Ok a couple of weeks ago I blew the head gasket. Had hydrocarbons in the coolant. I pulled the head this weekend and found that the rear cylinder had about 5mm of coolant sitting on top of the piston, and the associated valve section on the head is rusted (obviously this is where the leak is). So I'm wondering, is the block goign to be OK? Can I just get the head re-worked assuming it's not cracked, put it back together and move on?

Also, anyone know where I can get new head bolts? One or 2 of them were very rusted. Another reason the block could be trouble I guess as some of the threads are rusted out. Thanks for any advice!!!

Here are a couple of pics:
pic of head
pic of cylinders

I would:

1. Check the flatness of the head with a straightedge

2. lap the valves by hand with some valve grind compound grit

3. Test the valves for leakage

4. Clean up the block deck and head face

5. Use a wire brush on the head bolts. Chase the threads in the block

6. Bolt it back together and get on with life ...

So I guess this looks about how you would expect for a blown gasket? I've never pulled a head before so I don't know. So anyway, next weekend I'll take it to the shop to have it checked out, resurfaced, valve job or whatever it needs. I don't want to mess with it myself. Thanks DD
Michael

If you do it yourself, it'll cost about $40 for a new head gasket set. And about 2-8 hours of work. Some guys leave the manifold attached and just get a $20 head gasket. I've seen the gasket changed in two hours.

The shop will likely charge you $300-$400 dollars. They will always surface the head -- whether it needs it or not. They do this because it is easier and more profitable than checking the straightedge. This is one reason it will take them many days to do it (they send the head out to a shop, and wait for it to come back).

On the plus side, they will presumably be thorough, and will check the head for cracks. If you show them the block they'll probably say it needs a rebuild (and maybe it does -- did you do a compression test before dissasembling?)

I've got a quote to clean it, check it all out, re-surface it, and do a valve job (I assume 1-angle because he didn't say) for ~$150. They don't send it out - the have the machine shop there. Not too bad I think. There may be other things they'll check out that I wouldn't know how to do such as inspect the valves for damage etc.

Oops and no I didn't do a compression check before I disassembled. Should have I guess....

Michael

edit: that quote doesn't include parts.

I had the exact same problem on my a15, cost me $60 to get the head shaved (many people say that an alloy head should be shaved every time) and whatever the headgasket and manifold gasket cost. As well as many hours with the emery paper.

Quote:Those people do not include the auto manufacturers. Nissan's specification is listed here: Changing Head Gasket

Really, the only time that the head needs to be re-surfaced, is if it is outside specifications. If the head is cleaned of all surface imperfections [old gasket material] & a straight edge is placed along it, just like they show in the manual, you can check with a feeler guage. If it is within the service limit shown in the book, then it is OK to re-use.

The book will also show how to remove the valves & lap them in. It is something that i recomend be done every time a head is pulled. No point in re-installing valves that are half way through a service life. A couple of hours spent here can help to freshen up an engine that is starting to show signs of age & mileage related weariness, & that can only be a good thing.
If the valves are beyond just laping, then you KNOW that the valve job was justified. All shops should do a 3 angle valve job. It's the only way to get the seat within the correct width & position specs.

The workshop manual for your car can be the best investment you can get. Even at say, $50, it needs to be able to save you that much on only one job & it's paid for itself. The best part, ..it never wears out.

from looking at the pix you have, the head gasket failed, notice how the ring around the cylinder opening has come out of place. if you didn't over heat it, you'll most likely not need to surface the head, how ever it needs to be checked for flatness. the reason why shops have them surfaced each time is that it is cheap insurance that the problem will not return.
I also noticed that you have an excessive amount of rust in your cooling system, do you not use coolant?, there is more than one reason for using coolant, it will prevent freezing, it has a higher boiling tempeture, and most important it will prevent corrosion and rusting of internal coolant passages. plain water will not prevent the latter, in fact it will accelerate the effects of electrolisis and over time can and will corrode and rust parts to the point where they can no longer be used.