EA81 Overhaul thread

littlewhiteute · Post by **littlewhiteute** » Fri May 27, 2011 7:03 pm

Personally, I wouldn't have pulled it out.

It will help if you put the tube in the freezer for an hour and warm the block a fraction.

Silverbullet · Post by **Silverbullet** » Fri May 27, 2011 7:32 pm

Probably could have left it in, but then I wouldn't be able to have the engine sitting on the bench the way I had it.

I've properly come to the next hurdle now; getting the crankcase apart. Cracking the bolts I could manage, but this has me stumped. Unless I'm missing a bolt (I've looked up and down all over and can't find one) this thing must be stuck together with super glue

I've managed to get a minuscule gap in one corner of the seam, and you can see the two halves have kind of twisted apart about .5mm if that makes sense but the rest of it is properly sealed.

So, how do I break this thing?

steptoe · Post by **steptoe** » Fri May 27, 2011 11:57 pm

got the two camshaft retainer bolts removed? That plate holds left and right blocks together. As for oil tube - I used a small gas torch to warm the block before chilled chube with an open end spanner over the collar to help tap in place, so tight dunno why an O ring is used. Also need Greymaxx silicone to goo up the two halves again so the next time someone comes along to separate them they will have same trouble you have now:)

steptoe · Post by **steptoe** » Fri May 27, 2011 11:59 pm

oil pump is out too ?

Silverbullet · Post by **Silverbullet** » Sat May 28, 2011 11:46 am

Yeah the lockplate is loose, oil pump needed some persuading but that's out too. I think I must be missing a bolt, on the diagram for 1800cc engine that toonga posted, there is a short bolt, number 9 on the diagram. I can't tell where it goes in from the drawings so dunno where it could be. So far I've got 7 bolts removed of varying sizes, don't suppose anyone knows how many there are meant to be?

RSR 555 · Post by **RSR 555** » Sat May 28, 2011 12:37 pm

Like Jonno (steptoe) said the blocks are stuck together with some pretty strong silicone but you do really need to be sure all of the bolts are removed first. For me it's been too long and too many CC & Drys since building my last EA81 but from memory there should be 1 or 2 bolts inside the water jackets (around the bores) and the should be near the centre of the 2 bores. Can you take a pretty close pic of both sides and post them up?

steptoe · Post by **steptoe** » Sat May 28, 2011 12:48 pm

Dead crtain it is just the one M10 bolt down in there on EA81, never split an EA82 to see if any different in this regard.

Silverbullet · Post by **Silverbullet** » Sat May 28, 2011 1:59 pm

I just came running in to say never mind I got them apart but there's already 2 replies

Turns out there are 4 around the front end of the crankshaft, I only got the two big ones. There are two smaller 10mm bolts right at the front which were hidden by grease. Got those out and presto, two halves popped apart in no time

The joy of getting them apart was short lived though, first looks at the camshaft and lifters and there was no chipping or scratches or any damage that I could tell, so no cause of the knock yet. Main bearings have a darker wear line through the middle and I haven't inspected the big end bearings yet, don't know if I will take the rods apart at all since #3 looks fine; trying to move it around it doesn't move any more than the other 3 rods. What could be making the knock then?

Some pics:

Trying to figure out what happened to that water channel, squashed in half!

Post by **TOONGA** » Sat May 28, 2011 2:42 pm

Silverbullet wrote: don't know if I will take the rods apart at all since #3 looks fine; trying to move it around it doesn't move any more than the other 3 rods. What could be making the knock then?

A spun bearing, a stuck/sticky lifter lots of things

Silverbullet don't just take it for granted that the rods are ok, pull them down and inspect the bearings. then get the crank linished at least.

and replace the bearings

You could regret it if you don't

TOONGA

littlewhiteute · Post by **littlewhiteute** » Sat May 28, 2011 3:50 pm

I'd check the gudgeon pin fit in the rods.

If they're ok, I'd bet you have a big end knock.

Silverbullet · Post by **Silverbullet** » Sat May 28, 2011 4:09 pm

TOONGA wrote:A spun bearing, a stuck/sticky lifter lots of things

Silverbullet don't just take it for granted that the rods are ok, pull them down and inspect the bearings. then get the crank linished at least.

and replace the bearings

You could regret it if you don't

TOONGA

Very true. I'm going to do a big clean of the shed and bench to reduce the risk of bits of dirt getting into the parts, then disassemble everything for a full inspection, lots of photos. Getting a micrometer on Monday as well to find out what sized bearings etc I will need.

littlewhiteute, I'll check that as well, the pin on #3 was the hardest to remove so maybe a clue there.

Cheers!

