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Comp Cams Choices?

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On Comp Cams website they state in the notes for the 4.0L camshafts that only one is for fuel injected (Grind#: X4250H-13, Part#: 68-232-4). It’s puzzling. On retailers (Summit, etc) websites nothing is said about it. My choice is the Part#: 68-200-4, Grind#: 252H due to your build channel. Given Comp Cams choices and whatever someone’s personal choice is, does it really matter between fuel injected or not just as long as it is a hydraulic flat tappet camshaft? Ref: http://www.compcams.com/Company/CC/cam-specs/cam-search-results.aspx?sc=1&sm=By%20Engine%20Family

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Wayman, this question comes up consistently, and of course, you should read footnotes from the manufacturer's listings. The camshaft I recommend with the 4.6L stroker build, and with the Mopar EFI conversions on the 4.2L, is the CompCams 252 grind—not the 232. Tony Hewes and I both run this camshaft in fuel injected inline six-cylinder engines without issue.

The grind has been around for a long time, I first tried it on 383 Chevy SB V-8 stroker motors built for off-road use and trailer pulling in the late 1980s/early '90s timeframe. It was phenomenal for low-end torque, a lower rpm ceiling (4,200-4,600 rpm, will run out around 5,000 rpm) with peak torque by 2000-2400 rpm, depending upon engine application. Manifold vacuum at lower speeds is excellent.

All of that said, my first use in an inline six was a Ford 300 with MPI. It ran flawlessly, again with a quick torque rise and great bottom end. Move to the 4.0L and 4.2L or 4.6L Jeep inline six, again a success story.

The 4.6L in the '98 XJ Cherokee that I talk about in the vlog discussion was built by Hewes Performance with the 252 grind, as was the 4.6L in the CJ-8 Scrambler walk-around video. This camshaft delivers! I use it...We've run the cam with stock injectors and with Ford 24 pound injectors in 4.6L Jeep buildups.

Perhaps CompCams wants to avoid emissions controversy here, although there's no reason to suspect higher tailpipe emission readings...We've seen no check lights, either, even with the 24 pound injectors. We're holding compression to 8.7:1.

Moses

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Same problem here with cam listings for E.F.I. and the 4.0..... Comp cams shows the year ending in 1997. My engine is 1998 and is basically the same as 1997. These are distributor ignitions with fuel injection compared to the later coil pack over plug engines.In an E-mail to Comp Cams to ask what they recommend for my application ,they replied with this....." We have a cam that we grind for that to work with the fuel injection. The lift is 435/448 so it will work with the stock springs also. The duration is 255/263 advertised and it has a 113 lobe separation."....I trust Comp cams and have used them many times over the years. The problem is a few other forums on this subject say that cam is for the later 99-05 ? coil over plug engine...? I'm now waiting for a reply from Crane Cams about their listing for the efi 4.0.....the number is 753901....lift  456/484  duration 260/272  112 lobe separation. The listing says exactly what I'm looking for which is 2200-2600 cruise rpm and stock compression ratio. http://www.cranecams.com/40-41.pdf   My questions to Crane....will the listed springs work with stock retainers? and when they mention for Fuel injection I assume they are talking about factory bone stock efi,computer and ignition...? Bottom line in my case is this.....While freshening up the valvetrain in an otherwise mechanically sound engine, I'd like some extra performance and fuel economy at highway speeds and medium towing without extra mods.and expense.....

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DrDale...Thanks for joining the forums and entering this discussion...Like you, I'm a CompCams fan, have been since the 'eighties.  

From what you describe, the 252 grind (our traditional, time-tested application for a carbureted or non-COP EFI/MPI Jeep inline engine) would be best for your purposes unless CompCams has data showing the COP camshaft will outperform the 252 in a non-COP engine.  Compared to a stock camshaft, the 252 grind will provide great bottom end torque, a quicker torque rise, and solid mid-range power.  

