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Another 1725 died the heat death...

bernd_st

Bronze Level Sponsor
A late Hunter 1725 engine which recently died the heat death in the hands of a club mate. Everything looked beautiful from the outside incl. the freeze plugs. What a mess inside - still scraping gunk and rust...

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bernd_st

Bronze Level Sponsor
While talking about heat with today's 35°C temperature out here, time for a good bavarian beer...

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jumpinjan

Bronze Level Sponsor
For every engine rebuild that I undertake, I take the engine block to our local industrial metal cleaning place. There all the interior rust and whatever is ALL removed. This is NOT an acid dip, it's electrolysis. They come back better than new and ready for a new rebuild.
Jan
 

65sunbeam

SAOCA Membership Director
Diamond Level Sponsor
Ein prost Bernd! About the same temperature here but storms most every day to cool things down some. Keep us updated on your rebuild. Eric
 

bernd_st

Bronze Level Sponsor
Yes, it overheated heavily and once more it was because of inefficient coolant flow especially around cylinders 3 & 4. It became so bad that the Pistons started to bind in their bores. At the very end it spun a rod, however seemingly this was because of oil thinning...

Jan, still looking for a company which could do electrolysis on engine blocks over here, but nothing found yet...

Thanks for the cheers Eric. That beer was well deserved. Will keep you posted on the progress I make. Never had such a late engine with a casting date from May 68 yet. Engine number starts with 75... so looks like a Hunter engine. Several unique "findings" already. The cylinder head is the late design with no tubes anymore. The head gasket was an Asbestos type which stuck heavily to both the block and head. The head has conical inlets with no steps for the manifold locator rings. There were rather thick green gaskets on camshaft cover and holding plate - not the normal paper affair. Still investigating though...
 
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65beam

Donation Time
Just looking at the rust tells me the coolant was either water or there was no maintenance of the coolant. Coolant needs flushed at regular intervals and replaced with a 50/50 blended ethylene glycol product.
 

DanR

Diamond Level Sponsor
Dan, what specifically do you see that looks "overheated".

Tom
From past experience, I see a dark brown looking cylinder block (#3&4 piston areas) to me show lots of extensive heat in those pistons.

Then looking at the foreign matter Bernie has shown from the inside of the block tends to have been heated also.

Saw a few diesel power generators at some AF millitary sites with same same conditions. All from lack of tender loving care. A real No-No in Air Force Preventive Maintenance.
 

65beam

Donation Time
One of the reasons for conventional coolants being green is so if rust starts to form the coolant will start turning brown. Time to flush and clean.
 

bernd_st

Bronze Level Sponsor
Dan hit the point regarding overheating. Perhaps not so easy to see but the rear cylinders - despite still showing cross hatch patterns- show partial wear marks . Will try to post some close ups later. Believe the pistons/rings will also show similar damage. Definitely this block will require a rebore...
 

bernd_st

Bronze Level Sponsor
P.S. Earlier shot with the first freeze plug removed. You can see "the horror" waiting behind, despite the plugs looked still very good from the outside...

IMG_20200811_073848.jpg
 

65beam

Donation Time
From past experience, I see a dark brown looking cylinder block (#3&4 piston areas) to me show lots of extensive heat in those pistons.

Then looking at the foreign matter Bernie has shown from the inside of the block tends to have been heated also.

Saw a few diesel power generators at some AF millitary sites with same same conditions. All from lack of tender loving care. A real No-No in Air Force Preventive Maintenance.
Dan,
I've run into many over the years that don't think you need to change any of the fluids or even grease the car. Maintenance of fluids, grease, etc. is the cheapest protection there is. Did you notice the block drain is plugged off with a bolt?
 

DanR

Diamond Level Sponsor
Yes Bob, I did notice the plug. Just did not make a comment because it did not register to my slow reasoning mind:)
 

bernd_st

Bronze Level Sponsor
Here are the close ups after taking the bastard apart today:


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Heat/Friction marks on Cylinders 1 & 4 and the spun #3 rod...
 

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DanR

Diamond Level Sponsor
Bernie, A word of caution.... I would not reuse the rods under any condition.

That thing got HOT! Even the cylinder walls may be questionable?
 

bernd_st

Bronze Level Sponsor
Who was that guy asking how overheating marks look like ;-)
Indeed this buddy got extremely hot and I wonder what actually can be reused. Assume not much. Let's try a summary :

1) Crank gone (#3 rod journal)
2) #3 rod gone (others questionable)
3) camshaft gone ( pitting on the main journals)
4) Block needs dipping, decking and a complete rebore but was at +0.040" already
5) Cylinder head useable but needs new valves ( earlier "rebuilder" mounted the rocker shafts in the wrong way, i.e. no oil flow and all valve stems are mushroomed now)
6) Pistons pins are all sloppy on their rod bushes. Wonder why the bushes weren't renewed during the previous "rebuild"

Quite some fun over here. Beer time again and going " nuts " ;-)

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