95 3VZE Crossover Modification

[mikedks]

I'm re-doing the 3.0 in my 95 4Runner and was looking at relatively cheap options to possibly gain power and efficiency. Not much to do with the engine(cheaply anyway), so I'm looking at the exhaust. Obviously the crossover is poorly designed and probably contributed to the head gasket issues on this model. Would love to put headers on, but the operative word here is cheaply, stupid headers start at 600 bucks, no thanks. So I'm thinking, why can't I ditch the crossover, and have the local boys at Meineke fabricate a new crossover? Two straight pipes down, and then cross-over under the vehicle rather than behind the engine. At the very least, it should make the 3.0 more efficient with cooler under hood temps, more efficient exhaust gas evacuation, and possibly extend head gasket life. Seems like a simple and cheap mod, in theory anyway.
Has anyone here done this? think its worth it?

 

[zammy]

Mikedks I'm in the same boat you are in. I was thinking of doing that to my 89 3.0. I thought it was some sort of cat so i was not going to monkey with it. I have read that the crossover is a major heat source on these motors. I'm redoing the whole system and I still need to be smog legal in Cal. I'm on a slow pace but i will let ya know what i come up with.

 

[4runner_kid]

I'm re-doing the 3.0 in my 95 4Runner and was looking at relatively cheap options to possibly gain power and efficiency. Not much to do with the engine(cheaply anyway), so I'm looking at the exhaust. Obviously the crossover is poorly designed and probably contributed to the head gasket issues on this model. Would love to put headers on, but the operative word here is cheaply, stupid headers start at 600 bucks, no thanks. So I'm thinking, why can't I ditch the crossover, and have the local boys at Meineke fabricate a new crossover? Two straight pipes down, and then cross-over under the vehicle rather than behind the engine. At the very least, it should make the 3.0 more efficient with cooler under hood temps, more efficient exhaust gas evacuation, and possibly extend head gasket life. Seems like a simple and cheap mod, in theory anyway.
Has anyone here done this? think its worth it?

It is very much worth it to give the head gasket's a little bit more life. Easiest way is to buy header's but if your in California you will not smog.

 

[niteman]

Great question. I would like to know the same. Headers are a little pricey for me too at this point. If redoing the crossover is an option, that would be a great way to go.

 

[mikedks]

Great question. I would like to know the same. Headers are a little pricey for me too at this point. If redoing the crossover is an option, that would be a great way to go.

I find it kind of odd that there has not been any feedback from someone who has done this. Just about every head gasket post for the 3.0 mentions either what a pain it is to remove the crossover, or the crossover causing the head gasket issues, I thought someone must have redone the crossover. Will probably have it towed to the local Meineke once the engine is complete.
Can't imagine it being too difficult for them to create a new pipe.

 

[Krazynative]

I find it kind of odd that there has not been any feedback from someone who has done this. Just about every head gasket post for the 3.0 mentions either what a pain it is to remove the crossover, or the crossover causing the head gasket issues, I thought someone must have redone the crossover. Will probably have it towed to the local Meineke once the engine is complete.
Can't imagine it being too difficult for them to create a new pipe.

When I put mine on it didn't get much better gas mileage. I did have better pick up and the power kicked in at lower RPM's

You could see if they can fabricate one, but I think it might be tough and maybe pricey. Might want to try and get a used set of Downeys or Thorleys.

What about having them fabricate a dual exhaust system. You could use 2 cheaper cats and this would eliminate the x-over all together..

The big difference with the Downeys from stock is there route. IIRC the stock x-over goes over the drive shaft and the Downeys go under it. This makes for more room for the Downeys x-over and doesnt cause the heat to back-up into the manifold causing the dreaded head gasket fail.

 

[gigger]

Anyone think header wrap on the crossover would work to keep some heat out of there?

 

[mikedks]

When I put mine on it didn't get much better gas mileage. I did have better pick up and the power kicked in at lower RPM's

You could see if they can fabricate one, but I think it might be tough and maybe pricey. Might want to try and get a used set of Downeys or Thorleys.

What about having them fabricate a dual exhaust system. You could use 2 cheaper cats and this would eliminate the x-over all together..

The big difference with the Downeys from stock is there route. IIRC the stock x-over goes over the drive shaft and the Downeys go under it. This makes for more room for the Downeys x-over and doesnt cause the heat to back-up into the manifold causing the dreaded head gasket fail.

I'm sure the dual exhaust method would take some serious reworking of the O2 sensors and reprogramming. I think, hell if I know.

Anyway, still haven't seen any used headers around, even still, did they even come with a crossover?. I think the only ones I saw with an actual crossover were the $900 ones from LRE(or something like that, or whatever they are called).

Still kind of leaves me at square one, not really interested in a $900 set of headers on a $1500 truck. Oh, by the way, I need a complete new exhaust system as well. I refuse to spend more on the exhaust then I bought the truck for!

Maybe I should just spend a few hundred bucks on a cheap mig welder and learn how to do it myself. May wound up ugly, and leaky, and probably won't pass inspection, but I'd have my redesigned crossover!

 

[4runner_kid]

Anyone think header wrap on the crossover would work to keep some heat out of there?

Never thought of that. I want to know the same thing.

