Scramblur

I need some help with a problem...
94 4Runner 3.0vze - 100k miles
just bought it - $3,000 for my 16 year old (knew it had a severe miss)

Dollar bill test - exhaust sucks bill in
Cylinder 3 is misfiring and plug is fouled

I had toyota dealer do a diag on the engine code and they said it was "misfire", they did a leakdown test (without my agreeing to pay for it by the way) and said it was a burnt valve, she also mentioned the mechanic said the water pump showed a leak.

If I have a burnt exhaust valve, what's my best option? (other than paying them 3k to fix it) Can I replace the valve? Should I send the heads off and have them worked? Any ideas on cost?

Also, if I take the heads off, I'm thinking I'll replace the H.G.s with LC Engineerings MLS set, any feedback about them?
Thanks

Jay351

So Im guessing the headgasket re-call has been done on your rig.. Seems pretty low mileage to burn a valve..

I would remove the heads and do a valve job. Consider going to oversized valves, they would really help your 3.0 breath. If you go with o/s valves, some nice cams would complement them very nicely... But if you don't want to drop the coin. Going with stock stuff would be okay, but you might be back in the same position way down the road...

Use toyota gaskets on your engine, engbldr has good kits for a good price.

Matt16

Pardon my ignorance, but describe the dollar bill test.

Rocketwrencher

Just wondering why you would consider spending three grand to repair a 3.0 when you could put a 3.4 in for less and have a much more dependable engine?

93toyrunner

I just went throught this about three months ago, cylinders 1 & 3 were burnt on mine with only 130,000 miles, I went on ebay ordered a HG set with all gaskets and new head bolts and I ordered a new water pump kit with timing belt and pullys all totaled about $200 including shipping. Then you have two options, 1) take to local machine shop and have the clean and resurface the head have them do a suction test to make sure all valves are good, and have them replace the valves. Or you can buy new remanufactured heads also off ebay for about $500. I went to the machine shop my heads were still good The total build for every thing was between $400-$500.

Scramblur

So this sounds like a good option, thanks. I'll tear into it next weekend when I get back home.

Scramblur

When a valve burns the cylinder will no longer fire. If an intake valve burns the engine will backfire through the intake manifold. An exhaust valve is less noticeable. An old trick is to hold a dollar bill so it flaps over the exhaust pipe: if the bill gets "sucked in" every so often it can be a burned exhaust valve.

93toyrunner

One thing that helped me is I ordered all my parts off Ebay because it was so much cheaper, and I ordered long before I tore my truck apart, I think it took about a week to get the parts in, this way when I got my heads back from the machinest I could put it all together with very few trips to the parts store.

Scramblur

Not considering 3k, I'm looking for a 1k or less option. Chances are the kid will wreck it before the 3.0 dies (I hope not, but new drivers...).

Scramblur

Okay, I like tis option along with the "just fix what's broke option".

I agree on the mileage, the truck is bone stock and near mint inside and excellent exterior, not sure if it got hot or what happened.

Yes the recall work was done in 98.

Curious about a couple things. Why not go with the LC Engineering MLS HGs? Seems like from what I've read MLS is a perfect way to deal with the weak Toyota HGs, mostly caused by dissimilar metals of the block and heads. They are $200, so if the consensus is they aren't any better than the OEM, I'll ditch that idea. Any cost estimate for the solution you propose with OS valves, new cams?

Also, how about time for all of this? Is 16 hours of my labor a good estimate?

I did get the FSM ordered.

zlathim

I did just that with a couple of burnt exhaust valves on a 3RZ. Removed the head, bought two new valves, and lapped them in to the existing seats. Very inexpensive, but certainly not a textbook repair either. It worked fine and the truck ran great after the repair.

Here's the burnt valves:



Here are the two new valves after lapping:



I tested the seal of the valves by filling the combustion chamber with mineral spirits. The thing in the middle is a spark plug adapter from my compression tester that I installed to keep the mineral spirits from running out the spark plug holes. You could just position the head differently and fill the exhaust port with solvent or water to accomplish the same thing:

Matt16

Cool. I will probably never get to use that though, cause I have the almighty 22RE!

Scramblur

Any feedback on Multi Layered Steel (MLS) HGs made by LC Engineering or anyone else? Are they worth the money?
bkh

Scramblur

MLS HGs yes or no???

Scramblur

Still looking for someone to give me a technical perspective on Multi Layered Steel HGs versus standard OEM version. Is it worth the extra coin?

BoostinChick

I know this is a late reply but for general knowledge if anyone else were to search and stumble on this thread. In order to use the MLS gaskets BOTH mating surfaces need to be level and it's recommended they both be decked. If the block is not decked or straight then the MLS gasket is useless and will eventually leak.

2DoorRunner

Why 3k for a 4runner with a misfire? It must be really nice, or have no rust.