CompCams "NOT FOR FUEL INJECTION"

[titan]

Most comp cams such as the 115 http://www.compcams.com/Company/CC/cam- ... sid=7&sb=2 have a description of "High Energy™ Hydraulic Flat Tappet Camshafts NOT FOR FUEL INJECTION"

This "NOT FOR FUEL INJECTION" phrase is written everywhere, except for the 232 http://www.compperformancegroupstores.c ... CAMSx4X4FI

Why is this? It is scary...

I am confused that many recipes suggest comp cams and AFAICT are for fuel injection, and many on the board are running them with success. It seems strange compcams is effectively writing in capital letters DO NOT BUY OUR PRODUCT when so many people are "misusing " them with success. I can't see how the 232 can be special to work any differently with a fuel injected engine.

[Cheromaniac]

Why is this? It is scary...

Not scary. Just a head scratcher.
All of the CompCams cams in my spreadsheet at http://www.angelfire.com/my/fan/Jeep4.0Camshafts.htm will work with EFI. They just don't work with the '99+ stock timing set and don't bolt into the '99+ block with the later-style cam retainer plate. To use them in a '99+ block you need the earlier style recessed cam bolt with spring/pin and either the '94-'98 stock timing set or a Cloyes dual roller.

[SIXPAK]

Most of the time a "not for fuel injecton" tag is due to a poor signal to the MAP sensor. When overlap gets out of the comfort zone of the stock computer it can not read a MAP signal that is week, eratic and out of the area that the stock computer is tailored from the factory. Not to mention what it does those nice emissions people!

[jsawduste]

Most of the time a "not for fuel injecton" tag is due to a poor signal to the MAP sensor. When overlap gets out of the comfort zone of the stock computer it can not read a MAP signal that is week, eratic and out of the area that the stock computer is tailored from the factory. Not to mention what it does those nice emissions people!

Bingo
Look at the cam lobe separation angle. A cam with 113/114 degrees on centerline will pull enough vacuum at idle to keep the MAP happy.

All the Comps are not that wide except for the 232.

[SilverXJ]

I believe it is a blanket statement that Comp uses for cams under a certain centerline. They can't test every engine and every parts combination to see what will work with EFI and what won't.

What bothers me more is comp's kits for the 4.0L. The fact that the springs, retainers and locks are for the 4.2L head and can not be used on the 4.0L head, yet they keep on advertising it for the 4.0L. Which leads to uninformed people purchasing the kits and finding out that they can't use them. I know that this has been brought up with Comp's tech line several time. At one time their "solution" was to custom grind a cam that would work with the stock springs, not actually trying to work out a usable spring package.

[titan]

...
Look at the cam lobe separation angle. A cam with 113/114 degrees on centerline will pull enough vacuum at idle to keep the MAP happy.
All the Comps are not that wide except for the 232.

The intake center line? According to the chart other than stock only one Hesco and all 505s fit that description. Not even the mopar cams and surely those work well enough to keep the manifold absolute pressure within spec?

BTW the chart says 107, but http://www.compcams.com/Company/CC/cam- ... id=12&sb=2 says 110.

[jsawduste]

...
Look at the cam lobe separation angle. A cam with 113/114 degrees on centerline will pull enough vacuum at idle to keep the MAP happy.
All the Comps are not that wide except for the 232.

The intake center line? According to the chart other than stock only one Hesco and all 505s fit that description. Not even the mopar cams and surely those work well enough to keep the manifold absolute pressure within spec?

BTW the chart says 107, but http://www.compcams.com/Company/CC/cam- ... id=12&sb=2 says 110.

Nope, Lobe Separation Angle deg. 3rd from the bottom in Dino`s list.

Factory 87-95 112*
Factory 96-06 107.3
Most Hesco and 505 114*

[Cheromaniac]

BTW the chart says 107, but http://www.compcams.com/Company/CC/cam- ... id=12&sb=2 says 110.

The specs that CompCams have quoted in that link seem to be all over the shop. They quote an advertised duration of 250/256 degrees and an ICA of 110 degrees for the 68-232-4 cam but when you compute their quoted valve timing events, the duration actually comes to 249/255 and the ICA comes to 111.5 degrees.
The LSA and ICA numbers that I quoted on my spreadsheet are numbers that I computed from CompCams' 0.050" lift valve timing events instead of the 0.006.

Most of the time a "not for fuel injecton" tag is due to a poor signal to the MAP sensor. When overlap gets out of the comfort zone of the stock computer it can not read a MAP signal that is week, erratic and out of the area that the stock computer is tailored from the factory.

What you're saying is technically correct except that CompCams also quoted their short duration/short overlap cams as "not for fuel injection" so go figure. It's also not a given that cams with less than 112* LSA are going to produce low idle vacuum 'cause that also depends on duration and overlap.
My original Crane 753905 cam (260/272 advertised duration, 204/216 0.050" duration, 112 LSA, 107 ICA) pulled 17" of vacuum at idle while my current stock '92 cam (also 112* LSA) pulls 20".

[SilverXJ]

BTW the chart says 107, but http://www.compcams.com/Company/CC/cam- ... id=12&sb=2 says 110.

The specs that CompCams have quoted in that link seem to be all over the shop. They quote an advertised duration of 250/256 degrees and an ICA of 110 degrees for the 68-232-4 cam but when you compute their quoted valve timing events, the duration actually comes to 249/255 and the ICA comes to 111.5 degrees.
The LSA and ICA numbers that I quoted on my spreadsheet are numbers that I computed from CompCams' 0.050" lift valve timing events instead of the 0.006.

My grind card for my 68-232-4 has 110* for intake center line and 113* for lobe separation.

The one for the 68-231-4 has a 107* intake center line and 111* lobe separation.