Replacing Heads

[lexushead]

Background:
Have 92 LS400 with 270,000 miles. Engine is ticking loud, louder than a 350 Heavy Duty diesel. Ticking is from the left bank. In July, fan bracket went bad. So I went and bought a 93 LS400 engine with 100K miles to get the bracket as well as a few other things since the engine was only $350+$100 core. While everything were off from the car, I decided to replaced the timing belt, water pump, idlers, tensioners, serp belt, dist. rotors, caps, and misc others.
Suggestion?
Should I replace the heads from the new engine? 93 heads with 100k.

• I rather not replacing the engine. Might be more problems to encounter.
• I rather not replacing the shims in the old engine. Cost of shims, tools, and just afraid to.
• I bought a head gasket set, so I will replace all the gaskets and o-rings.

 

[Lextreme II]

Since your motor is pretty much strip might as well replacing the heads. Taking out the headers is pretty hard. However, you dont really have to take it out.

 

[lexushead]

Thanks, I guess I was not clear of what I said above.
I'm basically debating/contemplating on replacing heads v.s. replacing shims.

 

[striker]

How sure are you on valve clearance on the newer heads?

if not sure about than it's up to you, but checking valve clerance and adjusting if needed seems logical anyway.... regardless of which heads you keep.

grtz Thomas

 

[mshawari1]

Check If the new one is in good condition ... then replace the complete block is easier

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[Zuffen]

If you replace the heads you will need to re-set the valves so you will most likely need to repalce a few shims along the way.

If you engine is running OK use check what shims you need. You may get them out of your spare engine.

 

[lexushead]

Thanks for all your recommendations. The engine is running good. My wife is driving it every day and she wants a new Camry.
I think I will swap the shim(s) from the spare engine. Now the valve cover gasket is leaking.....

 

[jibbby]

I've been considering port matching my 1uz-fe heads...After reading the difficulties of removing and or replacing the heads I may just pass... I did not know you had to set the valves when installing the 1uz-fe heads... How exactly is that done? Is there a certain trick to doing that?...

Sounds like changing the block and heads as one unit maybe the easier route to take...

 

[lexplay]

if u dont pull your cams out and play around you shouldnt have to play with the shims, their not fun to stuff around with especially when in the car. even form factory their not all the same. i havent pulled my heads of yet do you have to take the cams out to get to the head bolts? im guessing yes.

 

[Smitherz]

There are two schools of doing this. You can simply pull the old heads off, clean the gasket surfaces, slap on some new gaskets and put the new heads on with the proper torque sequence/spec and you will be fine. This is assuming that the newer heads look good and you believe the mileage on them. I HIGHLY recommend a carfax report on the engine block #. All engine places will just tell you what you want to hear in order to sell their inventory.

BUT if it were my car that I wanted to keep: While you have it apart you could take the new heads to a machine shop and have them clean the valve passageways (maybe lap the seats for a tad more $) and set your shims properly for you. If you have them off you might as well pay a couple hundred for this very important head inspection/shim adjust. Good machine shops do this alllll the time, have brains enough to mix and match the shims that need adjusting and can get any new shims at a decent price. If the mechanic or machinist acts like it's a HUGE deal or doesn't look familiar with your heads just find another shop. The shops around me all know how to work with them. Heck you can have them just check the valve specs when they are cleaning the heads and report back to you with their findings and they will give you advice on any needed adjustments.

 

[gloverman]

To change the heads you will need to remove the cams to get at the head studs and disturb the buckets and shims. When reassembling I would always recommend rechecking the clearances. If you are worried about checking valve clearances on the old motor I would not recommend changing the heads - changing the motor is a less complicated job. The motors come out quite easily and you will be getting a motor with 170000miles less wear on the bottom end. Just my thoughts - cheers

 

[lexushead]

Thanks for all the input. I haven't have time or desire to go into the cold garage to do/contemplate of doing the job yet. I just got an engine hoist from Santa and will assembling it this week.

 

[striker]

Come on guys, since when is changing the engine, when valve clearance is out, the solution.....
sounds the same as buying a new car when the tyres wear out, "since you won't have the tools to change the tyre"

nahh if you're uncertain of valve adjustment David has a nice tutorial on this site somewhere, else pay someone to do it for you....

grtz Thomas

 

[spf_lexus]

Frankly I would love to learn how to re-adjust the shims, just so I can do it from now on w/o having to call a mechanic to do the swap. But striker is right... why change out our entire engine because of 1 bad apple? I wonder if anyone has posted about shim adjusting.

 

[striker]

sure the subject's been on here once or twice, try a search.

Now where did you put all the tutorials david?

grtz Thomas