DaYotaMeister813

Hey everyone, this is my first post on yotatech. I recently acquired a 94 4runner with a 3.0, automatic, 4wd, about 190k miles on her. It has no compression on cylinders 1 and 6. After a compression and leakdown test I'm thinking the issue is in the valve train. Before rip these heads out, are there any common valve train issues or weak spots with these 3.0's I should be looking out for? I may just end up having the heads completely rebuilt, depending on how my wallets feeling this month. If so, any suggestions of things to modify or upgrade to improve gas mileage and reliability? Power's not really the goal here, just trying to get her running anddo the job right the first time. Thanks guys!

thefishguy77

iTrader: (1)

The 3.0 is a love or hate motor. Some will tell you it's great and most do not care for it. Often times with this motor if you need to pull the heads some people will say its better faster and sometimes cheaper to just put a newer 3.0 in and do a complete engine swap. I am not personally familiar with these motors but from what I have read they can be challenging to work on at times. (Kinda true with all motors but these more that most). Other less common solutions are different motor swaps. The 3.4 motor is a very sought after swap and I believe the motor mounts are the same. But that's about it so thats a fair amount of work you would have to find time for or pay someone else to do it. That can be pricey. Good luck and I hope this helps.

millball

Valve clearance adjustment on the 3vze is a pain and is often neglected,
When clearances dissappear, valves burn. Maybe what happened to yours.

It is important to use factory parts when rebuilding these heads, especially the valves and seat inserts.
Use of inferior parts sometimes results in premature valve resession and/or valve stem stretching that causes rapid loss of valve clearances and leads to early valve sealing troubles.

DaYotaMeister813

Fishguy this motor really is a p.i.t.a. to work on, just getting at the valve covers was a nightmare! And i do have plans for a 3.4 swap down the road. Just waiting for my fathers 2000 to finally die (shes got 460k on the clock and still tickin!) Thanks millball ill be sure to source my parts from toyota for the rebuild. This was exactly the info i was looking for guys thnks for taking the time to respond.

rattlewagon

These are known for headgaskets going, especially in the #6 cylinder.. Thats where I would start.

Headers to help and are really the best bang for the buck thing you can do the 3.0.

Also a good time to do the timing belt and water pump if it needs it.

DaYotaMeister813

Well my compression-less cylinders happen to be #1 and #6... although at zero compression dry/wet... I'm thinking burned or damaged valves may be the issue. I'll check the gasket as well though. Thanks @rattlewagon. Anything that can be done parts or machining-wise to prevent future head gasket issues while I'm in there? I'd like to cure any weakspots the first time cause I DO NOT want to pull this motor apart again untill it's time for the transplant. Also any recommendations good value (price and quality) headers to go with? I can see where that crossover design could create a heat issue in that cylinder so this is definitely gonna be first on my list of mods. Sorry for the avalanche of questions guys... I appreciate the knowledge