Final days of the 401 on the dyno

etjeep

Jeff,

Your vids clearly indicate additional oiling mods are not needed (assuming the oil passages are clear). If I had I seen your vids before I added this line, I would not have wasted my time and $30 (IIRC).

So I understand your comment not to add this line because it is not necessary. Do you think the relatively small flow rate at this location would be enough to cause lack of oiling elsewhere? I don't have flow data, but I can't see a couple extra squirts on the chain hurting. Its easy enough to cap though, even though its already installed.

Getting back to the cam gear wear, Jeff said ‚ÄúI believe my problem was excessive oil pressure resulting in the cam gear trying to turn the dizzy/oil pump shaft beyond it's designed operating torque input.‚Äù 900 Hp may be the limit on the stock oil pump shaft, wonder if a stronger shaft material is warranted.

There was another Q I wanted to ask you.....I cut out the middle of my valley pan gasket http://rides.webshots.com/photo/1465998733069564115yGMllG
to do the other galley oiling modification. Was I dreaming or did I hear somebody say they would leave the valley pan gasket off due to the massive quantity of oil in the valley. If I was dreaming, please ignore, otherwise I would be interested in learning why. This thread has been excellent tech.

Blown7

etjeep wrote
Jeff,

Your vids clearly indicate additional oiling mods are not needed (assuming the oil passages are clear). If I had I seen your vids before I added this line, I would not have wasted my time and $30 (IIRC).

So I understand your comment not to add this line because it is not necessary. Do you think the relatively small flow rate at this location would be enough to cause lack of oiling elsewhere? I don't have flow data, but I can't see a couple extra squirts on the chain hurting. Its easy enough to cap though, even though its already installed.

Well I'm certainly not a expert but the issues as I see them for the added line are:

Vibration fatigue of the line over time.

The extra oil could always be used for better items like your bearings.

The timing cover area has more than enough oiling[/b].

Getting back to the cam gear wear, Jeff said ‚ÄúI believe my problem was excessive oil pressure resulting in the cam gear trying to turn the dizzy/oil pump shaft beyond it's designed operating torque input.‚Äù 900 Hp may be the limit on the stock oil pump shaft, wonder if a stronger shaft material is warranted.

The 900 Hp isn't the problem, or the material of the oil pump shaft. Its the TORQUE required to turn the pump if the oil pressure is too high whether it be at idle or Wide open throttle actually I was talking about the gears themselves.

There was another Q I wanted to ask you.....I cut out the middle of my valley pan gasket http://rides.webshots.com/photo/1465998733069564115yGMllG
to do the other galley oiling modification. Was I dreaming or did I hear somebody say they would leave the valley pan gasket off due to the massive quantity of oil in the valley. If I was dreaming, please ignore, otherwise I would be interested in learning why. This thread has been excellent tech.[
/quote]

Most people leave the valley pan and either cut it, or install the valley line close to the engine block to prevent interference. I cut the valley pan myself but on the reinstallation I will use the SCE gaskets and a crankcase EVAC system. You have to use the valley pan if you don't have a intake pan (sucks oil into PCV valve)

Jeff

Blown7

So moving on the pushrods are fine

The valve geometry is correct

Upon removal of the oil pan clean, clean, clean, except for undrained oil. And all the little bottom end parts are still where they need to be.

Maybe I can get to the bearings tomorrow.

Jeff

etjeep

Jeff, Thanks. Looks good.

Blown7

Well it's been a few weeks, and I have removed all the bearings for checking and after inspection I have rolled in all new bearings. When people say wash that block after machining they mean it. I washed, pressure washed, washed with gun barrel brushes, oil galley brushes, washed until I thought I could drink clear water out of it and still I had some debris stuck somewhere. It ended up in the bearings, but then again thats what they are for (besides a foundation for oil). No damage to the crank so I'm good to go.

Stats
Clevite 77 bearings, copper back, standard size.
.003-.0035 clearance.
All bearings show high load (but thats to be expected with Nitrous, and remember I had oil pressure issues in the beginning.
Id like to have a choice of High Performance bearings but what choices have we got for our AMC's? ACL or Clevite. MC should pursue a new vendor.

Connecting rod bearings, number 8 cylinder. The oiling hole is not standard I installed it because I have drilled conn rods for floating pins.

Number 8 journal.

Notice the rub on the crank from the Carillo rods. No big deal. No temperature discolor just a rub, it'll wear in.

Bottom cap of number 8 conn rod, notice the rub on the cap from the crank cheek.

Number 5 main journal.

More pics comming.

