At a loss. New crank, new motor...??? What to do.

atblis

New Member
Joined
Jul 4, 2006
Location
SW VA
Alright, some background. 3 out of 6 of the crankshaft flange holes are stripped. I am having doubts about being able to repair them. so... This is all for a 79 CJ5 with a 258.

Here's a link to my previous post about it
http://www.nc4x4.com/forums/showthread.php?t=27441

3 questions/possibilities. Feel free to comment on all.

1) Do you guys think a helicoil or time-sert would work? The flange is only .366" thick, and the holes are perilously close to the edge of the flange. That actually worries me more the than the thickness. I am most curious about the time-serts.
http://www.timesert.com/
I am looking at $100ish for the kit. If putting a new crank in is about the same, I'd rather go that route despite the extra work.

2) Supposing I do decide to put a new crank in the motor, what am I looking at effort/cost wise? I think
a. find a new crank (I've already got a 77 Cj with a 258 for parts)
b. Make sure crank is serviceable (polish/grind if necessary).
c. obtain correct bearings for mains and rods

Would it be better just to rebuild a motor? The engine ran decently except for an odd knock, which I suspect could have been the flywheel/crank issue.

3) New motor. I like the 258, but if I can get my hands on a decent 401... What do I need to swap to a V8. Just motor mounts? Possibly a bigger radiator...?
 
atblis said:
3) New motor. I like the 258, but if I can get my hands on a decent 401... What do I need to swap to a V8. Just motor mounts? Possibly a bigger radiator...?
Click to expand...

Better plant a whole fawkin grove of money trees, get a larger wallet, & then start repairing all the stuff you'll break!

Seriously, it shouldn't be hard to find a 258 crank & a set of bearings for under a couple Benjamin's...
 
atblis said:
a. find a new crank (I've already got a 77 Cj with a 258 for parts)
b. Make sure crank is serviceable (polish/grind if necessary).
c. obtain correct bearings for mains and rods
Click to expand...

You already have the crank, having it checked out, polished and sized for new bearings you'll have maybe $200 tops unless you feel the need to balance it ( I wouldn't)

Replacment is probably the best and most reliabe option.

Helicoils and Timeserts both remove a small amount of material, and with out knowing if damage has been done to the crank thru harmonics of a loose flywheel, it could frag not long after you repair.

If you already have it, use it, you now have a tall doorstop, wheel chock, boat anchor (pick one)
 
Yeah

I was thinking mailbox. I6 cranks make nice mailboxes.

Yep I pretty much decided to put a new crank in the 258. I was getting 21mpg Hwy with it. I don't think I'd get that with a 401.

I'll start ripping apart the 77 tomorrow. The motor in it ran, and didn't sound bad so hopefully the crank will be decent.
 
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