*Just a quick update of this post, tidied the bench and went about disassembling the crankshaft and rods. No spun bearings or any damage that I can see

All side clearances were within spec too. So far then it looks like I'm getting new main and big end bearings at least, going to get the camshaft and crank inspected for roundness and runout etc and cylinders honed. Since there's nothing obvious wrong with the big ends, I'm going back to the heads. I've got new oil seals for the valves to install anyway so going to disassemble the heads for inspection. Turning out to be quite a mystery this

Silverbullet · Post by **Silverbullet** » Sun May 29, 2011 1:04 pm

Had a chat today with someone I know who's rebuilt quite a few engines, talking about what happened and how there's no signs of damage on the rods/bearings. He brought up an interesting idea; Since the rag was holding the intake/exhaust valve wide open and the piston obviously smashed into the valve, that could have bent the valve very slightly. Not enough to show up on a vacuum test like the machine shop did, but enough so that when the engine is running and valve is opened there is enough bend in the stem to keep it from closing again causing the piston to smack it closed, making the noise.

Kinda praying that this is what's happened since there's no other signs anywhere else

Going to have to get a spring compressor and check it out.

Post by **TOONGA** » Sun May 29, 2011 1:27 pm

Any signs on the top of the piston that it hit the valve it should be very apparent

I have a nasty suspicion that the number 3 lifter got mashed (it sticks in its guide) and the whole system is faulty (push rod, rocker arm, valve)

as well the gudgeon my have been bent causing the top of the pushrod to be mis-shapened making it extra hard to get out

TOONGA

littlewhiteute · Post by **littlewhiteute** » Sun May 29, 2011 4:34 pm

Silverbullet wrote:Had a chat today with someone I know who's rebuilt quite a few engines, talking about what happened and how there's no signs of damage on the rods/bearings. He brought up an interesting idea; Since the rag was holding the intake/exhaust valve wide open and the piston obviously smashed into the valve, that could have bent the valve very slightly. Not enough to show up on a vacuum test like the machine shop did, but enough so that when the engine is running and valve is opened there is enough bend in the stem to keep it from closing again causing the piston to smack it closed, making the noise.

Kinda praying that this is what's happened since there's no other signs anywhere else Going to have to get a spring compressor and check it out.

If a piston hits a valve, the valve will be bent, end of story.

A vacuum test on the valves WILL reveal ANY bend, however slight, since the valves and seats would be been concentric to start with.

A quick check of the valve stems with a straight edge is worthy, as is filling the ports with kerosene to check for leaks.

Silverbullet · Post by **Silverbullet** » Sun May 29, 2011 4:50 pm

littlewhiteute wrote:If a piston hits a valve, the valve will be bent, end of story.

A vacuum test on the valves WILL reveal ANY bend, however slight, since the valves and seats would be been concentric to start with.

A quick check of the valve stems with a straight edge is worthy, as is filling the ports with kerosene to check for leaks.

I see, so there is no in between properly bent and perfectly straight. Only suggested this since I can't find anything else obvious that might be making the noise

TOONGA that sounds very nasty indeed

That would mean 4 new pistons, pins, rods, lifters, pushrods, rockers... Might as well fork out for another engine if it's something that serious.

This might end up less of an overhaul thread and more of an autopsy thread if that is the way it's going

littlewhiteute · Post by **littlewhiteute** » Sun May 29, 2011 5:39 pm

Can you post some pics?

Combustion chambers, valve stem heights, camshaft showing all the lobes, base of lifters and any piston that's had valve contact.

Post by **TOONGA** » Sun May 29, 2011 5:44 pm

Silverbullet wrote: TOONGA that sounds very nasty indeed That would mean 4 new pistons, pins, rods, lifters, pushrods, rockers... Might as well fork out for another engine if it's something that serious.

you would only need to replace the stuff for number 3 and if you are doing it on a budget you could do it with second hand parts.

there is a complete EA81 in the ACT for sale

vbclassified.php?do=ad&id=1553

TOONGA

Silverbullet · Post by **Silverbullet** » Sun May 29, 2011 5:52 pm

That looks great for $200, but ACT is a bummer. How much does it cost to freight an engine?

littlwhiteute, ok then give me a minute

Silverbullet · Post by **Silverbullet** » Sun May 29, 2011 6:20 pm

#3

Valves/springs, #3 are the two on the right, intake is far right

Camshaft, #3 is second from the gear

#3 lifters, a bit blurry. Intake is on the right, exhaust on the left

#3 piston

#3 valves, intake on the right

littlewhiteute · Post by **littlewhiteute** » Sun May 29, 2011 7:11 pm

The intake lobe for cylinders 3 & 4 is the rear lobe of the camshaft.