Since i won't be putting it back together for another three weeks... got everything marked.

 

First question, so i need to take the old gasket out... what is the best way?

Second question, condition of the pistons... looks good or bad

Thanks!

 

Just curious, is it possible on these engines for the valves to punch though the pistons in a case like this? Does not look like much carbon build up, how are the rings?

 

I don't think the valves would be able to punch a hole in the pistons because the valves don't come down far enough. This engine has 10.5 :1 compression, so the pistons come up REAL close to the head. Those notches in the pistons are where the valves went into when they were out of time, and the valves still got bent. That is why the pistons are dished. When the timing varies (VVT) during high speed, the valves open even sooner, so clearance is CRITICAL.

The head gasket is sitting right on top of the block, and HAS to be changed...no question! To remove it, just take a flat blade or scraper on the side of the block, and put it in between the gasket and the block and lightly pry it off. Just go from one end to the other, and it will break loose. It should be clean underneath because there is no adhesive. The only ridges will be around the cylinder bores themselves. Clean that off and you're ready to go.

The whole head will be completely de-carbonized when you get it back, so I like it all clean. Don't obsess over it, but clean up things as much as you can. If you can't do any piston cleanup, just leave it alone.... it will run like it is, and I assume the other pistons have the same light carbon on them as well.

Are you sending the cams in to the machine shop as well? I assume you are, so they can be checked as well. I am sure they will go in the clean tank as well, and you will have a sweet looking head when it comes back.

I also assume that the engine does not burn oil or smoke. It looks good, go ahead and rebuild it. The cam gears look good also.

Good luck, and I am sure you are learning a lot about this engine in this operation.

Great pictures!

 

Pardesi,

Sorry to come in so late and I am sorry for your headaches. Like some other members had stated timing is pretty easy. Here are some articles on it if you decided to do it again.

The articles are for the pre-98 1uzfe, but its very similar. Good luck.
Timging1
Timing2
Cams

 

David,
This is a different engine set up!!! We all know it's still in the same family but VVT-I set up is different ball game.
JP Importz

 

I'll pick something up to scrape the old gasket out. The head is at the machine shop so he is going to clean everything including the cams. Engine never burned any oil so i should be okay on that. So lets see and wait.

Till then I have to order all new gaskets and few new bolts. Instructions i have said to replace the header bolts. And i need two new bolts for the exhaust. Plus i'm thinking of replacing the starter and the pcv valve as well since i have everything open. My brothers GS400 starter went out earlier this summer and his has 20 more thousand miles then mine. So i figured might as well do it.

Anyways, yes I am learning quite a bit about the engine but there is so much more. I was trying look up information on the hydraulic valves setup and how that works. Does that mean the valves get adjusted automatically at different engine speed?

 

I am well aware of that. That is why I stated: The articles are for the pre-98 1uzfe, but its very similar.

 

Just got the head back from the shop.. looks good now waiting on the gasket set kit from lexus.

 

It should be easier and cheaper to purchase a new engine from a crashed GS400.

 

Yeah, but it wouldn't be as much fun. Besides, changng the engine out is a lot more work than this.

It is a learning experience like no other.

 

Yeah i don't think i want to sign up for changing an engine on a GS400 just yet. This will do for now and the cost is not that bad compared to replacing the engine.

Just flew back in town over the weekend so i should have the car up and running by Saturday.

 

It should be somewhat easy to change an engine in a RWD car with so much
engine space. Changing engines in AWD and FWD cars is a different story.

I also don't think its a good idea to just change one head, I would say that
its better to change both heads at the same time. Compression in left bank
will be different from the right bank its not a good.

Also get new head bolts, its a good idea to change head bolts when replacing
heads and see if the block needs to be decked.

The right way to change heads is out of the car and to do both of them at
the same time. You need to cut the head and the block to make sure that
both surfaces are prepped and new head gaskets and bolts should be purchased
to make sure that compression is perfect and the same both banks.

 

Since his engine is apart, would it be worth it for him to get the heads ported for some extra power?

 

I think pictures speak for itself... what a difference in performance.

Thank you everyone who posted on the forum for all your help, tips, feedback, etc.