New guy sayin' hi...and a question

[OldIron82]

Hello all. I have lurked around here for over a year and finally became a member. Got a soft spot in my heart for the IDI's and I finally bought my first mini dump work truck, a 89 F350 cab and chassis (10' dump body) dana 60 king pin front, sterling rear, 7.3 NA with a zf5 behind it with a pto. Looking into a turbo and
doing research I decided to go with a 6.9 and today I purchased one from the grandson of a original owner out of a 1984 F350. Unfortunately, I just found out about the block cracking problem at the block heater and as it turns out this one falls into the category of the cracking years. The owners grandson installed a first gen Banks turbo with bb code injectors and was very good with the maintenance. The mileage is approximately 85,000. He said he never used the heater and as far as he knows his grand pop never did either. Sooooo, tomorrow when I lift it out of the back of the truck I will immediately inspect the area around the heater.

So here is my question: Even if the block is not cracked, should I plop a for sale sign on it immediately and keep looking for the coveted 87 6.9? Is the rest of the engine still stout? I remember reading the rockers could have been better... I'm not in a real rush but my plans were to tear this down to the short block and reseal every gasket from the bottom up and add head studs and then decide on how to turbocharge. I don't think ill be using the first gen Banks. I'd like to have this done by winter so I can flip flop engines in a timely manner over the winter months.

Thanks for reading. I'll share more about myself when I have more time. This place rocks! I look forward to speaking with everyone.

 

[F350camper]

Welcome Old Iron! Congrats on your purchase. As far as I know, you can just replace the heater with a frost plug and you'll be good to go. But you should post your question in the tech forum. TONS of traffic there and those guys will steer you straight.
http://www.oilburners.net/forums/forumdisplay.php?34-6-9L-IH-amp-7-3L-IDI-Diesels

Again, welcome to the best vintage diesel site.

 

[snicklas]

OldIron, welcome.

The cracking issue is from the block being a bit thinner in the area where the block heater installs ("A" Block). Where the problem lies is plugging in the block heater when the engine is COLD. The block heats unevenly and can cause the cracking. There are members here that have used the block heater in their "A" Block 6.9's for decades without issue, but they always plug in the heater while the block is WARM. I actually do the same on my diesels, it is easier to keep the warm coolant warm, and it doesn't stress the block. If this new one is not cracked, pull the heater, and replace with a standard freeze plug, or just remove the cord, and leave the heater in the block. This freeze plug hole is the only one that can be replaced with a standard plug. The rest are a special plug, with a special tool to install them.

If you live in an area that you feel you may need the block heater, install a lower radiator hose heater, or a better option, a tank style one that actually pumps the coolant around the block. I've seen this type actually keep the windshield clear via the defroster convection......

The ultimate heater is something like a Webasto!!!! These are a self contained, diesel-fired heater that needs no external power. So you can run the block heater in the middle of a desolate parking lot..... the down side is I believe these system are close to a grand!!!!! I would like one of these.......

 

[The Warden]

Welcome aboard

As I understand it, using the block heater exacerbates the block cracking problem, but it is possible for the block to crack on the early engines without using the heater. Personally, if I were going to be building up an engine, I'd want to use a later block.

It's up to you, of course, but I would lean towards selling it and looking for a later block. Take a look at this:

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There are two major problems with the early 6.9L IMHO. The first one's the block cracking...the other is the piston cooling jets. All 7.3L's, along with late 6.9L's after the block number listed on the sheet above, use bolt-in piston cooling jets that can be reused, and still have replacements available. The earlier 6.9L's, used press-in cooling jets that are one-time use (IIRC they can't be removed without ruining them), and they have to come out before the piston can come out! And, to make matters worse, IIRC the early piston cooling jets are no longer available to purchase.

You're right about the rocker arm assemblies being changed on the newer engines, but it's easy enough to get your hands on the later design, and they bolt right in place of the earlier rocker arms.

If this '84 6.9L were the engine that's in your truck now, I'd run it, but if you're planning to do a tear-down and rebuild, I would strongly suggest getting a later block with the bolt-in piston cooling jets and the sidewall ribs by the block heater.

As pointed out, posting in the 6.9L/7.3L IDI forum will get you more traffic and more answers, but I hope this will help you some.

Best of luck!

 

[OldIron82]

Thank you very much for all the info everyone! This place is great. I have to say finding out that my awesome score isn't so awesome after all, highly discouraging. Seeing as its a October of '83 I do not think I'll be playing with this block at all. What a shame. Catch ya later. Thanks again everyone.