PDA

View Full Version : fj40 manifold leak. go header? fix manny?


CardinalFJ60
03-21-2012, 06:57 AM
I'm re-focusing efforts on the 40 again (still?) and have an exhaust leak I'm not too fond of. fumes me make kinda stupid late now.

the leak, I believe is coming from that thermostatically controlled spindle/rod. and it's leaking from that 'cradle' where it rotates. Is this something that can be welded up (cast is tough to weld I hear).... or since lucked out and got in under the wire with my Collector plates, should I start going down this road? (header and total desmog?) sorry for the giant pic

CardinalFJ60
03-21-2012, 07:02 AM
I know Rezarf has a header on his 2f, Subzali, do you? Anyone else with good or bad experiences? In my reading it seems hit or miss that you'll either always be plagued with exhaust leaks or it'll be nice with a full de-smog.

I picked up that header anticipating to use it on my 60 motor build, but didn't. so I have it in my garage. :D

Tommy the Cat
03-21-2012, 07:20 AM
I installed a set of headers when my manifold went south. That was at least ten years ago and I kick myself to this day every time I drive it. It takes way longer to warm up and drive decent and the coolant heaters for the bottom of the manifold are not a good solution. I haven't had any leakage problems but I don't like the sound and I'm all but certain I lost power and mileage. I had dual 2.25" exhaust run so I know it isn't being "choked". I have contemplated putting a "Y" in and running it single but always feel that if I'm going to that length I should put a manifold back on and let it work like Toyota designed it to.

But that's just my opinion.

RicardoJM
03-21-2012, 07:24 AM
I'm running a header on my F.5 and Air Randy has a header on the 2F in the Mule. My header experience has been OK. I did have an exhaust leak upon initial installation which was likely do to installer error. I then put on a REMFLEX gasket which worked great until I damaged it while tearing down for a rebuild. I'm sure it flows the exhaust better than the stock exhaust manifold, but I can't really notice a difference.

With a header, I strongly recommend a fluid heat riser:D. After installing the fluid heat riser; I have not ever vapor locked in the summer and my engine warms up much better in the winter.

rover67
03-21-2012, 08:36 AM
we could cut that thing out and weld it. then re install it with a SOR block off plate and a good OEM gasket and probably be set to go.

I'd recommend getting the intake/exhaust combo machined flat by Spitfire automotive before re installing to ensure a nice flat surface for a good seal.

I went the remflex route twice and think it's a band aid for a poorly fitting intake/exhaust that just leads to more leaks in the future.

MDH33
03-21-2012, 08:41 AM
I'm running a header on my 2F with no complaints. If you already have it, then I would say bolt it on and try it out. :thumb:

Rezarf
03-21-2012, 08:45 AM
I have the MAF 6-1 headers, never had the truck without a header so I have nothing to compare it to. I have no vapor lock, no issues starting/warming up with a little choke and gas pedal pump. It's a great place to add chrome!:) I do have a heat riser installed and I am fully desmogged.

I just put on a new one. Copper gasket sealer and a felpro gasket, sealed it up nicely.

subzali
03-21-2012, 11:35 AM
I have a little leak from that same location as well, but don't think it fumes me out in any way. Some day I want to tear that all apart again and take a good look at it; it seems that a metal bushing could be pressed in there to seal that up better. If you're going to keep your stock manifold you need to be sure that that assembly is working properly or you'll crack the bottom of your intake manifold. So do not just weld it up without having a provision for the plate to rotate.

On headers, not all headers are created equal. There is the common 6-1 header, which I think just about everyone here in RS has who has a header (including the one in your picture). There is also the Downey Tri-Y 3-2-1 header, which some claim (Marks Offroad for example) flow better than the 6-1. Finally there is the tuned header like MAF and SOR sell, which suppposedly are the best designed for flow and optimized for the engine performance. They are also (surprise surprise) the most expensive. The cool thing I personally like about the MAF design is that it has an EGR port so you can have a header and lose very little of your emissions components (The HAI and intake pre-heater being the only two exceptions I can think of right now), if you need to keep them. You can read more on the MAF website and marksoffroad.net website about headers, some pretty good info there.

I'm running the stock manifold still, and Ricardo and I have yet to race and see who wins!

