greetings and help kind ladies and sirs...

[Redwookie]

I am new to the forum so hello! I just typed out a huge intro and the **** thing timed out so AARRRGGHHH!!!! Anyways I am a new Jeep owner and am here to maybe get some help and maybe make a few new friends! So here's my deal: I just bought about 6mos ago a 1991 Grand Wagoneer that aesthetically at least is in great shape! It's even been featured in a few ads and magazines but I think the former owners never hear of "regular maintenance". So I just had a local shop rebuild the AMC 360. It was rebuil and I asked them to add a hotter cam. Well I opted for the Edelbrock Performer 600cfm carb, intake, and cam. They recommended the ProComp 260H instead for a Cam. I usually do my own work btw but with where I live right now that's impossible (high rise/tools across town). So I had it rebuilt with new cam/carb/intake. Now once I got the car back I had a local hot rod shop dyno and tune it. Well I'm less than impressed with the results! It came back and they told me they had to retard the timing a little more than they figured they would to keep it from detonating. Well it still does anyways under heavy acceleration. And the numbers, oh the numbers, 139rwhp and 197ft/lbs! What a dog folks! Now what do you guys think? This is my first Jeep/AMC. Always had Chevys b4. Did the shop rip me off? Or is about what you would expect from a 360 with those mods? I know its only like 8 1/4 compression stock but man! Little help would go a long ways guys and nice to meet ya too

[Casey]

Welcome!

There are quite a few members in AZ and they're pretty active off-road.

Sounds like a dog to me. I'm not familiar with the ProComp 260H cam, but my old 360 w/Edelbrock cam/intake/carb ran like a scalded dog. I never had it on a dyno, but it would whup a '03 Tahoe in a 1/4 mile.

Someone will be along with better 'facts'.

[Ristow]

260H is awfully wimpy. don't worry,i've been bit in the butt by letting "experts" pick my parts before myself.

still,it should be a little snappy.

what is the timing settting currently?

we're gonna need to recurve that distibutor for sure to eliminate ping-the vacuum advamnce specifically,and gain some needed timing back. also,the vacuum advance will be on manifold vacuum,giving it a crisp off idle.

[Redwookie]

Well first off thanks for your input and glad to meet ya both! Well I left the Hot rod shop yesterday in such a fluster! I felt violated! I didn't even ask about the timing. I'll have to give em a call when they open and ask em where they ended up with the timing. The real stink of it is the guys in that shop actually didn't even ask me before they decided to change from the Edelbrock Performer I asked for to the 260H! They just did it then after the fact told me I'd be better for my application! What a crock!

[Ristow]

if that's the case they'd putting MY cam choice in MY engine on their dime.

that engine properly set up should be able to run in the 12-15 degree intial advance. if they have it down around 5-8 it'll run sluggish.

[Redwookie]

Well I may just be doing that Ristow. I am waiting to hear back from a buddy of mine. My buddy owns a body shop and I actually sent the Wagee his way and he recommended the engine rebuilder and sent it to em. I just gotta make sure he didn't go ahead and ok them to do the change. Gosh I hope he didn't ok it! If he did I'm gonna have to just eat it but if not...yeah they are putting a new cam in their on their dime! So my Blazer is actually my off roader where the Jeep is all original except for our recent engine mods. Most guys on here wheel er like the original set up?

[Dumpy]

Greetings! Don't forget the Ma'ams in your title, too

[jaber]

Welcome to the land of empty pockets and unfinished projects....

I'm just up the hill a little N. of Prescott. I did a rebuild and used the Comp Cams 260H grind and have been VERY pleased with it. I also did a TBI and mine is very strong. I have not dyno'ed it, but it is fun to drive. You should look into doing the ignition upgrade, get the distributer adapter, cap, rotor, and coil from an '86 Ford 460. Very nice and inexpensive, you'll feel the diff.

Check in to the S.W. thread on the lower part of the first page.

