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gt380 chirp

Posted: Sun Sep 28, 2014 3:43 pm
by smokingbanana90
Hello, recently I got my 380 working again and Ive been driving but its back in the shop again because the right side cylinder doesnt like to fire and when it does it pops and chirps especially when its cold . It has good spark and the other cylinders work great. What could be any causes of this right cylinder just quitting like that? Thanks!!

Re: gt380 chirp

Posted: Sun Sep 28, 2014 6:57 pm
by Vintageman
Did you have the points changed not too long ago? If so they may be pitted due to a bad condenser.

Pop sounds like points to me ("Chirp" like a bird?, check timing maybe too far advanced)

Plug cap may be bad too

Re: gt380 chirp

Posted: Mon Sep 29, 2014 1:29 am
by yeadon_m
'Chirup' sounds might be metal on metal? maybe check carefully the lubrication system in case oil is not being injected into the right side upper cylinder.
Mike

Re: gt380 chirp

Posted: Mon Sep 29, 2014 2:42 am
by Suzukidave
If the points cam felt isnt lubed i have heard before the rubbing blocks on the points make a chirping sound as they contact the cam .

Re: gt380 chirp

Posted: Mon Sep 29, 2014 6:13 am
by Coyote
There is one pissed off bird living in your right pipe! :roll: Seriously, pull the baffle and check the inner plate (about a foot down in there). It could be coming loose and squeaking. While you're at it, see if the right side picks up without the baffle in place. Could be a clog.

Re: gt380 chirp

Posted: Mon Sep 29, 2014 5:15 pm
by Cliff
Check for a head gasket leak on that cylinder.

Re: gt380 chirp

Posted: Wed Oct 01, 2014 6:53 am
by jeff kushner
Cliff's right, head gasket leak......



jeff

Re: gt380 chirp

Posted: Wed Oct 01, 2014 1:51 pm
by yeadon_m
Good spot, top marks to Cliff!

Re: gt380 chirp

Posted: Mon Oct 06, 2014 6:26 pm
by smokingbanana90
Thanks guys! When I get back into the shop I will check all those things and get to the bottom of it!

Re: gt380 chirp

Posted: Fri Oct 10, 2014 7:58 am
by vanillaice
Would compression test show up bad cylinder gasket?

Re: gt380 chirp

Posted: Fri Oct 10, 2014 11:09 am
by Vintageman
Cliff is most likely correct about head gasket leak for chirp (nice call!). I may have used a polite “fart” sound

But I suspect more maybe ?(need more info to be sure)

If head gasket was leaking, bad enough to stop firing or power significantly from cyl it would sound more steady and loud. I don't think you would called it a just a pop and chirp only when cold. still does run that cyl when warm and no more chirping???

for example if the engine was not firing consitently, building up unspent fuel and then ignited the explosion would be very strong and maybe at the wrong time. This can stress the head more than normal causing it to bow up (only 4 bolts per head that design) and some combustion gas would leak by (chirp/pop).

So yes you probably have a bad head gasket, warped head, eroded Aluminum and/or, loose head bolts. But sound slike not firing as it should?

So if head leaking it should fixed, but a leak would have to be bad and steady to affect it that bad?

If it leaks significantly you will hear and will show up on a compression test

Re: gt380 chirp

Posted: Fri Oct 10, 2014 8:42 pm
by tz375
vanillaice wrote:Would compression test show up bad cylinder gasket?

The answer to that is "perhaps". It might show up on a compression test, but there's no guarantee that it will. Do one anyway to see.

Fortunately the head comes off really easily and as long as the barrel surfaces are OK it's an easy fix.

Re: gt380 chirp

Posted: Fri Oct 17, 2014 9:18 am
by mike1161
Hmm, very interesting. I've noticed a chirping sound from my T350 also, sometime after the rebuild. Funny, though, I did re-torque all the head bolts to spec a 2nd time after running for maybe 100 miles or so.
But I'm going to check them again, because otherwise not sure where that chirping comes from. I does seem to happen just when I rev it a bit. For example, I don't hear it a steady speed. I will report back what I find out.

Re: gt380 chirp

Posted: Mon Oct 20, 2014 5:57 am
by pearljam724
Suzukidave wrote:If the points cam felt isnt lubed i have heard before the rubbing blocks on the points make a chirping sound as they contact the cam .
Agree on the chirp noise. Points need addressed or it's out of time.