EA81 heads differences - pics up

steptoe · Post by **steptoe** » Tue Oct 04, 2011 6:50 pm

OK.

I always thought these looked later version than the other to be posted up. It was off an EA81 with solid lifters likely 3/84 MY sedan i wrecked

,
and these to be the earlier version

but, with some searching the memory banks, these heads came off a supposed import API engine. Supposed sounds correct because it was a hydraulic lifter unit, with sleeves in the block for the hydraulics - like EA81T as well. Subaru claim Australia never got hydraulic lifters in EA81 units. Now, lookng at original engine from 92 Brumby they must be later style heads. Then there was supposed to be early EA81 heads with smaller valves. These two in the pics have same size.

Anyone know much about the differences of these dinosaurs??

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revmax · Post by **revmax** » Tue Oct 04, 2011 8:14 pm

on the other side of the heads there is also markings in particular a number. 13 or 16
the 16 from what I can gather is the black rocker cover version 89 and on. Think it had to do with australian standards changing in 89.
I think 83 and on had the bigger valves with 86 and on having harder valve seats, but can't be sure cause I havent hardness tested them.

steptoe · Post by **steptoe** » Tue Oct 04, 2011 9:36 pm

Well, the second pic ones are same as 92 Brumby with black rocker covers.

Wonder if the ADR's you speak of affected the BRumby - being a commercial veehickle?

spike · Post by **spike** » Tue Oct 04, 2011 9:50 pm

a little bit of the book

There are 4 types of heads for the EA81 engines all depending on the designation of the engines.
Small valve heads anything prior to 1982 manufacture date had exhaust valves 2mm smaller in diameter.
Large valve heads manufactured after 1982, and all hydraulic lifter engines. The exhaust valves are 2mm larger in diameter and provide an extra 1 horse power overall. This added 2mm of valve diameter allows for more power to be worked from the engine.

Figure 1, large valve EA81 head on left, smaller valve EA81 head on right

Duel carb heads difference from the standard EA81 heads in the the exhaust tract, into the exhaust, has a much larger area than standard, they were oval shaped. These heads also featured opposite valves with the exhaust valves being on the outside and the intake being on iside. These heads are hard to find as from factory they were rare, engines were over worked and the heads destroyed and some have simply been lost due to the duel carburettor intake system being sold and replaced with a standard system.
The turbo heads included fuel injector ports and added water and oil lines to minimise temperature caused by the added power.