Gs400 Engine Re-Build

[1990LS400]

The cylinders not dry? A proper compression test is done by testing each cylinder mutliple times and averaging the readings. Then for each cylinder, a small amount of fairly heavy oil (30W or 40W) is squirted through the spark plug hole before testing compression again. The compression in a worn cylinder should jump significantly after the heavy oil is squirted in.

I guess you could buy a compression gauge and test it yourself. They are pretty inexpensive and it's certainly not brain surgery. You would also need a remote starter button if you do not have someone to assist.

[1990LS400]

Just one more thing. I've never heard of cylinder compression failing and falling uniformly. When an engine is worn out or damaged, the cylinder compression is (I hate to use the word "always") all over the map. You might have multiple cylinders with the correct compression and one or more with far less and even no measurable compression. It would be extraordinary and maybe unheard of for all eight of your engine cylinders to uniformly test between 80 and 90 psi.

[SRK]

Jim is correct. No engine will have low and even compression as a result of wear. Far too much emphasis is placed on the numbers, rather than the variation. Some of the compression gauges are lousy brands that hardly work at all.

It's the engine that will do the talking here - does it burn oil, is it down on power, does it idle roughly or unevenly - those kind of things. Believing a stupid gauge over what the engine is saying is foolish.

I rarely used my compression gauge when I ran my shop. I listened to the engine during cranking to hear the starter unload on a weak cylinder, or how it idled. I only used the gauge when isolating a problem.

So why do you not want the valve cover gaskets replaced?

[MrChainBlueLightnin]

The second mechanic said all I need is to have the gaskets replaced. They both leak from the vents. They leak on the alternator which shorts out, but I don't think these leaks will be enough to short it. I also wonder how long it will continue to fire with oil in all the tubes.

[MrChainBlueLightnin]

ok, here is the finality of this thread. first off, SRK and 1990LS400 you were right about the setting me up, lube etc. The second mechanic replaced the valve cover gaskets, spark tube seals and vent seals. he showed them to me and in his expert opinion they are all the originals from the factory. that was the whole problem, they just needed replacing. (although, that is the 4th time I have paid someone to do it.) so no new engine needed. you guys were right on. Thank you for all the help.

[SRK]

I'm glad it's fixed properly and that you dodged the "big bill". Drive the car and enjoy it, they are incredible machines.

Thanks for the reply back too.

[1990LS400]

Well, not be be pessimistic, but let's wait a month or so before breaking out the Champagne - when of course you will send one bottle each of 1907 Heidsieck to SRK and me.

I hope this fix holds!

[SRK]

That Heidsieck is a bit pricey....every burp would be worth a $1000.00! Wonder what cigar would go with that stuff?

[Kundre]

Hey, i also have a question to this topic. But im looking for a rebuilt engine for my Lexus not for rebuilding services. Found one website who sells rebuilt engines but need some more information about them https://orbimotors.com/rebuilt-engines/lexus/ Maybe someone have bought an engine from this seller?