Is this head gasket seepage acceptable?

[Pete]

Pete could you expand on what you do when fixing one with a plug?
Thanks
Dave

Set the block in the mill, bore the bad hole for a 3/8 taper pipe thread. Make a steel plug with 3/8 pipe on the outside and 7/16-14 on the inside. Screw the plug in with a threaded rod and jam nut. When the plug is bottomed, it sits about 1/16 high. This is cut off when the block is surfaced. On a race engine I just do all of the holes at once.
Also, this operation is done BEFORE the block is bored so there are no bulges left in the cylinder. walls.

 

[1crosscut]

That's a solid fix.

 

[Johnny Nitro]

Pete,

Thanks for your insight.

12.0 cr! Why not 13.0?

 

[Pete]

Pete,

Thanks for your insight.

12.0 cr! Why not 13.0?

Could have but got tired of welding and machining the chambers.

We run 14 on the flathead V8's.

As what's his name used to say, "if you are winning, there is no reason to spend money to go faster till someone beats you".

 

[Bruce of MN]

I used a couple of these that have more meat than a heli-coil https://www.mcmaster.com/90259A154/

McMaster has thicker wall inserts, too. https://www.mcmaster.com/catalog/126/3504

 

[Bruce of MN]

“ I have found that if I use clear water for the first 4-5 heat cycles and then clear water for 500 to 1000 miles of operation”

Dave, did you mean clear water both places? I saw this advice earlier from you and followed it, so I am looking forward to the seepage decreasing. I did put in water wetter, though.

My seepage has stopped, so after it reaches the 1000 mile mark, I'll hold off on the antifreeze.

 

[Flathead]

How do you get 14 to 1 compression on a V8 and have any breathing area left? I wouldn't expect you to reveal secrets but it is an interesting topic.

 

[Pete]

How do you get 14 to 1 compression on a V8 and have any breathing area left? I wouldn't expect you to reveal secrets but it is an interesting topic.

It's no secret.
First off, you use flat top pistons that come deck high.
Then in the old days, we filled a set of NEW aluminum heads so after surfacing, the area over the pistons and some of the transfer area is flat. Then you re-machine the transfer area to the volume you need for the ratio you want.
All of our engines are 321 ci minimum so there is plenty of breathing area. The more ci the easier it is to get compression.
Nowdays we make 2 piece heads from scratch so there is no welding involved.

 

[Flathead]

Thanks for the reply! So the transfer area is in the head and there is no relief in the block?

 

[Pete]

Thanks for the reply! So the transfer area is in the head and there is no relief in the block?

Yes, there is a relief in the block. Usually about .150 deep.
Here is a pic. This is an old engine. We put the big valve in the exhaust now.

 

[Flathead]

Larger valve for the exhaust, there's a conversation starter.