EA81 Head questions

[JRD]

Hi, I'm new to USMB. Please forgive if I longwinded, I don't have all the lingo down yet. Here's the story.

I'm re-ringing an EA81 for low compression in the #4 cylinder, when I pulled off the heads I saw it has cracks between the intake and exhaust valves on one of the heads. I saw a post for the EA82 mentioning this isn't a big deal and you can have them staked. Is this true for the EA81 as well, or do I need to start looking for new heads?

Also, I have another EA81 that the heads and block have bolt holes (on the lower side 12 mm bolt heads) that are not on the other heads or block. Is this normal? Could I use these heads (w/ extra bolt holes) on the block without them, and vise versa?

Thanks in advance, John.

[Ross]

Small cracks are argualbly not worth worrying about in that area. However, if you noticed them without a really good clean and close inspection I'd be inclined to find some more heads.

 

Any ea81 head will fit, but there are some differences you'll want to look into. There are two different sizes for the valves, you'll probably want to check that your spare heads don't have smaller ones than your originals... You can still use them in any case, but there will be a minor performance difference.

 

Where on the heads are these extra bolt holes?

[Gloyale]

The two bolts at eht bottom of the head were eliminated in ?83? I believe? perhaps 84?

 

But it doens't matter, you can still bolt that head onto your block. Definately check the valve size, as the older head may have smaller valves.

 

I personally would just peen the crack closed and run the head that was on it.

[JRD]

Good points, thanks.

Where on the heads are these extra bolt holes?

These holes are on either side of the exhaust port on the under side of the heads.

I would have never thought about the different size valves. I just thought an EA81 was an EA81 and so on.

I guess I can presume that the engine with out the extra bolts is probably not the original, as a wild guess.

Thanks guys.

[subiemech85]

there may be issues with using hydro lifter heads

 

TURBO heads are different

[Ross]

Pretty sure you can use hydraulic and solid heads interchangeably, but you do need to keep the pushrods and lifters together as a set -- using pushrods from a hydraulic setup with solid lifters leads to drastically changing tappet clearances as the engine warms up. Pushrods from hydraulic lifter engines are all steel, ones from solid lifter engines are aluminium with steel end caps -- this ensures the pushrods expand with temperature at the same rate as the aluminium block (not important when you use hydraulic lifters).

 

So far as I can remember, that and the different sized valves are the only differences....

[Gloyale]

Good points, thanks.

 

These holes are on either side of the exhaust port on the under side of the heads.

I would have never thought about the different size valves. I just thought an EA81 was an EA81 and so on.

I guess I can presume that the engine with out the extra bolts is probably not the original, as a wild guess.

 

No, If the car is newer than 84, then the motor without the lower bolt holes is likely original.

 

IT's the older one that have those extra bolt holes.

 

Make sure to swap you're rockers onto the new (older) head if you use it. You want to keep all the Vavle Train stuff matched.

[JRD]

No, If the car is newer than 84, then the motor without the lower bolt holes is likely original.

 

Body I pulled it out of is an 81, so from what you guys are telling me, I think the engine is not the original. What do you think?