Tweety's ea81 build

Tweety · Post by **Tweety** » Wed Mar 12, 2014 4:36 pm

This ea81 1992 large valve has been through the wringer. 32/36 carb, SC12 supercharger, SPFI that never really ran 100% and now weber 38/38 on a SPFI manifold. I want this to be my last rebuild of my life.

We have got plenty of ea81 build so this one will be different only in the breathing, mating the weber 38 to the SPFI manifold, a cam choice, head shave etc to suit the project.

So what do I have and what do I want.

-Good no slop ea81 electronic dizzy with spare module
-near new water pump
-new PCV
-New alternator
-near new blaster 2 coil
-stock spark plugs (iridiums left aside for now)
-SPFI manifold which is about 6mm larger in diameter
-new genuine weber 38/38 synchronous carbie with jets =

Main venturi 27, Aux. venturi 4.0, Main jet 145, Emulsion tube f50, Air correction 185, Idle jet 45, Pump jet 70, Pump bleed 30(1) Needle valve 250, Float level 40/52.5 All these were from Toongas previous post and wer eon the carbie new.
Daniel from Weber performance Braeside Victoria told me the idle jets are good for up to around 2500 rpm before the mains come in. He said it was the idle jets that might need tweeking and you go up not down. I left there a little confused but I did buy 2x 55 idles to experiment with.

What do I want. A solid sound and brand new engine. Rebore with oversized pistons. Heads with new valve guides. A suitable cam to match the extra breathing and exhaust efficiency. A slightly higher than stock compression ratio 8.7 to 9.0.

Two things I ask you guys for advice on currently.

- Camshaft. I know Steptoe has some knowledge and experience here. Bearing in mind the information supplied. Any advice appreciated.

- adapter for weber to SPFI

Lets start with the adapter. The following pics with paint the picture. A wedge shape will be needed. there is 70mm between the front mounting bolts to the rear mounting bolts and 20mm rise is required to make the carbie horizontal. A friend that runs his own engineering shop will make this adapter. My question is:

1/ There are 2 holes at the bottom of the base for rad fluid. Can they be tapped and blocked as I did with my 32/36 on my original ea81 manifold?

2/ I will want the hole of the manifold enlarged, as large as possible for least restriction. Can I cut out the meat between these two fluid holes? eg if I accidentally break into the fluid cavity I'll be in strife.

YouTube · Post by **El_Freddo** » Wed Mar 12, 2014 8:30 pm

G'day mate,

I've been following your other thread about the SPFI between being busy with other stuff!

Bummer to hear about the engine detonating, but glad you got home during that crap weather!

To me this says that the SPFI unit was most likely running fine and the lack of performance was due to the mechanical issues the engine may have been experiencing - to the point I'd say that the flat spot could've been due to the mechanical issue.

I would encourage you to stick with the SPFI after the build to see what you think of it from that point on. I know you've got the carb but I reckon it's worth the last go - if that doesn't work I'll be happy to remove it and install the carb for you

I say this because I reckon EFI can be easier to maintain than a carb - I know some stick with the carb and that's usually due to what they know rather than going out on a limb - you've already done that bit and I reckon you know enough to maintain it if it does what you want it to after the rebuild.

About the engine rebuild

Look into running with EJ20 pistons - you remove the collar in the conrod at the gudgeon pin end, the EJ gudgeon pin fits the remaining hole perfectly without issue. Two reasons for this move: 1) better oil ring holes for lubrication I believe and 2) easier to source new EJ20 pistons compared to aftermarket EA81 units.

Read up on the fitment here

Steptoe will have a good cam grind for sure!

Time to look for some dual port heads???

And a good time to do some port and polishing if you want. Some say it's a waste but the boys on the USMB seem to do it a lot and swear by it.

Other than that I'd look into a new kit to refreshen the oil pump as well. I know with the EA82 you can get a new rotor set, shaft and seals - I'm sure you could do the same with the EA81 - ask FROG.

Otherwise, enjoy the build

I'll be happy to help out!

Cheers

Bennie

Matt · Post by **Matt** » Wed Mar 12, 2014 9:06 pm

Can i ask why u want to use the SPFI Manifold on it? Why not switch to the larger EA81 carbie manifold, as then you should be able to run the adaptor off the 32/36 weber as i think the bolt holes are the same???

And agree the dual port heads are unreal :P Insert evil laugh here :P

Subydoug · Post by **Subydoug** » Wed Mar 12, 2014 9:11 pm

or sell all your spfi stuff and grab a manifold from this guy,

http://www.rotorcraft.com/bandit/parts.htm

Doug

steptoe · Post by **steptoe** » Wed Mar 12, 2014 9:40 pm

Matt, not likely you seen an EA82 spfi inlet manifold, they are like a fat lizards belly compared to any EA81 or EA82 carby inlet manifold ` at a guess they are 6mm wider externally and I think this will translate to inside

YouTube · Post by **El_Freddo** » Wed Mar 12, 2014 10:15 pm

steptoe wrote:Matt, not likely you seen an EA82 spfi inlet manifold, they are like a fat lizards belly compared to any EA81 or EA82 carby inlet manifold ` at a guess they are 6mm wider externally and I think this will translate to inside

Yep that's what it's about. The stock EA81 and EA82 inlet manifolds are smaller than the SPFI unit. I'm sure the ports are the same size at the head ends which would increase the velocity of the air/fuel mix...