In nearly three decades of using this 252 cam, on everything from inline Jeep sixes and a Ford 300 six (1987 MPI version) to 383 Chevy V-8 stroker motors, this camshaft has been my choice.  My best metaphor is the 383 stroker that I build for an FJ40 Land Cruiser, an OFF-ROAD Magazine project in the late 'eighties.  I installed a hefty 168 tooth iron flywheel and built the engine to 8.7:1 compression.  With a four-barrel Quadrajet carburetor, blueprinted for sea level tune, I took the 'Cruiser over the Rubicon Trail without a whimper.  In low range, first gear, I could brake against the engine down to 400 rpm, and the 383 would tick over dutifully.  When I lifted my foot off the brake pedal, the engine resumed its stone steady, 650 rpm idle.  I never touched the idle mix screws yet drove over 7,000 feet elevation.

Will you experience this with a Jeep 4.0L?  Not exactly.  The 4.0L engine lacks the stroke length to have diesel-like power.  The 383 stroker, or even a 4.6L Jeep inline stroker, will build exceptional torque from idle to 2000 rpm.  Other modifications aside, will you gain from the 252 grind in a 4.0L?  Absolutely, with more bottom end and useful torque and horsepower.  A reasonable ceiling for this engine and camshaft is 4,200-4,500 rpm, plenty for sure.  You can spin to 5,000 without trouble, the power will not build, though.

I would emphasize that a 260 CompCam is a whole other story and requires lower axle gears and closer gear ratios in the transmission to perform at its best.  The 260 grind is a strong mid-range to higher rpm camshaft if that is what you want.  The Crane cam sounds similar.  As a rule of thumb, if you want great bottom end torque, increase the valve lift and be conservative on the duration and valve overlap.  260 and "bigger" camshafts require more fuel and CFM air flow, and they lack the exceptional idle vacuum of a 252 grind.  Manifold vacuum is the key to power, efficiency and fuel mileage.  I want strong manifold vacuum from an idle through mid-range rpm.

Worth the expense to buy a 252 CompCams camshaft and kit?  Yes, in my view, and this camshaft is completely compatible with non-COP (distributor type) engines into 1999.  I have not tried the COP camshaft discussed in this topic; however, if I wanted a camshaft for a Coil-On-Plug (first shows up in some 1999 4.0L engines) Jeep inline 4.0L or a 4.6L stroker in a COP chassis, the newer CompCams 255/263 grind with 113 lobe separation sounds worthy of attention.  It's at least compatible with the late PCM!

Moses

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Thanx Moses....You helped  make my decision a tad bit easier ! I will decide which Comp Cams to use  after one last E-mail to them as far as 252 vs custom grind COP cam.....

I'm a "General" Master Auto Tech of 37 years and still going strong, not willing to make repairs to my own vehicles without some kind of performance increase. Yep...I'm a hot rodder,grease monkey,drag racer,mud bogger,hill climber,road racer,nascar,....anyway you look at it  I'm an.......Auto Enthusiast and love my Jeeps.....!

                     Thanx Again for the great help , Dr.Dale

 

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DrDale...I am very interested in whether CompCams recommends the new grind over the traditional 252 for pre-COP engines.  This new grind began as a solution to engine codes and faults when installing the original 252 grind in the COP engines.  Apparently, the manifold vacuum, cam and crank position sensor feedback is interpreted differently between the COP's PCM and the PCMs of earlier engines with a distributor.  Valve overlap/timing (lobe center) is the issue from what I understand.

I'm curious what CompCams recommends now for a distributor type (pre-COP) 232, 4.0L and the 4.2L.  There was a "disclaimer" on the 4.0L engine regarding the EFI not being endorsed for the 252 grind, but this could have been a cataloging band aid when the later COP engines threw codes.  

Your findings with CompCams will be valuable, please share.  I have not run into issues with the 252 grind on distributor-type Jeep inline engines, whether conventional ignition, EFI/MPI or stroked to 4.6L.  Curious if the "new" grind (252/263 split duration, new lobe separationis regarded as better than the traditional 252 for bottom end and mid-range power.  Or at least the same...Also, will this new grind of 255/263 advertised degrees work on carbureted and conventional ignition engines like the 252?  Does CompCams plan to keep the 252 grind for AMC/Jeep inline sixes other than the COP 4.0L?  Or will this 255/263 camshaft phase out the 252 grind?  

Moses

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