COLLAPSED PISTON

jeepsr4ever

I believe you should bring it back to them. Almost all machine shops will have various levels of experienced staff. You may have had a new guy working on your motor. I would bring it back to them and tell them how rare this engine actually is and that you have alot of time into the downtime on the motor and you need to have this done one time and right. I would also be strait forward without being to rude about it. They screwed up and they know it. Good thing is that they will fix their screw up :t: As much as you want to tear their f@#$ing heads off. :(:

1980_Cj7

Mudrat wrote
1980_Cj7 wrote
Was just reading about the cam anti-walk kit in the sticky post on distributor gears. Would it be a good idea to install one on our re-rebuild?

300 broke-back miles? 8) Or is this a different cam 111!!! :idea: :-| :!: :t: 8) :?

Same cam, if we decide that grind will work for us. I was wondering if installing the anti-walk kit at this point might change the wear pattern that is already started.

1980_Cj7

jeepsr4ever wrote
You may have had a new guy working on your motor.

Sad part is it was the OWNER himself, the one and same guy I've been talking to about the remedy, who assembled our engine! What does that say for the place???

And yes, we did tell him already that these engines are rare and it took us 3 years to find this one. Also told him that AMC recommended going no more than .025 over on the bores. We're already at .030 over and now have to go more.

The other thing we reminded him of is how terribly long it took him to get our engine done. He acknowledged that too.

jeepsr4ever

I wouldnt quote AMC on the bore recomendation as many have run .060 over without issues. You should have him sonic check the bores so you can gurantee you wont need any block filler.

1980_Cj7

jeepsr4ever wrote
I wouldnt quote AMC on the bore recomendation as many have run .060 over without issues. You should have him sonic check the bores so you can gurantee you wont need any block filler.

MC, can you please explain that so we can talk fairly intelligently about it when we approach him again?

Do most machine shops generally have the capability to do the sonic testing? What does it show, thin, weak spots?

How does the block filler work? Does it reinforce the weak areas? Wouldn't that mess up the cooling?

Excuse my ignorance on this and help educate me.

ironman_gq

you usually only fill the block to the bottom of the core plugs. it helps keep the cylinders from distorting from heat and use and also helps to dampen vibration in the block. Overall it stabalizes the block and makes it stronger.

Mudrat

DAMN!!! Not sure on the legal side. Did you just ask for your money back, (machining, labor and material) that you paid him?

1980_Cj7

AMX69PHATTY wrote
Here is the specs I fould for what I believe is your Clevite Cam
and the results of the SilvoLite Compression Calculator for your 401.

OK you experts, in the specs above, what does the "Lobe C/L" mean? Our cam is No. 2 in the charts.

I'm trying to draw up a cam diagram, since we didn't get one with the cam. I have everything figured out and matching up, but that "Lobe C/L 110".

If it's the angle between the intake and exhaust lobe centerlines, I'm getting 140 degrees the way I'm calculating it.

Here's what I've come up with:
Intake opening 42* BTC
Intake closing 72* ABC
Intake centerline 105* ATC
Exhaust opening 82* BBC
Exhaust closing 32* ATC
Exhaust centerline 115* BTC
294* duration on both intake and exhaust
74* overlap
140* separation between lobe centerlines

Am I doing anything wrong?

82Waggy

On your chart, the Lobe C/L refers to the LSA, or Lobe Seperation Angle. The lobe centers for intake and exhaust refer to the point at which maximum lobe lift occurs relative to crank rotation. Two times the LSA minus the intake lobe center equals exhaust lobe center, or, two times the LSA minus the exhaust lobe center equals intake lobe center.

Mudrat

This stuff makes my head hurt - isn't there an easier way to figure out a good cam, the difference between dynamic and static compression ratios and "ultimate" flow rates ??? :-|

Holeshot

This stuff makes my head hurt - isn't there an easier way to figure out a good cam, the difference between dynamic and static compression ratios and "ultimate" flow rates ???

Sure is - call the cam maker of your choice with ALL the other specs of your vehicle & it's intended useage!!!

1980_Cj7

I was just comparing Fuzz's cam to ours. They are actually very similar. Ours: Intake opening 42* BTC Intake closing 72* ABC Intake centerline 105* ATC Exhaust opening 82* BBC Exhaust closing 32* ATC Exhaust centerline 115* BTC 294* duration on both intake and exhaust LSA 110* Fuzz's: Intake opening 42* BTC Intake closing 70* ABC Intake centerline 104* ATC Exhaust opening 81* BBC Exhaust closing 37* ATC Exhaust centerline 112* BTC 292* duration on intake 298* duration on exhaust LSA 108* Looks like the biggest difference is in the ramps. Our .050 duration is 218/218, Fuzz's is 246/250. Also, our lift is .488/.488, Fuzz's is .500/.510.

fuzz401

my cam card

1980_Cj7

Yeah, I just realized I screwed up in my comparison above. The valve events I showed for yours are at .050. I'm working on adjusting them so it's an apples to apples comparison. Stay tuned. Previous post is corrected now.

1980_Cj7

Next chapter in the continuing saga... We were at the machine shop that screwed up our engine last night to see what agreement we could come to. The owner was very apolgetic and most cooperative in helping us get our engine back in shape. We presented him with a list of parts we wanted replaced that came to over $1000, and he had no problem with that. We told him if he could get the parts at a better price than us, no problem, just give us the parts. If not, give us the money and we'd get them. We agreed that we would get the exact parts specified. He was willing to do the machine work and assembly at no cost to us also, but wouldn't pay to have another shop do the work. We decided we wanted to have the machine work done elsewhere, and agreed we would eat that cost. (Now, I just hope the new machine shop bill doesn't get too big.) Now we're gonna get the engine to the new shop ASAP and start making some progress finally.

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