 

[hondaracer11]

im re-doing my exhaust again lol cuz i feel like it but if your cat is good then go to autozone and pick up a thrush welded muffler (30 bucks) and have a muffler shop put it on ( mine was 200 and he did 2.5 inch piping from the cat to the back and he included a polished 3 inch tip ) for the price it sounds pretty damn good!!:drummer:

 

[Jamesd]

I find it kind of odd that there has not been any feedback from someone who has done this. Just about every head gasket post for the 3.0 mentions either what a pain it is to remove the crossover, or the crossover causing the head gasket issues, I thought someone must have redone the crossover. Will probably have it towed to the local Meineke once the engine is complete.
Can't imagine it being too difficult for them to create a new pipe.

The exhaust crossover is not what causes head gasket failures so I do not know who told you that. You can do a dual exhaust but one major issue is the driver's side exhaust manifold is where the crossover pipe runs into. You would have to weld shut that opening and run a completely new exhaust system which most likely would not be cheap unless you know someone.

James

 

[mikedks]

The exhaust crossover is not what causes head gasket failures so I do not know who told you that. You can do a dual exhaust but one major issue is the driver's side exhaust manifold is where the crossover pipe runs into. You would have to weld shut that opening and run a completely new exhaust system which most likely would not be cheap unless you know someone.

James

I have said before that I am new to Toyota's, but not to mechanical work. That being said, a minimal amount of searching on forum's(this one included) and the internet will bring an endless list of 3.0 owners with head problems. Not just the original recall head gasket issues, but burnt valves and dead cylinders. We all know Toyota had a recall, something about defective head gaskets. But I'm not so sure that is the whole story. Search for yourself and see how many 4runner owners have issues with #6 cylinder. Just so happens to be right next to the crossover. I took my heads into the machinist, and he had to replace the #6 exhaust valve, was burnt. I am a firm believer in where there is smoke there is fire. You may not want to believe there is any issue with the heads other than the gasket recall, but I on the other hand do think this is a design flaw.

Even if the crossover causes no head issues, you can't argue that the crossover is designed poorly.

 

[Jamesd]

I have said before that I am new to Toyota's, but not to mechanical work. That being said, a minimal amount of searching on forum's(this one included) and the internet will bring an endless list of 3.0 owners with head problems. Not just the original recall head gasket issues, but burnt valves and dead cylinders. We all know Toyota had a recall, something about defective head gaskets. But I'm not so sure that is the whole story. Search for yourself and see how many 4runner owners have issues with #6 cylinder. Just so happens to be right next to the crossover. I took my heads into the machinist, and he had to replace the #6 exhaust valve, was burnt. I am a firm believer in where there is smoke there is fire. You may not want to believe there is any issue with the heads other than the gasket recall, but I on the other hand do think this is a design flaw.

Even if the crossover causes no head issues, you can't argue that the crossover is designed poorly.

I know all about the head issues and I have repaired them. I owned many Toyota trucks so I very familiar with them. The 3.4 has the same style crossover as well and they run fine. Very few issues with the 3.4 heads.

James

 

[mikedks]

I know all about the head issues and I have repaired them. I owned many Toyota trucks so I very familiar with them. The 3.4 has the same style crossover as well and they run fine. Very few issues with the 3.4 heads.

James

If the crossover doesn't cause the 3.0 head issues, what does?

 

[glideraz]

If the crossover doesn't cause the 3.0 head issues, what does?

god???????????????:biggrin2:

 

[4runner_kid]

If the crossover doesn't cause the 3.0 head issues, what does?

****y design from factory.

 

[gigger]

I know all about the head issues and I have repaired them. I owned many Toyota trucks so I very familiar with them. The 3.4 has the same style crossover as well and they run fine. Very few issues with the 3.4 heads.

James

Does the 3.4 have aluminum heads on an iron block?

 

[Krazynative]

The exhaust crossover is not what causes head gasket failures so I do not know who told you that.James

It might not be the main cause of it, but it doesn't help either.

If the crossover doesn't cause the 3.0 head issues, what does?

By having that restricted portion at the x-over, the heat backs up to the main reason... The Exhaust manifold. All three cylinders dumping into one compartment so quickly/close to the head really gets it hot. IIRC when they replaced mine they told me it was a beefier gasget that would hold-up to the heat better. Not sure if that was true or not tho.

So by having Headers that have seperate paths away from the head and a bigger x-over, the heat doesn't get trapped at the head.

 

[sizematters]

crossover issue

I have come up with a way to do away with the crossover pipe. I benefited by being an inside machinist so I was able to do the work myself. What I did was made a flange just like the one on the crossover pipe that bolts to the factory exhaust manifold on the driver side I counter bored it enough the factory gasket fits in it but left the flange sold and bolted it up to seal off the opening. Then I made another flange for the passenger side. I bored a hole all the way through the center and cut a counter bore for the same gasket that you would use in the crossover pipe for the manifold. Then we modified a prebent 45 degree 2 inch exhaust pipe and had it tig welded to the flange. I trailered the truck to the muffler shop and he flared the new pipe to slide over the pipe I stubbed off the flange and ran the pipe down and through the cross member and then bent it to go to the driver side and he cut the original exhaust pipe and added a Y on the rear piece and tied the two pipes into the Y. Oh by the way I not a 4runner owner. I have a 94 Toyota 4x4 pickup with the 3vze and I was online searching for pipe with crossover problems and I seen y"all talking about it so I figured I would offer my fix.

 

[77'911]

I've looked into this a bit for our 1990 4runner, and the cost on a set of NWOR headers/cross over pipe/exhaust stud kit is $1050. This is supposed to be plug and play. Unfortunately, there are not very many proper exhaust options for these trucks.
regards