Blew a headgasket, is it necessary to resurface the block and head? Or only the head?

 

Take a straight edge to both and find out. The helms manual has allowable tolerances for both listed.

 

I read you could use a sheet of glass instead of a good straight edge. You might get more accurate results by carefully placing the head on an oil'd sheet of glass than some cheap straight edge. If its small enough glass you could prolly make this work with the block too

 

did it overheat? 99 times out of 100 if one warps, its the head.

 

Yeah the antifreeze leaked out the overflow, and I think that's what caused the head gasket to go when I took a long drive.

I've heard and read that the head is always necessary to resurface so I went ahead and did that but was just curious if the block needed to get resurfaced also.
The head looked kinda beat, but the block looks pretty good.

 

its probably not necessary but if I were you I would do something to check the block out too. Even if its 1000/1 odds, there's prolly been 1000 easy head gaskets put in civics since the last unlucky bloke. You might be unlucky, prolly not but maybe.

 

Glass? No. Glass warps over time, and is no where near perfectly straight. A machinist's straight edge is as close to perfectly flat as you're going to get. They aren't expensive. There's no reason not to do it correctly.

 

I'd rather spend $50 or so to have the head surfaced so I don't have to go through the process again.

 

I've only ever needed to do the head. Like the previous posts said though check the tolerances on the block

 

Why is it that majority of the time the head is always the one that needs a resurface. Is it because of combustion?

 

^^ Good question, I would guess its the quality of metal on the block vs the head.

 

Not so much the quality of the metal, as what kind of metal is used. The head is more prone to warpage, because the head's metal is softer. The block (specifically the sleeves) have to handle a lot more abuse, so they're made out of a harder metal that's less likely to warp.

 

I would resurface the head and block to be on the safe side thats my 2 cents.

 

co-sign...



if your hg blew and the engine over heated there is a strong chance that the head is warped. If so, I would just resurface the head.

Warping a block from overheating is pretty hard to do. I've yet to a block "needing" to be decked to correct block distorition. Manytimes when we do deck a block it's because the top surface is crusty, dirty, light scratches.

 

can you cite your source or back that up with facts?

I ask because it seems to me that the hardness of the head would be more critical than the block since the cam journals are integrated into it. The block uses steel inserts for the bearings and cylinder liners.

two other factors contribute to heads warping before blocks. for one, the head is at the top so as the coolant level drops the shortage of cooling is seen there first. the other is the overall shape of the head compared to the block. it's more thin and long in general, whereas the block is... like a block.

 

Take both to a machine shop and have them check it. They should only charge you a small fee. Check it or find out the hard way by having it blow the head gasket again!!! Also as a bonus you can get the head milled a few thousandths and raise the compression = more power.

Cylinder heads warp because they are aluminum which is much softer than a cast iron engine block. Go put an aluminum pan and a cast iron frying pan on the barbaque grill. Crank it up let me know which one warps first. A

 

the head/block gets warped because of the pressure of the coolant chambers, obviously when coolant gets hot it boils and the steam it lets off is what warps the aluminum over time.

I'm sure the combustion chambers play a role as well, but pressure+steam would take a toll more than just hot air in the combustion chamber I would think because it has an exit out the manifold.

I've been running evan's pressureless coolant in my civic and I'm going to put it in my other car just to have a lower risk of ever blowing a headgasket down the road. I'm pretty sure the cooling system is what causes most headgaskets to go bad.

It costs more initially but it's reusable, lasts as long as the car, has a higher boiling point which will never boil in a motor because it doesn't reach those temps. And it doesn't corrode the internals. If you do ever get this run evans prep fluid with evans coolant first so that it draws water out with it when you drain, then fill completely with evans coolant.

Look it up, good stuff.

 

It's best to find a machine shop that will heat the head in an oven(around 500 degrees) and straighten it out.

 

Modern Hondas (1989 and later) don't use cast iron blocks. they use iron liners (about 5mm thick) in a die-cast aluminum block. also aluminum frying pans are not made of the same aluminum as cylinder heads. the type of alloy makes a big difference as does the aging, heat-treating and tempering process that cylinder heads go through.