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Re: [GMCnet] Transmission vacuum modulator leaking? [message #329189 is a reply to message #326961]

Thu, 15 February 2018 20:12

gibsongo

Messages: 116
Registered: October 2012
Location: Montreal West, Quebec, Ca...

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Senior Member

So the verdict is in - hairline crack in the left cylinder head (#3) between the intake and exhaust valves. I guess the big question is why? Engine rebuilt 10,000 km ago (new rings , bearings, timing chain, etc., heads done but not magnafluxed) Really sweet running mill, burned less than a 1 quart of oil over the 10K km. I did experience a stuck thermostat at 2,500 KM, but thought I caught it quick enough before the digital temp reading exceeded 225....and it ran without a hiccup for 7,500 km afterwards,

Matt mentioned short cycles in cold weather, and it was below 0 centigrade when I started it up and saw a puff of white smoke for the first time. But I'd done a bunch of driving in Northern Alberta at the 5,000 KM mark in -10C with no problems - driving another 5,000 problem-free kms after that. And surely lots of Toronados got driven to the grocery store in the dead of winter....

Frank Borrmann has some J heads. We are going to magnaflux one before doing the machining just in case, as well as doing the same for my "good" head and my manifold before reassembling just to be safe.

If anyone has ideas on what should NOT be done to avoid a repeat, I'd love to hear them.

Gordon Gibson 1976 23" Norris Upfit Montreal West, Quebec, Canada

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[Message index]

		Re: [GMCnet] Transmission vacuum modulator leaking? By: jimk on Sat, 09 December 2017 23:27
		Re: [GMCnet] Transmission vacuum modulator leaking? By: GMC.LES on Sun, 10 December 2017 05:18
		Re: [GMCnet] Transmission vacuum modulator leaking? By: gibsongo on Sun, 10 December 2017 09:15
		Re: [GMCnet] Transmission vacuum modulator leaking? By: Ken Burton on Sun, 10 December 2017 10:15
		Re: [GMCnet] Transmission vacuum modulator leaking? By: gibsongo on Sun, 10 December 2017 11:18
		Re: [GMCnet] Transmission vacuum modulator leaking? By: bdub on Sun, 10 December 2017 11:28
		Re: [GMCnet] Transmission vacuum modulator leaking? By: GMC.LES on Sun, 10 December 2017 11:45
		Re: [GMCnet] Transmission vacuum modulator leaking? By: Larry on Sun, 10 December 2017 15:55
		Re: [GMCnet] Transmission vacuum modulator leaking? By: gibsongo on Mon, 11 December 2017 22:33
		Re: [GMCnet] Transmission vacuum modulator leaking? By: GMC.LES on Mon, 11 December 2017 23:02
		Re: [GMCnet] Transmission vacuum modulator leaking? By: Ken Burton on Mon, 11 December 2017 23:57
		Re: [GMCnet] Transmission vacuum modulator leaking? By: gibsongo on Tue, 12 December 2017 10:49
		Re: [GMCnet] Transmission vacuum modulator leaking? By: bdub on Tue, 12 December 2017 11:09
		Re: [GMCnet] Transmission vacuum modulator leaking? By: jimk on Tue, 12 December 2017 11:39
		Question By: gibsongo on Wed, 20 December 2017 09:36
		Re: [GMCnet] Question By: Kingsley Coach on Wed, 20 December 2017 11:23
		Re: Question By: Matt Colie on Wed, 20 December 2017 20:28
		Re: Question By: gibsongo on Sun, 24 December 2017 12:31
		Re: Question By: Matt Colie on Sun, 24 December 2017 18:56
		Re: [GMCnet] Question By: GMC.LES on Tue, 26 December 2017 08:25
		Re: [GMCnet] Question By: gibsongo on Tue, 26 December 2017 21:43
		Re: [GMCnet] Question By: GMC.LES on Tue, 26 December 2017 22:30
		Re: Question By: DetroitDan on Wed, 27 December 2017 14:49
		Re: [GMCnet] Question By: powwerjon on Wed, 27 December 2017 15:39
		Re: [GMCnet] Transmission vacuum modulator leaking? By: jhbridges on Wed, 20 December 2017 10:09
		Re: [GMCnet] Transmission vacuum modulator leaking? By: gibsongo on Thu, 15 February 2018 20:12
		Re: [GMCnet] Transmission vacuum modulator leaking? By: James Hupy on Thu, 15 February 2018 21:13
		Re: [GMCnet] Transmission vacuum modulator leaking? By: Matt Colie on Fri, 16 February 2018 07:55
		Re: [GMCnet] Transmission vacuum modulator leaking? By: gibsongo on Fri, 16 February 2018 20:54
		Re: [GMCnet] Transmission vacuum modulator leaking? By: James Hupy on Fri, 16 February 2018 21:18

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