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VX cam or K cam? (245/LH2.2/M46)

rallybrick

Member
Joined
Jan 12, 2007
Location
People's Republik of Socal
Been a while. A few months ago, I got back my old 86 245DL (which I had purchased in 1995).

This is a bit of a project car I'm doing with my two young sons (neither are driving age yet -- 8 and 11) who are turning out to be car nerds. Over the past few weekends, we pulled the M46, tore it down to install new synchros, and put it back together with great success. Now that the bad 2nd gear synchro is gone, it's fun to drive again and we're picking away at other projects. I have a bit of a parts hoard due to having project 240s and a race car way back when. There are a bunch of bits we could put on together.

The car's drivetrain is an unmodified 86 B230 running lh 2.2 with 375k miles on it and an M46. Never been torn down (or the head pulled). It's always been a solid runner. I have the following laying around -- what do you think we ought to use? We're mostly running stoplight to stoplight in the city and hooning over the hills to the post office.

VX Cam (NIB)
K Cam (used)

MVP aluminum adjustable timing gear (NIB)
Avalanche/Dale steel adjustable timing gear

Would like a little more umph around 2500-3000 RPM (or higher). I used to have all the bench racing specs and timing info in my head, but they've long since vanished. I'm leaning toward the K. Either needs to be able to pass smog in CA.

Thanks!
 
Not sure how 2.2 responds to cam changes as we do not have it here
I would start with the K on the factory timing gear and see how you like it. If not so keen on it give the VX a bash.

Hold onto the original cam incase you need to drop it back in for smog
 
I would use a mild aftermarket kam, with about 250degrees at 0.050 and something about 12mm lift.

Then when yours emissions is checked, just change the original cam.
 
A K-cam likely won't pass CA emissions but is more fun.

I would recommend advancing the ignition and cam timing some with the K cam as it will get you that 2500-3000rpm bump you seek. Advancing both helps you with the rough idle and lack of off idle power you get when running it straight up in a lower compression motor like the B230F. Advance the cam 2-4 degrees depending on what feels right to you and the ignition as far as you can get without ping on your desired grade of pump gas. You won't make as much on the low end but the motor should just pull itself gently into the power band. At which point the fun starts. When my '89 had a K cam it pulled nicely from 2k to redline after some experimentation.

The VX will pass CA emissions. Just put the timing cover on to hide the adjustable gear during the visual inspection. It won't be as fun as the K when you wring it out but it would be better for a daily driver once you dial in the cam timing.

Really the easy way is just to swap the M cam back in and drive the car a bit so the ECU knows what is going on before the test.

I wish CA would just let you modify OBD 1 cars to your heart's content so long as it passes the dyno test. If anything we should also be dyno testing OBD II cars as it isn't hard to cheat with all electronic tests (VW taught us that).
 
If you don't mind POTENTIALLY doing a camshaft swap more than once, I would definitely slap in the K cam first because it'll be faster and more fun, even if the low rpm torque off idle takes a large hit. As mentioned, more compression would be ideal, but that might be best for another time when your boys want to help pitch in with costs, hah.

When installing the K cam, set the valve clearances on the looser side of things, .018-.020" to make the camshaft "smaller" and have slightly less duration. This will improve idle quality, emissions and low rpm torque at the expense of some high rpm power that you don't really care about. I also would advance the camshaft timing 2-4 degrees and advance the ignition timing to somewhere around 16 degrees at idle with the vacuum disconnected. It might even like more than that, but it may not. Listen for detonation, but with the K cam it might even be ok at that point on regular octane.

Give it a whirl and see what you think! Also do a seafoam or similar soak on the pistons overnight when you do the next oil change to clean any carbon build up from the piston rings that is likely reducing your compression. Get some good fuel system cleaner in the tank to try and clean up the injectors and intake valves as well.

While you're at it, remove the pre-heat flapper and route the pre-heat hose to cold air at the front of the car somewhere for slightly more top end pull and power on the highway.

The VX is definitely an upgrade from the factory M camshaft, but the one experience I have with it did not leave me impressed(1986 244 AT). I only compared it to the T cam that was, relatively speaking, a torque monster. I think I liked the T cam better, even though it didn't pull as much at high rpm(I had set the valves around .012" with the T cam and retarded it 4 degrees). The VX in comparison just felt flat and meh. I never made it to the drag strip with the VX in it, but the T set up like I mentioned was good enough for a 17.3s 1/4 mile compared to the M cam's 17.6s when set up the same way.

