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Going to replace the cam IN-CAR tomorrow on the Road Runner.

I've worked on engines with replaceable individual lobes...... A Chicago Pneumatic Diesel Generator..... Here's a picture of a smaller one... This one is 450 Hp, The ones I worked on were 720 HP @ 320 RPM's... Navy stuff.... And yes, we did replace a few lobes that had gone flat....

Screen Shot 2021-05-24 at 3.28.06 PM.png
 
Ok I think I figured out why the lobe got hammered. When I pulled the oil pump shaft out I noticed that it was forward of the gear a tad and not centered. My thoughts are that the aluminum bushing that was in there caused the shaft to go off center pushing the cam farther back than it should be. Just a guess. But I have it going back together and I replaced that bushing with a bronze bushing.
D093C22F-8948-497F-BE57-1BD37662BE06.jpeg
FFB3442B-1C99-4953-A834-DF45B6FF03F5.jpeg
FC617F97-EDC2-4B20-98F3-B396D3D975EB.jpeg
D4AB6E9D-8ED9-4E7D-89B9-5CABC8F0BDB2.jpeg
18752D12-D39D-439D-8848-AA1A00FE3627.jpeg
 
BeepBeepRR said:
Ok I think I figured out why the lobe got hammered. My thoughts are that the aluminum bushing that was in there caused the shaft to go off center pushing the cam farther back than it should be.
Click to expand...

OR the lifter was just a POS.
OR the bore was a little tight and the lifter didn't spin.
OR the hardening on that lobe wasn't deep enough.
 
On the topic of cam walk. Maybe someone here can verify that my thoughts are correct.

I made a couple example pictures.. Now not to scale but I hope it helps to give an idea.
First off the aluminum bushing was completely trashed and the hole for the oil pump shaft was oblong and the shaft gear was riding more towards the front of the cam gear. Is it possible that with that gear forward that it pushed the cam back causing the rear most lifter to ride on the outer most part of the lobe. Here are some examples Of what im talking about.

Right is front of the engine
shaft.png

riding more towards the front of the cam gear would force it backwards.
shaft2.png


Here is a picture of the wear on the back of the cam sprocket.
IMG_4518[1].JPG
 
I don't think so. Based on your logic, I'd expect more lobes to be damaged, not just that one.
 
Kern Dog said:
I don't think so. Based on your logic, I'd expect more lobes to be damaged, not just that one.
Click to expand...
I see your point. But, my buddy also asked me when the engine was built. I said We got the car in 2016 But the previous owner had it for a couple years. And that the engine was built prior to him getting it. So I would say probably around 2010. He said that would be around the time when everyone was building **** cams and even shittier lifters.
 
Well, If all goes right I will break in the cam Saturday. I have probably a couple more hours left on it just kind of dicking around on it. After work for a few hours. Anyhow fingers crossed that all goes well.
 
I bought the lifters almost 2 years ago prior to the covid deal. The cam was purchased a month ago. Now a new damn problem lol. I noticed the front seal on the PS pump was dripping. Apparently all night and now its empty. I'm pretty sure its a saginaw pump anyone got a part number for a rebuild kit.

IMG_4520[1].JPG
 
Or buy a rebuilt one.....
I'll send you a used one FREE if you pay for shipping. I have several. They might not leak.
 
The lifters always put a rearward thrust on the cam, thats how it's designed... the lifter bottom is slightly crowned & the lobes are slightly tapered taller in the rear and shorter in the front... So the valve spring pressure always pushing the lifter down also always puts rearward pressure on the cam... Thrust is taken by the back of the cam gear and the face of the block...

When people put roller cams in the rearward thrust is eliminated because roller lifters & lobes aren't tapered/crowned... That's why a roller cam requires a thrust button be added...

All that said no the gear didn't push the cam back causing a lifter to eat a lobe...
 
It’s alive made it through cam break-in now just working out some bugs here and there. I’m pretty sure I have to drop the pan so I can replace the rear main seal. I’m a dumbass and had the engine out 3 years ago and didn’t do it then. I’ll pay for it now lol
 
Kern Dog said:
Or buy a rebuilt one.....
I'll send you a used one FREE if you pay for shipping. I have several. They might not leak.
Click to expand...
I found the kit for the saggy 18 bucks at auto zoo. If it doesn’t work I’ll hit you up. Pretty sure it’s just the seal behind the pulley.
 
BeepBeepRR said:
It’s alive made it through cam break-in now just working out some bugs here and there. I’m pretty sure I have to drop the pan so I can replace the rear main seal. I’m a dumbass and had the engine out 3 years ago and didn’t do it then. I’ll pay for it now lol
Click to expand...
congrats :thumbsup:
 
Next up will be getting the Sure Grip put together and installed. Then I have to clean up that wiring from when I replaced the heater core and rebuilt the box. I forgot to go back over to do it. THe car was 20 miles away. Easy to forget when you don't see it every day. Should be road ready soon. Lots of little stuff.
 
The kit I found on autozone was not the correct one. The main part I needed was the shaft seal and the one that was in the kit was way smaller. So I ordered the actual part number from Oriellys. Was able to get it clean enough to see it. In case anyone else needs one the part number for a saginaw power steering pump shaft seal it is 5686644 or this is the alternate PN SKF-7475
 
Let’s talk about fate. Went to the flea market with a buddy and got this for 2 bucks.
5F432BE6-CBA2-4C05-855F-6CB96D1A0330.jpeg
 
Kern Dog said:
What is that?
Click to expand...

Sneaky Pete is a device thats supposed to help replace a rear main seal.... Accept it's for the old rawhide/asbestos seals... I've replaced hundreds of seals including old rawhide seals... I've never used/needed a Sneaky Pete....
 
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