Detroit Head

Go to the truck stop, ask around about getting a good head job. Surely one of them ole veteran truckers would help ya out.

 

some days we just can't help ourselves. sorry about that, it was my moment for a second there.

 

most likely rings wore out also, ck. on inframe

 

You may want to check resurfacing prices at a machine shop vs just getting a new head. If the head is old it is prone to cracking. It would suck to have to pay labor time for two heads

 

Unless I misunderstood your post, a leaking valve seal, a head job, and resurfacing are 3 separate things.

I never worked on the Detroit head, but on cars you can fill the cylinder with air and remove the valve spring and replace the seal (put piston close to top first) with the head on the car.

A head job requires that the head is removed and the valves and seats are reground and vacuum tested that they do not leak, replacing injector sleeves, check springs, etc.

While the head is off, they will check for cracks and warpage. If it is warped, it needs to be resurfaced. If it is straight, it does not have to be resurfaced.

I agree with baha. If you need an inframe, the time to do it would be when the head is off.

If the engine has over 800,000 on it have the gears on the front of the engine checked. They tend to have problems after that point and can cause engine damage. Good luck.

 

If the seal is worn out to the point it is passing oil then the valve guide is also worn out, if one is worn they will all be worn, Take it in and get a reman head, it comes with a Warranty. When the mechanic is dismantling the engine he can, after the injectors are taken out put in a dummy injector and turn the motor till the cylinder is at TDC and pressurize the cylinder doing a leak down test, then you will know if you have a bad cylinder.
Just a thought!

 

What year/engine is it? On the older ones, the head needs to come off to do injector cups, so if it's coming off, you might as well have them replaced. Also, when you pull the head, liner protrusion must be checked. If it's low, you'll be setting yourself up for head gasket failures if you let it go. This job can easily turn into an in-frame. Add up valves, guides, surface, pressure test for cracks, injector cups, you're looking north of $1000.00. A reman head is around $1700.00 with a good core that will have some form of warranty (on the head only if you install it). Also factor in the few days that the head will be at the machine shop, increasing down time, lost revenue.

It's your call on what is really cheaper. For us, losing $900-1000 per day not running makes it a no brainer, we swap heads.

Valve train is a valid point on bearing type bull gears, but newer engines with the compact gear train don't have the bull gear problems like the older ones. If you don't have the compact gear train, I'd suggest checking all the gears and at least replacing the bull gear if you have 800,000+ miles on it.

 

Be careful when you get the head surfaced. If they take more than 7 thousands off it you will need to reset the camshaft gear lash. Also depending on the year you might have to change head bolts since the new genuine Detroit head gaskets spec for 220 ft lbs of torque and I think engines from about 07/03 and older torqued to 180lbs and the bolts will not go 220 ft lbs. You can tell by a dash in the top of the head bolt. I would also recommend replacing the injector pockets. Valve replacement is very critical on Detroits. There are very close tolerances of how far the valves can recess into the seats. If they are sunk in too far it will lower your compression and cause it to not run right and smoke. Either get a reman genuine Detroit head or find a machine shop that is familiar with Detroits. I just did mine myself and the total cost was under a $1000 for everything including machine work and gaskets. I had all my intake valves replaced and new injector pockets replaced. Also if you have excessive blowby it might need a inframe. The way I can tell that is if the blowby tube is puffing out smoke instead of a steady stream of smoke. You might want to hook up a gauge to it and check the blowby pressure to determine if the bottom end is still good.