Block failures

[Robyn]

Does anyone know any history about the number of stick shift trucks with broken blocks/cranks as opposed to auto tranny trucks with same failure??

Just currious :0)

[a5150nut]

Oh, now that is a good question. I am interested in where this goes. Now is it going to be the difrence in transmisions or in the drivers?

[dieseldummy]

I know of a 1:1 ratio between my truck and a friends. Mine is auto his manual. Both cracked blocks. Mine cracked in the front his in the rear.

[gmctd]

I've noticed failing harmonic balancer\acccesory drive pulley breaks the front of the crankshaft behind the 1\2 rod journal, where failing dual-mass flywheel breaks the rear of the crank in front of the 7\8 rod journal.

Either\both can result in unique three-piece crank....................

[Hubert]

archives maybe there use to be a sticky or poll thread at top of forum.

I am pretty sure the data collected pointed to a larger percentage of manuals that towed heavy cracked than autos but can't remember the numbers.

Having a 5 spd I can attest to significant harsh torsion wrap in drive train with sudden throttle changes and speed differences. I can get a heck of a clunk and jar taking cruise off with button over 65 mph such that I try my hardest never to do it. I'll match throttle speed or use clutch etc. In fact I can get a pretty good torsional unbinding pop and see movement in shifter indicating motor/transmission torqing against mounts if I mash clutch too fast with load on gears. Probably my motor mounts are tired and exaggerate it. That might also be part of blocks cracking.

[Robyn]

I was reading recently that the 6.5 has a Nodular Iron crank shaft in it.
I would have thought they would have had enough sense to use a forged steel crank.

I wonder how much of the block cracking is due to the cranks flexing under torque and then flexing the block untill they both break.
The HP 454's and 502 engines all use forged cranks, I wonder why they cheeezed and went with iron shafts?????

[dieseldummy]

Cheap production I'd guess... IIRC, I read an article that about the new AMG optimizer motors and a forged crank was one of the upgrades.

[gmctd]

This forum harbors a considerable amount of information on broken cranks and broken blocks, including info on why GM chose the nodular iron material - a search of Member's Area articles and in the archives should keep you reading for a long while

[DA BIG ONE]

All these issues of 6.5td block failure I'm leaning towards a cummins 6cyl, 12 valve & turbo as the fix.............IMHO

[gvig]

Robyn,

Perhaps you didn't know that Holman and Moody, of Ford Nascar fame, always used stock cranks in their 427s which of course were all cast. Never had a crank failure the last I read on the subject.

Some cast cranks can take the guff and keep on smiling.:)

Even so, I prefer forged cranks too.

[Robyn]

Interesting
I have owned two FE series Fords back in my younger years.
I had a cammer 427 and a Medium riser side oiler 427.
These blocks had the right stuff with the center mains having select fit spacers and cross bolts to make the thing real strong.

The long skirted block was a real plus.
I had the cammer in a 1976 F250 4X4. OMG that thing was awesome.
use to crank that sucker deep into the 7 grand RPM range in 1st and 2nd gear. Had a set of custom crane cams made for the cammer and a set of 10:1 forged pistons so it would run on the crap gas

That thing was a sleeper for sure

Used to scare the sh&$ out of dad when I would wind that thing up.

The two engine I had were both setup with forged steel cranks.
The side oiler medium riser was in a 67 Fairlane GTA.
Sweet little rocket that was. Got the car cheap with a grenaded 390 in it.

Dad had connections with the Ford High perf parts people and got some very nice goodies for us to play with.

When we went into boat racing we went GM and used 454 blocks and then got crazy from there.

Learned a lot about setting up 671 blowers to huff a big inch gasser.

We never got into doing fuel injection or alky with our boats.
Strictly Blown gas drags.

Had a lot of fun and met a lot of neat folks.

Later

Robyn