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Re: Stupid Engine Compression [Re: SHAD] #445753 05/06/04 04:02 AM
Joined: Oct 2001
Posts: 926
fpkelly Offline OP
Rock Warrior
How do I do that? Use a feeler gauge between the cam and valve? Also, to remove the head to do I need to pull the front cover off and the timing belt sprocket too?

Re: Stupid Engine Compression #445754 05/06/04 04:42 AM
Joined: Jun 2003
Posts: 3,576
engnbldr Offline
Roll Me Over
*****
Quote
Engnbldr,

It seems you have seen this many times before with this engine.(#6 exh vlv burnt)

What do you think the problem is that so many tend to do this?


>>>*Yep, many times, and at the risk of sounding like a Genius, *LOL**... I am sure only that I don't know for sure.

I do know valves start to burn due to overheat, no other real reason. Now lots of things can cause overheat. Once the valve begins to burn, (which happens in seconds, by the way) compression falls, the cylinder cools, (OOPS, sometimes it runs even hotter...long story there...) and it can take several thousand miles for the condition to deteriorate to where it becomes noticable..

We also learned the $$$$$ way that folks who don't invest in new exhaust valves come back to see us way too soon, usually unhappy with us even though all was in spec...Often enough that now we don't rebuild these heads without installing new exhaust valves. And yep, we pay the extra for stainless or black nitride..cheap, considering...
*As I look at the design on the manifolding and exhaust system, I see suspicious points where heat can collect. I put a digital heat gun on a 4Runner a year or two ago, curious. I was reading nearly 40? hotter near #6 and I don't yet know why. Then I checked another one and it was normal..?????...*Yep, not sure yet...

If I owned a 3VZE engine, the very first thing I would do is try to figure out how to lower the temperature that the fan kicks in at. I would like to see 210?, I don't know for sure but I bet it currently is 220? or more..

One example of this is the Mopar 2.7L, it kicks in at 230?. Nice for mileage, but those engines come apart around 60,000 miles regular as clockwork.

(*EB be betting I now know the cause of "engine sludging" we hear so much about...)Another long story...

That fan temp change just might help..No idea on how to do it, bet there are some bright young techs in here who DO know how......*EB


*Beats the he** outa me!....*LOL**...
Re: Stupid Engine Compression [Re: engnbldr] #445755 05/06/04 07:52 AM
Joined: Oct 2001
Posts: 926
fpkelly Offline OP
Rock Warrior
Holy crap, that sounds about spot on. Truck started with a little bump in acceleration and over the next 550+ miles it got to the point where it didnt want to idle. Ended with the longest tow ride ever, 270 miles of making small talk with a driver that smoked like a chimney, literally lighting one off another.

Re: Stupid Engine Compression [Re: fpkelly] #445756 05/06/04 01:50 PM
Joined: Jun 2002
Posts: 1,698
SHAD Offline
Body Damage is Cool
Quote
If I owned a 3VZE engine, the very first thing I would do is try to figure out how to lower the temperature that the fan kicks in at. I would like to see 210?, I don't know for sure but I bet it currently is 220? or more..


I have 180deg thermostat and a taurus electric fan setup on mine I have it so it kicks on after it passes 185 deg cools it right down after a few seconds.

I heard a rumour that the coolant flow passages aren't adeqate on the headgasket towards the rear of the engine that's why it heats up so on the back of the #6 but like I said that's only a rumour.


I was only getting 143 psi compression out of the #6 cyl before I had the valve job done and it did have a burn't exhaust valve on that cylinder. I just put all new bearing and rings in and had a 3 angle valve job and 4 new exhaust valves in mine I'll see how it goes once I get it all put back together. The 3VZE isn't hard to work on it's just getting the valves back to spec if you don't have a box of valve shims running back and forth to a engine shop is a lenghty process.

Quote
How do I do that? Use a feeler gauge between the cam and valve? Also, to remove the head to do I need to pull the front cover off and the timing belt sprocket too?

Yes you check with a feeler guage between the cam and the top of valve shim. Use a scrap of paper and write down all the gaps per intake and exhaust valve per cylinder. You do this process with everything connected the timing belt still on. Then once you find the out of spec valve you add a different sized sime to compensate but you really want to do this after you get the heads back from a shop and have everything assembled again.

Last edited by SHAD; 05/06/04 02:11 PM.

86 Toyota 4 runner
35x12.5 BFG MT's, 4.56's XRC8 winch
My cardomain page
Re: Stupid Engine Compression [Re: SHAD] #445757 05/06/04 01:55 PM
Joined: Sep 2002
Posts: 1,878
M
mt_goat Offline
Body Damage is Cool
What is involved with the Taurus electric fan setup?


93 4X4 ext-cab, auto, SR5, 3.4 V6, supercharged, 2.1" pulley, URD fuel mods, Aquamist WI, IPT valve body mod, dual cases, 4" superlift, Alcan springs, 33 BFG MT, ARB locked front & rear, 5.29 US Gears, RB 1" BL, 1.5" BJ spacers, TJM T-17, Warn m8000.
Re: Stupid Engine Compression [Re: mt_goat] #445758 05/06/04 02:23 PM
Joined: Jun 2002
Posts: 1,698
SHAD Offline
Body Damage is Cool
Quote
What is involved with the Taurus electric fan setup?


Just pull your old manual fan out adding a electric fan to it with a 40 anp relay and cut off switch or maunal override switch with a temperate sensor on the raditor.
There's quite a few writeups on how to do it.


86 Toyota 4 runner
35x12.5 BFG MT's, 4.56's XRC8 winch
My cardomain page
Re: Stupid Engine Compression [Re: SHAD] #445759 05/06/04 02:33 PM
Joined: Sep 2002
Posts: 1,878
M
mt_goat Offline
Body Damage is Cool
Thanks Shad.


93 4X4 ext-cab, auto, SR5, 3.4 V6, supercharged, 2.1" pulley, URD fuel mods, Aquamist WI, IPT valve body mod, dual cases, 4" superlift, Alcan springs, 33 BFG MT, ARB locked front & rear, 5.29 US Gears, RB 1" BL, 1.5" BJ spacers, TJM T-17, Warn m8000.
Re: Stupid Engine Compression [Re: mt_goat] #445760 05/06/04 02:53 PM
Anonymous
Unregistered
engnbldr,

I've known certain head designs that will trap air in just one area when the coolant has been drained or gotten low then refilled. No amount of bleeding seemed to fix it short of a pressure flush with a garden hose.

The only fix was to drill n tap a place for a bleeder plug in the head very near that area....And then only if the head design allowed it.

Re: Stupid Engine Compression #445761 05/06/04 05:37 PM
Anonymous
Unregistered
fpkelly,

While you are in there with the heads off, see if you can borrow a magnetic base dial indicator.

Check deck height on all pistons when they hit TDC. If 6 or any one of them falls short even by a few .000's, you might have a bent rod.(that's if you discover you have a bent valve from oil ingestion)

If you got the touch for it, you can also check rod bearing clearances this way....But that's another story.

Dealer wants $1667?....Cool, you can pat yourself on the back when this is done.

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