EA81 Hitachi carb baseline or what is wrong?

RatCamper · Post by **RatCamper** » Sun Apr 10, 2011 5:58 pm

I've been unable to access the forums for a while now. It's finally all fixed and I can log in again.

Anyway, I replaced the Hitachi with my Holley 5200 today. Not quite finished but it was enough to run it. There is a major coolant leak which may be coming from the top heater line but I can't see it. Also it's running a bit unsteady but hey I just started. It's very responsive!

I'm using a modified manifold picked up on eBay coupled with a big aluminium spacer with tapered holes. For a throttle linkage I'm using one of those curved cable ones which I pulled off some variety of Japanese carburettor. It fit as an underslung setup with about 1mm to spare once I filed off some casting flash. I had to mount it the "wrong" way round because trying to put a 5200 the "right" way results in the accelerator pump being a couple of mm away from the distributor cap and the fuel inlet being a few mm away from one of the spark plug lead connectors.

Once I get the issues sorted out it should be great. It's already running adequately and not smoking at all finally.

I'm looking forward to sorting out the accelerator setup a bit more cleanly, figuring out a way to fit a more useful air filter and seeing if I can tune it a bit better.

RatCamper · Post by **RatCamper** » Mon Apr 18, 2011 10:06 am

Thought some of you may appreciate this:

Modified manifold. Aluminium spacer with tapered holes. Holley 5200. Nissan(?) throttle linkage. Air horn adapter. Mazda air cleaner. Mitsubishi charcoal canister (not mounted yet). The red thing is an intake pipe size adapter I used to replace the worn out crush ring on the air cleaner.
I'm not finished yet. Things like brackets, that crooked return spring, some detail work on the throttle linkage and tidying the wiring still need to be done.

It purrs now. Trouble is it screeches intermittently when it's cold. When it screeches the tachometer shoots up by 1000rpm / double. I've only seen it at idle when I've started it cold.
After replicating this a few times on different days it seems like the sound is coming from the distributor. That makes me very sad.

edit: Also Magnecor stainless inductive spark plug leads. Surprisingly they did make a small but perceptible difference.

Post by **TOONGA** » Mon Apr 18, 2011 10:11 am

RatCamper wrote: It purrs now. Trouble is it screeches intermittently when it's cold. When it screeches the tachometer shoots up by 1000rpm / double. I've only seen it at idle when I've started it cold.
After replicating this a few times on different days it seems like the sound is coming from the distributor. That makes me very sad.

Looking good that screech coming from the distributor could be broken balance springs or weights.

the dizzy is pretty easy to pull apart and rebuild

TOONGA

RatCamper · Post by **RatCamper** » Mon Apr 18, 2011 11:34 am

TOONGA wrote:Looking good that screech coming from the distributor could be broken balance springs or weights.

the dizzy is pretty easy to pull apart and rebuild

TOONGA

I hope you are right. The screech sounds like when a sleeve bearing fails on an electric motor and the shaft starts walking. I mean I'd love to convert to the electronic distributor or even EDIS, but not right now. That manifold setup has been steadily eating money over a period of months to set up. I know it looks pretty basic but it's the little things that add up. So I guess I'll have a look and see what's up with it.

Now I think of it, a walking shaft might explain why the old rotor kept coming adrift and binding on the cap. Hmm this could be interesting.

RatCamper · Post by **RatCamper** » Sat Jun 11, 2011 9:46 am

Hey again. been busy on other stuff, like connecting a land cruiser under seat heater to the motor. etc.

Does anyone have a writeup of which jets they use on an EA81? At idle I can tune it fine, but at about 2000RPM it starts to get really smokey rich. It's still jetted for the 1800 VW, which had stone cold manifolds and much slower intake velocity because it had individual runners to each cylinder about as big as the Subie single port ones.
So the subie motor would have a lot less dropout.