Cheers

Bennie

Tweety · Post by **Tweety** » Wed Mar 12, 2014 11:03 pm

http://www.rpmmachine.com/shop/index.ph ... ail&p=5381 cheap plus postage.

but I really like the EJ20 idea. Scott, is there enough 'meat' on the bore walls? do you know the diameter of the pistons compared to the ea81 and wall thickness?

had zephyrs and they used bedford pistons and left only 2-3mm on the walls and often cracked the wall

YouTube · Post by **El_Freddo** » Wed Mar 12, 2014 11:34 pm

Apparently they're the same diameter - it's the stroke of the EJ that increases the capacity as well as the combustion chamber I believe.

You should be able to get suitable oversized pistions to suit your application.

That link - it's for an EA82, so the gasket kit wouldn't be what you require, plus other bits won't fit, but the bearings and pistons should be ok. Don't put an EA82 in the trike - that's a very backwards step!

Cheers

Bennie

Tweety · Post by **Tweety** » Thu Mar 13, 2014 1:17 am

ea82- not me, timing belts nah!.

I reckon knowing my ea81 history it hasnt been rebored ever. the last owner a mechanic had replaced the rings and bearings.

What I will need is an estimate of cost for the block reco at this point. Rebore, new EJ20 pistons etc etc. any guesstimates out there?

I think I'd like to source a new oil pump. any ideas there? hard to find

Tweety · Post by **Tweety** » Thu Mar 13, 2014 3:22 pm

busy busy. out by 4pm

steptoe · Post by **steptoe** » Thu Mar 13, 2014 5:38 pm

Tony, check with Ivans Imports on USMB, he is the one to have put EJ20 NA pistons in EA series, likely EA82

Tweety · Post by **Tweety** » Sun Mar 16, 2014 10:41 pm

This is the answer I got Jonno

"Addvantages has small comp rings and more room between them so less chance of ring land failure piston pin bushings need to be pressed out to get pins in. I think you would want non turbo pistons to get a good comp ratio. I have not tried running this yet but do know it will work. I the last one I built I used 94 loyale pistons out of ea82 they are strong to"

steptoe · Post by **steptoe** » Mon Mar 17, 2014 6:48 am

oh ! You don't wanna be the guinea pig do you ?

Tweety · Post by **Tweety** » Mon Mar 17, 2014 10:11 am

psychic again. After 5000 kms on the EA/EJ piston engine it blows smoke and no one can determine the source without pulling it apart again. Then chasing oversize eA81 pistons and throwing money away. With all the work I've done on this machine over 6 years I dont want that to happen. Whereas it might be hard to find oversized EA81 pistons but once I've found them I wont likely ever need them again. eg a hone in 15 years maybe not.

So I'm leaning towards what should be in there.

Tweety · Post by **Tweety** » Thu Mar 20, 2014 12:18 pm

Engine and trans out. Engine was a tad heavy to lift on my own esp up onto a stand. next time will get my neighbour to help lol. Trans about 80 kgms.

I will soon take the heads off the engine. Clean up etc.

I have a friend in the aCT who has a mate that specialises in reconditioning older auto trans and torque converters. This guy only does projects 100%. no shortcuts and is a wizz apparently.

He has told me that to recondition the auto and rebuild the torque converter the absolute worse case senario cost wise is $2500. the auto is working and has one fault- the auto stays in forst gear too long when over half throttle and over revs the engine. Could be a mere adjustment.

Question is do I take up the offer or get someone local to inspect the auto and make minor repair and rebuild the TC fully at less cost. I'm ;leaning this way as I have to also save for the engine rebuild.

Tweety · Post by **Tweety** » Mon Mar 24, 2014 5:22 pm

Been busy. made up a accelerator/throttle crank for the end of the cable at the carbie. bit od heat paint, made the intake large to assist in the carbie breathing department.

next step is clean the exhaust and paint it. Then take the heads off the engine to ahve a little peak!

Tweety · Post by **Tweety** » Wed Mar 26, 2014 10:42 am

another question about crankcase ventilation please.

I've got it all under control for the reco engine in terms of this. got a new barb on the top of the carbie for the end of the "F" fitting from the alt side rocker cover. now am wondering about the dizzy side rocker. I have a cone filter with trumpet foam inside it- no restriction and cold air intake once located. so it wont be easy and rather untidy to put a barb on it for the rocker vent. Am thinking to use a mini filter instead. My thoughts are though- shouldnt it have a one way valve? to allow air to enter but fumes to not exit? I could use a spare pcv valve as I have one.

Tweety · Post by **Tweety** » Fri Mar 28, 2014 8:06 pm

c'mon guys, I put deoderant on.....

Subydoug · Post by **Subydoug** » Fri Mar 28, 2014 8:36 pm

No need for a one way valve tweety. The PCV valve only draws the fumes out of the engine under light load. Coasting and cruse. At WOT there isnt enough mani vac to suck the air out so no circulation occurs. The spring in the valve shuts it off and lets the pressure bypass into the airbox. Typically on the ea81, the #1,3 head's breather went into the air box so any fumes that did come out would go into the engine, but this was only for emissions. In your case a little filter should work a treat, though make sure its unable to get splashed with water.

Regards

Doug

Tweety · Post by **Tweety** » Fri Mar 28, 2014 9:40 pm

Thanks Doug, question answered fully. yeh I'll put the mini filter near the oil filler mount. Am tidying up the electrics ATM then will take the heads off and split the block to get that cam out and send it off as per Jonno's recommendation. Tony