Back to the basics...

[ENafziger]

Well, I'm back in the 1st Gen crowd! I just bought a 1991. 5 W250 5-speed. It's in AMAZING original condition, and the truck is pretty stock. The only mods to the engine are 4" downpipe and exhaust, K&N, and 40 hp injectors. The truck also has a 6" Skyjacker lift, 35s, moonroof, Rhino liner, stereo stuff, etc.

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I'm taking a trip to Colorado in 2 weeks to pick up the truck, and boy am I excited! It's got 180k miles, and it's just had a new injector pump and injectors installed.

I plan on going through things first... re-torquing head bolts, setting valves, checking KDP, etc. I'll be putting a 366 spring and Denny T as soon as possible as well.

I'd also like to set/check the timing, but I've not been able to find out the "right" way to do this. It seems like it mostly works to advance 1/8", but I'd really like to do it right. From reading, I gather that 1. 45 - 1. 50 mm is ideal for economy/performance? Does anyone have a link on how to KNOW what you're setting the timing to?

I've done all the work on my '06, and have been building up a 1987 W150 frame-off rock crawler, but I'm looking forward to learning about the 1st Gen Cummins!

Thanks, Eric

 

[ENafziger]

I know at least in the 3rd Gen crowd, K&N's are not a recommended filter at all, as they seem to let a relatively large amount of dirt into the engine. Does this hold true for the 1st Gen as well?

--Eric

 

[MMeier]

Looks sweet !! Nothing wrong with a K&N filter . Been running them for decades in the desert SW on several vehicles and never an issue. Go for 7 months with no rain, hiways always under construction, constant dust/ dirt, etc. Where abouts in Colo. you picking it up ?

 

[cerberusiam]

Very nice!



If its an oiled filter, get rid of it. They are the problem children and should NEVER be used on a diesel, especially if you turn them up.



BHAF time!

 

[Greenleaf]

The Cummins Publication "Injection Pumps and Injectors" for midrange engines would be an ideal read. You can buy one order through and dealer selling CUMMINS PARTS.



Publication is 3666037



You can also pickup a copy of the engine operators manual. I didn't grab one off the shelf for a item number, but it is the 12 valve book you'd want. And, I "think" it too has the timing method with the dial indicator.



You will want to purchase the dial and then the adapter for our pump. You position the engine at TDC. It is best to use a dial indicator on top the piston to do this as the "pin" is generally off a number of degrees. Pull the No 1 valve cover. And mark the damper.



Then to use the dial you'd need to remove a few of the injector lines at the pump and looses some clamps to hange them out of the way.



All in all it is best to tune by sound and or sight per the timing mark on the pump/cover, But if you like to "wrench" on your rig, then by the book is a fun Saturday afternoon spent.



If your truck's engine had a "new injection pump recently installed" it wouldn't have any paint on it.

 

[JLEONARD]

I never had a problem with my K&N filter. I checked many times for dust inhalation and never found evidence of it.

Maybe driving in NE it's not as dusty as other regions.

 

[ENafziger]

or sight per the timing mark on the pump/cover

I've read that the timing mark on the cover can have significant variation engine to engine. One person bumped their's up 1/8" and was actually at 1. 8 mm after they had it checked by a shop!

If it's safe and acceptable, I'd rather just bump it an 1/8"... but I was under the impression that this may or may not give you the timing you were looking for?

Thanks, Eric

 

[AH64ID]

Great truck!!

I have no need for one of those, but I really want one

 

[Greenleaf]

but I was under the impression that this may or may not give you the timing you were looking for?



Thanks, Eric

Right. You'd have to have an all original engine or one serviced by the dealer. That would ensure the OE timing. If the PO was messing with it, then all bets are off and you'd want to ensure it is closer to 1. 7mm lift with the dial.



Too much timing and it will sound like a 5 cyl Mercadies (spelling?) a sharp knocking/rattle. Too little advance, then it will be a quiet rattle and possible white smoke more than it should. That, and it will be sorta laggy when you blip the throttle.



If it wants to jump up in a tree when you blip the throttle, it is just about right.

