Re-Torquing Head Bolts

[wthompson01]

I am getting ready finally to install a turbo on my 92 F-350 7.3 IDI. I have read that it is good practice to re-torque the head bolts. I plan to run a max of 12-15psi boost. Should I remove each head bolt in the sequence, clean the threads and oil the threads prior to torqueing them to 10 pounds over spec? I would install studs if I could afford it. But that may happen down the road. I have a new latest gen Banks kit, Stage 1 Injectors ordered from Wes, 90cc Moose pump from Wes. So I am trying to eliminate a problem before it happens. An Air to Water intercooler is on the list to be had soonest also. I think it may be a bit simpler to do as far as space required and piping. And 2 ways to do that even! Use engine cooling system or a separate dedicated smallish radiator and electric water pump for it.

 

[IDIBRONCO]

I wouldn't recommend removing them. In my opinion, cleaning the threads on the bolts, but not in the holes in the block is kind of a waste of time. The same kind of crud that's on the bolt threads will be in the holes too. I think that most people just break them loose and retorque them. When I say "break them loose", I mean just moving them counterclockwise enough for them to move, not releasing most or all of the clamping force that they have on the head gaskets. I feel that if you go through the trouble to remove the bolts, you might as well pull the heads and install new gaskets too.

 

[Kevin 007]

No, for re-torqueing purposes you don't remove them. You also don't just put a torque wrench on them and start torqueing. You have to "break them loose" a bit by loosening them about a 1/3 of a turn to free them up, and THEN you retorque to the desired spec.
I do them in the same sequence as the initial torque spec, working your way from the inside out. 1 at a time.

I personally strongly believe in re-torqueing head bolts once on high mileage diesels because they do stretch. There are some good write up's here on oilburners about the subject that go into pretty good detail and discussion

 

[IDIBRONCO]

I also forgot to mention last night that you can't remove all of the head bolts with the engine in the truck and the HVAC box in place. You have a few that will hit the HVAC box and not be able to come all of the way out.

 

[wthompson01]

Thanks guys. I am a master Honda tech. But this diesel engine is OJT for me. It's been years since I worked on diesel engines, and those were all Class 8 heavy trucks.
All Cummins engines. So different fuel system, no wastegate on the turbos and so on. I appreciate the answer to my uninformed question.

 

[cre1992]

I also forgot to mention last night that you can't remove all of the head bolts with the engine in the truck and the HVAC box in place. You have a few that will hit the HVAC box and not be able to come all of the way out.

I have heard you cant remove the bolts with the heads/air box in place, but you can zip tie the bolt in the up position when its completely unthreaded and remove it with the head.. Is this correct?

 

[IDIBRONCO]

I have heard you cant remove the bolts with the heads/air box in place, but you can zip tie the bolt in the up position when its completely unthreaded and remove it with the head.. Is this correct?

Yes. I've done it many times. You also have to do the same to a push rod or two. I used to use rubber bands, but zip ties will work just fine. Rem,ember to be VERY careful when you put the head back on. Sometimes a bolt or push rod likes to hang down below the head. This can bump the head gasket out of place or even damage it. And DON'T forget to put those back in the head before you put it back on the engine.

 

[wthompson01]

Thanks for the replies guys. I am not intending on pulling either head. In fact I bought the kit for removing swelled glow plugs as mine need to be replaced. I won't go into why they may be swelled.
But I don't want to pull a head if it can be avoided. If heads come off I'll spring for studs. Just because I'm wired that way. Insurance. So I will crack each head bolt a half turn and then re-torque to
10 pounds over spec. And go from there.

 

[IDIBRONCO]

I am not intending on pulling either head.

I remember this from your first post.

 

[wthompson01]

I DO appreciate all of the advice given. Thank all of you. Like I said. This is OJT for me. And thankfully I learn fast. In this case many of you have gone before me and I'll take experience over a book any day of the week. At this point
all parts bought other than the turbo kit (ignorant at the time) I have ordered from Wes @ CDD. So I'm confident that this project will work out well. I DO want to use an air to water intercooler and am undecided between a separate
small radiator and small water pump vs just plumbing the cooling water/coolant from the engine. I am not well versed on just how large that radiator would have to be. But I also have an air to air intercooler that would work as well with
coolant flowing through it. 3 inch thick core x 5 inches tall x 30 inches long. Just figuring out which way to go. Intercooled will happen. One way or another.

