Brumby power problems, with shuddering...

sven '2' · Post by **sven '2'** » Sat Sep 04, 2010 3:29 pm

Pootcrum wrote:
Regardless, this is now a mechanics job, I have not the means to fix this at home. Trustworthy Adelaide mechanics anyone? Preferably south?

Rising Sun is your best option. Promise you, well worth the drive

Sven

RSR 555 · Post by **RSR 555** » Sat Sep 04, 2010 10:26 pm

Pootcrum wrote: cyl #1 160 psi
cyl #3 160 psi
cyl #4 175-180 psi
cyl #2 <50 psi!!!!

Clearly #2 cylinder is bad for some reason, stuck open valve, bad ring, bad gasket I don't know. I would have thought that if the gasket was bad, both cylinders 4 and 2 would show low compression, but is there any significance to the high compression in cyl 4? Could that be a cause rather than a symptom?

Glad to see why I put #1 check as a compression check.. always best to see what you're dealling with before spending too much money

I would say that #3 is where it should be and that #1 & #3 are low due to a leak in betwen cyl but a 20psi drop overall is nothing to worry about. I'd just adjust # 2 valve clearance and carry on happy motoring

Pootcrum · Post by **Pootcrum** » Sat Sep 04, 2010 11:03 pm

RSR 555 wrote:Glad to see why I put #1 check as a compression check.. always best to see what you're dealling with before spending too much money

I would say that #3 is where it should be and that #1 & #3 are low due to a leak in betwen cyl but a 20psi drop overall is nothing to worry about. I'd just adjust # 2 valve clearance and carry on happy motoring

Yeh wish I had, but I didn't have the gauge to do the test and felt spending the $60 it would cost to get a gauge was better spent on simple things to rule them out. Since then I found a great compression kit at a local auto place for only $35. Oh well, hindsight is a bitch.

Just checking what you said, you think #4 is right (the first #3 in your post), with the 1 and 3 bank leaking cross cylinders, and #2 has a problematic valve? I thought that 160 psi was more of a normal pressure (going by manuals), but then I suppose its not the absolute value of the compression, its the balance across all cylinders?

Haven't explored further as its been pretty bloody rough here and I have no cover.

And cheers Sven, once I narrow it down further I may give em a call to get an idea of time and cost. Certainly not the first time Rising Sun have been recommended to me, but me being at Reynella and them at Gepps Cross, a fair drive away.

RSR 555 · Post by **RSR 555** » Sun Sep 05, 2010 12:09 am

Yeah those compression gauges are the best money spent items in any toolbox

Sorry.. yes #4 cyl is normal in my opinion. All depends on how the compression check is done but most good used (not abused) EA81 will run 170-180psi

I would buy yourself a new rocker cover gasket and get hold of some good quality feeler gaudes and check out # 2 valve to rocker clearance. This would definately contribute to your shuddering problem.

Pootcrum · Post by **Pootcrum** » Sun Sep 05, 2010 3:34 pm

How hard should it be to get this rocker cover off? Theres only the two bolts holding it on right? I can see bits of blue shit between the head and the cover, is that some sort of sealant that has been used in place of a gasket and now its holding it on?

EDIT: Got it, but it was stuck on pretty good, had to get a bunch of the emission crap out of the way so i could lever it off against the block. Checked valve clearances and with the dizzy rotor pointing at the #2 spark plug lead the inlet clearance was right, but the exhaust valve stem was in hard contact with the rocker so the valve would have been partly open on the compression cycle. Have reset it to factory and am in process of cleaning all that blue shit off the rocker cover so i can cleanly mount new gasket. Fingers crossed.

DOUBLE EDIT: Comp. test on #2 cylinder up to 150 psi cold. Woot. Rebuilt and started her up, and she purred again, going for a test drive after shes warm and I have checked for oil leaks.

TRIPLE EDIT: Haha couldn't wait, took her for a drive round the burbs and she was smooth as silk. I am so happy that I found the problem finally, no emoticon appropriately conveys this feeling. All in all I spent around $100 on parts, and maybe another $100 on tools to get the old girl running smooth again. Peanuts compared to what I would've paid to have it done somewhere else no doubt. Will monitor the water and oil and such over the next week or so, make sure there's no other underlying problem, then do a service with fresh oil, filter and coolant.

Big thanks to all those who have contributed, your discussions helped me immensely in deciding what to do and how to diagnose the problem.

RSR 555 · Post by **RSR 555** » Sun Sep 05, 2010 7:01 pm

Awesome

glad to see another subie wins and lives again

steptoe · Post by **steptoe** » Tue Sep 07, 2010 8:57 pm

Well done Pootcrum ! And top marks to RSR for mention of the valve clearances. Crappy how they do not just creep up on you but just bite and give you 50 psi. I admit I forgot this is what got a friend a long time ago - changed his mufflers , all the tune up bits, and finally someone said do a comp test then check valves, do not assume burnt valve or dud gasket.

Those rocker gaskets designed to used without sealant for the consideration of next one to roll along. Have bent a few trying to lever off after I had sealed with silastic.
You hacve had a good tune up and built up tool collection

RSR 555 · Post by **RSR 555** » Wed Sep 08, 2010 3:43 pm

Thanks Jonno

Rocker cover gaskets are a pain when others have used silicone on them

with 2 clean surfaces then the cork gaskets are perfect

Pootcrum · Post by **Pootcrum** » Wed Sep 08, 2010 6:31 pm

Cheers steptoe, have been enjoying my morning drives to uni again, its incredible how smooth it is now compared to before. And talk about the sudden onset of compression loss, I cant fathom why it occurs like that after seeing the rockers and adjusting them, it seems like it should stay the same, or slowly over time wiggle out.

I was worried when I couldn't get the rocker cover off, was thinking it was going to bend I would have another parts hunt on my hands, but luckily a firm but consistent levering slowly edged it off. I don't get why when a factory designed two mating surfaces to seal with a certain type of gasket that people dont follow that procedure to the tee, unless a mechanic does not want a customer returning because of a small oil leak and the sealant ensures that wont happen? I had a look through my service records and a couple years back it had both gaskets changed by a service place so it would have happened then.

Now I can start pinpointing my oil leak, my target is the sump gasket, whilst underneathe I could see bits of the gasket cracked and falling away...

RSR 555 · Post by **RSR 555** » Wed Sep 08, 2010 9:13 pm

Front Crankshaft Seal and Oil Pump are the major causes of leakes on the EA81s

I'd change them first, then degrease and check for further leaks

steptoe · Post by **steptoe** » Thu Sep 09, 2010 5:20 am

I also find dip stick tube and oil filler neck sources of leaks. On EA82 mfi it can be a cracked rear PCV hose

RSR 555 · Post by **RSR 555** » Thu Sep 09, 2010 8:56 am

steptoe wrote:I also find dip stick tube and oil filler neck sources of leaks. On EA82 mfi it can be a cracked rear PCV hose

Good advice for an EA82 but doesn't really happen on the Brumby's EA81