Dv 800 crankshaft

[350 diesel]

Hello, I bought a 4786 a few years ago with a bad engine, I bought a replacement for it and thought id go through it and freshen it up while it was out. I took the crank to a machine shop and they informed me it has a crack where the flywheel bolts on and dont recommend using it. Anyone have some places I could call for a good used one? I know these things are getting hard to find. Thanks in advance 

[IH FARMS]

I'd try Meyer's tractor salvage Aberdeen South Dakota. 

[350 diesel]

Thank you, they had one on the shelf ready to go

[350 diesel]

Just incase anyone wondered what the original engine looked like here is the journal of the one that let go and the parts left in the pan.

[Powered by IH]

16 minutes ago, 350 diesel said:

Just incase anyone wondered what the original engine looked like here is the journal of the one that let go and the parts left in the pan.

Not good...

[Alan Dinan]

Remember an old IH mechanic say that the downfall of those engines was the rpm’s being too high.

[Dave Shepard]

And the cylinders being arranged in a V pattern.

[supermechanic]

 Below is a list of fuel-efficient tractors that utilize the V8 engine.                                                                                                                                                                                        :

[Sask466]

19 hours ago, Alan Dinan said:

Remember an old IH mechanic say that the downfall of those engines was the rpm’s being too high.

This forum seems split on this subject.  I don’t know what to think.   I have heard it both ways.  

We had a 4586 (back in the mid 1990’s) and the older IH mechanics at the time said to keep the revs up, as it was lugging that killed the bottom end.  They said keep it at 2400+rpm.  I recall that tractor had poor power under 2100rpm, but I was still pretty young so that may not be an accurate memory.  I also remember it feeling powerful  and sounding like a freight train at 2500rpm.  

I wonder what the official corporate IH message was on this subject back in the day.

[Alan Dinan]

6 hours ago, Sask466 said:

This forum seems split on this subject.  I don’t know what to think.   I have heard it both ways.  

We had a 4586 (back in the mid 1990’s) and the older IH mechanics at the time said to keep the revs up, as it was lugging that killed the bottom end.  They said keep it at 2400+rpm.  I recall that tractor had poor power under 2100rpm, but I was still pretty young so that may not be an accurate memory.  I also remember it feeling powerful  and sounding like a freight train at 2500rpm.  

I wonder what the official corporate IH message was on this subject back in the day.

Dad bought a used 4586 in 81 and I don’t remember how many hours were on it when he got it, but it was in the shop twice for head gaskets and not positive for what else. The second time, they turned down the rpm’s, again, not sure how much, but we ran it for 4 more years without any more issues.

[Sask466]

I have also heard that same engine was in dozers and ran slower (also probably less power output) and lasted much longer.  

[rustred]

yes, a V8 needs rpm kept up, and dont lug it. while a straight 6 can be lugged.

[hardtail]

The subject was discussed before, couple models of the TD20 had the V800, rpm IIRC was 300 rpm lower than the tractors, the other factor was in certain operations the ag tractors air filters could plug up and then it started pulling air and oil from other locations 

[rustred]

 all I'm saying is you cant lug a v8 they loose rpm then just stall. a 6  cyl. will slow down and keep chugging along. a v8 will not do that under load.

[farmalldr]

Here are a couple construction eq. examples that used the V800.  TD20E-2325 hi idle, 228bhp @2100rpm;  400 series scrapers-2850 hi idle, 350bhp @2600rpm.  Quite a difference for the same engine.  I did witness a flywheel coming off the crankshaft in a 444 Scraper.  Operator said, everything quite suddenly, no travel, no hydraulics.  I was only around one 20E.  Ran very smooth and started easily in cold weather.     Dennis

[jeeper61]

When designing the bottom end on HD diesel you would think they would go a little over kill 

There are quite a few other tractor brands that had frequent failures of bottom end parts as well   

[SDman]

I thought the bottom end of the DV-800 was actually built pretty stout for a V-8 diesel. The DV-800 used cross-bolted main bearings caps that used 2 bolts coming in from the side to make the main cap more rigid. The only other V-8 engine that I have ever seen with this design is the venerable 426 Chrysler Hemi.

As far as IH's thought on the DV-800 and engine RPM....well if you look at the proposed 7588/7788 tractors that were supposed to replace the 45/4786 tractors, one big difference is that the rated RPM for the 75/7788s was reduced to 2400 RPM as compared to the previous 45/4786 rated RPM of 2600. This was done in conjunction with reducing the HP ratings on the 75/7788 to 280/330 engine HP respectively from the previous 300/350 engine HP ratings of the 45/4786s.

[jeeper61]

If the cranks are getting cracks at the fly wheel flange they need to drop the RPM more than 200 RPM.

Would have been easy at the design stage to add a little more beef and remove the chances of a higher failure rate which ruins reputation. 

Here's a thread about it 

 

[hardtail]

There was some issues with balancer rubber bonding deterioration contributing to failures if not caught