Head Decking w/ head gasket replacement

2937 Views 5 Replies 4 Participants Last post by Brett San Diego, Aug 1, 2009

cynack

Discussion Starter · Jul 29, 2009

hello,

I have a 2001 RR with 101k miles. I had the typical coolant leak from the rear coolant channel in the heads, so I have removed the heads to replace new head gaskets. I called a machine shop about having the heads and intakes cleaned and they recommended that I have the heads "decked" and said that I may not get a proper fit until this procedure was performed. I understand that this simply means shaving off a few thousands of an inch to get a completely flat surface again. Is this something I shoudl do? Are there pros and cons associated with this type of procedure?

I understand that I will have to go further and completely break down the heads to do the cleaning and the decking or else the "gunk will just build up inside the head on the valves". Is cleaning the heads at this mileage a good idea?

Also, I was considering using a dremmel tool to polish off the rough areas inside the air flow channels inside the manifolds and head ports. Will this give a significant performance enhancement? Are there pros and cons to doing this type of polishing? Could this negatively affect performance in any way? Is this a dangerous thing to do?

Lastly, are there any other procedures that I should consider since I have the engine opened up to this level and with this mileage? timing chain? etc.?

Any comments are greatly appreciated!

Jason

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Cornishman

· #2 · Jul 29, 2009

If your getting the heads off, having them shaved a few thou' would be a good move. If they've heated up at all then they may have warped slightly.
As for cleaning up the intake manifold (porting) there's good and bad about doing it. The good is, it will improve the smoothness and speed of the airflow. The bad is, there's something to be said for tumbling air, it helps mix the fuel in the air.

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cynack

Discussion Starter · #3 · Jul 30, 2009

So in the process of removing the RH head I broke both exhaust manifold bolts on the 3rd cylinder back. Should I simply have the machine shop remove them? Is this terribly abnormal to have them break?

Jason

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Cornishman

· #4 · Jul 30, 2009

Not uncommon to have them break. If your taking the heads to the machine shop, you may as well have them extract the studs.

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Jos Geuze

· #5 · Jul 31, 2009

Hi

Apply ample copper anti seize on all the bolts before assembly. This will make sure you will not break them again during a dismantling job in the future.

To extract the broken bolts use a set off tools like:

http://www1.conrad-uk.com/scripts/wgate ... 1&cookie_n[1]=uk_insert&cookie_v[1]=8V&cookie_d[1]=&cookie_p[1]=%2f&cookie_e[1]=Tue%2c+01-Sep-2009+16%3a35%3a52+GMT&scrwidth=1024

Do not use the tappered shaped easy out extractors. These will jam the bolt tighter and cause you to break the easy out in many cases.

Regards

Jos

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Brett San Diego

· #6 · Aug 1, 2009

It's pretty common to want to do this, but I don't think you necessarily have to. Put a straight edge on the head surface. Any obvious imperfections? Any obvious valve problems? If you don't see anything with the naked eye, I'd be inclined to just slap them back on with the new gaskets. I just went through this. Engine at 100,000 miles, couple of mild overheats caused head gasket leak. Visual inspection of the heads looked good, so we just put them back on.

Brett

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