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671TA Detroit Diesel Overhaul & Upgrade

Vanman

Subscriber
Last Subscription Date
07/10/2019
The head was dripping coolant from a particularly deep dent adjacent to the injector, so it’s definitely cracked.

I wondered about the condition of the crank too. If I end up wanting to use it, it’ll need to be carefully inspected.

At this point I’m on the lookout for another engine, a rebuildable core. Ideally one that I can hear run, but at least crank it over and listen for even compression and so on.

Keith
 

Airfooled

Registered
Wow, a 1955 Crown, that is cool. We had 3 6L71-TAC Crowns in service for years where I work. The turbo motors were a turd to drive as ours only had the Fuller 5 speed and the 1-2 ratios were way off. The NA motors were much more forgiving. Great power with the turbos once you were on the boil though. Still have 2 in service, one is a twin screw Supercoach with a Cummins 300/350 and HT series auto. The other is an odd one, old body style but with a rear engine. Cummins 8.3 with an MT series auto. Yours with the RR is going to be awesome, those are by far the best school bus bodies made. We had to scrap most of ours for CA emissions and even at 400,000+ miles were still solid and in daily service.
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
So I recently picked up some parts books for my 6-71 project. In - line 71 series, volumes one and two. I was hoping to use them to help me determine which parts are best suited to a higher hp engine, but the books evidently are not conducive to that.

Is there another type of book that I should be looking for? Like a catalog listing all of the different specs that were available?

Keith 5E0D410B-E511-4148-8668-BC36A37AB59E.png
 

The Diesel Doctor

Subscriber
Last Subscription Date
12/28/2019
Keith The coolant appears to be coming from the damaged area around the injector tube where it is flared into the head. It would be hard to get a new tube to seat. The head to block seals did not melt so it looks like there was no overheating. Noticed the block is stamped 0.10 so it has oversize liners. Dropped a valve and punched a hole in that piston. The Jake Brake on that cylinder may have been the primary cause of failure. The rod is bent and needs to be replaced. The lower ends on these engines are very strong and i suspect the crank is okay. Looking into the exhaust ports it is very clean and must have been a good running engine. AL
 
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