Subject: [TR] TR4A - Head Gasket Blown Sanity Check

From: Guy Huggins <[email-masked]>
Date: Wed, 6 Oct 2021 09:42:12 -0500

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Greetings from Texas,

So there I was=E2=80=A6 about to take an evening drive, and the car =
wouldn't start.
I have been having some issues with this recently (suspect I have a =
parasitic drain), so I rolled-started the car down the driveway.  I =
remember it being a hard start, but the engine came to life.

As I drove down the street, the car was running very, very roughly.  =
When I turned onto the main road, I immediately pulled into a parking =
lot to check it out.  Then I saw it=E2=80=A6 clouds of steam coming from =
the tailpipes.  Dammit!!

I got back in the car and was in my garage in less than a minute.  =
Suspecting a catastrophic issue of coolant pouring into a cylinder, I =
dutifully pulled the plugs to perform a compression check with the =
engine still warm.  #3 plug was soaking wet.  All compressions looked =
good and held for over a minute, save #3, which was reading at 72 =
=E2=80=98ish.  Found the problem cylinder.

I recently pulled the head off, and sure enough, the gasket had been =
=E2=80=9Cpushed=E2=80=9D into the water jacket space between #3 and #2.  =
A closer inspection revealed that none of the =E2=80=9Cfire rings=E2=80=9D=
 of the gasket were ever perfectly aligned over each cylinder, leading =
me to believe that maybe I did not get an appropriately sized 87mm =
gasket, or the torque-down didn=E2=80=99t go perfectly, maybe somehow =
skewing the gasket in the process.

The good news is that I got almost 10 years and 22K miles before this =
happened!!
I=E2=80=99m a little disappointed seeing how when I rebuilt the engine =
about 12 years ago, I had the block and the head mating surface machined =
to be flat.

Now to the sanity check items=E2=80=A6

Fo8 Gaskets - I have refilled the water jacket, and it remained at the =
same level overnight. I assume they are still 100% sealed.  Is this a =
safe assumption?  Also, #2 liner is prouder of the block than the others =
(by feel), but I haven=E2=80=99t measured by how much yet.

Pistons & Liners - I poured 1/2 cup of fluid onto the top of each piston =
and it remained there for an hour until I removed it.  #2 did drain out =
more than the others, so I know it is not perfect, but none of them are =
completely fluid tight.  This tells me the pistons and rings are OK, =
confirming the last compression check numbers.  Is this reasonable? =20
Also, what is the best why to clean carbon from the pistons?

Head - I am planning on cleaning it up and checking for it to be flat =
with a straight edge.  Is there anything I can do to check the valves =
while I have it off?  Again, the compression check suggests they are =
fine. =20
Is there a safe way to clean off carbon deposits from the valves =
themselves?

Pushrods - If they are straight, I plan to reuse them

Replacing - I plan on replacing all gaskets and head studs.  I could use =
recommendations on the best 87mm head gasket out there.  The one that =
blew was a copper Payen gasket.  I also installed it with some copper =
gasket sealant (spray on), which I wonder about, as there are clear =
imprints and residue on the mating surfaces that I somehow have to clean =
without harming the surfaces. Any suggestions for this?

My working theory is that some serious detonation occurred in #3 on the =
roll start, and the gasket gave way to the weaker side, into the water =
jacket space.  Compression has historically been in the 160=E2=80=99s =
for each cylinder, 180=E2=80=99s when freshly rebuilt.  I can=E2=80=99t =
help but wonder if this is just too damn high, and the gasket=E2=80=99s =
fire rings are all out-of-round because of this, as opposed to my =
earlier thought about them being distorted due to the head being torqued =
down.

I have pictures to share if anyone would like to see them.

Thanks in advance for any thoughts and comments you share.

