I have a candidate 6.9 and when I get time I am going to check this thing out.

You can fool with duration and lift by fooling with the rockers and I can measure that.

Also the heads are going to get looked at very closely.

There is room to work on the chambers. They can be opened up alot with out messing with the air flow, I think.

You also don't want to advance a motor to much. You can alot more damage then good. I have fooled with a 3406 Cat on a dino quit abit and figured out that advancing the timing alone doesn't give you near the power as you would think. I was suprised at how little it was, I mean very minimal. It did change the torque curve a HP range but full load power didn't increase enough to be worth melting pistons. Now if you start throwing fool to it then you need to move it up some top give the extra fuel time to burn.

I have a cracked head that I am going to cut in cross sections and see where and how much you can port the exhaust and intake ports and also the t-chamber area to see how it can be opened up.

 

On the older Cummins (1980's) cam timing could make a real difference. Set wrong and the engine sounded terrible, got poor mileage and just didn't feel right.

I had a small cam 400 that my pump and injector guy built an IP and injectors for. He said it was a marine application. I changed the turbo, installed the new pump and injectors and set the cam timing at around 30 degrees (if I remember right). It would run with my buddy's 3406, got between 5.5-6.5 mpg and unless it was a real hot day, you could stand on the throttle on a hill and the heat stayed a lot lower than before. Was lucky to get 4-4.5 mpg before the changes.

I didn't have any experience with cats at that time but have since then. I think the cat engines and fuel systems are pretty much dialed in from the factory. Course since they put the computers in trucks, it was a matter of hooking up a hand held device and jacking up the power with a keyboard.

The older engines had more "wiggle room" for making changes and trying out ideas than these newer, computer controlled engines.

 

Hey cheaper, is the paragraph about the "recently sold glow plugs not working to fix the ten year old engine" about you?

 

Yeah, why? The guy's a moron. Doesn't know how the ID GP system works. Obviously doesn't even know what year the ones he's selling will fit - 'cause they're for a 20 year old IDI....

After the set he sold me burned out (apparently the first time voltage was applied - the truck never started with them, even one time), Autozone exchanged them for me for free. They agreed they pretty much had to be factory defective. The set they gave me have been in the truck and working perfectly ever since with no other changes.

 

Dude, I didn't identify you as "the guy" - you identified yourself, so maybe you are the one needs to get over it.

Wanna' know the reason I got ticked off? 'Cause YOU made the comment, and when asked about HOW you did it, and HOW MUCH you changed it, you changed the subject and started being flip with me and laying the the same old "spend the money and get a turbo" song and dance on me. All you had to do was answer the question and you would have had 100% of my respect. See, I view this forum (and others of this type) as a place to SHARE info. Not hint at and then refuse to share it. That doesn't earn anyone ANY respect in my book. It is totally counter to what this type of "community" is all about.

Every mod I've done to my truck, and every thing I've learned I have freely shared here. Even going to the trouble to take picts and post them, answer questions in detail, etc. No secrets. No "I've got an idea but I'm keeping it to myself". That's what this place is all about - sharing.

Yes, you are correct, I know the concept and the theory behind changing cam timing. I even know that changing the timing isn't going to increase the HP or torque dramatically. The most significant thing it will do is move - shift - the HP and torque peaks to different RPM ranges. - just like catfish101 said. These engines already have plenty of torque - at very low RPMs. What they lack is adequate HP at anything even resembling low RPMs. My interest was in balancing that a little - lowering the HP peak down the RPM range a few hundred RPMs. Cam timing is one way I'm still considering to do that.

What I don't know - and you seemed to at least claim to know, but refused to share, is the details of doing it. Things like "you can only retard it a max of 5 degrees and that will move the HP peak from 3300 down to 3000 RPMs." Info like "I bought a 6 degree offset cam key for a Chevy 350 and had to grind a couple thousandths off it to net a 5 degree offset".

THAT kind of info, if shared, can help keep people from having to re-invent the wheel a thousand times, not to mention informing people who aren't even familiar with the idea, and maybe keeping someone from going too far with it and having the pistons hit the valves and grenade their motor - again, like catfish101 hinted at. Your hedging indicated to me that either a) you don't really know the details of what was done - whoever did it - but weren't ready to admit you didn't know, or b) you aren't interested in sharing, and would rather sound like the mysterious know it all.

Neither of those is constructive to our little community here, and isn't what it is all about. And yeah, it ticked me off plenty. NOW DO YOU GET IT?!?

RIGHT, and WRONG

You're right, I have come up with a couple of decent-working ideas (which I shared in detail).

HOWEVER, I do NOT "see the truth" of what you told me before. I have produced some pretty DRAMATIC gains with the things I've alread done on my non-turbo. So while it still may not keep up with a turbo, a turbo isn't the only solution to worthwhile improvement. Not by a long shot.

Dave Sponaugle/cookie88, I hope you do not view my little rant as inappropriate, but if you do, and you feel the need to moderate me, I will understand. I do tend to get a bit worked up when someone's attitude rubs me the wrong way.

 

Love your avatar.

Where in SD are you?

 

Cheaper, I will concede before we both look bad.

