1987 6.9 Rebuild

[mr.cody.daniel]

Hey y'all, first post to the forum. Has been an invaluable resource for me already!

I recently acquired a beautiful 1987 F-250 6.9 for the glorious price of $900. 4wd, 4spd, minor surface rust but very clean an intact. 200k miles.


Of course, the problem. Excessive blowback in the intake. Excessive acrid white smoke out the exhaust. Loosen the intake cover and a chugging noise as the pressure pumped the intake. Sort of a "chuff chuff noise"

After reading the forums, seemed likely that the valve guides had worn and allowed the valves to start rocking, destroying the valve seat and creating all the blowback. So I set to work with my ~100pc Craftsman set and a borrowed garage space and tore the heads off. Have a ton of experience with race bikes and gas engines, but first diesel. Took all the proper steps, read Mel's great article (http://www.thedieselstop.com/contents/getitems.php3?6.9L Gasket and Turbo Install), kept push rods and rockers sorted, and heave hauled with three guys to get the heads out of the bay (heavy suckers!)


Took them down to the machine shop and have the preliminary report back now. Exhaust valves have all started to tulip. One precup is loose. Guides are all in spec.


Current plan is to remachine the valve seats, replace all exhaust valves, rebuild.

The question I have is whether I should preemptively have new guides inserted to avoid any potential future woes, or trust the factory guides to last. Another question is how afraid I should be of the loose precup. And lastly, should I have anything else done to the heads while they're out now?



Thanks for taking the time to read! Looking forward to the forum.

 

[icanfixall]

Welcome to the forum. Your doing the correct thing to the heads but I'm thinking you need new guides all the way around. We don't usually see guides ok and valves shot. Its mostly the other way. Now what shop is telling you this about the heads. Not many shop know much about the idi heads. Where are you located too. This forum has members all over the country and world that knows the best shops for parts and work as you have found out so far with Mel's article. Now with the heads off did you remove the injection pump still attached to the housing and drive gear. If so your making more work for yourself. No need to talk bout it till we know. Its not an easy fix but it can be done correctly. Congratulations on the new to you rig.

 

[mr.cody.daniel]

Thanks for the welcome!

I'm located in San Francisco, CA. Shop I'm working with is Zinola's Machine Shop in Mountain View, CA, on recommendation from Raineri Truck Repair from San Jose (where the previous owner had taken it last when blowback problems started)


Nah, I removed the pump from the drive gear. Didn't want to fuss with IP timing if I didn't have to.


Keep 'em coming!

 

[mr.cody.daniel]

Oh, also, new head bolts? Necessary?

 

[79jasper]

If you can swing it, get the head studs.

Sent from my SM-G900R4 using Tapatalk

 

[laserjock]

That is towcat's neck of the woods. Might pm him if you need recommendations on shops or whatever. While you are in there studs are never a bad idea. 6.9 studs are cheaper than 7.3 studs. Probably a good investment while you have it torn down to future proof yourself.

 

[icanfixall]

Definately get in touch with Calvin aka towcat. He is near San Jose Airport and really knows where the deals and steals are for great machine shops and parts. Worst he can say is I can't help. I'm not familiar with the shop you are using so far.

 

[mr.cody.daniel]

Thanks, I'll hit him up.

I quizzed him a bit, definitely very knowledgeable and experienced machinist, very honest and sincere, but agree that this is not the most common engine to be an expert on. He had worked on them before in fleet vehicles but says that far fewer have been around these days.


No worries about the precup being loose then?


Sounds like y'all are recommending new guides then? Any particular requirements/preferences on material?

Thanks all.

 

[JSVD]

honestly i'd just pick up a pair of rebuilt heads. You can find them for a good price. Not trying to steer you one way or another but I just went though my whole motor and spent more than I would have had i simply looked around for some rebuilt stuff.

 

[mr.cody.daniel]

I couldn't find them for less than $550/head. Unfortunately on a tight budget and a tight schedule!

Definitely understand that viewpoint, and given the right resources I'd go that route.

 

[snicklas]

One off topic question, is this the white truck in your Avatar photo? If so, that truck is not an 87. The body style in you pic is an 83-86 "Slantnose" An 87 would be the first year of the "bricknose" The one with the flat grill and large plastic headlights......

 

[mr.cody.daniel]

You are correct.. The plate listed it very late in 86 so I had assumed 87.... Guess I was wrong!

 

[snicklas]

Just to confirm.... the instrument cluster, is the speedometer on the left and a large square, either a tach or where a tach would be, and 4 square gauges on the right, the idiot lights in a row of rectangles under the top lip of the dash. The radio on top and HVAC controls down low it a section of the dash angled toward the drivers seat? If so, it is a 86 slantnose and not an 87.....

 

[mr.cody.daniel]

Yup, all true! She's an '86.

 

[IDIBRONCO]

Just remember, if you go with the head studs, you can't put the heads back on if the engine's still in the truck.