I just want to compare my jetting to others. If I can find where I wrote them down that is!
The richness is starting to kill the spark plugs again, and I even went up a temp range. I'm using it as a support vehicle to get the Ford started in the morning if I send it flat trying to get it to stay running. Man I can't wait for when I can get it registered again. Currently the biggest hurdles are I need a bit of brake line, and I have to get the carb tuned a little better.
One thing I will say is it starts with just a tickle of the key now, even stone cold. Maybe goes through one or two compression strokes before it fires right up. Don't even need to touch the accelerator. And it just idles nicely at 750RPM. Beautiful.

steptoe · Post by **steptoe** » Sat Jun 11, 2011 10:05 am

is it jets, power valve or even the acc pump plunger causing your richness?

Post by **TOONGA** » Sat Jun 11, 2011 10:28 am

hello Ratcamper Im taking it you are using the weber / holley that was on the VW ... don't hold me to this but Ive been told the best primary or main jet is a 135 and for the secondary a 150 or a 155. others have suggested a 130 for primary (main) and 140 or 145 for secondary.

On my EJ I have a 135 Primary and a 150 secondary, remember that it is a 2.2 litre.

Im not sure if you ever found this page http://www.subarubrat.com/Retrofitting% ... V%2032.htm look at the tuning and servicing section it will give you an idea of where to go tuning wise

good luck TOONGA

RatCamper · Post by **RatCamper** » Sat Jun 11, 2011 5:10 pm

I swapped around my idles and air corrections today and ended up with this:

Pri idle: 45
Sec Idle: 50
Pri main: 135
Sec Main: 140
Pri. Air corr: 170
Sec. Air corr: 180

It's the closest I can get with the jets I have.

The idle mixture screw doesn't need to be backed out so far, which is good.
I can't get it down below about 900rpm now, which is bad. I went nuts with carby cleaner and no surges. It didn't feel vacuum leaky anyway. The throttle plate screw is topped out... or whatever. At the end of its adjustment. If I unscrew it much more it'll fall out.

The next news is mixed. now that the jets are marginally closer to where they should be, I figured out the smoke was disguised white smoke. From what I read it's a perfect match for stuffed stem seals. If someone can tell me where to get four of them and where I can beg/borrow/steal a valve spring tool I can handle the rest. I have one but it's a bench one and I don't want to pull the heads off. Just do the usual and stuff the cylinder with nylon rope, crank it as far up to tdc as it'll go, smack the retainer with a socket and hammer, use ??? spring tool etc.
I need to get this thing roadworthy-able. So close now it hurts.

RatCamper · Post by **RatCamper** » Sat Jun 11, 2011 5:14 pm

Oh, sorry steptoe. The power valve seems fine. I have a rebuild kit I can put through anyway, but everything in there seems / is pretty new.
Jets seem pretty close now, and I suspect there is a bit too much squirt in the accelerator pump. I might shift the pivot pin to test at some point.

Post by **TOONGA** » Sun Jun 12, 2011 9:36 am

I know it is a pain in the arse but try the 180 air correcter as the primary, you may find the idle drops down.
Did you ever get this it is around 70 meg Weber Carburettor Manual
but it is well worth getting

TOONGA

RatCamper · Post by **RatCamper** » Sun Jun 12, 2011 11:28 am

TOONGA wrote:I know it is a pain in the arse but try the 180 air correcter as the primary, you may find the idle drops down.
Did you ever get this it is around 70 meg Weber Carburettor Manual
but it is well worth getting

TOONGA

I. Love. you.

I have been trying to get hold of that book for maybe two years.

Yeah, the idle revs went up when I swapped the airs and idles yesterday. The advice was good for sure as it got the idle mixture richer and above that leaner but it really messed up the idle speed. As it was 750 was the absolute floor of where I could set it. I've got to readjust the stop anyway because I wound it right out and now the primary is binding at closed throttle

Looks like I have some reading. So possibly I'd need another 180 or maybe larger when I set it up right? I'm actually looking forward to finally seeing the information I have been after.

