popping through the exhaust at 4500 rpm or so.. HELP!

[Zedyone_kenobi]

I used the thinnest layer of RTV possible on that when I put it on as I was not sure what L6 engines like in this department. I am a pretty big advocate of letting gaskets do their job and seal. I was planning on putting the gasket on dry, but some have recommended using ultra copper. I have used ultra copper on V8 head gaskets before, but never on an intake or exhaust gasket.

I am waiting on my 6 new super thick washers for the bottom of the manifold where it holds the exhaust and intake at the same time. I 2nd day aired them. I may as well make some improvements while I am at it.

sorry for my slow progress. I am also trying to move my sick dad in with me, sell his house, and get his accounts in order.

But nobody wants more closure on this than me!

Edited January 24, 2012 by Zedyone_kenobi

[Captain Obvious]

Could you please speed up the process a little-we need some closure here:)

Haha! x3!

As for the RTV issue... I know that gaskets are supposed to seal all by themselves, but even with surfaces surgically clean, I've not had a perfect record of success in the past. My current philosophy on the topic is to think about a bunch of questions:

Is it a "maintenance required" area like a valve cover?

How much of a pain is it to do the gasket again if there's a problem?

How much of a mess is it going to make if it starts to seep?

Have you had trouble with it sealing in the past?

If the job is a royal pain in the arse and I'm pretty sure that I'll never need to go in again, I'll use RTV. Especially if it's bathed in oil and going to make a mess if it seeps. Things like oil pans, timing covers, input snouts on the transmissions fit this category.

If the job is relatively easy and history shows I'm likely be in there again, I won't use it. Carbs and valve covers fit into this category.

Intake manifold? How many miles on the motor, and do you think you'll need to be in there again soon?

Which RTV to use? I used to use almost exclusively the Permatex Ultra Copper stuff because of the higher temperature rating, however, a few years ago I switched over to mostly the Permatex Gray stuff instead. I've found the gray to have much better adhesion and better resistance to oil creep past the joint over time. Also, the gray has a significantly higher durometer (hardness) once cured and better for gasket squirm.

I don't have the packages in front of me, but as I remember, the temperature ratings of the two weren't that far apart. Maybe 100 degrees or so? I still use the copper if I'm really concerned about the temp.

Remember though... YMMV! :classic:

One last thing about the RTV's. It's a pet peeve, but I hate seeing big ol' squeezed out beads of sealant from using way too much of the stuff. Remember that if you see a big bead hanging out on the outside, then you've probably got one on the inside as well.

I put it on with a syringe. Fill the syringe from the tube and then do the application with a small orifice and use a tiny bead of the stuff. I consider is success when I can juuusst barely see any sealant squeezing out of the joint in most spots, and maybe none of it squeezed out all in a few. Think about where you need to seal and where you don't. You don't need to seal the mounting studs to atmosphere. You do need to seal the intake holes to everything. Only put it around where you need it.

[madkaw]

My comment on sealer was more based on the fact that you be using a gasket that has a graphite layer to help seal. The sealant probably won't even stick to that gasket.

As far as my closure comment--all in good fun and I would be as meticulous as you

[Zedyone_kenobi]

NO worries man. I got the intake on last night, but I am waiting for some new bolts for my valve cover. But if they do not come in today, I will just use the old ones and fire her up to see if it was a manifold gasket. My carb insulator have not arrived from Courtesy Nissan yet, but they are the last thing in the area of interest.

[steve91tt]

Watch out for RTV on the gasket around the intake ports. Gasoline can destroy RTV. In a wet, carbureted intake such as ours raw gas can find its way onto the edge of the gasket, eat away at the RTV and cause a leak. I caused a vacuum leak myself last year by putting RTV on my intake gasket. Lesson learned, now I always install them dry with only a little high temp RTV around the exhaust ports.

[Zedyone_kenobi]

I put it on dry. That is my usual mode of operations. It is like what I told my buddies in my small block chevy days who did not use gaskets at all in favor of silicone around the ends of the intake manifold.

Chevy spent millions of dollars engineering the small block chevy to work with the gaskets designed for the engine. Do not think you can outsmart them.

[Zedyone_kenobi]

Well new intake gasket made the car start super quick and was able to idle while stone cold with zero choke! Just like it use to. Ah haaaa. This has to be good!

But initial drive shows same behavior as before but not as noticeable and higher up in the rpm. I need more time to recharacterize it. I had to rush my dad to the hospital last night do I will report back after his health improves or at least stabilizes

My idle quality has improved as has cold start so the gasket was a contributor! Good call guys. I have ready to go on two new carb insulators so those will be next

[Zedyone_kenobi]

While installing the new carb spacers (which I am sure was a complete waste of time), I had a brainstorm. If this does not fix it then where else could air be getting into the system? I did notice my intake valve was a little sludged up on the top. It is perfectly believable that the valve guides are a bit worn or the valve seals could be bad. That would allow air in from the valve cover region during high vacuum situations.

Not sure how to check the health of valve seals, but I am going to dive into the FSM today to check. My compression check sheds no light on the subject at all as that is only a test of rings and valve seats

[Travel'n Man]

Could the balance tube not be doing it's job? When I was running SU's I had taken mine out and inspected - it's couldn't hurt at this time.......offer still stands on the previous post I had a few pages back if it could help eliminate things................

[Zedyone_kenobi]

Well if the carb insulators do not fix it then I wil gladly take you up on your offer. But there is no need to ship the whole manifold, just carbs.

I would have pulled the balance tube off and inspected it but I was worried I could not find replacement gaskets

[madkaw]

So was there any impact on your AFR numbers?

Gaskets could easily be made, just go buy some gasket material.

I have still not read anywhere that it was verified that the fuel level was visible in the jets after removing the piston. It should be right there at the top.

[Zedyone_kenobi]

I thought the level was suppose to be about 10mm down from the top

My fuel level is exactly where the FSM says it should be