Pics of my heads - hows it look?

[fuzzydog]

You are correct - it is a 7.3 and the heads were worked on at some point in the past - the PO told me that but not exactly what was done. However, as you pointed out before at least one of the valves was replaced. I just got the pass side head off today and haven't got them to the machine shop yet. The one that was highly referred to me is an hour drive away and not open on Saturday, so probably will make a trip during the week.

My symptom was rapidly building high pressure in the coolant system shortly after start up. Within 2 minutes of starting up the coolant would be gushing out the overflow tank and that was with a new 13psi rad cap. I had no oil in the coolant, and no coolant in the oil. Because of the high pressure I expected to find one of the fire rings burnt through from combustion gas (I saw a pic of this somewhere on the net).

While I'm asking questions - am I being too paranoid worrying about the threads in the block where those rusty bolts came out of?

 

[icanfixall]

No... The rusty threads can easily be cleaned up... You will need a 1/2x13 threads bottoming tap so the threads at the bottom get cleaned too... These blocks are blind threaded holes... That means the head bolts do not go thru into the coolant passages like a chevy does.... If you can't find a bottoming tap just cut off the starting threads on the end of any 1/2x13 tap. Grind the first thread so it starts easy and don't allow the tap to turn blue or it will be ruined... Cutoff wheels do a fine job of making a bottoming tap out of a starting tap if you go slow and keep the heat down by a cold water dunk....

 

[IDIDieselJohn]

Interesting thread here!

 

[leftcoastjeff]

FYI

Thread chasing taps are made for this job, they do not remove any material, just clean out the threads. modify the same way for a bottoming tap. (to reach the last threads)

My .02,

LCjeff

 

[Knuckledragger]

I am not an owner of a 7.3 and have not encountered cavitation, but isn't his symptom a possible cavitation result? The pressure from the engine running would create pressure in the coolant. If the engine never totally warms up, there is never enough pressure for the coolant to migrate into the cylinder(s)?

Maybe I am thinking too hard about this, but it seemed to fit.

On the bottoming tap, buy one. They are not expensive (about $15 for a good one), and well worth it to avoid the headache you will get trying to modify another tap to do the job. In fact, I use bottom taps almost exclusively in my shop, even though I don't have to. Once you get one started on a new hole, they have much lower friction and turning resistance to a plug or taper tap.

Same goes for cleaning out pre tapped holes. If you are doing it in the truck without removing the engine, put some sticky axle grease on the tap before running it into the hole. When you back it out, all the chips and dirt will stick to the grease and tap, making it easier to keep things clean.

 

[yARIC008]

Could be cavitation. From everyone's experience though you usually get oil in the coolant though, especially if his system is pressurizing up like that...

As for the thread tap, make sure you DONT drop the thing in the coolant passage. The holes for the threads and holes for the coolant look exactly the same. I dropped it in there once and luckily had the engine on a stand. Had to turn it upside down and shake it all around. I believe JD dropped the tap in his engine and never even got it out.

Anyways, be careful.

 

[GOOSE]

Have you rotated the crank and checked all of the bores while the heads are off. I have not heard it to be too common but I had a crack in one of my cyllinders when I went through this. I think the worm weakened that area and I kept running it. I am definitely not wishing this this on you, I had a horrible mix of coolant and oil in both the radiator and in the block

Keep us posted, I love the pics.

 

[JLDickmon]

very first pic in the very first post..
gasket is leaking at the 10:30 point..

your latest post..
second pic..
leak is at 5:30

3rd pic..
both holes leaking around the pre-cups

I wasn't smart enough to read the whole thread before I posted..
"Icanfixall" called it.
that's been apart before.

 

[fuzzydog]

Thanks again guys, I appreciate all the insight.

keep in mind there was no external leak, no mixing of coolant and oil so when you say you see evidence of leaking gasket - is what you see consistent with a leak between combustion chamber and coolant passage? My non-professional eyes see where coolant could have been leaking but I expected to see at least one fire ring looking like this

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but didn't find that at all. That has me concerned about cavitation but I bought the truck in Jan 2007 and changed the coolant (precharged with SCA) and have tested and replaced the coolant regularly since then. I really think that cavitation is highly unlikely to be the issue, but I'm no expert. I will reinstall the injection pump on the gear and turn the crank to check each cylinder wall. If they are good then I am getting the heads checked out and machined if necessary and I will reinstall them and see where that goes. This engine ran like a top for me and I'm sure it still has lots of life left.

Just to be crystal clear - THE PIC IN THIS POST IS NOT MY ENGINE.

 

[fuzzydog]

Took the heads to the shop yesterday and confidence level is extremely high. First off he was referred by a friend who is a self employed heavy duty mechanic and sends all his machine work there, and has been for years. never a failure, according to the friend.
The guy gave me a tour of his shop and all the various high tech machines for honing cylinders, machining heads, line boring, valve grinding. Very impressive stuff.
We talked a bit about engines and he knew all the right stuff - the head cracks, he even showed me a head that had just been machined, and explained to me that mine would be a bit different because of the precups and went over the different metals and grinding stones, etc. The guy knows his stuff.

He is going to have a good look at the gaskets today, clean and magnaflux the heads, check them for flatness, and do the vacuum test on the valves. $50/head for all that, and then another $145/head if they need machining. i also brought my injectors to him and he is testing them for $10 each.

 

[Dieselcrawler]

damn good prices. i got qouted 80 just to mag my heads.

 

[fuzzydog]

Woohoo! The news is good.
Just talked to the shop and here's the verdict.
passenger side head was cupped in the area of the 3 centre head bolts, creating a weak spot for the pressure to get to the coolant passages. This matches with what I found - those 3 bolts had a lot of rusty crud on the threads.
only 3 or 4 valves failed the vac test and they touched those up.
all valve guides are good
all injectors passed the test
the heads have been cleaned, magnafluxed and machined. no cracks other than some minor cracks in a couple of the precups. shop tells me this is not an issue. any thoughts on that?

total damage was $488 Can.

 

[icanfixall]

Thats great news... Now clean out the threads... Clean off the block with a single edge razor blade... Then spray off with brake clean because it wont leave any residue on the metal. Use some victor rienz head gaskets and your golden... Glad thing were fixed properly... the other shop did a terrible job of the heads by not "finding" the warp... Any true straight edge would have shown that easily.... Sometimes I use a flashlite and straight edge to see the warps... Then double check it with a feeler gauge....

 

[fuzzydog]

Picked up a Dormer bottoming tap yesterday - 1/2 X 13 right?

Temps are vastly improved around here, should be able to get the block cleaned up this weekend and then put the engine back together in the evenings next week.

 

[icanfixall]

Yes... The 1/2x13 taps are for the 7.3 engines and the 7/16x14 are for the 6.9 engines....