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TR4/4A TR4 Block

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M

MoHealey

Senior Member
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Block for my TR4 project just came back from the shop with a hole at the base of the #4 cylinder. It appears as though it simply corroded away over time and the block cleaning exposed the 1/8" hole. Liner/block meeting surface is clean and solid. Is this a repairable condition? Don't want to swap the block if I can avoid it, but I really don't want to roll the dice with an "iffy" repair.
Any help much appreciated
 
My opinion, get another block. It probably is repairable IF you can find someone that actually knows (and practices!) all the right tricks; but I have seen way too many repairs in cast iron (done by people that swear they know how) that fail again within a fairly short time (few hours to a few years). Plus, if it is corroded all the way through at one spot, it's bound to be corroded enough in other places to be weak.

And TR4 blocks are just not that scarce/valuable. Yes, you'll lose whatever you've put into this one, but IMO that is a lot better than getting all the way through the rebuild (including installing it in the car) and then finding that it is unusable.

I'd offer to give you one, but it's not worth the cost of shipping to MO.
 
Agree with Randall. Get another block. Like Randall I have several block but shipping will get pricey. Hopefully someone closer will have one.

Marv
 
Curious to see this, can you post a picture?

Scott
 
Will post a photo shortly. I was afraid your opinions would be the concensus.
A bit deflated, as this car is a very late production '65 and unmolested. Literally, one of the last TR4's. Really wanted to keep it "whole". Still, I want a reliable driver - that's more important.
 
block.jpg



...best image I could get.
The hole is in the right hand cylinder very near the liner seat on the "top" of the image. To the right of the hole, you can see another area that appears to have lost a fair amount of material, but not corroded all the way through.
I'm amazed this motor ran as cool as it did. Never saw any coolant in the oil.
My guess is that it sat for a long time at some point.
 
Even zooming in, all I see is the opening for the block drain on the side ...
 
Sorry, I'm still not seeing it. The hole I've circled is for the block drain, and I don't see any others.
 

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Just for comparison, here's the drain hole on one of my blocks:
 

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If you must use this block it may be able to be repaired using tapered cast iron plugs. There may be a small amount of machining needed to true the bore if the repair distorts the lower bore, I have repaired several too expensive to replace blocks using this method, it would be cheaper to find another block and have the numbers milled off, but your block can be repaired with this method and the repair is permanent. here is a picture of a plug repair. If you use this block and it develops other pinholes later down the road you can use Water Glass (Sodium silicate) to seal them but you may have a h--- of a time getting the head off afterwards.


0709ch_15_z1972_350_chevy_pickup_engine.jpg


Also alot of people swear by this stuff for fixing cracks and water jacket repair.

Titanium Puddy
 
TR3driver said:
Even zooming in, all I see is the opening for the block drain on the side ...
Click to expand...

Randall and MoHealey,

That's why I was asked for a picture since there should be a hole in that general area for the drain. :smile:

Scott
 
So I am officially reduced to idiot status.
Had no idea that was a designed drain...jagged edges and all.
But, that's why I asked, and further proves this forum's value and the lack of knowledge at the macine shop.
Thanks a million.
I am pressing on.
 
Just to confirm: On the outside of the block there should be a raised circular surface that's machined flat (for the drain tap flange seal), and the hole should be tapped. If so, that's the block drain, and no need for a repair or a new block.
 
Just to be absolutely sure run a length of wire or shine a light through the hole and see where it comes out at. The way the shadow in the hole looks it seems the hole is going straight down towards the bottom and not out the side of the block.
 
MoHealey said:
Had no idea that was a designed drain...jagged edges and all.
But, that's why I asked, and further proves this forum's value and the lack of knowledge at the macine shop.
Click to expand...

Not sure I would trust that machine shop with the rest of the work if they missed the threads for the drain.

Did you remove the drain from the block before giving it to them or was this a bare block already?

Scott
 
I removed the drain - the block was bare when they tanked it. Don't think I'll go back to this shop. I'm replacing the liners and pistons complete; crank has already been turned. You may have guessed alreay, but this is my first TR engine rebuild. One of those things specific to this engine that I should have realized but didn't.
Here's what I started with. Thanks again to all
Bill
CIMG0724.jpg
 
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