I think the debate has been one of misunderstanding. I read your post as, Hey, I want more power. Well I know how to get power and what it takes so my reply was, Turbo, exhaust, pump work, gotta spend the money. My idea of power gains is on a diesel, if it's not significant, i.e. 25, 50, 100 h.p. it's not worth the trouble. A few gains in h.p. and torque doesn't impress me and will not pull that load a gear higher.

There is were the communication failed. On the cam timing, I now realize exactly what it was you were after. I did not reply on "exactly" how I made the change not to withhold anything that has not been done before but to try to keep some guys from making a mistake that could cost an engine. As you know, the easiest way is with an offset key. You can cut another keyway in the cam gear, you can advance, retard a tooth and try to make up the difference with the pump, distributor. You can have a cam ground to your specs (man that would run some bucks)

What I did not want to do is make some guy think....woah, I'm gonna try that and grab me some of that power, which is wrong....do it wrong and wind up with an engine failure, come back here and start complaining that they are owed and engine.

I will still say the same as I said before. As a PART of an overall attempt to get a good running, stay cool engine, changing the cam timing "can" make a difference. It's more of a "get it dialed in" because I got **** about it. Yeah the engine ran good, dads truck still runs good. Yeah it had good power and got 18 mpg loaded with a 9.5 ft camper and 21ft cuddy cabin boat. I don't think the cam timing made a whole lot of difference but it did run smooth and I had no problem standing on the throttle to get up a hill and overheating. With the same load, same hill, same time of year, the changes made a 44 mph difference and gained almost 2 mpg on fuel consumption. Thats the kind of power I think of when talking about making gains.

Point is, I apologize for the rant and misunderstanding. 2 minds thinking along the same lines but differently. I also apologize for the right turn in this thread and the hijack.

 

Apology accepted - assuming it was at least partially aimed my way. I also apologize for my contribution to the hijack of this thread.

Still interested in the details of how much the cam can be advanced or retarded without doing damage. If you don't want to post them in an open forum, I can appreciate that. If however you would like to PM the dtails to me, I would be grateful. From his post it sounds like catfish101 is interested as well. Looks like he intends to find some answers on his own though....

 

Wow, I thought the chapter forums had all the drama!

 

Nah, no drama. Just a bit of a disagreement. Settled in a gentlemanly manner. No big drama here. Move along. Nothing to see here folks. Move along....

 

Leave you guys alone for a day and look at what I come back to...


Looks like we are all on the same page again though.

 

Yes - Dave they have been talking about you in the "general discussion" area -about the engine your going to put in.....

 

Sheesh......I was going to say that I chose to cut another keyway in the cam gear. I have installed a few comp cams, double roller gear and chain sets on gas engines. They have a gearset with 3 keyways to set at 0 or advanced, retard, cam timing. I used that idea and cut another keyway.

It's been almost 17 years since then and I don't remember the specifics to tell where the cut was made. I do not remember if it was advance or retard. I do remember the IP was about 1 width of the marks, advanced.I have trouble remembering the last few years due either to an accident or the drugs I am still on...don't remember which An oldtimer mechanic on cummins engines helped out a bit there and he had the equipment. I sold the truck a couple years later to help pay the hospital bills from the accident. Last time I saw it was about 2 years ago and it was still running and the guy said the engine was running great but the road milage was down to between 20 and 21 mpg.

I remember some things with absolute clarity but other things are like trying to find an address in the fog.

 

Don't worry about it. It happens to the best of us . My buddy from the National Guard worked on IDI's for over 20 years and has problems remembering what he did to them to fix certain problems. To this day he still works on gassers and is sporting his 8 second mustang

Thanks, took me a bit to find a good IH logo. I am about an hour away from Rapid City over in West River.

 

Thanks for that mistakenID. I sure wish you'd have explained all that when we first got into the discussion/disagreement a couple months ago! Heck, I'd have never gotten ticked off in the first place had I known.

I can kinda' relate - not exactly 'cause I've not been through the aftermath of a major accident as it sounds like you have. BUT, I have a history of drug & alcohol abuse (sober 23 years now) and there are some pretty significant periods of time from those pre-sobriety days that I can hardly remember anything at all about.

Anyway, cutting a new keyway in the cam gear is certainly one viable way to do it. Not my first choice of ways to try it though - for a couple of reasons. 1) It is pretty complicated. You have to really precise measurements of where the existing keyway is - in terms of being exactly centered between teeth, even with the leading edge or trailing ede of a tooth etc. Then you have to skip 1/4 turn or a half turn around the cam gear and cut another one with the appropriate number of degrees offset from the (relative) position of the original. 2) Then there's still the issue of how to cut the new one with any degree of precision. If you have the machinery, probably no big deal, but if you don't, cutting a precise groove like that inside the bore of a part like that is pretty tough to do. 3) Lastly, now your timing marks on the gear are all reversed or 1/4 turn off, or whatever. Not a big deal when you are the one assembling it, or even if you have to tear it apart and reassemble it in the future - as long as you create new alignment marks. If you don't, or if anyone else ever has to work on it though, forget it. Overall, there are just too many ways to screw it up doing it that way for me to try it.

I like the idea of the offset cam key much better. Especially since the same key can be used to either advance OR retard it equal amounts, and different keys will allow you to adjust it different amounts. Generally the key itself isn't under much stress, it is just there to ensure proper indexing of the gear to the shaft, so even if your engine will allow you to do a radical offset - that leaves only 1/4 the thickness of the key untouched for example - it still isn't an issue.