u know how on stock dohc vtec motors the oil is fed from the block into the head for vtec, why is it necessary to plug this hole up when running lsvtec? of course theres no hole in the LS block for oil to be fed, but wouldnt it just be sealed off by the gasket? Both the head and the block are flat surfaces, this is what i always wondered....

 

I meant leak* in the title

 

nah the gasket wont keep it from leaking... cuz my friends build he used a plug from sears and it leaked.... so that means if it wasnt plugged at all it would be worse.. now he got a real plug and everything is fine...

 

yeah but what i dont understand is.. how come it wouldnt just seal with no plug? If it was on a gsr motor the hole would seal, only because it was meant for it

 

i believe a portion of the hole is exposed and not sealed by the gasket. also the head gasket uses raised areas on the gasket to help sealing and as you stated the ls gasket doesnt account for the vtec hole.

 

Right, the hole is basically hanging in the air, and there's nothing to press the gasket against it to seal. The gasket isn't nearly stiff enough to begin to keep oil in there.

 

Oh **** i didnt know that... I thought the gsr cast and ls cast are the same? With just no hole for provision of vtec, oh well learn something new every day

 

that's right the hole is exposed......put a LS head gasket on a vtec head and you can clearly see that the hole is fully exposed, this is why you need to plug it......or you can also take a ls head gasket and put it on the vtec block and you will see the same result.