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Technical => Driveline => Topic started by: Rothu on August 10, 2009, 06:32:54 PM

Title: Engine "Flutter" under load???
Post by: Rothu on August 10, 2009, 06:32:54 PM
I'm getting a bloody irritating "flutter" in a 186 engine when under load which cleans up when it gets up to 2750 revs. It will also rock and shudder at idle but after 2 minutes settles down to clean.
Have been running it on gas forever, but the engine was (5 years ago) recoed with hardened valve seats.
I've checked all the vacuum hoses, replaced brake booster, recoed carby, replaced manifold gasket, compression is equal across all cylinders, plugs fine, electronic dizzy shaft fine, at my wits end!!!

A friend mentioned that holden uses cheap neoprene timing gears that finally give up making it impossible to keep timing correct.
Or that it might be the coil dying under load..
Anyone had this before? Absolutely STUMPED!!
Title: Re: Engine "Flutter" under load???
Post by: ben on August 10, 2009, 08:28:50 PM
i think you know what i mean. and i have it when its cold only somtimes. ive had it with my old 173 and now i put a 202 in i think i still remember having it.


... just keep driving. if it blows up put another one in.. hehe

ben

ps i dont know??
Title: Re: Engine "Flutter" under load???
Post by: Rothu on August 11, 2009, 11:21:20 PM
Seriously? No-one has any ideas?? ???
Title: Re: Engine "Flutter" under load???
Post by: Marishka on August 12, 2009, 03:14:37 AM
have you checked the vacume advance unit on your distributor, if the diagrams perished it wont function properly and cause similar problems 2 what your saying
check it by removing distributor cap disconnecting tube on vacume unit and fitting a piece of 4ft long aquarium hose, suck end of aquarium hose and put ur tongue on it..
when u suck the tube watch the distributor base plate, it should turn a few degree,s and when u put your tongue on the tube it should stay there. if it creeps back or doesnt even advance the diagrams perished.
it does make a big difference to a motor running smooth and well.
its amazing how many people out there dont know about or even check this.
ive known about this for at least 30 years now, as i grew up on a farm and have been doing all my own mechanical stuff since i was 10. im 47 now.
 hope this might help.
if not ill try think of something else it might be.
regards marty

p.s. did u also know that the 6cyl harmonic bakllancers are 2 piece and when they get old and the rubber perishes that the outer can spin on the inner and the timing mark can move making it nearly imposable to get it timed right with a timing light.


Title: Re: Engine "Flutter" under load???
Post by: ben on August 12, 2009, 09:11:57 AM
hey marty that makes sense. my advance tube is cripted so not working. shoudl fix that lol..

Title: Re: Engine "Flutter" under load???
Post by: Merlin on August 12, 2009, 12:20:50 PM
If your gas mixer is more than 5 years old pull it apart and clean it out especially behind the lift diaphragm also if there is any red sludgy stuff in the vapour tube then the converter will need a birthday to   Cheers Neil
Title: Re: Engine "Flutter" under load???
Post by: Marishka on August 12, 2009, 06:15:08 PM
hey marty that makes sense. my advance tube is cripted so not working. shoudl fix that lol..



lol, yep id fix it ben, u will notice the difference and your motor will love u for it :)
did u hook up ur heater hoses right way yet?
Title: Re: Engine "Flutter" under load???
Post by: ben on August 12, 2009, 08:43:41 PM
heater had a hole in it so i pulled it out.. lol. found 1 good one gunna install later.

ben
Title: Re: Engine "Flutter" under load???
Post by: Marishka on August 13, 2009, 07:36:18 PM
i cant live without my heater ben,
i shudder 2 think of what it would be like now without it.
especially after i recored it.
 i love my heater.
:) :)
Title: Re: Engine "Flutter" under load???
Post by: Rothu on August 26, 2009, 08:40:45 PM
it was recessed valves, and a very slight leaking head gasket.
The exhaust valve on piston one had no seat left!
Replaced it with a reco'ed high comp 173 head from ebay for $150. stoked!
Title: Re: Engine "Flutter" under load???
Post by: Mr Whippy on August 26, 2009, 09:19:14 PM
So did your old hed have hardenedvalve seats like stated in the 1st post?

Just wondering how you ended up with valve seat  recession if you had hardened seats
Title: Re: Engine "Flutter" under load???
Post by: Rothu on August 27, 2009, 08:53:28 AM
I took the old and new head to a head reconditioner to find out.
Unfortunately for my mate who owned the van before me, he had been misled. the old head (202) did NOT have hardened valve seats while the new one (173) does.
Title: Re: Engine "Flutter" under load???
Post by: ben on August 27, 2009, 09:36:55 AM
well you really scored then didnt ya!!

did you get a quote on how much it would cost for a reco head done with hardened valves?

ill probably have to get my v8 heads done eventually.

ben
Title: Re: Engine "Flutter" under load???
Post by: ben on August 27, 2009, 09:47:46 AM
ok just got a couple of quotes.

$700 was cheapest for fully replaces valves, seats, strings everything for v8 heads.

not too bad.

ben
Title: Re: Engine "Flutter" under load???
Post by: Mr Whippy on August 27, 2009, 10:35:16 AM
wonder what it costs for a 6
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