best year for 6.9?

[hallgren87idi]

someone told me 87 was the best year for the 6.9, they said it had the upgraded 7.3 glowplug relay or whatever and a few other things the 7.3 used, was this person correct or are they just a little->

 

[thx997303]

They were correct.

 

[icanfixall]

Its either 87 or 88. I can't recall for sure. But as old as our rigs are who knows what engine they now have in them. Only the block numbers can tell you what it is.

 

[chris142]

Is there a way to tell if an engine is original to the truck? Mines a 6.9 according to the headbolts but I wonder if its original.

 

[rhkcommander]

87. There is a serial number on the block, but I don't think its tied to the truck. Can't promise that, just guessing..

That year has the rockers, oil cooler maybe, better glowplug controller, and maybe a few other things? All of which are standard replacements for people anyway, if you try to replace the part on a 6.9 the only ones available are the better "7.3" styles. As far as I understand it anyway

 

[Jake_IN]

With almost anything, I usually consider the last year of its production to be the best years. Seems like fairly often when a company finally perfects something they kill it the next year and introduce something new with new problems

 

[Agnem]

Thinking like an engineer, the rockers and glow plug controller, ZF trans, etc., were all new ideas tried on the last production run of 6.9's. The plan, obviously, was to use the 6.9 as a scapegoat, in the event that any of these changes gave the engine a bad rap. That way, they could bring out the 7.3 and all the old problems would just "go away" from a marketing perspective. It was a great way to test new components before actually commiting to them on the production of a "new" engine. Ironically, the biggest problem with the 7.3 would be, not the 6.9 "inherited" design components, but rather the fact that it was a bored out 6.9 block. They rolled the dice on thinner cylinder walls and an SCA free maintenance schedule, and they lost.

 

[texcl]

also didn't it have the upgraded block that didn't suffer from cracking around the block heater?

 

[The Warden]

also didn't it have the upgraded block that didn't suffer from cracking around the block heater?

That's correct...the upgraded block began about midway through the 1985 model year, specifically beginning with block #173828.

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[jaluhn83]

One thing to note though is that many of the improvements would be retroactively incorporated due to service - ie injection pump mods listed. Not uncommon to see the glow plugs and rocker arms replaced with the upgraded style too.

 

[darkbluefoxbody2]

Mid 85 engines have a 85 cast on the heads and block. Large can't miss it. But really there all good, most the crack issues are long gone and those blocks retired. 1983 being the exception do to parts interchange.
I'd say 1984 up are ALL great, I'm reringing/studding a 1984 even though I have great 1986 engines in the shop. Just find a low mile or maintained one.

I personally! haven't seen a destroyed 6.9, 7.3"s are a whole different story!

 

[FordGuy100]

Champion glow plugs?!?!?! E Gad!

 

[jaluhn83]

Mid 85 does have the improved block heater casting - shouldn't matter if you don't use the block heater, but in my mind it's worth trying to get the later block just in case you ever need it.

 

[Knuckledragger]

237016 New bolt in piston cooling jets is a terrific deal. I have the old style press in type and had to make tools to remove and replace them after boring. OTC no longer makes the tools or targeting template.

 

[jaluhn83]

Excellent point! Not only is the tool NLA, but the stupid jets are about $50 each....... I spent more replacing the 8 jets than I did on a crank kit......