mbe 4000

hungry

Seasoned Expediter
I have 2 wrist pins needing replaced. Would i have to have an in frame done or just replace wrist pins? Also is this something that when goes bad they all do? ty
 

davekc

Senior Moderator
Staff member
Fleet Owner
The wrist pins connect to the pistons. I would do them all if two are bad.
 

purgoose10

Veteran Expediter
I have 2 wrist pins needing replaced. Would i have to have an in frame done or just replace wrist pins? Also is this something that when goes bad they all do? ty

No. Drop the pan and replace all. Also new bearings and seals. Check the crank for gouges and deep scratchs. Make sure you don't put then on backwards if your doing it. Put everything back exactly in the same order you removed them.
If someone doing it for you, tell them to overhaul the bottom end. I would also put front and rear bearings on the crank along with new seals.;)

Not a difficult job, just time consuming.
 

greg334

Veteran Expediter
Won't you have to pull the head off to get the pistons out to replace the rod bushings and pins?
 

TeamCaffee

Administrator
Staff member
Owner/Operator
You need to inspect the pistons as well. With something this major replace all of the wrist pins and if not known find out why these two failed.
 

purgoose10

Veteran Expediter
Won't you have to pull the head off to get the pistons out to replace the rod bushings and pins?

No. Your crank will maintain the same position. It will take about 8 hrs to do that size engine.
About inspecting pistons, that's a personnal call. If your not loosing compression and not using oil I wouldn't bother. What does the lab say about your oil samples?? If your oil sample says theres a trace or more of Antifreeze then maybe. When you drop the pan and pull number one you can tell whats happening. I used to do mine that way before R/R the engine. I always did my own way back before the engines would go a million miles w/o an issue. I would do the bottom end in old Cat engines at about 400K. When I had 12 Petes with Cats I had a spare engine build on the shop floor ready to go. But times have changed and it's not cost effective anymore.
Oh yes you need to line the timing mark to top dead center than all the rods will be easy to get to.

In adding. I guess you have not been doing oil samples or this would have been picked up with metal samples. Always do oil samples on every oil change. One simple thing can be left undone and it can cost you 20+K to fix it.
 
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hungry

Seasoned Expediter
They failed due to wear. Pistons are not damaged 1,2,3,&6 are fine just 4&5 damaged wrist pins & connecting rod. Looked at DD step 1 through 3 all costly 6500 to 12500 or just repair whats broken. ty
 

purgoose10

Veteran Expediter
They failed due to wear. Pistons are not damaged 1,2,3,&6 are fine just 4&5 damaged wrist pins & connecting rod. Looked at DD step 1 through 3 all costly 6500 to 12500 or just repair whats broken. ty

Well forget what I said before. If you have rod issues and have pulled the pistons I would put in a inframe kit. If you are doing the work get a kit from Detroit, don't use generic on Detroits. Cost's alittle more but you won't regret it. If a shop is doing it, well dig deep and pray.
 

greg334

Veteran Expediter
So the answer is yes, you have to pull the head off the engine to get the pistons out?

I think that in frame kits don't come with rods, so your rods will have to be rebushed and checked for straightness, right?
 
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