Overheating, liners, heads, ad nauseam

Injuhneer

Injuhneer

Well-known member
Nov 9, 2011
399
0
Southeastern Arizona (near Tombstone)
www.ootfab.com
When I bought the '97 I have now it had ostensibly "overheated".

After removing the heads to repair the blown head gasket I found that one head had three bolts loose. While the heads were off all the liners were inspected for visible cracks, movement, or change in position.

Everything looked great. So after a cleanup and light planing of the heads (vales, guide seals, etc) it all went back together. It started and ran great except for the annoying problem of bleeding the heater core.

It continued to be annoying because somewhere there is an combustion leak into the coolant jacket.

So I guess it could be something worse like a cracked block but I can't figure this out. Clean cylinders. Clean surfaces. Good gaskets. Etc. Tightly torqued heads, more etc.

With clean head surfaces, a clean block, and good seal between the heads and cylinders the only way combustion gas can get into the coolant is through a cracked head, right?

I guess I am looking at a whole motor since there is no simple way to determine which it is.
 
R

robertf

Well-known member
Jan 22, 2006
4,801
366
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It's probably the block. I had one fail that the crack was almost impossible to find. I'm not even sure I properly identified it. Reused the heads on a new short block

Another one I had that failed had a very visible crack in the liner that went through the aluminum wall to the coolant passage.
 
Injuhneer

Injuhneer

Well-known member
Nov 9, 2011
399
0
Southeastern Arizona (near Tombstone)
www.ootfab.com
It is a tempting thought. I have access to a 400 SBC. All the basic sensors should be easy to put on but engine management is another project of its own.

On a related note;

I am convinced there is a leak somewhere. The gases make their way to the intake manifold and if the t-stat is not open there are temp spikes. To test this I routed the return line from the throttle body to the top of the expansion tank. The idea being to let any accumulated gases out and separate from the coolant. From there a pressure build up would be relieved at the cap and above the coolant. It works and works well. No more temperature spikes. However...

What I am trying to figure out is how the combustion gases are getting inside the car. I can't find any leaks in the heater core or the hoses. All other hoses are good. Are the coolant hoses permeable enough to allow CO to pass through their walls? I have not encountered this problem before and it makes driving the truck a headache, literally.
 
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Injuhneer

Injuhneer

Well-known member
Nov 9, 2011
399
0
Southeastern Arizona (near Tombstone)
www.ootfab.com
That is a tempting offer and only 96k. New bearings, seals, etc, and that one would be good for a long time,

I am however in the process of eliminating a lot of "stuff" around here because our house is for sale and we need to eliminate lots of stuff before we move (going to the St. George, UT area).

Wsh I could but have nohwere to put it here.

-Mike O.
 
Injuhneer

Injuhneer

Well-known member
Nov 9, 2011
399
0
Southeastern Arizona (near Tombstone)
www.ootfab.com
So, I am finally getting around to doing something about the engine in my D1.

Question; when these engines develop a combustion leak how often are they successfully repaired? I have read about the top-hat liners, etc, and am wondering if the engine is worth saving or if it should just be swapped out.
 
jymmiejamz

jymmiejamz

Well-known member
Dec 5, 2004
6,010
362
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Los Angeles, Ca
Probably more cost effective to just replace the block with a new one. You likely have a crack in the block behind one of the cylinder liners. We actually machined a liner out of a block and could see a tiny hairline crack in the block. A cracked head is possible, but a cracked block is a lot more likely.
 
pdogg

pdogg

Well-known member
Jul 18, 2005
1,216
29
Phoenix, AZ
What's your userid that you used to register on the web site?

I can see what I can do to clear it up... sometimes things get dropped. Often the email you get goes to junk mail..
 
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Injuhneer

Injuhneer

Well-known member
Nov 9, 2011
399
0
Southeastern Arizona (near Tombstone)
www.ootfab.com
So I finally picked up a spare motor. Top end is great as it had a valve job just before the donor was crashed. :)

Now inspecting the bearings. Strange thing. All of bearing shells indicate they are standard size but every one of the conrod journals are the same size, all of them are 2.185+.0005/-.0000.

Huh? :eek:

I checked them with mics and two sets of calipers (Mitutoyo and Brown/Sharpe). The tools all indicate 2.185. It seems very unlikely that these would all wear exactly the same amount.

So I thought about putting .010 bearings in and calling it good. Also thinking about cleaning and refinishing the existing shells in 4X nickel babbit (better than that lead/indium crap Vandervell uses).

The main journals are all fine. I just can't imagine how the truck ran all this time with .015 clearance on the rods. 90w in the crankcase?

Geez. :ack:
 
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ptschram

ptschram

Well-known member
Sep 27, 2004
21,955
50
In the shop doing the Lord's work one broken Rover
www.ptschram.com
If you opened up the journals, replace the bearings!

Also, main bearings are measured using telescoping gauges, not calipers. Calipers are no where near precise enough for these measurements.

Now that you've removed the rod caps, you need new bolts as they are
TTY/prevailing torque. As for Peter's observations, almost every Rover crankshaft I have pulled out had the rods worn at least 0.010, I have a 4.6 where you can visibly move the rod on the journal and this engine ran beautifully when I pulled it out, in spite of at least 0.100" of rod/crank/bearing damage.

Now that you've started, do it the rest of the way. Call me when your machine shop gets done and I can order up bearings. If you need pistons, I can get those in oversize as well, but they are pretty dear.
 
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