EA81 heads , some are different

steptoe · Post by **steptoe** » Mon Apr 14, 2008 9:18 pm

I recall some saying EA81 heads differed in valve size. I have found one of my spare motors just stripped have two extra bolts M6? with 10mm head that are located at the lower side of the head and screw into the block, the other heads have a slimline casting boss? covering same hole on the headgasket.

Curious if anyone knows where this difference occured early, mid or late MY's praps?? Or just to help the gasket not leak ?j

Matatak · Post by **Matatak** » Mon Apr 14, 2008 9:28 pm

http://www.ultimatesubaru.org/forum/sho ... hp?t=86623

have a read

i dont no nething bout them but. only had the one EA81 and turned out to be a Dual port...dunno if that meant big or small or what tho.

BaronVonChickenPants · Post by **BaronVonChickenPants** » Tue Apr 15, 2008 12:32 am

From what I've read from about '84 onwards had the larger ports.

Jordan.

steptoe · Post by **steptoe** » Tue Apr 15, 2008 9:53 pm

ah , ports not valves , time for some cc'ing (and I don't mean those chip things that smell like piddled pants )

Matatak, thanks for the link. Was a good read and good moral to the story too, just 2mm difference between valve sizes huh ?

steptoe · Post by **steptoe** » Wed Apr 16, 2008 10:44 pm

OK

I found I have one pair of smaller inlet valve heads ~ 40mm, they are the heads with the extra M6 10mm bolts. The RHS has a square and tapped lug tacked on and not part of the casting to accept the power steer bolt mount. Looks factory but as an after thought!!

the others are ~ 41.5mm . Not much difference really

and both have a chamber volume of ~ 250ml

I have a selection of pollution ports drilled and tapped too on some pairs

YouTube · Post by **El_Freddo** » Thu Apr 17, 2008 12:21 pm

Also checkout the exhaust port where the headers mount up to. The motor Chris (subarino's bro) got from Matatak (i think) had larger exhaust ports than the one that came out of the car and the one that subsequently went back in the car.

Something else to check out.

Bennie

steptoe · Post by **steptoe** » Fri Apr 18, 2008 12:23 am

I have sent off my heads from my original build - didn't think about the back passage