[xj-s] Many questions about '78 engine

XJ-S
1

I have many questions about a '78 XJ-S engine, so here we go…

  1. Is it really necessary to use cylinder liner retainer clamps (part JD41) when you crank the engine with the heads off? It seems that the liners couldn’t possibly move; they seem corroded in place. And where can I buy this (these) tools? I’ve looked in 4 different catalogs and I can’t find them.

  2. What is the best way of cleaning off all the carbon on the valves and especially inside the heads, without damaging the aluminum?

  3. any other tips before we rebuild the engine?

thanks,

-Jeff

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( Jeff Peirson )
\ @Jeff_Peirson1 /
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2

I have many questions about a '78 XJ-S engine, so here we go…

  1. Is it really necessary to use cylinder liner retainer clamps (part JD41) when you crank the engine with the heads off? It seems that the liners couldn’t possibly move; they seem corroded in place. And where can I buy this (these) tools? I’ve looked in 4 different catalogs and I can’t find them.

  2. What is the best way of cleaning off all the carbon on the valves and especially inside the heads, without damaging the aluminum?

  3. any other tips before we rebuild the engine?

Jeff,

keep us posted (or send me email privately) how it goes. Yesterday I took the
heads of the engine I bough last week. It was not too difficult. Amazing what damage
a valve can do to various parts of an engine. At least one head and tappet block
are shot. Are you removing the studs from your engine ?

Also my engine is seized. I pured in oil, but I think there will me bore damage to
the botton of the engine. The workshop had already removed one cylinder. Also
I need to buy a valve compressor, any good advice for this ?

  • Matthias
3

At 01:08 2/02/1998 -0800, Matthias wrote:
I need to buy a valve compressor, any good advice for this ?

The normal generic valve compressor from K-mart will do fine; there’s
nothing special about the V12 valves.

  • Jan
    The Gum Tree Garage, where oil and beer mix just fine…
4

I’ve been working on taking the carbon on for the last week or so now. About only one thing works.

For the bottoms of the heads, I sprayed the dirty area with brake cleaner (carb cleaner worked too, but not as good). Then I used a light scotch pad (I’m not sure what grades they come in but this one was the green kind). For the buildup of deposits around the water jackets, I used a red scotch pad (a courser texture). One must be careful though because it can scratch the aluminum if you work on one spot too long.

The intake valves can be perfectly cleaned, but the exhaust valves always seem to look bad, but most of the carbon seems to come off. Here’s what I did…
First I soaked the valve I was working on in brake cleaner for a few minutes. Then I used a small (about 3mm) flathead screwdriver and CAREFULLY scraped most of the carbon off the top and bottom. It shouldn’t scratch up the head of the valve, but I’d imagine it would scratch up the mating surface. Once you get most of the carbon off with the screwdriver, I sprayed a little more brake cleaner on it and used a maroon scotch pad (which is a little heavier than the green, but green still works ok on it)
All this seemed to get most of the carbon off, but it takes a bit of time.

The only thing that concerns me now is the insides of the head. I’ve tried the scotch pad, but it only gets the loose stuff off and it can only reach so far. Please give any ideas on this

hope all this helps,

-Jeff

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( Jeff Peirson )
\ @Jeff_Peirson1 /
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