On desmogging, I'm not sure what I gained by desmogging except for extra room in the engine bay. There seems to be no power difference for me. I do think, however, that I can attribute my very stinky exhaust to the desmog. Once I get all my smog components back together I'm going to throw it all back on and see if that's true. The other reason is that some "features" of the smog equipment is gone if you desmog. For instance, the throttle positioner is gone. Not a big deal, but with sloppy/worn drivetrain components, a worn engine, and a Lockrite in the back, it would be nice if the throttle wasn't so on-off like it is now without the VSV installed that controls that diaphragm. Just little things to think about.

IF YOU DO GO THE DESMOG ROUTE, KEEP EVERYTHING

You never know when the laws may change to disallow grandfathering, or change the cutoff dates, or you may move and will not be able to register your 40 at your new place without getting it back on the smog program. Just box it all up and store it in the attic. This stuff is very hard to find these days. 1977 seems particularly hard to find for some reason.

I have no doubt that headers help with exhaust flow and open things up a bit, but if you're always shifting early and keeping your rpm's low I doubt you'll ever notice. If you do go headers, definitely get a heat riser built or bought.

CardinalFJ60
03-21-2012, 12:38 PM
Hmmm...based on this feedback, I think I need to bribe Marco to allow me to come over to his pad for a "good Lookin' at". As far as the fumes in the cab go...maybe they are migrating from other not-so-sealed up places. I do know the manifold is leaking at that spot Subzali also described.

Like most things at this level, nothing is as easy as "remove and replace". If I can easily get that leak repaired with everything still on the truck that's great. doubtful, but would be great. the reality is that I have that header, and if everyone said DO IT!!!! it's a no brainer. I think I need to determine the root issue - I don't think there are any performance gains that would coerce me to go for it.

I wouldn't mind freeing up some space under the hood to put a PS pump (instead of an smog pump). Decisions, decisions...Oh...and money, money. :rolleyes:

subzali
03-21-2012, 01:07 PM
Keep your smog pump and get a JT Outfitters bracket for a Saginaw power steering pump. Or coerce CCOT to sell you their brackets to mount an OEM pump above the smog pump ;).

rover67
03-21-2012, 02:03 PM
no bribes necessary..

Air Randy
03-21-2012, 07:46 PM
I installed my header, along with the liquid heat riser and it works great. If you install a header and don't get even small power gains and you lose MPG, then it's because you didn't re-jet the carb after installing the header.

I also didn't have to go to any extremes to get my header to seal up without leaks. Just used a standard gasket and made sure I torqued it up evenly then hit it again when it was really hot.

It's a matter of personal choice, especially since you already have the header. Pull off the manifold and give the header a try. While you're doing that, get the manifold fixed, that way you can always swap back if you want.

CardinalFJ60
03-23-2012, 03:13 PM
I think I'll take the plunge and get rid of all the smog stuff and Header-it. So for now, I'll be getting ready for CM12 and research fluid heat risers and the right gasket as well as how to set the carb and dizzy.

:cheers:

Air Randy
03-24-2012, 07:43 AM
The liquid heat riser is a must have with a header IMHO. It will make it warm up nicely when it's cold and keep it from vapor locking when it's hot. You can buy one as a kit or you can make your own. You just need a square piece of thick plate (the kit ones are aluminum but steel would work if you powder coat it) drill 4 bolt holes to match the bottom of the intake then drill & tap 2 holes that you screw 90* right angle fittings into. These are for the in-out flow of coolant. Make sure you put an air bleed into the heater hose at the highest point near the firewall and you're ready to go.

MDH33
03-24-2012, 08:01 AM
The liquid heat riser is a must have with a header IMHO. It will make it warm up nicely when it's cold and keep it from vapor locking when it's hot.

Randy, I'm not running a liquid heat riser with my header. I've never had a problem with cold starts BUT I've had several instances of bad vapor lock when hot. How does the heat riser prevent it? Think I might try adding one if it will help with the vapor lock issue.

RicardoJM
03-24-2012, 08:17 AM
The heat riser passes coolant right under the intake manifold and moderates the temperature of the intake manifold and carb. It really is functionally the same purpose as the flap in the OEM exhaust manifold; at cold temps send additional heat to the intake/carb and at hot temps keep additional heat from the intake/carb - it just does this using the engines cooling system.

