New User with 2 1986 F350s

[Hydro-idi]

Hmm that looked like a crack but your magnafying glass pic confirms it’s not. Good news.
Yes, replace all seals & gaskets if you can. Much easier to do it now rather than later.

 

[onetonjohn]

Talked to the machine shop guy today. I've dealt with this shop for years. They do good work and I trust them. I"m thinking to have him just go though and check everything do valve job and square the heads. I've heard not to deck the heads on this forum, but as long as the valve to deck clearance is OK there is no problem, correct? I would think that since were cutting the valve seats too, valve should drop down and clearance would be OK. We are only taking around 5 tho off the heads. Is there something I haven't considered?

 

[Hydro-idi]

As long as they deck the heads within the given specs, it’ll be fine. Same with the valves and seats. Make sure they follow specs, as it’s very important especially with these idi cylinder heads.

 

[IDIBRONCO]

As long as they deck the heads within the given specs, it’ll be fine. Same with the valves and seats. Make sure they follow specs, as it’s very important especially with these idi cylinder heads.

This right here is the reason that I'm overhauling my 7.3 with -.015 pistons. too much was taken off of the heads and there would have been contact between the valves and pistons.

 

[onetonjohn]

Anyone have the clearance specs, or know where to find them. Should be pretty easy to check with depth micrometer.

 

[IDIBRONCO]

Macrobb knows them. You could send him a PM.

 

[pcwizzy16]

I wouldn't turbocharge an N/A IDI, the Stock turboed '93 and up 7.3L IDI had beefier rings and other components, and I've seen a ton of messed up IDIs that had aftermarket turbo kits.

 

[hesutton]

Anyone have the clearance specs, or know where to find them. Should be pretty easy to check with depth micrometer.

If your machine shop doesn't have these spec's or has experience with IDI heads.... I would not let them do the work. This is very different than a SBC head. You should NOT have to give the shop spec's, they should have them. If they don't, my guess is they don't have experience with IDI heads and the likelihood your heads will be correct is not good.

I drove four hours to a machine shop to have my heads done for this very reason.

Heath

 

[Thewespaul]

I wouldn't turbocharge an N/A IDI, the Stock turboed '93 and up 7.3L IDI had beefier rings and other components, and I've seen a ton of messed up IDIs that had aftermarket turbo kits.

Pcwizzy im sorry but I disagree with you there, the idit engines are stronger but only marginally so. An na 7.3 engine can handle producing double its stock power rating without even sweating, given you head stud it first.

 

[Hydro-idi]

I wouldn't turbocharge an N/A IDI, the Stock turboed '93 and up 7.3L IDI had beefier rings and other components, and I've seen a ton of messed up IDIs that had aftermarket turbo kits.

Where did you get this info from? And let’s hear about the engines that got messed up with a turbo added on them....
Any stock 6.9 (studded) or 7.3 idi will handle a turbo just fine. If one of these engines got “messed up” because of a turbo, it’s because the owner of the truck is a moron and screwed something up.

 

[pcwizzy16]

Where did you get this info from? And let’s hear about the engines that got messed up with a turbo added on them....
Any stock 6.9 (studded) or 7.3 idi will handle a turbo just fine. If one of these engines got “messed up” because of a turbo, it’s because the owner of the truck is a moron and screwed something up.

The first one I've seen fail, was burning a ton of oil, had bad compression, and downright clanked more than it should. Another one dropped a valve, and tore up the piston and destroyed the connecting rod and block, another one had a TON of blow by. They might not have all been related to having an aftermarket turbocharger, but the stock ones I see still run fine, and IDIs already have some blow by, and turbos make it worse, not to mention cavitation is worse on the 7.3L.

 

[snicklas]

The first one I've seen fail, was burning a ton of oil, had bad compression, and downright clanked more than it should. Another one dropped a valve, and tore up the piston and destroyed the connecting rod and block, another one had a TON of blow by. They might not have all been related to having an aftermarket turbocharger, but the stock ones I see still run fine, and IDIs already have some blow by, and turbos make it worse, not to mention cavitation is worse on the 7.3L.

None of these have anything to do with it being turbocharged.

Burning a lot of oil is high mileage/worn rings/valve guides.

Dropping a valve and destroying a cylinder/piston/rod/block, again, valve guides. IDI’s are known to have valve guide issues with high mileage.

I don’t understand how a turbo makes blow by noticeably worse, the 21:1 compression is more at play than a few PSI of boost.

Cavitation in the 7.3 is worse due to thinner cylinder walls, not adding a turbo. I’ve not seen where the cavitation happens more with a turbo than N/A.

I had a 92 N/A and now have an 88 with a hypermax turbo. The 88 runs better and has less blow by than the 92 had with about the same miles. The turbo has been on the engine for most of its life.

Most I’ve seen fail is due to valve guides, or just plain being beat on. Wether heavy loads, way over fueled, or trying to push them WAY past the limits with fuel, or water/methanol injection or Justin with his huge pump, sky high boost.

I know it’s just plain abuse, but you want to see just what an IDI can take, goto YouTube and search for “Zip Ties N Bias Plies” and watch his various videos of Slave Lake....... they are somewhat painful to watch...... but it shows these are not as fragile as many want to believe.

I and most everyone else has no intention of removing their turbo. A turbo used in reasonable limits, should not damage the engine or shorten its life..... but max the fuel, run the egt’s high.... then yes it will, but that’s not the turbos fault, it’s the operators fault...... I’ve seen many stories of someone pushing an engine past it’s breaking point with modifications, and when it breaks, call the entire engine family junk.......

 

[TahoeTom]

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This is for 7.3 IDI heads, should be the same as 6.9. Where you live a turbo would be a big help. If you deck the heads it may make the intake hard to install. I had to elongate the bolt holes to get it lined up. If the water pump doesn't leak, keep using it. I have gone through a couple of Motorcraft water pumps that began leaking way too soon, The later 6.9s have bolt in piston cooling nozzles (aka oil squirters) so are much preferred over the earlier press in nozzles. Also, the fuel water separator on the 86 (on firewall by brake booster) were prone to air intrusion so were eventually bypassed.

 

[towcat]

I wouldn't turbocharge an N/A IDI, the Stock turboed '93 and up 7.3L IDI had beefier rings and other components, and I've seen a ton of messed up IDIs that had aftermarket turbo kits.

total complete FUD about the stock NA motor.

 

[IDIBRONCO]

I have also seen a lot of them that had significant wear in the rear two cylinders because of turbos. Now for the rest of the story. Most of those didn't have a working pyrometer. None of those were installed in the correct location (within 8 inches of the head). None of them had an intercooler either. I think that the owners just burned the pistons up this way.