[Chevelleguy]

You will not be very impressed with the Edelbrock Performer cam, it is very mild. Those dyno numbers don't look too far off base considering you are losing 80-100hp through the drivetrain.

[The PIG Smith]

WELCOME!

There was a posting here in the last few months discussing cam choices.
In that posting, there were many charts showing the performance of different cams in a AMC 360.
While the CAM favorite of most users here is the Summit K8600, there one or maybe two cam that the charts showed better performance.

The search feature is not always the most cooperative here, but if someone remembers that post and provide a link, I am sure that would help!

[Redwookie]

Nice to hear from all ya! Thanks for the input too. Hey there to you Jaber too! Big fan of Prescott myself! And sorry I didn't mean to disinclude the ladies! The shop is gonna get back to me this afternoon and let me know what they ended up doing timing wise with it. So I know that for some reason they say that they had to retard the timing further then they thought they should have to to stop the pinging. So I'm ticked cuz even still it's pinging when you floor it. Any ideas what else could be the problem on a newly rebuilt motor folks? I'm afraid the only thing else I can think of is physical damage inside a cylinder leaving an area to heat up I hope that's not it. Mostly b/c I don't want to have to deal with these engine guys anymore. But I can't think of anything else. Also if I get a chance to replace that turd cam any suggestions for something that has power but not so much I gotta start doing springs, etc...

[Redwookie]

Thanks Pigsmith! I didn't see that till after I posted last. Yeah a link to that would be great guys and gals And like I said above any thoughts on the pinging?

WELCOME!

There was a posting here in the last few months discussing cam choices.
In that posting, there were many charts showing the performance of different cams in a AMC 360.
While the CAM favorite of most users here is the Summit K8600, there one or maybe two cam that the charts showed better performance.

The search feature is not always the most cooperative here, but if someone remembers that post and provide a link, I am sure that would help!

[Tad]

Welcome from Tucson.
Can't tell you much about a 360 other than they look pretty good sitting in the yard.
That's a Ford engine?
Never mind, a Dodge?

[Serious Johnson]

Even though the engine is new, there are other systems that can affect ping -- EGR for one, and operating temperature for another. Could even be the jetting of the carb or wear on the distributor advance bushings or a half-dozen other things. How extensive was the rebuild as regards the ancillary stuff?

Often with non-stock setups, particularly an "RV" cam that builds cylinder pressure with short overlap, it can be dang hard to avoid ping. A custom distributor curve is almost mandatory for good power, as is precise carb tuning for non-stock conditions.

While it can be beneficial to spread the cam lobes a good bit (as with an 8600), that tends to drop cylinder pressure at low revs, to the detriment of off-idle torque in an already low compression engine. In my opinion, something as aggressive as the 8600 cam (which is what I run) needs at least 9:1 compression to maintain something close to stock low-end jump. But you sure as hell won't ping with those valve events unless you go nuts twisting the distributor or have something else screwed up.

The old school way of getting enough timing while avoiding ping was to run the carb jets rich and keep the motor as cool as possible. The former nets crappy fuel mileage and mundo smog, while the latter is hard to do when you have a goofy slushbox tranny heating things up.

Thing is, the later iterations of these silly rigs tread a very fine line of driveability and certifyability. Money for Jeep development was tight (or gone by '91), and corners were cut to keep the lights on at the plant. The good thing about that is the possibility for a numb-nuts non-engineer to improve the hardware without too much trouble or expense.

To my mind, the simplest and most effective way to get one of these later models to run decently for any stretch of time is to convert it to GM throttle-body fuel injection. That lets you install a knock sensor and give complete control of fuel & ignition to the stinkin' computer. At least then it's not your fault, until you learn to burn chips .

S.J.

[Chevelleguy]

The reason it pings is because the factory distributor settings allow for a LOT of mechanical advance. You have to (1) spend a Saturday recurving and sorting out the distributor, or (2) replace it with an HEI unit that is more tuner friendly.