With a hot truck, the coolant draws heat from the intake manifold and carb which helps keep the fuel from turning to vapor. I had vapor lock on the 40s only run when I was not using the fluid heat riser, since installing it I have not had a any vapor lock.

With cold starts, as the coolant warms up, the heat is transferred to the intake manifold and carb which helps the fuel and air atomize more effectively. Cold fuel does not like to mix with air as well as warm fuel.

MDH33
03-24-2012, 09:30 AM
Thanks for the explanation Ricardo. Makes sense. :thumb: Now I need to look at my manifold and figure out what I need.

Tommy the Cat
03-24-2012, 10:13 AM
You're partially correct and definitely on the right track. However what is happening when the manifold is cold is the fuel is atomized as it is pulled from the carburetor by the air passing through but when it gets to the cold intake manifold and has to do a 90 degree turn it slams into the manifold and condenses from the cold and puddles up there.

The exhaust manifold is far more effective at combating this because it heats the intake much faster than waiting for water to heat up while the pooled up fuel hurts your emissions and sneaks past your rings when it gets to the combustion in liquid form thereby washing oil off the cylinder walls and contaminating the oil in the crankcase.

Vapor locking, by definition, does not occur to cold fuel. It is a result of hot fuel boiling and turning to "vapor". I'm not sure what you are experiencing when your truck is cold but it is not vapor lock. Perhaps you are experiencing an overly rich mixture caused by what I explained before.

If you simply must use a header (like I did before I knew better) the liquid heaters are better than nothing but it will never be as effective as a manifold and you WILL see increased wear from the overly rich condition before the water gets warm enough to have an effect. It may be academic but a fact just the same.

Carry on

Air Randy
03-24-2012, 02:04 PM
The exhaust manifold is far more effective at combating this because it heats the intake much faster than waiting for water to heat up while the pooled up fuel hurts your emissions and sneaks past your rings when it gets to the combustion in liquid form thereby washing oil off the cylinder walls and contaminating the oil in the crankcase.

Vapor locking, by definition, does not occur to cold fuel. It is a result of hot fuel boiling and turning to "vapor". I'm not sure what you are experiencing when your truck is cold but it is not vapor lock. Perhaps you are experiencing an overly rich mixture caused by what I explained before.

If you simply must use a header (like I did before I knew better) the liquid heaters are better than nothing but it will never be as effective as a manifold and you WILL see increased wear from the overly rich condition before the water gets warm enough to have an effect. It may be academic but a fact just the same.

Sorry, but I don't agree with you. First off, every carbed V8 engine in the world relies on either the water heating up or thermal transmission via the metal to metal contact with the cylinder heads to warm up. They have many more intake runners and bends than a 2F does. They have no more issue with emissions or cylinder scoring from wash down than any other engine. Very few engines have the exhaust manifold bolted directly under the intake & carb.

Also, even if you do get a miniscule amount of liquid fuel in a cylinder, it only lasts until the first time that cylinder ignites. Any that does get into the oil usually evaporates out of the oil and is ingested into the intake via the crankcase vent valve. I routinely do oil testing via Blackstone on my 2F with a header and my fuel content in the oil is always less tha 1%, up to 3% is acceptable.

Ricardo is not saying his truck vapor locks when it's cold. He is saying that by having the liquid heat riser wick the heat away from the bottom of the intak/carb, it prevents it from ever getting hot enough to boil and cause vapor lock.

Tommy the Cat
03-24-2012, 03:46 PM
I mean no disrespect, however some of the stuff reported here has some flaws.

A V8 engine, with a few exceptions (Ford FE comes to mind) do not have a sharp 90 degree bend before the valve such as the 2F. And you forget the exhaust crossover on most factory intake manifolds whose job it was to heat the intake. Not to mention the hot oil that splashes the underside of a lot of V configuration engines. I never stated the fluid heat riser didn't work, I stated it is less efficient (slower) than the factory exhaust manifold. It is a band-aid. I have used them and yes they are better than nothing but they are less than ideal. However the 2F was not designed to be pinnacle of automotive engineering and comes with MANY inherent flaws, the intake arrangement being just one of them.

