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I just wrote what he posted. What’s done is done, but if it was me, the bearings I would install would not be sealed or shielded and the highest quality I could find. Consolidated, SKF, ***, etc.

funny, they edited one bearing manufacturer that starts with F And ends in G.
 

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Thanks Peter! I believe you made the Oil Feed Holes in your Front Cover too. I think I read it on another thread here…
 

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The spark plug holes are very close to the valve seats on the Montreal heads. The old water pump bearing was really gnarly.

Thanks for sharing,
Mark
 

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...The spark plug holes are very close to the valve seats on the Montreal heads....Mark
I do wonder how the spacing might compare to other Alfa heads? For sure something seems to be a consistent problem with this particular feature. Obviously welding up the cracks is the only fix....but would not the inherent problem simply come back again in the future? It sure would be ideal if the exact issue causing this problem could be identified. Maybe an alloy issue ....or excessive interference fit with the seats....or stress corrosion cracking taking place? On my engine the PO parked the car after a valve seat dropped out which could have been caused by the same issue.
 

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I've read a few blogs on other forums on heads cracking and it seems even engines designed 50 years later are still having the same issues. Though admittedly, the problems are almost always attributed to overheating of the engine. Here's an interesting one that talks about different repair schemes...

Engine Block and Head Repair - Engine Builder Magazine
 

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I used a single-sealed bearing for the front of the water pump shaft. Standard non-sealed bearing for the rear.

Ball bearings will famously run a very long time if well lubricated. In my opinion, a double-sealed bearing will reduce oiling, rather than help. A double-sealed bearing is most often used where there can be no supply of oil, AND replacement is easy, ie an alternator. One never finds double sealed bearings inside a transmission, right?

The single sealed bearing I used was to help slow down oil leakage into the coolant, over time, so the seal is facing the water pump. Yes, I drilled an oil drip hole in the top of the timing chest housing boss for the bearing. Whether that makes a little, or a lot, or no difference is impossible to know.

My posture would be to drive the car often, possibly 10/50 oil to improve and speed up oil spray in the timing cabinet, and patience to allow full heating before flogging it.

All that aside, there are enough known problems with the Monty engine that we should be thankful it is relatively easy to remove from the car.

The engine I recently finished had, I think, four cracked plug holes. The torque value specified should be respected. We used "Tine Certs", not welding. Both will serve, but there are greater risks with welding.
 

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.....The engine I recently finished had, I think, four cracked plug holes. The torque value specified should be respected. We used "Tine Certs", not welding. Both will serve, but there are greater risks with welding.
Interesting solution...presumably the holes drilled for the installation of the time certs were sufficient to clean out the cracks fully? If the cracks extend from spark plug hole to the seats I would guess that this repair would not work.
 

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Interesting solution...presumably the holes drilled for the installation of the time certs were sufficient to clean out the cracks fully? If the cracks extend from spark plug hole to the seats I would guess that this repair would not work.
there are repair components that don't often circulate in the non--pro-shop world. The inserts used by the shop I employed were different than what I've seen before. Very high-end shop. I trust their work. We discussed the options beforehand, and I was convinced.
 

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Having a well-working grinding company is as essential as it is not easy to find. I consider myself lucky ...
 

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I'd say twin plugs and larger valves. That's a bunch of distributors on one engine, but oddly, not a big mod in itself as the engine was designed to have the diz on either side.
 
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Hey wait a minute there Sergio......twin plugs?
It is a (new) GTAm head with new valve seats and revised pipes. I put this photo to appreciate the grinding work we rely on.
 

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Very nice head work on those. Did you find any cracks on those at all?
However, the cracks found in the heads and bases, in the presence of thin thicknesses, are usually repaired by ultrasonic welding.
 

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..It is a (new) GTAm head with new valve seats and revised pipes. I put this photo to appreciate the grinding work we rely on.
Ok that explains that. As far as US welding goes... I would have thought that the area of the spark plug holes and valve seats would be quite thick ...perhaps too thick to US weld no? Most of the repair schemes I see being recommended show conventional TIG welding and grinding at the locations of the cracks with controlled pre-heating and control of the cooling down rate. But I suppose the shop selected to carry out the repair will have their preferred methods regardless.
 

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Dear Montreal enthusiasts,

Since summer last year I am the owner of a Montreal of 1972. During test drives of 15-30 mins the car was running without issues. When I extended to 45 mins plus I discovered bubbling of the cooling fluid in the expansion tank. The car has been at 2 Alfa shops now, gone through several tests and we still have not been able to indicate a root cause of the bubbling behavior.

Below I present an overview of all checks done and associated findings:
  • Cooling system cleaned with Bardahl
  • Fan and thermostat checked on function: good
  • Thermostat cap renewed: tighter spring version installed
  • Cooling fluid checked for exhaust gasses: none
  • Motor oil checked for cooling fluids: none
  • Radiator effectiveness tested: very good
  • Cylinder walls checked with endoscope for boiler scale presence by: very clean, just some corrosion
  • Engine is running very well, no white smoke whatsoever and oil and water temperatures are good also after long drives (the engine is not overheating)

The mechanics of both shops indicate that the head gaskets, neither head cracks can be the problem given their measurements and observations, but they do not know what is..

Any suggestions, advice, thoughts are very welcome to help solve this mystery

Many thanks,
Corwin
Hi do you know an Montréal engine for sale?
Thanks
Rama
 

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there are repair components that don't often circulate in the non--pro-shop world. The inserts used by the shop I employed were different than what I've seen before. Very high-end shop. I trust their work. We discussed the options beforehand, and I was convinced.
Time will tell if the repair works. I've used Time Certs before to repair stripped spark plug threads on a Touring Roadster head (...1844) with good results. Unless the cracks are tiny and do not extend into the water jacket, it is hard to see how Time Certs could be effective in this application. I believe that Bruce Taylor recommends having the cracks in the head ground out and the metal replaced by welding in new material.

Mark
 

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At the end of the welding operations (of any kind) it would be advisable to carry out the impregnation work (I hope that the translator indicates it correctly ...).
 
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