Cheers,

Guy D. Huggins
1965 Triumph TR4A
CTC 63569LO

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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html; =
charset=3Dutf-8"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; line-break: after-white-space;" class=3D""><div =
class=3D""><div style=3D"color: rgb(0, 0, 0); letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: =
break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" =
class=3D""><div style=3D"word-wrap: break-word; -webkit-nbsp-mode: =
space; line-break: after-white-space;" class=3D"">Greetings from =
Texas,</div><div style=3D"word-wrap: break-word; -webkit-nbsp-mode: =
space; line-break: after-white-space;" class=3D""><br =
class=3D""></div><div style=3D"word-wrap: break-word; -webkit-nbsp-mode: =
space; line-break: after-white-space;" class=3D"">So there I was=E2=80=A6 =
about to take an evening drive, and the car wouldn't start.<br =
class=3D"">I have been having some issues with this recently (suspect I =
have a parasitic drain), so I rolled-started the car down the driveway. =
&nbsp;I remember it being a hard start, but the engine came to life.<br =
class=3D""><br class=3D"">As I drove down the street, the car was =
running very, very roughly. &nbsp;When I turned onto the main road, I =
immediately pulled into a parking lot to check it out. &nbsp;Then I saw =
it=E2=80=A6 clouds of steam coming from the tailpipes. &nbsp;Dammit!!<br =
class=3D""><br class=3D"">I got back in the car and was in my garage in =
less than a minute. &nbsp;Suspecting a catastrophic issue of coolant =
pouring into a cylinder, I dutifully pulled the plugs to perform a =
compression check with the engine still warm. &nbsp;#3 plug was soaking =
wet. &nbsp;All compressions looked good and held for over a minute, save =
#3, which was reading at 72 =E2=80=98ish. &nbsp;Found the problem =
cylinder.<br class=3D""><br class=3D"">I recently pulled the head off, =
and sure enough, the gasket had been =E2=80=9Cpushed=E2=80=9D into the =
water jacket space between #3 and #2. &nbsp;A closer inspection revealed =
that none of the =E2=80=9Cfire rings=E2=80=9D of the gasket were ever =
perfectly aligned over each cylinder, leading me to believe that maybe I =
did not get an appropriately sized 87mm gasket, or the torque-down =
didn=E2=80=99t go perfectly, maybe somehow skewing the gasket in the =
process.<br class=3D""><br class=3D"">The good news is that I got almost =
10 years and 22K miles before this happened!!<br class=3D"">I=E2=80=99m =
a little disappointed seeing how when I rebuilt the engine about 12 =
years ago, I had the block and the head mating surface machined to be =
flat.<br class=3D""><br class=3D"">Now to the sanity check items=E2=80=A6<=
br class=3D""><br class=3D"">Fo8 Gaskets - I have refilled the water =
jacket, and it remained at the same level overnight. I assume they are =
still 100% sealed. &nbsp;Is this a safe assumption? &nbsp;Also, #2 liner =
is prouder of the block than the others (by feel), but I haven=E2=80=99t =
measured by how much yet.<br class=3D""><br class=3D"">Pistons &amp; =
Liners - I poured 1/2 cup of fluid onto the top of each piston and it =
remained there for an hour until I removed it. &nbsp;#2 did drain out =
more than the others, so I know it is not perfect, but none of them are =
completely fluid tight. &nbsp;This tells me the pistons and rings are =
OK, confirming the last compression check numbers. &nbsp;Is this =
reasonable? &nbsp;</div><div style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; line-break: after-white-space;" class=3D"">Also,=
 what is the best why to clean carbon from the pistons?<br class=3D""><br =
class=3D"">Head - I am planning on cleaning it up and checking for it to =
be flat with a straight edge. &nbsp;Is there anything I can do to check =
the valves while I have it off? &nbsp;Again, the compression check =
suggests they are fine. &nbsp;</div><div style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; line-break: after-white-space;" class=3D"">Is =
there a safe way to clean off carbon deposits from the valves =
themselves?<br class=3D""><br class=3D"">Pushrods - If they are =
straight, I plan to reuse them<br class=3D""><br class=3D"">Replacing - =
I plan on replacing all gaskets and head studs. &nbsp;I could use =
recommendations on the best 87mm head gasket out there. &nbsp;The one =
that blew was a copper Payen gasket. &nbsp;I also installed it with some =
copper gasket sealant (spray on), which I wonder about, as there are =
clear imprints and residue on the mating surfaces that I somehow have to =
clean without harming the surfaces. Any suggestions for this?<br =
class=3D""><br class=3D"">My working theory is that some serious =
detonation occurred in #3 on the roll start, and the gasket gave way to =
the weaker side, into the water jacket space. &nbsp;Compression has =
historically been in the 160=E2=80=99s for each cylinder, 180=E2=80=99s =
when freshly rebuilt. &nbsp;I can=E2=80=99t help but wonder if this is =
just too damn high, and the gasket=E2=80=99s fire rings are all =
out-of-round because of this, as opposed to my earlier thought about =
them being distorted due to the head being torqued down.<br class=3D""><br=
 class=3D"">I have pictures to share if anyone would like to see =
them.<br class=3D""><br class=3D"">Thanks in advance for any thoughts =
and comments you share.<br class=3D""><div style=3D"color: rgb(0, 0, 0); =
font-family: Helvetica; font-size: 14px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=3D""><br=
 class=3D""></div><br class=3D"Apple-interchange-newline"></div></div><br =
class=3D""></div><div class=3D"">
<span class=3D"Apple-style-span" style=3D"border-collapse: separate; =
color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; =
font-variant-ligatures: normal; font-variant-caps: normal; =
font-variant-east-asian: normal; font-variant-position: normal; =
font-weight: normal; letter-spacing: normal; line-height: normal; =
orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; =
widows: 2; word-spacing: 0px; border-spacing: 0px; =
-webkit-text-decorations-in-effect: none; -webkit-text-stroke-width: =
0px;"><div style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space;" class=3D"">Cheers,<br =
class=3D""><br class=3D"">Guy D. Huggins<br class=3D"">1965 Triumph =
TR4A<br class=3D"">CTC 63569LO<br class=3D""><br class=3D""><br =
class=3D""><br class=3D""></div></span>
</div>
<br class=3D""></body></html>=

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