Also, liquid gas isn't ignitable by spark. It must be converted to vapor or atomized. That is the function of the carburetor. If you doubt that then refrigerate some gas in a cup so that it is not giving off vapor and throw a match at it. Yes you can put a match out in liquid gasoline. It must be properly atomized to burn correctly. If liquid fuel makes it to the combustion chamber it will not be burn correctly and has the potential to wash the oil off the cylinder walls and contaminate the oil in the crankcase. I also stated that the amount may be academic and it depends on the condition of the rings. When enough liquid gas makes it to the cylinder to wash oil off the walls it will increase the wear. Again, this may be academic.

I did misread what MDH33 stated about vapor locking while cold. I read it too fast. My apologies.

MDH33
03-25-2012, 11:23 AM
All good info guys. I fixed my post, the wording was confusing.

Also, I am going to look into a stock 2F exhaust manifold. After thinking about it, I remembered I was going to pull the header off because it interferes with the PTO driveline. The stock manifold will allow it to clear and hopefully correct my vapor lock problem too.

Sorry for the thread hijack Shawn.

:wrench::thumb:

Air Randy
03-27-2012, 03:49 PM
I mean no disrespect, however some of the stuff reported here has some flaws.

A V8 engine, with a few exceptions (Ford FE comes to mind) do not have a sharp 90 degree bend before the valve such as the 2F. And you forget the exhaust crossover on most factory intake manifolds whose job it was to heat the intake. Not to mention the hot oil that splashes the underside of a lot of V configuration engines. I never stated the fluid heat riser didn't work, I stated it is less efficient (slower) than the factory exhaust manifold. It is a band-aid. I have used them and yes they are better than nothing but they are less than ideal. However the 2F was not designed to be pinnacle of automotive engineering and comes with MANY inherent flaws, the intake arrangement being just one of them.

Also, liquid gas isn't ignitable by spark. It must be converted to vapor or atomized. That is the function of the carburetor. If you doubt that then refrigerate some gas in a cup so that it is not giving off vapor and throw a match at it. Yes you can put a match out in liquid gasoline. It must be properly atomized to burn correctly. If liquid fuel makes it to the combustion chamber it will not be burn correctly and has the potential to wash the oil off the cylinder walls and contaminate the oil in the crankcase. I also stated that the amount may be academic and it depends on the condition of the rings. When enough liquid gas makes it to the cylinder to wash oil off the walls it will increase the wear. Again, this may be academic.

I did misread what MDH33 stated about vapor locking while cold. I read it too fast. My apologies.

No one takes any of this personal, it's just an interesting discussion.:thumb:

I have to take exception to some of your theories. First, if the incoming fuel/air charge was hot and the intake manifold was cold I might accept the condensation theory. Problem is, when the engine is cold everything from the carb to the engine block is the same temp, so not much chance of condensation. As the engine warms up the internal parts will be warmer than the incoming fuel/air charge so again no chance for condensation.

My understanding of why engines start harder and don't run as well when cold is because the cold air is denser and thus has a higher oxygen content. That makes the fuel/air charge too lean to run properly. Thats why on carbed engines the choke closes and richens the mixture to compensate for the dense air. Once the engine warms up (and in the process warms up the incoming fuel/air charge) the choke opens. Even on MPI injected engines the ECM adds more fuel when cold starting. Some of the Toyota's even have dedicated special injectors that operate only on cold starts.

If your condensation to liquid theory was correct, richening the mixture via choke or injector would make the problem worse and potentially flood the cylinders. Then the engine wouldn't start at all.

Contrary to your claim there are few engines I'm familiar with that have exhaust gas routed through the intake manifold. However virtually every engine other than some of the old straight sixes have coolant passages through the intake manifolds, so the OEM designers were concerned with warming the instakes up but also maintaining controlled temps.

You may get some oil splash on the manifold base on V8's but it's minimal, the older engines have valley plates to minimize that splash and most of the new engines don't even have open lifter gallies. besides the oil only heats up a little faster than the coolant does. The heat in the combustion chambers will have much more impact on engine warming than lifter galley splash.

I would also add that most of these 35-40 year old exhaust manifolds are so rusted the heat risers stopped working long ago. They're either stuck partially closed and robbing power or stuck wide open and making no contribution to warm up. Not to mention that the cast iron manifolds are prone to cracking and they contribute to vapor lock in the summer because they don't dissipate heat as quickly as the headers do. Oh, and it's a common problem on F/2F engines to develop a vacuum leak via cracks in the bottom of the intake manifold that are caused by the severe heat cycling that occurs over time with the exhaust manifold bolted to the bottom of the intake.

