Help! Wiped cam lobes? - Video inside

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RRR;Thanks for the kind words.
I think SGbarracuda (post24)is on the right track,as are others.
However, I have a different theory.I am imagining a lifter with little to no oil in it.In this case the plunger is able to freely move throughout its operating range.So when the lifter is on the base circle,that little spring inside it takes up all the slack. Then as the lobe starts to raise the lifter, the pushrod just moves down into the lifter until it bottoms.Then finally, the lobe is able to transmit motion to the rocker arm, how-be-it, not very much. This is a theory.
Its pretty simple to prove. Put that lifter on the base circle, then just push down on the rocker arm.If Im right the rockerarm will easily move the pushrod down into the lifter.
If Im wrong and nothing moves,then the lifter is full, and its hooped.
You may be able to shine a lite down beside the pushrod tunnels and see the lobes, but I think the angle is wrong. However if you remove the rocker-shaft assy and the one p-rod, you may be able to fish the lifter out of the bore(they make a tool for that).Once the lifter is out, lobe/lifter inspection is easy. If the lifter wont come out of the bore, SGbarracuda probably nailed it and the bottom of it is wiped, and mushroomed.Then the intake needs to come off for further inspection.
And if the lobe/lifter is wiped, you know whatchagotta do.
I, among others,have gotten away with not doing a complete tear-down and thorough cleaning of the parts. I think thats poor practice. That/those lobes went into the oilpan.Nobody can say they ended up in the oilfilter, 100%. I got lucky, and have gotten another 100,000 miles out of my engine.
 
He has a wiped cam lobe. That's my theory and I'm stickin to it.
 
You will get no argument from me on that.
Thats easy to prove too.
Put that lifter on the base circle and yank on the p-rod. If it comes out sideways, or seems to want to,(inso far as the tunnel allows) and is not buried in the lifter,the lobe is gone to nearly gone.
And; it will make an awful clattering noise while idling.
 
I learn stuff from y'all everyday. It may not be my thread but thank you. :) I may have this problem one day. Hopefully not though.
 
Yes, I didn't think everything was moving in the first videos, either. However, the expectation that all rockers will move the same amount is misplaced IMHO.

With the advent of dual pattern camshafts (e.g. Comp Cams Dual Energy line) there can be a difference in lift of exhaust and intake valves. Typically, the smaller exhaust valve receives compensation from the cam designer in the form of greater lift. That said, all intake valves should move the same amount and all exhaust valves should move the same amount.
 
Alright, Looks like i'm going to have to take her apart. I'll post some photos of the teardown and damage if anyone is interested. Probably going to be a few weeks though, I've got to collect some parts. Thanks for the input everyone I appreciate it.
 
Nins and peedles.
I amost aaughed my lass off.
Parts? What parts? We are not that far yet.
Remove the intake first. Lets see whats what. Actually, it would be real nice to hear/see that beast idling first,with the covers off. And a nice slow pan of each side, showing about 4 valves at a time, lasting about 10 to 15 seconds per side. If theres any clattering going on, zero in on those.
Please?
 
Alright everyone, thanks for the help! Looks like I'm going to have to make a decision here. I'm going to remove the intake and get a look at the lobes. If the cam is wiped is it feasible to just rebuild the top end or will there be a ton of metal debris requiring a complete rebuild?

I don't think I have the space or time to take the bottom end apart and have the block cleaned and everything else. I don't have much more money to invest in this project. I think I could handle just doing the top end myself, and I would make a write up with pictures about what to do and not to do as a newbie. I guess i could buy a second hand motor or something but that may open up another can of worms. Any suggestions? This whole situation is bumming me out.
 
I'll try to get videos of it running with the valves off too. stupid weekends are always so busy though. next one is mothers day, and then the maker's faire which is awesome if any of you are in the area you should absolutely check it out. http://makerfaire.com/
 
perko said:
I don't think I have the space or time to take the bottom end apart and have the block cleaned and everything else. I don't have much more money to invest in this project. I think I could handle just doing the top end myself, and I would make a write up with pictures about what to do and not to do as a newbie. I guess i could buy a second hand motor or something but that may open up another can of worms. Any suggestions? This whole situation is bumming me out.
Click to expand...

Don't get bummed, It sucks some times but the gratification is outstanding when it is completed.
 
Hey all. I finally got the manifold off to get a look at the cam. I've never really seen a camshaft, especially one thats trashed so I can't convince myself one way or another. It looks worn in some places but it doesn't look like its missing an entire lobe or anything. Heres some pictures. what do y'all think? Let me know if a better angle or something would help. Thanks for the advice and helping someone whos in a little over their head!
 

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The right hand lobe of the group of 4 shown in the 3rd lix looks odd. And the 2nd from the left lobe in the group of 4 in pix #4 looks like it may be really turned down in size and the normal shine&brown colorations are nowhere to be seen; I think that one is the 'lazy' rocker's lobe if the pix of groups are ordered front to rear.

