Engine "Flutter" under load???

[Rothu]

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!!

[ben]

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??

[Rothu]

Seriously? No-one has any ideas??

[Marishka]

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.

[ben]

hey marty that makes sense. my advance tube is cripted so not working. shoudl fix that lol..

[Merlin]

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

[Marishka]

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?

[ben]

heater had a hole in it so i pulled it out.. lol. found 1 good one gunna install later.

ben

[Marishka]

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.

[Rothu]

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!