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Good to meet you today Gabe And thanks for the 4Bbbl carb and pristine windshield!!!
My J20 will love 'em.
Don't forget to shoot me your email so I can pay you!!!
ktrosper wrote:Good to meet you today Gabe And thanks for the 4Bbbl carb and pristine windshield!!!
My J20 will love 'em.
Don't forget to shoot me your email so I can pay you!!!
Great to finally meet you in person too. Hopefully we can do it again in a less urban setting!
shimniok wrote:I am not annoyed. I am hoping to learn a lot which I already have!
It's all good man. Keep the questions coming.
Now... Where did I put my old copy of desktop Dyno?? Hmmm.
I played with cam grinds on DD for ages. I recall simulating a (crane, I think) 256-ish adv on a 401 but it seemed to be really anemic on the top end compared to even a 260-ish. I keep saying ish of course because advertised duration isn't quite the whole story anymore than peak HP or even peak TQ. In desktop Dyno you input cam timing events which are what really paint the picture. So some 260 adv were better than others. In addition to modeling 256-270 duration cams for half a dozen makers, I also tried a couple oem cams I found posted on the interwebs. One that I was intrigued by was a particular Pontiac grind that seemed to do better than my other favorites in terms of flat torque, relatively low peak TQ RPM without giving up much top end (4500rpm). I tried stock AMC cam (per timings from some site) and either they were wrong our our cams stink.
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The OEM cam grinds are interesting, without a doubt. The stock 401 cam was split pattern with 114° of lobe separation. I wish I could get a copy of desktop dyno working to model that 440 motorhome grind from earlier in the thread.
Well it's good to hear I was only annoying myself. Sorry if I offended anyone be leaving for a while, I just needed to take a break from asking questions and nerd out about it for awhile.
It didn't take a week as I had anticipated, but I made an inventory of what I want from this Jeep. What I need from it. And what I don't.
I want easy tuneability, reliability, and efficiency. I also want at least 280hp.
I need it to be reliable. I need parts to be readily available.
I don't need anything super fancy. I don't need anything really sensitive to altitude or temperature.
So I added up the cost of a CDI ignition, carb, tuning supplies, wideband O2, intake, new egr, and distributor rebuild stuff to a total of $1,366.73. For the same or less I can buy a TBI setup ready to go. And gain tunability later after I buy some stuff from Moates.
When it comes down to it the only reliability issues I've had with my other TBI is having a hard time tuning past the really poor intake design, and fuel delivery. Even though it's all used it been totally reliable. So without the janky Intake, and with my new tank that is setup for an in tank pump, the TBI should do everything I need. It might not flow quote enough air, but that issue can be remedied a few ways.
I think I'll go with Affordable Fuel Injection but that's still open to debate. I need to call them and see if they can accommodate my cam choice and some different wire terminations or if I will need to make some changes. I'll get a quote from Bill and a few others as well.
Good plan. Do you know if "mild RV cam" and motorhome cam are the same? Seriously. I followed a thread for about a year on another forum and I never figured out if that meant the same thing. I think an intake is not to expensive to add to take that out of the tuning problem. I look at Dr. Marnaeus problem and wonder if a cam and intake change would help him.
'81 Cherokee Chief 81 WT Chief/MSD 6/Holley Sniper/ Rusty 4" Spring lift/ Bulltear oil adapter/K&P Engineering Oil Filter/ NP 208/ Serehill Light Harness/KC LED Headlights/ Evil Twin Fab Roof Rack and sliders/ Ross mirror mounts.
az chip wrote:Good plan. Do you know if "mild RV cam" and motorhome cam are the same? Seriously. I followed a thread for about a year on another forum and I never figured out if that meant the same thing. I think an intake is not to expensive to add to take that out of the tuning problem. I look at Dr. Marnaeus problem and wonder if a cam and intake change would help him.
I believe it would! I believe the issue is that the atomic EFI system is for feeding a lot of horsepower. And is having trouble learning what his engine needs.
An RV cam is a Recreational Vehicle cam. That's a very broad term, but think of an RV cam as a little more than stock. A motorhome cam is something designed to move a heavy vehicle as effectively as possible. Some are also called towing cams, truck cam, truck pull cam, etc...
I'm going to stay with the stock intake for now because that's what the chip will be tuned for.
I admit to being a total noob at cam grinds. I would have to take someones word that it would work. There are a lot of variables that I just don't understand or know about. I would have to ask an expert. Include deck height, different gaskets for deck height spacing, pistons, and other stuff and I am lost pretty quick. The most changes I have done is add a Performer intake and a Holly Truck Avenger to a AMC 360. Lol.
'81 Cherokee Chief 81 WT Chief/MSD 6/Holley Sniper/ Rusty 4" Spring lift/ Bulltear oil adapter/K&P Engineering Oil Filter/ NP 208/ Serehill Light Harness/KC LED Headlights/ Evil Twin Fab Roof Rack and sliders/ Ross mirror mounts.
Profile intensity is how quickly the lifter goes from open to closed. AMC'S have big .409 lifters so we can have a fast opening rate. The stock cam lazily opens and closes the valve. The summit cam opens and closes about at fast as a profile for a smaller lifter in say a small block Chevy would. The really nice grinds for AMC take advantage of the large base circle of the lifter to throw the valve open faster and whip it closed. The advantage of that faster opening and closing is more time in "peak lift" where more air flows in through the port and increased velocity of the intake charge. Let's compare the stock cam to a real neat Engle grind I found...
As you can see, the Engle grind spends about half as many degrees of crankshaft rotation opening and closing the valves. So it's more "intense". If we combine the intensity of that cam with it's relatively short duration and it's tighter lobe separation angle (112° vs 114° stock) we get a cam that should idle smooth with tons of vacuum, produce absolutely fantastic tourqe, and produce peak horsepower in the upper 5000's of rpm. I retract my previous statement about the 440 motorhome cam. This Engle 5054H is the ultimate AMC tourqe cam! One of the old members Dusty ran a split grind from Engle featuring the same profile and reported a stable idle as low as 300 RPM! 300! Thats insane!
I'm really tempted to get one of those engles instead of the K8600. But I'll need new pushrods and valve springs. I also need to call and see how much they want for one. As long as I'm festering cash I might as well bleed some more right?
Running the numbers, I feel selling the parts wagoneer with the good floor and rebuilt engine may have doomed this project. I thought I was going to be making more than I am but im only getting 25 hours a week. I'm going to have to quote this out some more but it's not looking good.
Nikkormat wrote:Running the numbers, I feel selling the parts wagoneer with the good floor and rebuilt engine may have doomed this project. I thought I was going to be making more than I am but im only getting 25 hours a week. I'm going to have to quote this out some more but it's not looking good.
That sucks man... I feel your pain. I had thought we were on the road to recovery and I could actually give my CJ some much needed attention. Not looking likely now. Can you imagine the monsters we could all build if we were independently wealthy!?!