Turn the engine over by hand and slowly examine the lobe shapes. Look in particular at the shape of the lobe that is operating the lazy rocker; see if the toe (or peak) of the lobe is flattened or misshapen compared to the others and if the heel (smaller part) is abnormally small; it will become pretty obvious if it is worn down or mishappen. Then look at the tops of the lifters and see if they are popping up essentially equally out of their bores; you might want to compare intakes to intakes and exhausts to exhausts here. Then pull the rockers off on the passenger side, and remove that lazy rocker's lifter and pushrod and another one that is moving properly and compare them side by side; press in the plunger in the center of each and see what happens.

BTW, I just looked at this for the first time 5 minutes ago, and spotted the 'lazy' rocker on the first view of the 2nd video......you young guys need to bone up on things to keep up with us 60+ guys LOL
 
Pull the rocker shafts, then one at a time remove the lifters and look at the base, and return them to their bores - do not mix them up. Hold a straight edge on their bases (cam contact surface), they should be slightly convex, a high mileage cam may be flat - if any of them are at all concave they, and the cam are likely trash. If you have truly wiped a lobe you will know as soon as you see the base of the lifter - it will be visibly concave.
 
the 268 I just gave to Inertia doesn't show any obvious wear on the lobes but a quick look at the lifters revealed 3 that weren't turning by having very obvious grooves in the bottom end so I'm with d55Dave start checking lifters , mine didn't put any metal in the pan and didn't backfire but I chased that ticking sound for months before taking extreme measures { bought a 410 LOL } . Once I showed Grant the lifters the cam went straight to the regrind shelf , If he ever gets around to building his car I'll probably give him a very good Hydralic Roller for his stroker once I replace it during my strokers next refresh .
 
Alright. I'm going to go turn the engine over by hand and then pull the lifters out. Is the gold/silver coloration on the lobes a normal look for an older cam? There's some abrasions and some pitting on a few lobes as well (far right lobe in second close up). Is pitting and abrasions a normal wear pattern or is it totally unacceptable?
 
So... #6 cam lobe is round and you could take shots out of the lifter. I guess I have a few options now.



1. rebuild the current engine (its just a 318 and its already tired... and i've never rebuilt an engine). Although, there is a nice machine shop 10 minutes away called skips.

2. buy a used engine.
The guy I buy my tires from offered me one that he was going to put in a 76 dart sport.

There's also a few on craigslist.
http://sfbay.craigslist.org/eby/pts/5019594876.html
http://sfbay.craigslist.org/pen/pts/5035262879.html
http://modesto.craigslist.org/pts/5022462800.html (comes with a 727? but he says he pulled it to put a big block in)
http://sfbay.craigslist.org/sby/pts/5022748982.html

3. put a new cam and lifters in and then find religion.

4. cut my losses.
 

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Is this your daily driver? If not then no panic in getting it running right? This engine was running before??
Do it yourself. Get a cam lifters timing chain and gears.(dbl roller set)
You bought an old mopar so this is to be expected and doing an engine or parts of it isn't all that hard. Keep **** clean and triple chk whatever you do. Get a buddy to give you a hand. Female variety would be even better LOL
There is a ****-ton of good engine builders on here and lots will chime in to help.
Good luck and have fun!
 
not a daily driver. no panic, but the room mates aren't happy about me taking over the garage. I'm not opposed to fixing it but i'm not sure if I have the space. Can you pick an engine from the side? like from the front passenger quarter panel? my driveway is pretty steep just outside the garage and shes taking up a lot of realestate.

I've never rebuilt an engine before. I've got a book called "how to rebuild the small-block MOPAR" so that should help. I assume in a case like this I would need to have the block cleaned and honed by a shop to get rid of all the metal shavings?
 
I wouldn't pull the engine on a slope, especially if its your first time(no offense).
At this point, I would pull heads and see what you the cylinders look like. You got nothing to lose, then go from there and make your decisions.
 
You probably don't need to build the whole thing. Was it smoking? The oil filter probably got 99% of the metal shavings already. I would pick out a cam, lifters and springs and have at it. Summit 6900 comes to mind.
 
Assuming cost is an object, there are two sources for cams and lifters for less than $200.00 I can suggest. First is Rock Auto for a Sealed Power cam close to OEM specs for about $173. Summit Racing has a cam kit (P/N SUM-K6900) for $117.95 that includes free shipping. I don't know for sure who makes Summit's house brand cams. My SUM-K6901 appears to have been made by Crane. The respective web sites have specs for the cams so you can compare.

Late Add: All prices are for kits that include cam and lifters.
 
Crane makes Summit's cams.

Imagine that. Wiped cam lobe like I said all along. All of some of yall's wildest theories in the world cannot beat real experience.
 
nothing was smoking. Everything else seemed ok, although i'll admit I'm flying by the seat of my pants right now and I didn't have the car for long until this problem cropped. up.

Previous owner swore he and his brother re-built the whole engine about 40,000 miles ago for their mom before she got a honda and parked it. He seemed genuinely surprised when i let him know about the cam. He also had a whole shop and some completed projects if that lends him any credence.

I'll have to think about what do do. I'm considering just doing the cam and lifters and crossing my fingers. can't get much worse though. I am paranoid about killing the new cam during break in though after reading so many horror stores.

Whatever I do i'll make a write up with pictures so people can learn/laugh at my success/failure.
 
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