LB7: motor gone

[fishsmith]

I had experienced some of the same symptoms that you say ben, I just thought the same thing that it must be another injector going. I hadn't been running it that hard by my standards with the water/meth. I don't think I ever had my egts above 1500 with the water meth I was most of the time running water just to see what kind of a drop I would get. The only other thing I had pulled my fifthwheel 2 days before and I pulled it hard but only with water in tank and with a tow tune that kept egts to about 1200. I haven't had time to finish pulling mine yet so I don't know what all it broke in mine yet but hope to find out soon. I'm already ready for it to be back going even though I have an 08 lmm I miss my old lb7

 

[slowlmm]

I have like polsih marks on my cy walls all of them and there mostly towards the top its a little purple and polished the cross hatch out

 

[Stingpuller]

Motor

Look at the end of the rings were they would but up and see if the are shinny at all. If they are then the rings have come together. That would put the marks there and cause the purple from extra heat. Look at the pistons and see if they have scuff marks on them? Thanks Jeff

 

[JOHNBOY]

I also wondered if piston to wall clearance or ring end gap was part of the problem also. I got slammed some time back for asking if there was marks on the cylinder wall. Almost all that had piston problem had scuff's on the walls. Some had the piston's burn a hole which would scuff so hard to tell if it was there before the piston let go. Some just had pistons starting to go and had marks on the walls also which tells me there was problems starting before the piston went south. I will say one thing for sure, My new motor will have a LOT of clearance on the pistons and ring gap! I think "dumb ohio hillbilly thinking" alot of the piston problems are from all of use running stock motors(clearance wise) and high egt's. Things will expand and if not enough room things get ugly in a hurry. Jeff

I agree with you on the clearance thing Jeff! I don’t think clearance is the reason for all piston failures but defiantly some from what I have seen. You should what the bore does when you torque a set of head studs. There is no way I would put in a set of studs in a stock motor that was still in the truck. If I did I definitely would not torque them over 95ftlbs! Both nwpadmax and I measured a bore distortion of almost .004 when torqued to 125ftlbs per ARP spec with deck plates! I torqued the studs in my race motor to 125 but I had it bored and honed with deck plates and the main studs torqued.

I know of several that broke pistons shortly after installing head studs. I would lay large sums of money on the fact that the bore was distorted by the studs. The distortion eats up a lot of the piston to wall clearance. The pistons get warm they grow and grab the bore. Crack Ola!

You maybe a hillbilly but your far far from dumb my friend.

I have like polsih marks on my cy walls all of them and there mostly towards the top its a little purple and polished the cross hatch out

Are the marks adjacent to the head bolt holes? Did you have head studs? If so how long ago where they put in?

Look at the end of the rings were they would but up and see if the are shinny at all. If they are then the rings have come together. That would put the marks there and cause the purple from extra heat. Look at the pistons and see if they have scuff marks on them? Thanks Jeff

x2

 

[slowlmm]

OK ill check it out thanks No i dint have any head studs

 

[fishsmith]

Well I finally got my motor pulled tonight and it looks as though the oil was coming around the head gasket. Does that seem right? So Im guessing that maybe I pulled my motor for nothing but experience. I'm still going to tear it down and build it since it is out.

 

[LBZrcks]

maybe from your valve cover gasket

 

[fishsmith]

It looked as though from where the head and the block meet. I couldn't see any signs of oil from the valve covers. That was the only place I could see any sign of oil coming out of the motor other than the exhaust.

 

[duratothemax]

a leaky valve cover can make it look like the head gasket is leaking oil. Mine does the same thing, slightly leaky valve cover, but it looks like its coming from between the head nad block.

ben

 

[fishsmith]

Well I have it out now I have to decide what to do with it. It just kind of threw me off when I pulled everything off where I could see it better. The only hiccup I had when pulling the motor was what I think is the oil pressure wire got hung on the motor mount and I pulled it out of the sensor. I assume this is a readily available part otherwise the pull went smoothly. Still learning along the way.

 

[slowlmm]

Wow so no cracked piston or any thing ?

 

[fishsmith]

I haven't had time to get the head off yet.

 

[stroke250]

is there a possibility of it shearing the cam or crank pin?

 

[stroke250]

it might not be piston related

 

[sweetdiesel]

I agree with you on the clearance thing Jeff! I don’t think clearance is the reason for all piston failures but defiantly some from what I have seen. You should what the bore does when you torque a set of head studs. There is no way I would put in a set of studs in a stock motor that was still in the truck. If I did I definitely would not torque them over 95ftlbs! Both nwpadmax and I measured a bore distortion of almost .004 when torqued to 125ftlbs per ARP spec with deck plates! I torqued the studs in my race motor to 125 but I had it bored and honed with deck plates and the main studs torqued.

I know of several that broke pistons shortly after installing head studs. I would lay large sums of money on the fact that the bore was distorted by the studs. The distortion eats up a lot of the piston to wall clearance. The pistons get warm they grow and grab the bore. Crack Ola!

You maybe a hillbilly but your far far from dumb my friend.

Interesting

 

[stroke250]

any updates???

 

[fishsmith]

I have just decided to ship it to someone and get it built so I haven't tried pulling anything apart. I have it on a pallet ready to go I'm just waiting on the rods to get here so I can send it all together.

 

[LB7Diesel]

Interesting

You thinking what I am Mr. Air in the system