[CTALFA]

Chpt 2: Now that the head is off

...and I can get a really good look at things, the gasket seems to be in tact, no signs of blow thru or blow by, unless I'm just not clued into what that should look like, I'm assuming an obvious area of errosion, or fluid migration, but not seeing that.

#3 cylinder(head) and piston top are really pretty clean as opposed to the black carbon build up on numbers 1, 2 & 4. My guess is that #3 was getting a "steam cleaning" with the coolant being introduced to it, but I can't see where it was entering. I don't see any cracks, hairline or otherwise.

I tried a "leak test" of sorts on the bench, put plugs in, filled the head chambers with gasoline, and shot some air into the exhaust and intake ports; got a fine stream of bubbles on each of the exhaust, not so with the intake.

Any clues from the more knowledgeable? More tribal knowledge?

In case anyone is wondering, we're looking at a 2.0 L-Jet, '84 vintage.

UPDATE: Could it be that the intake manifold gasket was leaking? Finally was able to remove the manifold from the head and on the underside, where the coolant would be flowing, there's a distinct brown residue/film of sorts ONLY around the #3 intake port. Tough to say if the gasket failed for certain, but it does have a slight look of being faulty right where it is on the edge of the intake port itself. Make sense? Or am I barking up the wrong tree?
Thanks in advance-

 

[Andrew]

Hard to say without pics. You might take the head to a good machine shop for a pressure test and close inspection to see if there are any cracks; sometimes they are very hard to spot.

Blown head gaskets will generally show a dark path on the sealing rings right at the cylinder edge where combustion gases were leaking out, blackening the gasket. Sometimes it's subtle. Look both top and bottom.

My experience with Bosch heads is it's pretty easy to burn exhaust valves. These cars up set up to run relatively lean, and if you get (1) intake air leaks, and (2) closed down valve clearances due to deferred valve adjustment and/or pounded seats, the valves will burn more easily. I wonder if all the exhaust valves are a bit burned, or at least worn to the point of needing grinding?

Andrew

 

[Gordon Raymond]

Engine disassembly

Hi John,
Can you include some photo's? Particularly the intake manifold & head around #3 port. As it seems someone has already been "into" your engine, the manifold may be the only problem, but now, since the head is off, you will need to make some more decisions about head and valve work. Lots of little projects turn into big ones, due, as you mention, to lack of tribal knowledge.
How many miles are on this engine since it was last apart? What do the liners look like (without pulling them)? Have you dropped the pan? What does # 4 rod bearing look like? How about the main in front of it? Big, little or no groves cut in the front cover from the timing chain? I could continue, but don't want to get scarry here. Did you check the valve clearances before pulling the head? ..... and so on. Lets start with photos.
Best, Gordon Raymond

 

[CTALFA]

Thanks guys.

Luckily I was able to show the gaskets to an educated eye who right away pointed out it was a blown head gasket, in particular the area between #3 and #4 where the "fire rings" abutt. What was interesting how little a disturbed area there was for such a display of symptoms. I'll try to post some pics of the gasket for posterity.

Gasket's done, all put back together, and after some short test runs in the wee hours of this morning, was able to drive it out to Lime Rock Park for the Rolex Vintage Fest and even take a half dozen or so laps on the track.

What a blast!