Don't get me wrong, I am not saying a header is the panacea answer to everything. Headers can crack too and you have to be precise with how you install them to make sure you don't get exhaust leaks.

But I do believe if you install a header correctly, then properly re-jet your carb to compensate for it, you will see a small increase in performance, throttle response and fuel efficiency. In some engines headers can add 10%-15% improvement in those areas. In the F/2F it is a much smaller gain, maybe 2%-3% at best. If you add a liquid heat riser with a properly functioning choke you won't have any issues in cold weather and I believe your chances of suffering vapor lock in the summer is lessened.

My summary would be, if your existing exhaust manifold is not cracked and you're happy with the way your engine runs, don't touch it. I certainly wouldn't spend the money to add a header just for the performance gains if everything else is ok. But, if you have to replace your exhaust manifold anyways because it is broken, a header is a viable option. Cast iron manifolds in good shape are getting harder to come by too. There are trade-offs for any changes you make.

nakman
03-28-2012, 01:32 PM
Wow, cool thread.. thanks, guys! :beer:

Tommy the Cat
03-28-2012, 06:17 PM
I have to take exception to some of your theories. First, if the incoming fuel/air charge was hot and the intake manifold was cold I might accept the condensation theory. Problem is, when the engine is cold everything from the carb to the engine block is the same temp, so not much chance of condensation. As the engine warms up the internal parts will be warmer than the incoming fuel/air charge so again no chance for condensation.

This is not theory, it is fact. Cold gas resists atomization and can fall out of suspension easily if the much lighter air makes an abrupt change in direction as it does after it travels through the carburetor and makes the 90 degree turn in the manifold. Compounding it further is the cold intake manifold that then causes it to pool, much like a cold glass of iced tea in the summer. Of course not all of the fuel falls out of suspension or the engine would not run but enough to warrant the use of exhaust as a heater until convection takes over. You may do your own research and you will come to the same conclusion.



My understanding of why engines start harder and don't run as well when cold is because the cold air is denser and thus has a higher oxygen content. That makes the fuel/air charge too lean to run properly. Thats why on carbed engines the choke closes and richens the mixture to compensate for the dense air. Once the engine warms up (and in the process warms up the incoming fuel/air charge) the choke opens. Even on MPI injected engines the ECM adds more fuel when cold starting. Some of the Toyota's even have dedicated special injectors that operate only on cold starts.

If your condensation to liquid theory was correct, richening the mixture via choke or injector would make the problem worse and potentially flood the cylinders. Then the engine wouldn't start at all.

Your understanding is on the right track, however incomplete. The cold air is indeed denser and so is the fuel. I have stated the fact that cold fuel resists atomization and does so to a point that it is necessary to add more to keep enough in suspension (because gas must be atomized or a vapor to burn). So you are correct that the mixture must be enriched but it has more to with the gas' resistance to atomization than with the density of the air. The Toyota cold start injectors work for a very brief moment during start up and the injectors working in open loop take over from there. An injector mounted as close to the valve as possible and cold gas being drawn from a carburetor, changing direction several times before arriving at it's destination have very little in common. We can clearly see why fuel injection operates much more efficiently at cold engine temperatures.



Contrary to your claim there are few engines I'm familiar with that have exhaust gas routed through the intake manifold. However virtually every engine other than some of the old straight sixes have coolant passages through the intake manifolds, so the OEM designers were concerned with warming the instakes up but also maintaining controlled temps.

To the best of my knowledge all Chevy carbureted V8s had exhaust crossovers in the intake. I know that Ford and Dodge also employed exhaust crossovers on most, if not all, of their carbureted V8s as well. Fuel injection changed all of that, though. Perhaps you are more familiar with the modern stuff.



You may get some oil splash on the manifold base on V8's but it's minimal, the older engines have valley plates to minimize that splash and most of the new engines don't even have open lifter gallies. besides the oil only heats up a little faster than the coolant does. The heat in the combustion chambers will have much more impact on engine warming than lifter galley splash.

The amount of oil splash is rather minimal but enough of a concern that drag racers have been using shields under the intake for decades and that spawned the invention of Air-Gap intakes. It has little or no impact on the warming up period but a measurable amount on the density of the intake charge on a warmed up engine. Agreed, a moot point in this discussion.