Try them all if time and patience permits! You may or may not pass emissions testing with the K cam set up loose and advanced a bit. We don't have as strict of emissions testing up here, but I have heard that advancing the ignition timing isn't ideal for that, so you'll want to retard the timing to help heat up the cat as opposed to running it more advanced.

I would use a mild aftermarket kam, with about 250degrees at 0.050 and something about 12mm lift.

Then when yours emissions is checked, just change the original cam.
He has the VX and K to choose from. With a stock, unopened engine, a 250 degree duration camshaft at .050" of lift is too large. You need more compression to make such a camshaft be a good choice. For reference, according to Shoestring's MUCH APPRECIATED handiwork, the K's intake lobe has around 240 degrees at .050" and the VX's has around 232 degrees. A stock M cam has 196 and the T cam 212.

A K-cam likely won't pass CA emissions but is more fun.

I would recommend advancing the ignition and cam timing some with the K cam as it will get you that 2500-3000rpm bump you seek. Advancing both helps you with the rough idle and lack of off idle power you get when running it straight up in a lower compression motor like the B230F. Advance the cam 2-4 degrees depending on what feels right to you and the ignition as far as you can get without ping on your desired grade of pump gas. You won't make as much on the low end but the motor should just pull itself gently into the power band. At which point the fun starts. When my '89 had a K cam it pulled nicely from 2k to redline after some experimentation.

The VX will pass CA emissions. Just put the timing cover on to hide the adjustable gear during the visual inspection. It won't be as fun as the K when you wring it out but it would be better for a daily driver once you dial in the cam timing.
:nod:

With stock compression ratio, this is a no-brainer for the milder VX.
Well, it depends on your goals. The K will be faster on a drag strip. Haha. The VX will likely have a better powerband for a 3.31 rear end car with stock compression and stock engine management than the K, I agree. I would still try a K cam out over a VX though as the VX felt so darned bland to me when I tried it and the joy of a powerband that keeps climbing as the rpms rise makes me smile.

My NA performance sticky, if you want, here.
 
When i had the 1988 245, i tried A, B, and V.
I liked the A cam best.
In the 1983 with B23 (10:1) and ms1, K cam.
In newer cars, VX.
It all depends. Try a cam. Mess with it. You won?t see a big difference, but getting a somewhat normal cam in there is a good start.
 
Thanks all, esp. Kyle and Shoestring -- appreciate all the info you've put up over the years.

I'm thinking I'll try the K-cam with the settings Kyle recommended first. I have the valve tools, but no shims laying around, so I may throw it in there and then order a shim kit from IPD and adjust it properly once it arrives. Maybe having the boys do cam swaps and document the actual performance changes will be the fun thing to do at Christmas break. Is there a Scout merit badge for that?

I might use the MVP gear (see below) for ease of cam timing change for the time being until we really nail it down, as I recall that long term the similar IPD version suffered due to the steel bolts eating the aluminum. Thoughts on this long term?

Good reminder on the Seafoam trick. I did that years ago, but can't really get away with it in my current neighborhood.

I hate having to swap things when testing comes around. I have 5 cars at the moment and tend to forget what needs what before these bi-annual events, then I get caught off guard. The good thing is that this 245 is not a DD, so if it sits while needing work, not the end of the world.

spock345 said:
I wish CA would just let you modify OBD 1 cars to your heart's content so long as it passes the dyno test. If anything we should also be dyno testing OBD II cars as it isn't hard to cheat with all electronic tests (VW taught us that).

I have a 2.5l B21FT stroker, ported and polished 531 with T5 cam (SAM), ported matching exhaust manifold and big turbos sitting in pieces in boxes while my 82 242T still has a stock 398 with a Mitsu 12c on it because I'm shy of messing with emissions these days. And yet I had an '04 Subaru Forester 2.5XT that was a factory demo car that had been tuned by ESX and was like no other turbo Forester I ever drove (it was known as The Beast), but never had any issues with ODB II. :e-shrug:
 

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How did winter break go? Did you and the kids slap some fun into the car? :)

Use either timing gear, it'll be no problem. Just don't tighten the adjustment bolts too tight on the MVP gear. What is too tight? I'm not certain, but if they have washers under the heads of the bolts, you're ahead of the game and it likely won't be a problem. Definitely not if you aren't playing with it every weekend. I used to mess with it a lot on my 244 and use my Dale gear(like the one on the left in your picture).