 

[lotzagoodstuff]

small radiator and small water pump vs just plumbing the cooling water/coolant from the engine.

Coolant from the engine isn't cold enough to intercool, you'll need to run a separate system with pump/reservoir/etc. If you really want to go air to water, take a look at the intercooler that IDiot used on ASmith's build for some insight. Link attached below.

Front mounted air to air intercoolers are very popular as they are plentiful (read cheap) and work pretty well.

Good luck whichever way you end up going.

https://www.oilburners.net/threads/project-asmith.80305/

 

[wthompson01]

Coolant from the engine isn't cold enough to intercool, you'll need to run a separate system with pump/reservoir/etc. If you really want to go air to water, take a look at the intercooler that IDiot used on ASmith's build for some insight. Link attached below.

Front mounted air to air intercoolers are very popular as they are plentiful (read cheap) and work pretty well.

Good luck whichever way you end up going.

https://www.oilburners.net/threads/project-asmith.80305/

Awesome. Thank you!

 

[wthompson01]

Here is the reason for asking the further question about air to water intercoolers. Many moons ago I worked for a truck leasing company. All Cummins engines. They had air to water intercoolers that were plumbed into the cold side
of the engine coolant system. I am assuming that the radiator in our trucks isn't large enough to produce coolant that is cool enough to meet the objective of cooling the post turbo air charge enough to make a difference. So. Cooling system for air to water
will be done. Thanks for the education.

 

[Booyah45828]

A lot of your higher hp stationary gen sets use an air-water intercooler. As do all 2 stroke detroits that are aftercooled. IDK where they draw the water from, how cold it is, or any real specific details of them, but they do use engine coolant for it.

There are a few builds on here that utilize a water-air intercooler. The one here https://www.oilburners.net/threads/6-9-grenaded-new-6-9-build-underway.88410/#post-1070467 is one of the more creative/interesting ones I've seen, he's not using a typical IDI turbo though.

I plan on running a water-air intercooler, and to use/piggyback off the engine cooling system for it. I'm planning on drawing water from near the oil cooler, running it through a heat exchanger, through the intercooler, and then back into one of the plugs on the water pump. I want to do it like this to eliminate a seperate cooling tank, electric water pump/wiring/ etc. I feel the engine water pump is more then capable of it, and with the additional heat exchanger, the coolant should be cool enough to work. The cheap 6.0/7.3 intercoolers won't fit or look good in front of my bus radiator, and I haven't been able to find a cooling stack that would work at a reasonable cost.

I'm not sure if any of you have ever monitored your IAT fully loaded, but it's a lot warmer then what most would think it is, especially if you're not intercooled at all. So using engine coolant to cool it off isn't a real outlandish idea.

 

[wthompson01]

A lot of your higher hp stationary gen sets use an air-water intercooler. As do all 2 stroke detroits that are aftercooled. IDK where they draw the water from, how cold it is, or any real specific details of them, but they do use engine coolant for it.

There are a few builds on here that utilize a water-air intercooler. The one here https://www.oilburners.net/threads/6-9-grenaded-new-6-9-build-underway.88410/#post-1070467 is one of the more creative/interesting ones I've seen, he's not using a typical IDI turbo though.

I plan on running a water-air intercooler, and to use/piggyback off the engine cooling system for it. I'm planning on drawing water from near the oil cooler, running it through a heat exchanger, through the intercooler, and then back into one of the plugs on the water pump. I want to do it like this to eliminate a seperate cooling tank, electric water pump/wiring/ etc. I feel the engine water pump is more then capable of it, and with the additional heat exchanger, the coolant should be cool enough to work. The cheap 6.0/7.3 intercoolers won't fit or look good in front of my bus radiator, and I haven't been able to find a cooling stack that would work at a reasonable cost.

I'm not sure if any of you have ever monitored your IAT fully loaded, but it's a lot warmer then what most would think it is, especially if you're not intercooled at all. So using engine coolant to cool it off isn't a real outlandish idea.

What you propose makes a lot of sense. Looking back in time, technically the Cummins engines that I worked on were aftercooled. Engine coolant was used to cool that aftercooler. And there was no separate coolant cooling system for it.
After thinking on it for several hours I think that after the coolant goes through the air to water intercooler the temp of the coolant will be raised to a point that is very close to the temperature of the circulating engine coolant. That would
certainly simplify the plumbing and the complexity of a separate cooling system. I will investigate this.