Blown7

The full set of mains, the oiling hole has been drilled out to .343 diameter.

Thrust sides

Number 5 main journal

Back side pressure marks

Jeff

jeepsr4ever

:-| With the amount of power you were putting out you would expect to see some wear but the wear on the thrust is massive. I wonder if we arent seeing some dirt from assembly

82Waggy

Dirt followed by bearing babbit material. How do the cam bearings look? Did you clean the crank oil passages out good too?

Blown7

jeepsr4ever wrote
:-| With the amount of power you were putting out you would expect to see some wear but the wear on the thrust is massive. I wonder if we arent seeing some dirt from assembly

Well MC you would think so, however the thrust faces on the bearings are not coated. And actually only one side shows a little rubbing.
This is the only side that has a little rub. Thats the problem with Clevite bearings they don't coat the thrust side.

Yes crank was cleaned well too, however I did alot of machining on the block, drilled the main galley holes bigger etc.

Jeff

Blown7

Conn rod bearings.

Goose

How many hours on the motor? :shock:

Blown7

5-7 hours just dyno time. Hard to be specific about. Jeff

Goose

That supports my theory.. Most of the wear an engine experiences happens in the first 500 miles..after that (everything else being good) the wear is very slow. bearings etc .. I guess this may be one of those duhh yea we knew that kind of moments.. But I always felt that guys who swear by "tight" engines really didnt understand that by the time its "broken in" It's no tighter really than one built looser.. What do I know though.. I have 2 crescent wrenches (AKA Speedwrench) and twelve hammers in my toolbox.. And an unhealthy fascination with acetylene. :?

1980_Cj7

Wow, and I thought our bearings looked bad after only 300 miles. Of course we weren't making the kind of power Jeff is, and also had detonation problems from the machine shop installing the timing gear wrong.

jeepsr4ever

It almost looks like crank flex Jeff. I see what may appear to be chatter on one of the thrust bearings. It looks like you knicked the crank with a rod bolt on one of the rod bearings. I would also add that your oil viscosity looks to be too high for the bearing clearances. I also think the bearings that show the pitting could have been poorly plated.

82Waggy

MC, Do you think the pitting is from poor plating? Looks to me like he just had a bunch of grit that got embedded - maybe babit material that got knocked loose by dirt. Also looks like the crank was draggin around some debris or a burr on the crank that got into the copper - maybe from a poorly chamfered hole in the bearings or crank. I don't think the bearings themselves are faulty. Clean that sucker, install new bearings, and go again!

jeepsr4ever

It was either dirt or a knick from installing the rods. I am going with the dirt theory. Check your end play Jeff

Blown7

jeepsr4ever wrote
It was either dirt or a knick from installing the rods. I am going with the dirt theory. Check your end play Jeff

Yep MC it was dirt, or more specifically cast iron. I actually inspected the bearings with a high power magnifying glass and found cast iron specks. I did alot of drilling on the oil galley passages. And I cleaned the passages to what I thought was spotless, obviously I did get it clean enough. It almost impossible to nick a crank with the Carillo rods as the bolts are not part of the beam assembly. If you did nick the journals which I did inspect one would find a straight line across the journal like a chisel mark from the bearing parting line. The bolts go on thru the cap side at assembly. I think some crank flex was happening as this is about all the horsepower the stock crank can handle. I definately think I am at the horsepower limits of the engine.
As for one bearing loosing the plating I think the cast iron chips and a combination of substandard Clevite plating caused it.

I wish that some vendor would step up with some high performance AMC engine bearings.
Clevite offers several grades of bearings for other engine applications but only one grade for AMC's.

Heres a some pics of Carillo parts.

And then the thought of the bearing clearances being set up for the viscosity of 20 weight oil using the Machinerys Handbook.
Check out the section on Journal bearings MC. interesting info there.

So I'm still researching bearing options I was talking to someone that said Federal-Mongol was making them.

Jeff

Goose

You know.. I have read the concept of crank flex in this thread.. but you know I just read right over it and didnt think about it, till just now.. Crank Flex??? yikes.. thats enough to scare the wadding out of ya..(I mean if ya think about what happens when that crank decides to stop flexing and break... :shock: :-|

82Waggy

I don't think there is a bearing made that will endure having iron filings ground through them. Clevite bearings are used on a lot of high powered stuff without problems - I don't think they are at fault here. I think Federal Mogul and Clevite bearings are the same part these days. As far as I have been able to find, AMC bearing makers include Clevite, ACL, and King. Don't know if there is much significant difference between them, aside from the ACL's being the full groove type.

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