I'd like to hear how it went or is going to go! :)
 
K cam is more fun. Be wary of advancing the ignition timing, though. It will definitely cause the Chrysler ignition module's knock sensor to go bonkers, especially if the tank has 87 or 89 octane in it. I set the timing on my parents' '85 245DL around 7 deg BTDC when I had a K cam in there. Felt somewhat weak until 2000 rpm, then, like a B23E, it took off. Was still producing power when the rev limiter kicked in at 5800 rpm, whereas, with the M cam, you're lucky to be producing power over 4500 rpm. I do recommend setting the idle around 850-900 rpm or so. Gets quite lopey at 750 rpm. One benefit, tho, the engine doesn't make that whine above 2500 rpm anymore. Sounds throatier. Mileage didn't take much of a hit, surprisingly. Went from about 28-30 to 26-27 mpg highway.
 
Howdy! So the holiday break was a miss. I had to fix the speedo and there was some drama with an elderly relative and corona and work having hiccups that required a bunch of attention that wasn't expected. We ended up doing smaller jobs on the 242T (clean install of some new 6x9s in the rear deck, sub/amp, and things that didn't require a whole day). And then I realized that I read the DMV renewal wrong and the 245 was up for smog, so I waited until I could get it smogged (it passed).

Yesterday I saw Kyle's post and I felt guilty that I hadn't done this cam swap. The bigger boy and I did it today. Here's where we are:

K cam
Dale's cam gear set to +2 deg
Need to adjust valves
Haven't touched ignition (at idle it hunts between 8-12 deg)

Turns out I have two VX cams and a newer blue IPD gear (plus the MVP) in my stash. I went with Dale's because it's a steel gear and the advancement intervals are 2 degrees (+/-0-6); IPD is 2.5 degrees (+/-0-10). It was also the dirtiest, so I felt less bad about installing it. I may swap these around later, who knows.

I think I've got a vacuum leak, so I'll solve that at some point soon. It idles around 800-900 rpm (it jumped from 750 to constantly 1100 rpm after I fixed another vacuum issue at the FPR prior to the swap). It's now a bit lopey.

I took it out and hammered it for about 30 miles. It was a little soft on starts, but Holy Hell! I've never had it actually keep pulling (not like a turbo or anything, but still) up to 6k. I got on the freeway and we actually still had some power going up hills and when I got the M46 in 5/OD, there was still something left. I didn't realize it, but getting on the freeway the first time, I got it up to 90 mph while merging without even thinking and it didn't feel like it was struggling. Never had that before.

I was shifting it hard and turning a corner onto the freeway when I heard something bounce on the bottom of the car. We went back and found a bolt. When I got home, we found two of the bellhousing bolts to the inspection plate were gone! I'd like to think that this is due to all the power that we've unleashed and that the car is going to start tearing itself apart because it's such a beast, but likely I didn't torque those two bolts properly when I redid the trans (or I've got a problem with my air impact).

So I'll need to get a shim kit and mess with the idle. This is Bosch ignition, so no Chrysler issues. I didn't hear any pinging.

Kids loved it. Both came back car sick, so mission accomplished with the goofy hoon wagon! Thanks for your help!
 
So, the ignition box has been changed out for the EZK parts from a 700 series car or to Bosch Breakerless from a K-Jet car? The reason why I ask is that the Chrysler system was used through 1988 on non-turbo 240s. Early cars (1981-early 1983) used a mopar coil and distributor, but 1983.5 and newer cars did use a Bosch distributor and coil, but still had the Chrysler computer box and single wire knock sensor.

Anyway, yes, it's a monster with the cam, and yes, you did forget to torque the bolts down. If the car had an actual Bosch ignition system, like the breakerless system, it'd pull strongly all the way to 6500-7000 rpm. My old '81 242, which had an actual B23E from Canada installed in it, pulled strongly all the way to the redline, which, in that car, was 6500...
 
I was aware of the Chrysler coil on up to 83, but was under the impression that this 86 was Bosch all the way through. I guess it's Chrysler, since it's original. I've never revved the engine high enough to hit the limiter.

Rally car with chipped LH2.4, tons of go-fast bits, and a T3 running 20 psi, yep -- bounced off the rev limiter a few times. Also had some pinging on that one.

Curious what you mean by the engine whine above 2500 rpm. I'm starting to hear what I think is probably bearing whine, but with nearly 400k miles on the clock, I'm not really surprised.
 
On LH 2.0 cars the limiter is right at 6000 rpm. On 2.2 cars, it's around 5800 rpm or so. Breakerless ignition says "what limiter? Go as fast as you want..." I suspect the EZK ignition systems cut power to the system relay at 6000.

It's the characteristic B230 exhaust note with the M cam. Always sounds a bit whiny above 2500 rpm, then, around 4500, it's screaming. The K cam gets rid of that noise...
 
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