my headgasket is about to blown... if i get my head planned, will it develop more horsepower ? since less air will be able to enter in the cylinder... explosion will be less intense.

Help me on this please.

Will you suggest me to planned like 1mm or more to get more hp ?



Second important question:
Should i change tensionner, crank bearing, sproket when my mother is out ?

When i start my car... it had a clatter sound like 2-3 seconds after starting... is that tensionner malfunction ?

thanks

Should i change tensionner, crank bearing, sproket when my mother is out ?

She must be going out for quite a while. :D

If you shave the block don't you need to make adjustments to allow proper valve/piston clearance?

Shaving the head will raise the compression Ratio , but very slighly .. mabie good for like 2HP or so ...also yea, you will need to get cam gears so you can get the cam timing right .....

mistyped lol motor ;)

if the crank is coming out, get new bearings-rods and mains, as well as seals(its stupid as hell not to). think of the head removal as a timing chain replacement.....new chain, tensioner, and guides, as per the factory service manual. also, yes, if the head or the deck are shaved, you have to play with cam timing, which is why nissan strongly recomends AGINST doing, unless there is warpage. to raise the compression, its best to get new pistons (plenty to chose from, including euro de spec 10:1 from nismo)

thanks BRE92SER, i didn't thought *** saving the head will change the timing. I'm used to timing belt not timing chain ;)

I hope my head isn't wrapped or twisted. I don't think so... car never heated.

Second question, my cams lobes are a little bit scratched... as you can see on intake's lobes:
http://www.troisx.com/auto/spiderhead.jpg

Can i change cams for S4 cams or i need to rebuild? It this normal scratches?

this is a sr20de head 93 with 110k miles or more on it.

thanks

i cant really comment on this....when i did mine, it was after snapping rockers, so i had deep pitts in the lobes, so i was forced to replace them, and i was looking to get some performance back out of it, so i bought S3s. anyway, i think you should be ok on that head with getting s4, as long as you get new rockers along with them (160k). the good lobes on mine wernt scratched that much, so my guess is that yours had a little lack of lubrication at some point, or something like that. If you do go this way, or any way for that matter, getting rocker stoppers (mossy, jgy....other source) is a great way to save a few dollars in the long run....the tails of the rockers have a weak point , and can break at sustained high rpms. they are a great piece of insurance.

if you do cams, rockers, and stoppers, you might as well bleed the lifters, while you have the head partially disassembled. Its an easy job. while having the lifter submerged right(jet) side up in oil, stick a "proper tool" in the top and push down until air stops coming out. keep right side up, and re-insert into the head. keeps them oiling smooth and quiet.

At the dealership I worked at the head mechanic recommended not to shave the cylinder head on any SR20 block and not to bore anywhere from .020 over.

ok thanks to help nx2kdet :)

yeah i think ive seen there 1mm over (87.5mm) is the biggest without new sleves.....you CAN shave the head, but the timing has to be just right, or you'll run the valves into pistons

Hey $pider, just get a replacement JDM engine. Lots faster, and cheaper than rebuilding yours. And if you dont know what you are doing there is a very high chance you will mess something up.
Planing the head or shaving the head, increases the compression ratio, which basically means that when the piston comes up to compress the air/fuel mixture on the compression stroke, it stuff's the air/fuel mixture into a smaller volume than before you shaved the head. This results in higher cylinder pressure which means more POWER. But there is a catch...if you stuff the air/fuel mix into too small of a volume, it will spontaniously ignite. This will happen before the engine is ready for it to ignite (by the spark plug) and can cause bad problems and ruin an engine. This is called pre-ignition, or detonation, or knocking.

But in short, you dont need to shave the head when replacing a headgasket, unless the head is warped from overheating or something.