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Also I don’t think you are gonna want any smaller of a radiator or intercooler than a first gen Cummins has. I’m no stranger to those rigs and they are just adequate with mild turning up. I also have a thing for minivans (Astro vans mostly) so there is a lot about your project that interests me
 

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No cummins expert here, but if you ahve no power under 1k, I would bet the marine pistons are part to blame. Boats run at 60-100% of redline, they never (well nearly never) run at low engine speeds. Those pistons are probably designed with 80% of redline in mind
 

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Discussion Starter #24
Also I don’t think you are gonna want any smaller of a radiator or intercooler than a first gen Cummins has. I’m no stranger to those rigs and they are just adequate with mild turning up. I also have a thing for minivans (Astro vans mostly) so there is a lot about your project that interests me
Thanks for the helpful input! It certainly takes unique taste to cultivate a bias towards minivans, but they do make for a good time, and lots of smiles from others.

I did get my injectors tested. I wasn't expecting them to be great, but overall the pop pressures only varied from 225 to 250, with one exception being injector #5 at 270 bar, which is definitely too high. However, all things considered that isn't too bad for the variation, and again it did idle and run smoothly, never a hint of a miss or anything like that. So while they might not be the best engineered solution, I think for the most part the injectors are doing their job. I would like to get some that fuel more efficiently than the 370 tips, but that is $ that will have to be put aside later...

I am definitely lacking power throughout the powerband. For example, my buddies completely stock '94 p pump truck pulls much harder. I feel that all in I should at least be able to give him a run for his money. No such luck. But yes, I do have very little power down low. Unless I can keep rpm's up on the highway, the gap between 3rd and 4th (granted, my 3.07 gears don't help the gap size) is almost too much to pull up from on anything other than flat or downhill.

I think that my intercooler system is sufficient. I can read an 80 degree Fahrenheit drop in intake temp between having the pump on or off, so I think that is good for efficiency there. But I do agree that my radiator is quite likely too small. The only problem I have is real-estate. I basically have none. I am willing to re-design my front end to accommodate more radiator, but I still think I will have to tig up a custom unit that trades face surface for depth. Something like cutting a big radiator in half, merging the tanks, and having it 4" thick at half the height. Only way I can see it fitting with the tapered nose of the van.Frame rails are a bit tight too.

Once I get rebuild the new internals for my transmission I will try returning the timing back to stock and seeing what that does for me. However, as mentioned earlier, with the transmission and fuel system removed (three tanks, lots of valves and a transfer pump) now would be the time to do engine work if I have to. Though I still can't see affording the ~2k for new pistons and injectors anytime soon.

Also, I was talking with a few local diesel performance shops, and a bit of advice I saw regularly was to remove my heavy weight valve springs in favor of stockers. Because I have the 110# springs, heavy duty pushrods, and hardened tappets, but only a stock cam, I was told that they will eat up the camshaft and heavily/prematurely wear it down. To me, the spinning design of tappets should negate this type of wear, but I have little experience in this area. Is there any truth to this?

Thanks again.
 

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Discussion Starter #26
you should probably be posting this on one of the many different cummins specific forums

youve got compound turbos with an o-ringed arp head, you should have all the power you want, have you tried adjusting your low boost fuel levels?

https://www.dieseltruckresource.com/forums/1st-gen-ram-all-topics-93/difference-between-smoke-screw-star-wheel-176337/
Thanks, I have done a bit of adjusting with the pump, but by no means has it been enough. The recent inaugural 2500 mile road trip was done mostly below zero, so I was a bit reluctant to sit at a gas station with the pump open without full motor control of my fingers. But I definitely agree that tuning is contributing to my issues. However, having less of these problems before the engine build (namely fuel economy) I think this can't be completely responsible.

And I agree with the dedicated cummins and diesel forums, but I applied for accounts on 5 different ones, and they all have administrator supervision on early posts, and all but one of them has yet to approve my initial post and comments I submitted several weeks ago. And I seem to find the most ingenuitive people doing interesting/strange builds on here, so I figured this would be a great community to throw my project into the mix with.
 

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And I seem to find the most ingenuitive people doing interesting/strange builds on here, so I figured this would be a great community to throw my project into the mix with.
'swhat got me to make an account here
still don't own a 4x4 :flipoff2:

Post some goddamn pics, loves me some first gen caravans
 

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marine pistons should be fine, but ditch the 20 over head gasket, unless you decked the block or the head alot. its killing your compression. not sure how much the marine pistons lower it, mainly they have a larger bowl for the wider spray of marine injectors or higher timing. anything over 18-20 degrees of timing is going to kill your bottom end for a stickshift.
 

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marine pistons should be fine, but ditch the 20 over head gasket, unless you decked the block or the head alot. its killing your compression. not sure how much the marine pistons lower it, mainly they have a larger bowl for the wider spray of marine injectors or higher timing. anything over 18-20 degrees of timing is going to kill your bottom end for a stickshift.
Have you run marine pistons before or driven a rig that did? I can’t remember what I set my timing at but it was exactly stock what it said on the placard. I intended to start there then bump it up after but with the low low end power I felt like more timing was the last thing I need. Granted my problems sound way smaller than op but sounds familiar with the marine pistons and 370s.
 

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I've never seen anything like that...period.
Me neither, still don't know what to think of it:homer:
I'd like to see side pics, and some explanation of wtf is going on. I was really hoping this was maroon and wood paneled on some gold mods somehow proportioned just right:grinpimp:
 
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