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Does this mean a total engine rebuild or just head gaskets

P

pzvt

Member
1979 LM 318
Rebuilt 10 years ago
White smoke on port exhaust
Engine over heated - steam
Didn't run it after that
Took out plugs and did compression test with starter (34 deg F outside)
All cylinders are 100-160 psi except starboard front cylinder only showing 30 psi (checked twice)
Haven't checked exhaust manifold gaskets (coolant leaking into exhaust)
Engine is exchanger cooled - not fresh water cooled
Pulled both water pumps and checked - all impellers OK - installed new gaskets
Oil is milky

Any input much appreciated!!
 
Might be a head gasket. Yank the head and pray a bunch.

Hell; it's Christmas, you might get lucky!

Jeff
 
Not sure what extra info that would give you. But DON'T continue running the motor for, if the head gasket is blown through between the cylinder and a water jacket, you will gouge out the block, which requires a complete rebuild.

I did that on mine, not realizing the gasket was shot. Expensive mistake.

Jeff
 
My bet is the gasket. Before you pull those heads make sure you mark the valve train parts as they only work right when installed correctly. Check flatness on block and heads before assembly. Inspect head bolts for stress cracks or any distortion.
 
Thanks all for your input - will let you know how it goes. Boat's outside & covered so will wait for a warm day to start tearing it apart. Remanufactured motor - have to look into that......
 
IF the block is toast, that's the only way to go. Rebuilt Chryslers are actually cheaper than Chevies, believe it or not.

Jeff
 
This is none of my business as to how or what you choose to do.... it's your call all the way!

However, if you were to custom build a 318/360, keep in mind that some of the Chrysler 318/360 cylinder heads offer a quench surface.
This surface will be off to the side of the main wedge shaped combustion chamber.

If your cylinder heads are of this style, you could take advantage of the same thing that the SBC guys can take advantage of.
See this thread beginning at post #7.

Here's a Chrysler article that may also interest you.
This is Automotive... but many of the same principles may apply.

It's all about LPCP (location of peak cylinder pressure), and what we can do to place LPCP at the best crankshaft angle for better torque and horse power.
(LPCP at/near 12* to 14* ATDC is near ideal)

With no quench effect (with a wedge shaped chamber), ignition advance must be held back some, and we may end up leaving HP and Torque on the table due to a lazy LPCP.

The cost to do this is peanuts, comparatively speaking.


The Chrysler Wedge Head boys have known about the Quench Effect for years. It's nothing new at all, but is now days often over-looked.


This image is from that article.
I'm not a Chrysler expert, and I'm assuming that both of these cylinder heads are for the 318/360.

Above is a wedge shaped chamber w/ a quench surface, very similar to the SBC cylinder heads.
The piston profile for this cylinder head should not be dished out underneath the quench surfaces.

Bellow is a hemispherical shaped chamber... no quench possible, nor necessary.
hrdp_9808-04-o%2Bchrysler-360-380-a-series-crate-engine%2Bports.jpg
 
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300hb said:
Pretty much.... :p
Aren't you in the engine business...?
Click to expand...
Jack, kidding aside.... the mention of a Q/E build does occasionally turn some people away. The benefits area just not understood.

As for being in the engine business.... not necessarily engines alone.... I do have a small AQ series V/P biz.
And quite honestly, I know very little about the Chrysler 318/360's in the Marine version. But as long as an engine incorporates a wedge style chamber w/ a quench or squish area...... why not take advantage of it?

The silliest thing that a SBC owner can do (when custom building one), is to use this piston profile in his build.

attachment.php


I can't help but to think that this could/may apply to the Chrysler 318/360's also.


.
 
"Bellow is a hemispherical shaped chamber... "

Not sure that's a hemi shape Rick. Looks like wedge head to me.

360 wedge................
360.jpg
Now the "old style" or "poly" 318 is more of the "Hemi shape" with the canted valves (sometimes referred to as a semi-hemi).......
318-poly head.jpg
And now the "Hemi"
hemi.jpg
 
Dave, you no doubt know these better than I do. Perhaps I wasn't defining the heads correctly.
The point that I was trying to make, is regarding the quench or squish area.

Not sure what you Chrysler guys call this style, but here it looks like there'd be a potential quench surface.

