Hi all,


I've looked around and there's not much guidance to removing the head gasket so i though this thread would be a good place to bring together anything useful.

I am at the point where the heads are off the block and I have the old gaskets out. I used a mixture of the Factory service manual and some bits and pieces from around the web and just general common sense. Unlike the service manual I didn't remove the upper oil pan as it says to do, when removing both front and rear timing covers.

Now I have the heads out. I have checked the decks and there is little to no warping. I couldn't fit my smallest feeler gauge in. However, the cylinder heads both have some warping of around 0.2mm. The Factory service manual states anything over 0.1mm requires replacement. Does anyone know if it's possible, and how much, can be planed/skimmed from the cylinder heads? How much clearance is there with the valves? I see the pistons have the little indentations in them of the valves so I figure the pistons come VERY close to the valves. What if I skimmed and used a thicker gasket?

The engine had overheated and seized up, after it cooled it cranked but had no compression and was pressuring the cooling system. I just want to know what's my options if I try and re use the heads I have already.


Thanks
Brad

 

The heads can be tried up, but remember to make up the difference with the head gaskets. Depending on how much is removed, you could end up with way to much compression.

 

It's about 0.2mm (double the tolerance stated in FSM) that it is warped.
The heat treating - Annealing - would reduce that.

I have heard people planeing 0.5mm for gains by increased compression so it thought 0.2mm or less would be okay. But I wanted to hear from anyone else going down this route too.

 

I rebuilt my motor me and my dad own a machine shop In mobile Alabama and I resurfaced my heads 0.005 just enough to get it flat so I wouldn't have any problems out of the HG and I been driving it for 9k mile and it runs great still (and I run it pretty hard at that haha). And if you ran it hot ya might wanna get it pressure tested to check for cracks and I would resurface it just for that safety so just I case ya don't have to tear it back down just because of that. And 0.2 mm is a good bit never taken that much off a VQ but taken more off plenty of other cars heads and they say they run good so idk on that situation.

 

0.005" is a HELL of a lot less than 0.02"...

 

So that is 0.127mm - or there abouts - and I am 0.2mm out. I may try to straighten the head out by annealing it to see if I can reduce the 0.2mm warpage.

 

The right bank (passenger side) deck is about 0.08mm out which is still in spec but I will pass some sandpaper over that with something flat.
I wanted to heat the cylinder heads to try and reduce the warping before I sand them but I am concerned about removing the valve stem seals. Can these be removed and re used?

 

Sorry I can't help much but I'm definitely interested in what you are doing. From what I understand, the heads aren't serviceable because of the affect on valve timing. When you factor in all the variables, on an engine like this, there is very little margin between a running engine and one that self destructs by way of valve to piston contact. I assume that's why Infiniti rather say it's "not serviceable" than provide any guidelines.

I did a search and found one user on another forum say "Min thickness is 4.972" max thickness is 4.980 If that is in fact true, that leaves you with only 8 tho material to remove best case scenario. Unless you can find someone who makes thicker than stock head gaskets.

As weak as the stock gaskets are and have proven to be, I wouldn't recommend any DIY machining. I suggest trying to find a machine shop in you area that has experience with this type of engine.

FYI, all valve grind kits come with valve stem seals. So if you take the head apart, you'll have new seals available.

 

Wise words those...

 

8 thousands is just over 0.2mm which is around the warpage I have. Factor in the 0.1mm tolerance on the head and the block as per FSM gives a little more margin.

For the sake of two headgaskets and a days worth to put it back together I will give it a try. If it works, it works and if not I'll be looking to pick up an engine I've seen.....

Regarding the headgaskets, I've heard to avoid any eBay cheap stuff.
I have found Fel-Pro at $50 for the pair
http://www.ebay.com/itm/Engine-Cylin...14ec76&vxp=mtr

Or should I stick to the OEM head gaskets provided by Z1 Motorsports?

 

OEM would be my choice, but I never heard of anyone having problems with fel-pro. My dealer sells them for $56 a piece so that is a good price. Here is the part # for the fel-pro gasket kit

 

Which do you think would be better at sealing?

 

fel-pro is probably an exact copy of the oem part. Unless someone told me otherwise, I have no way of knowing which one seals better. My money is with oem, but if you looking to save some money, I can't blame you for using fel-pro

 

I decided to go with the Fel pro gaskets to save a little, but the head gaskets for the HR.
This link below shows the differences with the DE and HR head gaskets. I'll modify my block to allow for this revised head gasket designed for the HR engine. Hopefully this will help keep the temps down/stable more than the DE design.

http://5523motorsports.com/the-three...n-just-3-days/

 

I'll be removing the rest of the engine - the block really - so I can flat the cylinder block and then reassemble everything with the engine on a stand. This will make it easier to put it back together so gaskets can be put properly, sealant where it's needed, just better access really.

Whilst the engine is out, I am thinking to check the piston rings, as the engine did blow the gasket and it did overheat enough to seize. The cylinder bores look fine though, no scores or damage of any sort. If I do decide to check the rings, what do I look for? I'd rather not mess with things that are okay.

Also, as I'm taking the engine out the car, what else should I do whilst it's out? Any tell tale signs that the rear main seal is bad? Or just anything wise to do whilst the engine is out....

EDIT: According to that link I posted above regarding the HR head gasket, it says HR bolts 'can' be used with DE block when using HR gasket. But does that mean it's okay to still use DE bolts with HR gasket? Everything is stock on the engine, no FI/High rev etc