 

[ENafziger]

If it wants to jump up in a tree when you blip the throttle, it is just about right. <!-- google_ad_section_end --> <!-- / message --><!-- sig -->

:-laf Great description! Well, I'll play with it a little and go from there!

On another note, is there any place that sells the factory on-the-dash tachometers? I like how they look better than the Isspro, Autometer, etc I've seen.

--Eric

 

[Grizzly]

I'm impressed. Nice truck. I always wanted a 1st gen Dodge/Cummins. I almost bought a new one in 93, only thing that kept me was the very rough ride, so I waited for a 2nd gen 94. However since they never had an extended cab in 04, I waited some more for a 95 Club Cab dually.



george

 

[ENafziger]

Where abouts in Colo. you picking it up ?<!-- google_ad_section_end -->

Headed to Fort Collins. I can only take one day off work, so it's going to be driving 48 hour in 3 days... but I'm looking forward to it!

--Eric

 

[MMeier]

:-laf Great description! Well, I'll play with it a little and go from there!



On another note, is there any place that sells the factory on-the-dash tachometers? I like how they look better than the Isspro, Autometer, etc I've seen.



--Eric

Ahhh, one of the joys of owning a 1st gen !!! :-laf Let EBay and diesel truck forums be your friend .

 

[Coalsmoke]

Nice clean truck. My observations form working in a stealership and seeing a lot of dirty turbo intakes with K&Ns on them are that they may be great at flow, but they do not filter well. Paper elements filter very well, but they have their own demons. The best option for an air filter, in my humble opinion, is an oversized paper filter, like the BHAF, or a high-grade performance filter like the 7 layer AFE which is a good filter which still offers increased flow rates without sacrificing filtering capability.

 

[ENafziger]

Well, I picked up the truck this weekend. Overall the trip was uneventful, and went great! Dad and I drove continuously in shifts, and made the 2,750 miles in 46 hours.

We towed my Ford Festiva on a U-Haul dolly back, and got 16 mpg running 70 mph. I was hoping to get a little better than that. The timing has not been bumped, so I plan to bump an 1/8" and install the M&H dynamic timing spacer.

From a turbo perspective, what is the best thing to do for fuel mileage and ~300 hp? With the stocker with a 14cm wastegated housing work? Or should I look for a HX35?

Thanks, Eric

 

[ENafziger]

Oh... one other quick question. The options sticker under the hood indicates the truck has a 3. 5 gear ratio. All other trucks I've seen of this vintage have either a 3. 7x or 4. 10 ratio for the 4x4? Was this a special order option?

--Eric

 

[AH64ID]

I didn't think Dodge offered a 3. 73 until the 3rd gen? I am 99% sure my brothers 93 250 had 3. 55's.

What about a stock 3rd gen turbo, HE351? Cheap, good for 35ish psi.

 

[cerberusiam]

Gears are probably 3. 55's, that was the norm in that configuration.



A different turbo is going to help the power but the mileage. Good addition would be an HE351, HE351VE with a little more work, or an aftermartket turbo.



I suspect the ride height and tire size is robbing your mileage a bit. You might actually gain by going to 4. 10's but its could be a wash with the aerodynamics on it.

 

[Flexiheep]

I'm impressed. Nice truck. I always wanted a 1st gen Dodge/Cummins. I almost bought a new one in 93, only thing that kept me was the very rough ride, so I waited for a 2nd gen 94. However since they never had an extended cab in 04, I waited some more for a 95 Club Cab dually.



george

My dad bought his 93 because he didn't want to wait 2 years for the club cab in 95..... I also don't think his old truck would have made it 2 more years either though.

 

[ENafziger]

What about a stock 3rd gen turbo, HE351? Cheap, good for 35ish psi. <!-- google_ad_section_end --> <!-- / message --><!-- sig -->

I actually seriously considered this, until I found out it had a 9 cm exhaust housing... this seems really small? Also (for a reason unknown to me) I read that while a HE351 will support 350 - 400 hp on a 3rd gen, it will only support 200 - 250 on a 1st gen. Do you have any experience here?

modified HX35 16cm housing

Cerberusium, I see you're running the turbo I quoted above. Can you elaborate? Is this a PDR HX35 modified with a 60 mm compressor wheel? What hp level are you at with this turbo and the 370s?

--Eric