RatCamper · Post by **RatCamper** » Sun Jun 12, 2011 1:05 pm

Thanks again! I've been looking at it and am now wondering if there is a leak around the top gasket after I swapped airs. No big deal. I've got a rebuild kit ready.
It also opens more questions to me like why the air correction jets affect idle at all. Learning is fun!

Post by **TOONGA** » Sun Jun 12, 2011 1:31 pm

Not a problem and Im sure some one will use that statement against me at some point

750rpm is quite acceptable as an Idle speed my brubmys under bonnet sticker says 800 rpm with + / - 6 degrees timing and idle set by factory

TOONGA

littlewhiteute · Post by **littlewhiteute** » Sun Jun 12, 2011 2:26 pm

The air correction jets won't affect idle speed.

The idle circuit has it's own idle air bleed, considerably smaller than the main air bleed.

More than likely the idle air bleeds are too large for your engine.

If your engine won't run slower than expected, it's still getting air from somewhere, a vacuum leak as a fault or incorrect hose routing, or the secondary butterfly is open to far.
I've had 5200 Holleys, DGV and DCD Webers, DCOEs, IDFs on all sorts engines and all of them could be adjusted to run slower than normal.

I've seen a 5 litre Holden run with's its Quadrajet butterflies all shut, the engine still ran at 1000rpm. Hose routing/charcoal canister issue.

RatCamper · Post by **RatCamper** » Sun Jun 12, 2011 4:11 pm

I used to be able to wind it down until it stalled.

According to the diagrams the air correction jets don't seem to do much to the idle, except perhaps influence the emulsion tube levels a little.

I swapped the air correction jets back and put the top gasket in from my rebuild kit for peace of mind. Idle went back to roughly where it was before the last tweak, perhaps slightly higher.
It sounded fine. No surging or popping. I went nuts with the carby cleaner again and didn't get as much as a murmur of difference from it rev wise.

Then something bad happened. There is a small vacuum line off the manifold that I have plugged because I have no use for it. I decided to pull the bung out to see how that influenced idle. It made the idle much louder and smokey but the revs didn't really change. Maybe I dropped the vac enough for the power valve to drop or something.
I put my thumb on and off the hose a few times, observing what was happening. Then it stayed smokey. Even smokier even.
I gave it a rev and it gave out batmobile levels of white-ish smoke!
When I let it settle it was still smoking away. Aaaahhhh! Not cool!
I figure I've broken it enough and gave it up for the day. Either the float got stuck, the pressure regulator packed it, the power valve jammed, it ate a stem seal or ??? Rings? Unlikely.

RatCamper · Post by **RatCamper** » Sun Jun 12, 2011 4:48 pm

I just slapped a vac gauge on it. Pretty bloody good actually. between 19 and 20" Hg. When I wind it up a bit and keep it there, it always seems to find roughly that vacuum. I didn't see anything indicative of a valve or compression problem on any cylinder either. I wish my VW motor had readings that good. And that consistent. Wow.

RatCamper · Post by **RatCamper** » Wed Jun 22, 2011 6:03 pm

I never saw, what air correction jets are people running?

Did a lot of tinkering since the last post. I just want to make sure my AC jets aren't way off.

RatCamper · Post by **RatCamper** » Wed Jun 29, 2011 9:06 am

A little post on a few jetting sizes I've found on teh web for reference. No idea how good they are as I haven't tested them:

idle: 50/55
main: 132/130
air: 160/165
emulsions: F66

idle:55/50
main:132/130
air:175/135

idle:60/55
main:140/140
air:165/160

I'm about as far removed from an expert as a person can be, but I'm kind of getting why the jetting is so different for each person.

littlewhiteute · Post by **littlewhiteute** » Wed Jun 29, 2011 6:39 pm

I reckon you have a blocked PRIMARY IDLE AIR BLEED, completely separate circuit to the main system (main jet / emulsion tube / air corrector).

Silverbullet · Post by **Silverbullet** » Wed Jun 29, 2011 8:07 pm

Have you rebuilt the/any carb yet? If it is second hand (?) and hasn't been rebuilt there could be all sorts of blockages and bits in there.