Several performance questions

[seeker1056]

after cleanin an dissassemblin my oil cover - is the oil pressure regulated by the spring and plug assembly that removes from the outside of the cover? What is the other valve that sits horizontal in the cover for
If the fisrt one regulates pressure - would raising the pressure be as simple as puttin a washer under the spring cap?

Timing gears - what would happen if one were to put a second gen cam gear on a first gen cam given they are about 6 degrees or so different - meaing the 1st gen is retarded and the second gen isnt

what would happen to the IP if one were to remove the return orrifice and use a regulator to restrict the returm pressure and really up the inlet fuel pressure - would this not help move more fuel thru the pump thereby coolin it, and keepin up flow - and if boost referenced - then would it not then make the IP supply more by virtue of the boost restricted return? Apparrently this is what some of the higher end P-pumps are doin?

thoughts?

[KTA]

#1 The other valve is a filter bypass to provide oil if the filter gets plugged. Yes you can shim the spring to get more pressure assuming of course it is releasing it now and the oil isn't going some where else first.
#2 Obviously you would end up with a diffrent cam timing.
#3 You will disable te timing piston in your pump because the case pressure is now fixed by the regulator rathe than related to variable case pressure from rpm.

[seeker1056]

Thanx KTA

#2

I know it would be different cam timing but for example our old 460 Fords were purposely retarded after 1972 for emmissions and it was an easy performance fix to put the cam chain n gear set from an early motor into it to pick up about 40 hp

I was wonderin if the same wouldnt happen in this instance as i have read the cam retarding was done to change the power range when the motor was first installed into Dodge trucks as they were supposedly worried about drivetrain longevity.

even the cams from first gen to second gen are somewhat different

but then so are the heads n such too

so maybe a fast performance fix on the first gen is to exchange second gen cam, cam gear, and head all of which can be had for peanuts on Ebay and such

[KTA]

Are you sure the gears are cut diffrent? I will have to check into it and see but I was un aware of there being a timing diffrence in the gears. The IC 1 gen cam and the P-pump cam are the same, or at least close enough that cummins subs them all to the same part number nowdays. The IC should be 102 on these cams. For a cheap upgrade the 24V cam would be better for HP but will be a bit more laggy and make less torque down low. It has quite a bit more lift and duration than the stock cam.

[crewcabxlt]

the non i/c cam has alot more opening duration, i would think better performance. the intercooled heads are more open than non i/c head. in comparing heads i could not see much differrence between p-pump head and intercooled 1st gen, but noticable difference between non i/c and later heads. from my limited experience i think the non i/c cam is the best,ive only compared to p-pump cam,never pulled a 1st gen i/c cam but from what kta states they must be like p-pump cam, emissions grind more than performance.

[seeker1056]

yes in a side by side comparison the 1st and second gen gears are almost a third of a tooth different when the keyways are lined up - meaning 2/3 of a tooth advanced which I understand represents about 6 degrees

Some 1st gen and second gen cams may be the same but not all from what I measured for lift and base circle, last week - and in talkin to Colt cams, there is considerable difference in the lobe seperation and duration numbers as well

All that aside - the 24v cam reground is oen of the better choices as the lobe spread, ICL, lift and duration numbers are much better.

I had an 89 cam, a 93 cam and a 97 cam and all were different both visually and with a digital mike

255/269 235/263 234/293
stock first gen = 255/269, lobe ?, dur ?
stock 12v = 235/263 102 lobe sep, 204 dur
stock 24v = 235/297, 107.5 lobe sep 206 dur

without a doubt, the lobes on the 89 cam were far more pronounced or wider (tranlsate as more duration) than the other two cams.

[RSWORDS]

What kind of inprovements could us "cheap" people see by running a 24v cam in our Non-I/Ced truck. I saw above that it would decrease low end and spool up but pick up at higher RPM's. Think its enough of a difference to do a swap on my pulling truck?

[seeker1056]

I cant tell you - too many variables

what rpm you run, what turbo, how much fuel, ported, not ported, exhaust size etc etc

then at what setting "0" degrees, retarded or advanced?

at first glance more lift on the exhaust may be beneficial, if you have the time and the resources to play with the cam timing.

only way I would attempt that is with an adjustable cam gear, and a aftermarket timing cover so one would not have to re n ree the cam a dozen times - but there goes a $1000 +/- for those two parts

I was just thinkin on the cam gear as a change by itself, but it appears maybe that wouldnt work either without some R&D

I can get you a Colt regrind 181/212 drop in cam for what i consider to be a decent price

[KTA]

I had an 89 cam, a 93 cam and a 97 cam and all were different both visually and with a digital mike

255/269 235/263 234/293
stock first gen = 255/269, lobe ?, dur ?
stock 12v = 235/263 102 lobe sep, 204 dur
stock 24v = 235/297, 107.5 lobe sep 206 dur

without a doubt, the lobes on the 89 cam were far more pronounced or wider (tranlsate as more duration) than the other two cams.

With the exception of the lobe seperation I don't understand the numbers you are quoting. I have cam profile sheets on the 370 marine, last generation 12 v truck and 24v cams so I know what they all should be. I also know if you go buy a new cam from cummins for a 92 or a 97 truck you will get the same part number one, now it wouldn't surprise me that there could be .020" diffrence and up to 5deg variance in the same part number cam. These things are mass produced.

[seeker1056]

the first three figures were measured lobe lift on the three cams

the second set of figures are the numbers that include the duration etc are numbers I got from Colt cams who grinds cams for a living

KTA, I have no doubt that the pt number is the same today - but thats not to say that the cams werent slightly different back in the day or that what I measured is from worn/used cams so tha t there is in fact some variations in actual lifts etc