360 quench surface.jpg

It appears that the quench or squish deck on this head is recessed some, of which would require a positive piston deck profile to gain a good quench dimension... if even possible.

attachment.php
 
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Getting ready to pull the heads off. As this is a closed circuit cooled engine can I use regular 318 chrysler head gasket kit or does it have to be the marine head gasket kit. My engine is 1979 LM 318. I see Victor Reinz has discontinued the head gasket kit for marine engines.
 
Thanks Jeff!! Bought Felpro

Finally pulled the head off today (Balmy 40 deg F under the boat cover) - head gasket looks brand new - no steam cutting or anything???. Cylinder wall looks fine. # 2 cylinder was at 40 psi with compression gauge. Will put piston half way up cylinder tomorrow and add some kero to see if it leaks out (ring failure) Could it be a gasket leak in the exhaust manifold sending coolant back through the valves? Any suggestions? See picture links

https://picasaweb.google.com/lh/photo/SoddBYSyzqIv7TMWvv4MQuI-d_92YmT77B5aX1u4nlY?feat=directlink

https://picasaweb.google.com/lh/photo/nrjN86la7tr_RgrY9yVqo-I-d_92YmT77B5aX1u4nlY?feat=directlink

https://picasaweb.google.com/lh/photo/26pbto_J6_rDavtwUqbcL-I-d_92YmT77B5aX1u4nlY?feat=directlink

Thanks all for your help!!!
 
Filled the cylinder (as much as you can with piston on the bottom and cylinder angle) - nothing leaks out. Cleaned up the top of the piston - no damage, hole, anything that I can see?? Sprayed with oil to stop rust. All the gaskets (head, inlet and exhaust) look OK? Any suggestions?
 
pzvt:

I've had LOTS of trouble with water getting in the motor from the exhaust system on my 360s. I've replaced every one of the components over the years, yet the problem still happens now and then. When the water gets in, I have to pull the plug(s) out and spin it over (ignition disabled) to "dry it out".

Perhaps that is what's been happening all the time here. If so, the solution is new manifolds/ risers.

Good luck!

Jeff

PS: Head gaskets looked fine to me.
 
Thanks everyone for your input. Head is at VT engine now for magnaflux. I will let you know the result. Next would be to pressure test exhaust manifolds.
 
And the risers! If they leak, water runs down into the end cylinders (or middle ones with center dumps).

Jeff

PS: I have a custom rig for testing the risers and elbows. Not as simple a task as one would think!
 
Took the right head in and turns out the seats are toast (especially cylinder 2 (low compression)) and there are a couple of bent valves. Waiting on a price to do both heads. They can also pressure test the manifolds so will take them in also. Should this have happened in 10 years of 40 hrs/year use? Is this just a 318 issue? Will keep you informed.
 
pzvt said:
Took the right head in and turns out the seats are toast (especially cylinder 2 (low compression)) and there are a couple of bent valves. Waiting on a price to do both heads. They can also pressure test the manifolds so will take them in also. Should this have happened in 10 years of 40 hrs/year use? Is this just a 318 issue? Will keep you informed.
Click to expand...

How did this happen?
 
Good oil pressure when took it apart
Boat is regularly started and used weekly in the summer (April to November) - can't do that in a VT winter
Oil changed every season
Quote is $300/head to put in all new sleeves and any bent valves - they mentioned that it looked like someone had worked on the head before. Engine was rebuilt 10 years ago and receipt says heads were used.
There are no marks on the piston
Have to pull the other head (once I get the 20" of snow I got last night out of the way) - I don't think it will have the same issues - all cylinders were 120 psi or above
I suspect the trip down and up the Hudson in 100 deg F weather may have had something to do with it........
 
Any tips on how to/tricks to adjust valves when I put it back together?
Does it matter which end of the rod goes into the lifter - looks like one end has a larger hole so suspect that end goes against the lifter
For the inlet manifold I got a metal and composite gasket (Felpro) - I assume the metal goes against the head? Both are full length not like the picture Jeff posted on little metal plates.....
 
Water in the motor rusts the valve in place. It sticks in the open position and gets whacked by the piston, bending it.

Jeff
 
Have you checked for a rebuilt set of heads?

The rocker train is specific. You need to replace it correctly or lubrication won't be adequate.
 
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