Preparing block for New headgasket

psx_man, May 14, 2:08pm
I have an old 85 corolla that im doing a head gasket on. Head has been checked and skimmed which ended up fine. How fussy do i need to be on the block!
I have scraped off the old headgasket carefully with a scraper and lightly gone over it with some emery tape. The block is very smooth to touch but there are still a stain/discolouration on the deck from the gasket. Do i need to remove all this to be safe!
happylad3, May 14, 2:30pm
I'm gunna say no. What grit paper are you using! When we sand a block we use old 80 grit with a large flat file. Just to ensure its flat.
happylad3, May 14, 2:33pm
Just a note to say as long as its good around the bore binder area and water jacket holes.
realtrader1, May 14, 4:01pm
I hope you sealed up the bores good and well.You wouldn't want to get any of that nasty grit in there.Surface needs to be thoroughly clean and free from any remaining gasket material, oil etc.Look out for any pitting etc. around the water jackets and other crucial areas.
snoopy221, May 14, 4:48pm
Picture is worth a thousand words here.
Grab ya digi save to ya comp- upload to ya tard moi my pictures and copy nd paste da link.
K
intrade, May 14, 5:08pm
you clean the block then you use a lapping stone and go over it with that needs to be sparkeling clean stone and kerose . then you use a hairline straight edge and see if the block still is all straight befor you put the gasket on and the head on top. here a picture of what i am on about tools you probably have to borrow form mechanic or engine rebuilder
http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/18/cf/9f/medium/0900c1528018cf9f.gif
andrewph, May 14, 5:49pm
This is what i do at work when im fitting a head. Scrape off all the old gasket. Rotate the motor a small amount to drop the pistons below the surface of the block. Pick up my block of steel and wrap some 220 dry lube sand paper clean up the surface area. Try not to get any of the dust down the oil hole or oil returns to the sump. My block of steel is a piece of 40 by 10 steel strap about 180 long. put a rag over the hole for the head bolts and blow them out one at at time with the air gun. This gets all the oil and crap out of the holes so the head bolts are torqued down properly not trying to copress the oilforcing it back up the treadson to the head surface.Then wipe over the surface with brakleen or thinners, check timing marks. fit the head with new bolts if necessary. I
oil the threads and under the heads. Check the headgasket is the correct one and the right way up. blow out the oil passage in the head and blow it off to remove any bits of swarf that the eng reconditioner has missed. They usually get it all. fit the head. Rotate the crank back up to TDC. torque the head bolts down. double check the timing marks. have fun
hijacka, May 14, 10:01pm
I use grease around the top of the piston between the bore and top of the ring landings while the piston is positioned just below TDC, once that area is done simply move piston downward and wipe off excess.
drew2009, May 15, 9:29am
It also pays to have a visual inspection and make sure there is no "lip" sticking out on the very top of the bore due to wear. If it is only mild then you should be able to smooth it off with emery cloth.
psx_man, May 15, 4:48pm
Thanks for your replies. I'm not going to go too nuts with it since its only a $500 car but i do want it to last at least another year. I will post up some pictures tomorrow. One thing i did notice is the oil & water galleries on the block are bigger than the ones on the head gasket. Is this normal! Both the New & old headgasket are identical.

There also seems to be chips on the edge of the water & oil galleries that do look old. Should i worry about them!

Are there any tricks to remove the dels! Would make life easier to clean up the block if they weren't there (of course being put back when installing the gasket)
realtrader1, May 15, 5:29pm
dels!Do you mean the (locating) dowels!If so, why would you want to remove them for!Personally, I don't remember having removed them and would not do so without good reason.A stud extractor might do the trick or a pair of vice grips I guess.
wellyguynz, May 15, 7:36pm
What ever you do DO NOT oil the threads, when you go to Torque the head bolts up , As the oil does not compress you will get incorrect readings you want them clean and dry.
peril787b1, May 15, 9:42pm
On a $500 car, sand the head with a block to get rid of any major lumps then brush paint the surface with hi metallic content silver paint (not spray). This will fill any minor imperfections. This trick was passed onto me by my grandfather who was an old school A grade mechanic for almost his entie life. I've done this a number of times on engines that had a bad habit of blowing gaskets, and it fixed all of them.