Well there is all this talk of getting this person's cam ground for their EA81 n/a or someone elses EA82T and yadda yadda yadda. Now I want to know if anyone has had a cam ground for an EA81T yet. I want to put a big nasty cam into my EA81TT project but I don't know what kind of specs I want or any of that junk. If anyone has had one done or would like to help me figure out what kind of specs I am looking for I would appreciate it. Thanks

I'd give the guys at Delta a call and see what they recommend for your setup.

www.deltacam.com

 

Craven

I

Well there is all this talk of getting this person's cam ground for their EA81 n/a or someone elses EA82T and yadda yadda yadda. Now I want to know if anyone has had a cam ground for an EA81T yet. I want to put a big nasty cam into my EA81TT project but I don't know what kind of specs I want or any of that junk. If anyone has had one done or would like to help me figure out what kind of specs I am looking for I would appreciate it. Thanks[

/QUOTE]

I owned a 84 ea81 wagon for 11 years and I finally had to do the motor.As a joke I had the cam done to stage one(power economy) and it went amazingly well.I would suggest stage two and advance your timing to compensate.Ask a mechanic about doing the timing.Twin carbs will also help with the new cam.

wel if I was running a twin carb setup then it might be a little easier but since I'm running an MPFI setup with twin turbos, well it makes it a wee bit more difficult:-\

Oops my mistake.I was thinking of a ea81 silly me.You will have overcam and you can still get a grind done it will make a difference.We didnt get many ea81T models over here.

 

Kevin

wel if I was running a twin carb setup then it might be a little easier but since I'm running an MPFI setup with twin turbos, well it makes it a wee bit more difficult:-\

can anyone tell me specs for the stock ea81t cam shaft?

As per the 1984 service manual:

 

Int opens: 16* btdc

Int closes:  68*abdc

 

Ext opens:  68*bbdc

Ext closes:  20* atdc

 

No word on lift.

i was hoping for lift.  i saw 36mm cam diameter.  Not sure if that is with or with out the lobe.  If i knew lobe height and cross section diameter we could figure it out.

The Rocker is probably 2:1.

 

No one has a cam laying around?

Edited February 9, 201511 yr by coronan

I've got a loose N/A cam from Delta Cam, but it has a modified lobe profile, etc.

if it helps - I had a NA cam ground to a spec to suit both propane and /or turbo, done by a way experienced machinist specialist, so experienced he is now way retired and closed shop. 20/60  60/20 with a 0.225" lift was so strong with wet motion lotion, pretty good with propane - waiting to add a turbo one day. It does however hate me adding loads to it - the lighter the better

I have several loose N/A EA81 cams right now. It will take me a few to round them up, if helpful. I am not sure solid, hydro, etc.

Messing with the grind on an EA81T cam is asking for trouble. The valve train geometry is very temperamental and the lift and overlap have to be figured precisely for a turbo motor or any low end or mid range torque you had will be non-existent. Boost pressure and head flow have to be taken into account as well. No, the ratio is not 2:1. I don't know what it is exactly as I haven't spec'd it yet, but almost all production vehicles lie in the range of 1.5-1.7:1. The lift is .210 and I would figure the ratio would be 1.5:1. Changing the ratio of the exhaust rocker and a slightly more aggressive lift and duration on the intake will net you better power without sacrificing too much low end to mid range torque. Yes, you can change out the rockers in the EA81 for Chevy SB roller rockers and change the ratio. It's been done. You have to stud the rockers and make your own valve covers to do it. If you're doing a full power build, address the cam and valves. Bigger valves will fir with some head work. If you're rebuilding and looking to gain power cheaply, I'd look at VERY mild porting, turning up the boost, getting a bigger down pipe and opening the intake.

I couldn't agree more with the above ^^^. I have had nothing but trouble with modifying the valve train on the EA81(T) and also the EA82. There just isn't a lot of room for for improvement without a sacrifice in some other area.. In other words in my opinion based on many EA rebuilds and repairs, it will never run properly, it will be so noisy you will be embarrassed to drive it, it will idle like crap, etc. Just my opinion, use it or burn it...  Good Luck!

SkiShop:

 

Have more beta on that rocker mod?

Is valve lift realy only 0.210"?  Or is the that the cam lobe?

That's the cam lobe. If the cam is .210, then the valve lift would be .294 at 1.4, .315 at 1.5 and .336 at 1.6.  The rocker arm is an aftermarket roller rocker that fits mid 70's to mid 90's small block Chevy. 1.5 is the original ratio. They make them in both 1.5 & 1.6 ratios. You have to get the Chevy style screw in studs to mount them. Remove the Subie studs from the head and install them. I don't know if you then have to change the pushrods or not. You'll have to take measurements to see. That part is easy as there are all kinds of pushrod sources. When you do this, it's all to high to sit under the valve cover, so you'll have to modify the old one or fab something new entirely.

Edited February 19, 201511 yr by skishop69