Water jacket rust on bare block

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Tylinol

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So I've got my '69 318 block back from the machine shop, and as I'm rotating it on the engine stand some bits of corrosion fall out the water jacket holes on the top of the block. Looking down in the jacket I can see some chunks of flaky rust the I can knock loose with a screwdriver, but now I've got to actually get them out of the block. What's the best way to do this? Knock out a freeze plug and run my shop vac or compressor through it? Flush it out with something? The block is bare, so I'm a little worried about corroding or damaging the freshly machined surfaces.

Additionally, it looks like there's some really tough corrosion at the bottom of some head bolt holes. I can knock out some with my pick but not all. My fear is that this corrosion will prevent the head bolts from torqueing correctly. Thoughts?

AC6A8925-24E4-4A8F-BCE0-127BD70C7C98.jpeg


8E95632B-EB82-4073-8926-B76B5F38A3D3.jpeg
 
Knock out the plugs, power washer, coat hanger, air hose, and a 6 pac of beer...your done.
 
Tylinol said:
So I've got my '69 318 block back from the machine shop, and as I'm rotating it on the engine stand some bits of corrosion fall out the water jacket holes on the top of the block. Looking down in the jacket I can see some chunks of flaky rust the I can knock loose with a screwdriver, but now I've got to actually get them out of the block. What's the best way to do this? Knock out a freeze plug and run my shop vac or compressor through it? Flush it out with something? The block is bare, so I'm a little worried about corroding or damaging the freshly machined surfaces.

Additionally, it looks like there's some really tough corrosion at the bottom of some head bolt holes. I can knock out some with my pick but not all. My fear is that this corrosion will prevent the head bolts from torqueing correctly. Thoughts?

View attachment 1715749268

View attachment 1715749269
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Read this thread or go to the bottom of it to walk you through how to clean out the water jackets...

How to Rebuild a Small Block Part 1: Block Prep
 
Tylinol said:
Additionally, it looks like there's some really tough corrosion at the bottom of some head bolt holes. I can knock out some with my pick but not all. My fear is that this corrosion will prevent the head bolts from torqueing correctly. Thoughts?

View attachment 1715749268

View attachment 1715749269
Click to expand...


To clean out the crud from the head bolt holes (and all holes tapped in the block) get the proper thread taps and chase them.... That will clean out any debris and make the threads true again... You may need to chase them two or three times to get them perfectly clean....

Then chase the threads of the bolts with the proper die to clean the threads off and make them true again...

When you are done chasing the holes with taps and the bolts with dies, you will be able to thread the bolts into the holes mostly by hand and only need a wrench to tighten them....

This thread shows you how to tap the holes in the block:

How to Rebuild a Small Block Part 5: Crankshaft Install


This is also a good one for you to look at before assembling:

How to Rebuild a Small Block Part 4: Pre Flight Inspection After Machine Shop Before Assembly


You may want to start off with the first one in the series and follow them in order.... I haven't gotten to do any more past short block assembly, but hope to soon... When I am done with the whole series, you will be able to follow them through and it will walk you through how to rebuild a small block engine by yourself, even if it's your first time....
 
Sad that the machine shop didn't offer to boil the block before machining.Maybe EPA won't allow it.It has been along time since I had any Machine shop work done.
 
Just a note for you, take your time running a tap through the holes so you don't break one off in the block & use oil on the tap to make it easier.
 
I had a block boiled about a year and a half ago. Cleaned it up well. Didn't think about the EPA, but maybe they haven't made it to small town Georgia yet!!!
 
Make sure you put a filter in the top rad hose. Because it is nigh impossible to get to every nook & cranny inside the w/jackets to remove rusting bits of metal. The bits will dislodge at higher rpms from the increased water pump flow & without a filter, will likely block your radiator core.
 
Water and compressed air at the same time seems to work **** loose turning the block in all directions.
 
Good advice all around - I wish I had seen that awesome rebuild thread before I started, but thankfully see it now before I start any of my own work on the engine. Since my machine work has already been done, is there anything special I need to do to protect the block if I'm pressure washing the water jackets? Spray the bores and bearing races down with WD-40 first, then brake cleaner to clean it off before assembly lubricant?

As for the head bolts - the threads themselves look fine to me. It seems like it's corrosion below the threads at the bottom of the blind hole.
 
Demonracer said:
Just a note for you, take your time running a tap through the holes so you don't break one off in the block & use oil on the tap to make it easier.
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That's why I don't use taps but use thread chasers.

thread chaser.jpg
 
Not a machinist, but go on most of the machinists pages and ask about thread chasers. Most just giggle, a dull tap is what they are. How far out of spec does the tap or the original threads need to be to cause an issue? Pretty far, the thread pitch, threads per inch. I will use a quality tap and die.
 
Tylinol said:
Good advice all around - I wish I had seen that awesome rebuild thread before I started, but thankfully see it now before I start any of my own work on the engine. Since my machine work has already been done, is there anything special I need to do to protect the block if I'm pressure washing the water jackets? Spray the bores and bearing races down with WD-40 first, then brake cleaner to clean it off before assembly lubricant?

As for the head bolts - the threads themselves look fine to me. It seems like it's corrosion below the threads at the bottom of the blind hole.
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WD-40 is garbage it will wash right of.
Good old axle grease may be the best way to protect the machined surfaces but either way you are going to have a hell of a mess.
 
512Stroker said:
Of course Mike you are the "Tool Man"
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I used to get a lot of horror stories from guys using taps to clean threads. Catch a shaving or a chunk of rust and pop. Broken tap, and they are a booger to remove. The rethreader's are designed to clean and straighten and not cut new threads and are soft enough to drill out if necessary. Now if you break a tap off I sold tap extractors as well.

walton extractor.jpg


walton.jpg
 
A life long machinist is a special breed. They can do things a hobbyist cannot. And they have the “feel” for things.

So for the hobbyist I recommend thread chasers. It will keep you out of trouble.

I’ve never broken off a tap in a hole. No reason to go that far, it will tell there is a problem, but you have to listen.

Use a thread chaser in one hole, and a tap in the next hole. Then compare the amount of shavings you have. We did this in school to prove it to the non believers. Use The right tool for the job.
 
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413 said:
A life long machinist is a special breed. They can do things a hobbyist cannot. And they have the “feel” for things.

So for the hobbyist I recommend thread chasers. It will keep you out of trouble.

I’ve never broken off a tap in a hole. No reason to go that far, it will tell ere is a problem, but you have to listen.

Use a thread chaser in one hole, and a tap in the next hole. Then compare the amount of shavings you have. We did this in school to prove it to the non believers. Use The right tool for the job.
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I gave away my thread chasers years ago because they were worthless.

The reason the tap takes out metal is because the hole is no longer round from being pulled on and the screw load applied to the thread. A chaser can’t get the hole back to round.

If you break a tap off in a hole that’s on the end user.

The right tool for the job gets the hole back to round and should cut the threads to the bottom of the hole. A chaser won’t do that either.
 
Agree with #20. No reason to break a tap off , just be Careful.
 
If you bust a tap chasing threads, you went way to deep! Don't chasers have a bottom tap shape, ie no taper?
 
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