I would also add that most of these 35-40 year old exhaust manifolds are so rusted the heat risers stopped working long ago. They're either stuck partially closed and robbing power or stuck wide open and making no contribution to warm up. Not to mention that the cast iron manifolds are prone to cracking and they contribute to vapor lock in the summer because they don't dissipate heat as quickly as the headers do. Oh, and it's a common problem on F/2F engines to develop a vacuum leak via cracks in the bottom of the intake manifold that are caused by the severe heat cycling that occurs over time with the exhaust manifold bolted to the bottom of the intake.

Don't get me wrong, I am not saying a header is the panacea answer to everything. Headers can crack too and you have to be precise with how you install them to make sure you don't get exhaust leaks.

But I do believe if you install a header correctly, then properly re-jet your carb to compensate for it, you will see a small increase in performance, throttle response and fuel efficiency. In some engines headers can add 10%-15% improvement in those areas. In the F/2F it is a much smaller gain, maybe 2%-3% at best. If you add a liquid heat riser with a properly functioning choke you won't have any issues in cold weather and I believe your chances of suffering vapor lock in the summer is lessened.

My summary would be, if your existing exhaust manifold is not cracked and you're happy with the way your engine runs, don't touch it. I certainly wouldn't spend the money to add a header just for the performance gains if everything else is ok. But, if you have to replace your exhaust manifold anyways because it is broken, a header is a viable option. Cast iron manifolds in good shape are getting harder to come by too. There are trade-offs for any changes you make.

I agree with everything you said there. But without a doubt, a properly functioning exhaust manifold will heat the intake quicker and thus be more efficient through the warming cycle. It may not be financially viable to most and perhaps not even possible as usable parts dwindle. It is my preference to use a manifold whenever possible.

subzali
03-28-2012, 06:24 PM
I think conventional Land Cruiser wisdom says that the cracks in the intake manifold are due to the exhaust recirculation plate getting stuck in the closed or slightly closed position, which constantly redirects air upwards against the bottom of the intake manifold, overheating it, and cracking it. I could see that the CTE differential in the cast iron and aluminum could contribute to that though with thermal cycling. Haven't heard of a cracked intake on an engine that had a properly working exhaust recirculation plate in the exhaust manifold though.

Air Randy
03-28-2012, 07:13 PM
I think conventional Land Cruiser wisdom says that the cracks in the intake manifold are due to the exhaust recirculation plate getting stuck in the closed or slightly closed position, which constantly redirects air upwards against the bottom of the intake manifold, overheating it, and cracking it. I could see that the CTE differential in the cast iron and aluminum could contribute to that though with thermal cycling. Haven't heard of a cracked intake on an engine that had a properly working exhaust recirculation plate in the exhaust manifold though.

Agreed. But how many of these 30 - 50 year old rigs have properly functioning recirculating plates?

rover67
03-28-2012, 08:43 PM
Yeah, cooler intakes don't let the fuel atomize as well. Tommy's analogy of the iced tea glass is a good one. the fuel sticks to the intake rather than remaining in suspension when it's all cold. choking the motor just adds more fuel so at least some will be held in suspension in the intake charge and burn. exhaust heating the manifold shortens the amount of time you gotta run it richer to keep it going. A water heated manifold won't heat up as fast.

None of that is quite as bad with fuel injection where an injector is squirting directly into a port in the head.

Did they route water through the intakes to keep the intake charge warm/hot to reduce emissions once up and running? I kinda thought that's what that was for.

the recirc plates do work, but yeah, most are dead now. Adding the block off plate between the intake and exhaust still preserves some of the exhaust heating and dosen't allow a blow torch effect on the bottom of the manifold.

CardinalFJ60
06-08-2012, 04:31 PM
so....I'm about to start ordering the stuff I need for the Header project.

1. MAF has a fluid heat riser, do you recommend any other vendors for something like this? Just thought I'd ask. I've had fine luck with them and their products.

2. What the best gasket to get? Remflex?

3. what else do I need to consider for de-smog? (yes, I have the good plates). I'm WAAAAAY over my head on that.

thanks! Hmmm......maybe Outlaws in the 40 this year??

:thumb: