340 coolant in oil

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A compression check on all eight cylinders before tear down would have very beneficial, indeed. It’s hard to tell from the picture but I think you were losing fire between the rear three cylinders and even a little from between two and four. The coolant in the valley coincides with the appearance of the head gasket between six and four, and that piston in number four looks to have been getting steam cleaned. I am curious how long you have had the car and what you know about the engine history. That hone pattern looks relatively fresh.
 
BTW, are there any oversized markings on those pistons? I don’t know what your budget may allow at the present, but if it’s had coolant in a cylinder long enough to pit, there may be more concerns below the pistons... some experienced outside in person help may be in order at this point. I don’t think the rings in that cylinder are going to be very healthy either...
 
Garrett Ellison said:
A compression check on all eight cylinders before tear down would have very beneficial, indeed. It’s hard to tell from the picture but I think you were losing fire between the rear three cylinders and even a little from between two and four. The coolant in the valley coincides with the appearance of the head gasket between six and four, and that piston in number four looks to have been getting steam cleaned. I am curious how long you have had the car and what you know about the engine history. That hone pattern looks relatively fresh.
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The pic of the steam cleaned piston top seems to show a part number and .030, so it has likely been bored.
 
Being it’s a 340 and 340’s are so hard to come by, (especially if it’s a numbers matching car!) you may be better off planning on a full teardown and rebuild, even if it means installing something more garden variety while you get a game plan together on the original iron...
 
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I should ask if if it is a 4.07 bore in the block? (4.04 +.030 340) It would measure just a hair over 4-1/16. I ask because of what looks like 2318 piston number... i hope I’m not bombarding you with too much at once here, I didn’t get the weather I hoped to have here so I am unable to work on my own junk today...
 
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If it were mine and a 318 or 360, I would turn my head and make like the pitting wasn’t there and get things good enough to go again. I would then plan on a fresh build for later on. If it’s a numbers matching 340 I would have the engine out to assess before I had irreversible damage occur, you only get one, after all!
 
looks like an mp purple shaft cam. Valley looks quite clean. from pics I don't see a crack in the valley. coolant in the valley is most likely from not draining the coolant properly prior to unbolting stuff.
 
J heads it appears with 2.02/1.60, what is the casting number on those? I believe that is a set of TRW LF 2316 .030 pistons in that engine, indicating .030 over 340, thus matching the heads... Time to break out the shop hoist!
 
Garrett Ellison said:
I should ask if if it is a 4.07 bore in the block? (4.04 +.030 340) It would measure just a hair over 4-1/16. I ask because of what looks like 2318 piston number... i hope I’m not bombarding you with too much at once here, I didn’t get the weather I hoped to have here so I am unable to work on my own junk today...
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No, I appreciate all of yall taking the time to come up with ideas and suggestions. The casting number on the heads looks to be 3418915C it also has the letters AAWJ and 360. The pistons are L2316 .030 over. Another thing I noticed when tearing it down yesterday was that the distributor was loose, you could easily turn it by hand. So did yall think the gasket looks to be ok? I've only owned the car a month, I bought it from a kid who did not know much about the motor. He said it had recently been rebuilt and had a "cam" put in it. It does idle like it has a stout cam in it.
 
Yes, it is indeed a 340... I have had timing jump advanced during cranking from a loose distributor, it could have contributed to blowing a head gasket. Being it is a rare and expensive to replace (impossible to replace if it is a matching numbers block!) 340, I would plan on pulling the engine to at a minimum pressure test, magnaflux, hone the pitting out of cylinders and re-ring (if it doesn't open piston to ring up excessively), and making sure coolant oil mix hasn't started corroding or spalling the bearings. Even if it means having to save up to do it, drain the crank case before putting it in storage, overfill crank case with fresh lube, cosmoline spray the crap out of the exposed cylinder walls and heads. If you need to, score a boneyard 318 or 360 if you want to drive it while waiting to refresh current engine. You could even use your cylinder heads, intake,cam, etc. in it if they check out okay. It's just not worth the risk of irreparably damaging a 340 (especially if it's numbers matching) block with a bearing failure or gouging out a cylinder wall with a broken ring... It would be advisable to use Cometic MLS head gaskets and head studs during the rebuild! I guess if it were mine and the block checked out good, I would be looking hard at 416 stroker, numbers matching or not!
 
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Garrett Ellison said:
Yes, it is indeed a 340... I have had timing jump advanced during cranking from a loose distributor, it could have contributed to blowing a head gasket. Being it is a rare and expensive to replace (impossible to replace if it is a matching numbers block!) 340, I would plan on pulling the engine to at a minimum pressure test, magnaflux, hone the pitting out of cylinders and re-ring (if it doesn't open piston to ring up excessively), and making sure coolant oil mix hasn't started corroding or spalling the bearings. Even if it means having to save up to do it, drain the crank case before putting it in storage, overfill crank case with fresh lube, cosmoline spray the crap out of the exposed cylinder walls and heads. If you need to, score a boneyard 318 or 360 if you want to drive it while waiting to refresh current engine. You could even use your cylinder heads, intake,cam, etc. in it if they check out okay. It's just not worth the risk of irreparably damaging a 340 (especially if it's numbers matching) block with a bearing failure or gouging out a cylinder wall with a broken ring...
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Ok, I do believe I will take your advice and just plan on breaking it all down and taking it to the machine shop. Say it does not hone out. How big can you safely bore out a 340?
 
Mmmmm. I am not agreeing that any piston looks 'steam cleaned'; the one looks like it has been wiped clean. And the head chambers look at pretty uniform; if one cylinder was burning water in an amount to steam the piston, it would show up in the head chamber too.

The pitting on the cylinder could be from moisture, or from the bore not being 100%. And yes, L2316's; the little notches in the eyebrows are a clue to that. The coolant in the 1-3-5-7 side of the valley is concerning; that would not come from removing the 2-4-6-8 side head, though it might have come from removing the intake.

Look at the upper center area of the head surface. It looks like there has been some leakage there, based on the feathered markings coming out from the the water jacket hole just to the left of center in that top center area.

Based on the head gasket pattern on the head removed, it looks to me like the head gasket has not been well clamped. Possibilities:
  • Head bolts not torqued properly
  • Head bolts not re-torqued
  • Gunk in head bolt holes preventing proper clamping of the head
  • Head bolts stretched
Heads may be warped, or the block deck warped. Same could be going on the other side, so it would be foolish to not remove it based on the head gasket pattern seen on the first side removed. IMHO, it all needs to be checked.

Let us know what you see/find when you drain the oil, OP. And yes, the distributor loose might have been the issue. But the milky oil reports is a concern.
 
Sonic check for sure but all I have seen have been good for .060 over, T/A blocks and direct connection/mopar performance blocks will go a will go a whole lot more.
 
nm9stheham said:
Mmmmm. I am not agreeing that any piston looks 'steam cleaned'; the one looks like it has been wiped clean. And the head chambers look at pretty uniform; if one cylinder was burning water in an amount to steam the piston, it would show up in the head chamber too.

The pitting on the cylinder could be from moisture, or from the bore not being 100%. And yes, L2316's; the little notches in the eyebrows are a clue to that. The coolant in the 1-3-5-7 side of the valley is concerning; that would not come from removing the 2-4-6-8 side head, though it might have come from removing the intake.

Look at the upper center area of the head surface. It looks like there has been some leakage there, based on the feathered markings coming out from the the water jacket hole just to the left of center in that top center area.

Based on the head gasket pattern on the head removed, it looks to me like the head gasket has not been well clamped. Possibilities:
  • Head bolts not torqued properly
  • Head bolts not re-torqued
  • Gunk in head bolt holes preventing proper clamping of the head
  • Head bolts stretched
Heads may be warped, or the block deck warped. Same could be going on the other side, so it would be foolish to not remove it based on the head gasket pattern seen on the first side removed. IMHO, it all needs to be checked.

Let us know what you see/find when you drain the oil, OP. And yes, the distributor loose might have been the issue. But the milky oil reports is a concern.
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True, number six chamber looks cleaner than number four, but in my experience, burned on carbon usually doesn't wipe that clean that easily unless it has been getting some steam.
 
nm9stheham said:
Mmmmm. I am not agreeing that any piston looks 'steam cleaned'; the one looks like it has been wiped clean. And the head chambers look at pretty uniform; if one cylinder was burning water in an amount to steam the piston, it would show up in the head chamber too.

The pitting on the cylinder could be from moisture, or from the bore not being 100%. And yes, L2316's; the little notches in the eyebrows are a clue to that. The coolant in the 1-3-5-7 side of the valley is concerning; that would not come from removing the 2-4-6-8 side head, though it might have come from removing the intake.

Look at the upper center area of the head surface. It looks like there has been some leakage there, based on the feathered markings coming out from the the water jacket hole just to the left of center in that top center area.

Based on the head gasket pattern on the head removed, it looks to me like the head gasket has not been well clamped. Possibilities:
  • Head bolts not torqued properly
  • Head bolts not re-torqued
  • Gunk in head bolt holes preventing proper clamping of the head
  • Head bolts stretched
Heads may be warped, or the block deck warped. Same could be going on the other side, so it would be foolish to not remove it based on the head gasket pattern seen on the first side removed. IMHO, it all needs to be checked.

Let us know what you see/find when you drain the oil, OP. And yes, the distributor loose might have been the issue. But the milky oil reports is a concern.
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I will remove the other head in the next couple of days and get the oil drained and let you guys know what I find, thanks for the help.
 
That is possible too, I figured the pitting was indicative of some long term steaming as well. I am glad he caught it before he had a catastrophic failure!
 
if you're going to rehone it, I'd have them do it with a torque plate. If you're going to remove any material, you might as well remove it where it's going to help you seal the rings better.
 
rustycowll69 said:
if you're going to rehone it, I'd have them do it with a torque plate. If you're going to remove any material, you might as well remove it where it's going to help you seal the rings better.
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The plate on the bottom of the intake manifold has a small gap. Would this cause any issues?

79B3C43E-DEED-4A8B-A6A8-FDE63855B540.jpeg


2C277C7B-2C62-4DD0-A3C3-953D07DFBFD6.jpeg
 
What 4 spdragtop said, it's a heat shield to keep oil from sludging or baking to bottom of manifold. One question I failed to as, were any of the bolts noticeably loose on the right side of the engine? Usually on the ones with head gasket issues, the short head bolts on the exhaust side are the ones that are loosest... I am glad you are planning on going ahead and doing it right, there are too few 340 blocks out there as it is.
 
Garrett Ellison said:
What 4 spdragtop said, it's a heat shield to keep oil from sludging or baking to bottom of manifold. One question I failed to as, were any of the bolts noticeably loose on the right side of the engine? Usually on the ones with head gasket issues, the short head bolts on the exhaust side are the ones that are loosest... I am glad you are planning on going ahead and doing it right, there are too few 340 blocks out there as it is.
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I was looking at the head after removing intake gasket and looks like some pitting around the coolant port. Is this normal or a big issue?

B31AE3F2-6ABD-47B0-91E7-B8C198285B7E.jpeg
 
Thats normal, ive seen waaayyy worse. What intake gaskets were you using? Those are sometimes blocked off depending on gasket mfg/style. I believe thats for the coolant crossover in the intake. supposed to help keep intake/fuel cool.

**edit** heat/exhaust crossover not coolant, sorry
 
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