engine is in the frame. They're normally put in when the lower end is out of the frame & lying on it's side. One trick I've used is cleaning the area thoroughly & used a little bit of 3M weatherstrip cement to make them stay in place while I get the timing cover back on, I've even seen others, including myself, use a little bit of heavy axle grease to do it as well (the little bit of grease will melt with the hot engine oil & won't do any damage to the engine).
Now something that I neglected to address the first time, I'm going to take a guess & assume that you're using either the original style 41-49 oil pump, or perhaps whoever you bought the bike from upgraded to the 50-67 oil pump, either way, when the bike is warmed up & at idle, the oil pressure should be at about 10lbs, and at speed, the pressure should be running at about 45-50lbs.
And remember this also, the further the distance between the oil pump & the oil pressure gauge, the more accurate the oil pressure reading, you can get a 'T'-fitting to go between the sensor on the oil pump for the idiot light on the dash panel that you can screw the fitting for the oil gauge line into, panel lights are fine for a quick glance, but I prefer to see what's actually going on with my oil pressure.
Finally, what AMF carb are you running ? If it's a Keihin, then let me know & I'll teach you a few tricks to make it work better, if it's a Bendix, even better. Most folks look with disdain on both of these carbs because they just don't understand how easy it is to get the most out of the two, not to mention just how simple it is to fix the two most common issues with two otherwise fine carburetors...
-Ron
Yes, solid lifters do make noise, but I've found through the years that it makes for easier pushrod adjustment & a more positive valve train.
When tightening the pushrods with solid lifters you want to have a cold engine, take the plugs out & slowly push the kicker by hand, starting with the front exhaust pushrod & make sure that the lifter is at it's lowest point.
Then adjust the pushrod until you can just barely spin the pushrod with your fingers, tighten the locknut & recheck the spin, repeat the procedure for the other three pushrods & you'll be done.
The oil separator & breather screen can be a bit of a pain at times, and yes, sometimes you have to play with them to get them to stay in place while you get the cover back on, especially when the engine is in the frame. They're normally put in when the lower end is out of the frame & lying on it's side. One trick I've used is cleaning the area thoroughly & used a little bit of 3M weatherstrip cement to make them stay in place while I get the timing cover back on, I've even seen others, including myself, use a little bit of heavy axle grease to do it as well (the little bit of grease will melt with the hot engine oil & won't do any damage to the engine).
Now something that I neglected to address the first time, I'm going to take a guess & assume that you're using either the original style 41-49 oil pump, or perhaps whoever you bought the bike from upgraded to the 50-67 oil pump, either way, when the bike is warmed up & at idle, the oil pressure should be at about 10lbs, and at speed, the pressure should be running at about 45-50lbs.
And remember this also, the further the distance between the oil pump & the oil pressure gauge, the more accurate the oil pressure reading, you can get a 'T'-fitting to go between the sensor on the oil pump for the idiot light on the dash panel that you can screw the fitting for the oil gauge line into, panel lights are fine for a quick glance, but I prefer to see what's actually going on with my oil pressure.
Finally, what AMF carb are you running ? If it's a Keihin, then let me know & I'll teach you a few tricks to make it work better, if it's a Bendix, even better. Most folks look with disdain on both of these carbs because they just don't understand how easy it is to get the most out of the two, not to mention just how simple it is to fix the two most common issues with two otherwise fine carburetors...
-Ron
Thread Starter
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6th Gear
Joined: Aug 2009
Posts: 10
Likes: 0
From: East Texas
I adjusted the valves on my '48 at zero lash and worked my way down to backing off 2 flats to get valve closure at operating temperature. Thanks.
My oil pump, as best I can tell, is a S&S 31-6001 (1936-1991) with a 31-6041 cover. The question I have here is exactly how to plumb to the heads, which have been tapped for external oil. I asked the folks at S&S but they didn't answer.
And my carb is a Bendix, and I don't know anything about them.
I'm on a job and won't be able to do any scooter work for a few days, but I'm soaking up what info I can get...
My oil pump, as best I can tell, is a S&S 31-6001 (1936-1991) with a 31-6041 cover. The question I have here is exactly how to plumb to the heads, which have been tapped for external oil. I asked the folks at S&S but they didn't answer.
And my carb is a Bendix, and I don't know anything about them.
I'm on a job and won't be able to do any scooter work for a few days, but I'm soaking up what info I can get...
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