QUESTION!! (non urgent!!)

***cleatus12r*** · #1 Mon, August 17th, 2009, 08:17 PM

I have ZERO experience with breaking anything (not complaining about that).

However, looking at some math and all of the physics that go with it, I really don't think that I personally would want single shot injectors in my PMR truck. Yes, mine has PMRs and I'm not trying to dissuade you from getting them. It just happens to bother me that the one large unbuffered "bang" from a single shot injector may not be conducive to long PMR life.

I may be talking out of my butt though.
I'm sure that Jonathan at Swamps will get you some kick-*** tunes made up for those injectors. I'll get something similar once I get my forged rod short block rebuilt.....

Cadash · #2 Mon, August 17th, 2009, 10:56 PM

Quote:

Originally Posted by cleatus12r

I have ZERO experience with breaking anything (not complaining about that).

However, looking at some math and all of the physics that go with it, I really don't think that I personally would want single shot injectors in my PMR truck. Yes, mine has PMRs and I'm not trying to dissuade you from getting them. It just happens to bother me that the one large unbuffered "bang" from a single shot injector may not be conducive to long PMR life.

I may be talking out of my butt though.
I'm sure that Jonathan at Swamps will get you some kick-*** tunes made up for those injectors. I'll get something similar once I get my forged rod short block rebuilt.....

I hate making decisions like this!!! Hes the one I spoke to today and helped me make the decision on the single shots. I was gonna get splits but after talking to him for a while I decided on the splits. I said I had PMRs almost a million times too!!! Im lost!!! Now I definitely dont know what to do...

***Power Hungry*** · #3 Mon, August 17th, 2009, 11:40 PM

Quote:

Originally Posted by Cadash

I hate making decisions like this!!! Hes the one I spoke to today and helped me make the decision on the single shots. I was gonna get splits but after talking to him for a while I decided on the splits. I said I had PMRs almost a million times too!!! Im lost!!! Now I definitely dont know what to do...

Well, which is it?

I'm assuming you are going with singles. Singles will work fine on a PMR engine as long as the injection timing is kept to a reasonable limit. It's the overly aggressive timing curves associated with the jump to singles (which will inherently increase the point of combustion) along with the additional timing that would normally be used for standard performance programs. Between the two, well... as Dennis Hopper once said, "Bad things, man. Bad things."

We'd still like to get you down here for some live tuning when you've got time.

If you can swing it, let me know.

Take care.

Cadash · #4 Tue, August 18th, 2009, 12:02 AM

Quote:

Originally Posted by Power Hungry

Well, which is it?

I'm assuming you are going with singles. Singles will work fine on a PMR engine as long as the injection timing is kept to a reasonable limit. It's the overly aggressive timing curves associated with the jump to singles (which will inherently increase the point of combustion) along with the additional timing that would normally be used for standard performance programs. Between the two, well... as Dennis Hopper once said, "Bad things, man. Bad things."

We'd still like to get you down here for some live tuning when you've got time.

If you can swing it, let me know.

Take care.

Lovely!!! You see what happens when I get all worked up!!! I cant even type straight!! But yes, I was looking at splits but after a long talk with Jonathan at Swamps I decided on the singles. Well thats good news then!! As long as my tuner keeps things reasonable that will be my route

I most definitely can make the trip!! Just a matter of when. BUT.....and I do stress the BUT!!!! My whole injector thing started with my #3 injector failing the cylinder contribution test. Truck feels great and runs great. Its just messing with my head now!!!

***cleatus12r*** · #5 Tue, August 18th, 2009, 08:33 AM

Dan,

I didn't mean to scare you. All of the things I mentioned are concerns of MY OWN.

You brought up another point in your last post though; failure of your CCT on #3 cylinder.
That test is a guideline only. Yes, it could simply be a weak injector or injector o-rings that have finally eroded away. On the other hand, it could be a compression problem too.

Disclaimer:

This is why friends of my friends DON'T let me look at their vehicles. I'm too much a realist and far too straightforward; I point out every little detail about what is a potential problem with their rigs.

Don't pay any attention to the man on the soap box.

Diesel Rookie · #6 Tue, August 18th, 2009, 11:01 AM

Exactly what do you guys mean by PMR why are they weaker? I think it has something to do with the piston conecting rods but am not sure. From what I can tell on the forum my 2003 F350 7.3L may be a PMR truck, is that corret?

Joe

***cleatus12r*** · #7 Tue, August 18th, 2009, 02:05 PM

Quote:

Originally Posted by Diesel Rookie

Exactly what do you guys mean by PMR why are they weaker? I think it has something to do with the piston conecting rods but am not sure. From what I can tell on the forum my 2003 F350 7.3L may be a PMR truck, is that corret?

Joe

Yes, the term PMR (powdered metal [connecting] rod) refers to the connecting rods. It is so named because of the process used to manufacture them.

Forged rods are constructed from molten metal poured into a forging press and pressed by many tons of force. They are then allowed to cool and machining processes take place to cut the "big end" bearing journal bore in half, install rod bolts (studs in this case) and then hone the journal bore to size.

Powdered metal (or sinter forged) connecting rods are created when a fine metal powder is heated to near melting and then pressed into the desired shape. The rod "big ends" are actually broken off instead of cut. This creates a unique mating surface that more perfectly aligns the two parts. Then the bolt holes are drilled/tapped and the final machining begins.

The problems associated with PMRs are plentiful.
1. No set grain structure.
2. High probablility of porosity (pinholes/air pockets in forging)
3. Very brittle. There is very little flexibility and resilience inherent in the material.

4. The 7.3L PMRs were designed like the forged rods. Comparing forged to powdered metal rods shows that they are very similar in their construction. This leads to weak spots and areas that should have been more carefully developed to take advantage of the different manufacturing processes/materials.

There is nothing wrong with powdered metal connecting rods so long as they were DESIGNED to be PMR. Take the 6.0L Powerstroke and 6.6L Duramax for example. They are able to handle much more than the 7.3L PMRs due to their design.

Cadash · #8 Tue, August 18th, 2009, 01:50 PM

Quote:

Originally Posted by cleatus12r

Dan,

I didn't mean to scare you. All of the things I mentioned are concerns of MY OWN.

You brought up another point in your last post though; failure of your CCT on #3 cylinder.
That test is a guideline only. Yes, it could simply be a weak injector or injector o-rings that have finally eroded away. On the other hand, it could be a compression problem too.

Disclaimer:

This is why friends of my friends DON'T let me look at their vehicles. I'm too much a realist and far too straightforward; I point out every little detail about what is a potential problem with their rigs.

Don't pay any attention to the man on the soap box.

Its all good!! When I have something that dont sound right on my rig or a little shake it bugs the crap out of me!! My mind starts playing tricks on me!! Also during the Buzz test that injector sounded off and 1 and 2 were ify as well. I know the risk is always there with these rods but I just want to keep it as minimal as possible. Also too my glow plugs have never been changed on this truck. It has 137xxx miles on it.

I was scared before your post Cody!!!!!