I have a exhaust manifold leak on one side of my engine (can hear it). I decided to take the manifolds off to: Sandblast Metalize Port (how?) I have several questions. I would like to sand/plane the surface of the manifold to a true "flat plane"to make sure there are no leaks when i set the manifold back. But it seems that the exhaust ports are not all on the same plane (see pic). Am i wrong ? or should i assume that i can just sand the manifolds on a true flat surface to make sure they fit on the block perfectly ? Other question how do i match the ports ? If i put the manifold on the engine i have no access or visual access to the matching of the ports ! How do you guys do it without removing the head ? Last question: On the passenger side the manifold has two holes (see pic). One has a brass nipple. I assume this is for the heat tube going to the carb (I have a tube but its aftermarket and hooks up to a box tied to the manifold). There is also a small hole in the center of the manifold. What is that for ? Should I close it off ? Should I also block the brass nipple outlet ? Roland
By the way i plan to eliminate the exhaust valve thingy that is stuck (passenger side). I assume I can just cut it out and close off the 2 holes left by the shaft.
Hi, To get the manifold leak free you might be able to clean off any gasket material and then put a light coat (like a smear of your finger) of high heat copper silicone (its designed for exhaust manifolds) on the mating surfaces, or you can go the exhaust manifold gasket route ,but I have had success with just the high heat copper silicone and is cheaper and more available than waiting on gaskets to get shipped (as from the factory they did not have gaskets just metal to metal) either route make sure you get any old manifold gasket material removed. Regards,
Thanks How tight should I torque the bolts down ? i have new stainless steel bolts (part of a kit I used). Should I use them or stick to the steel stuff that was on the car ?
Certainly no expert on this but I used stainless bolts and anti seize lubricant with my exhaust manifolds and they always seem to be backing out just a bit. Need to re-tighten them at least once a season. I'd stick with regular steel. Here's a link to torque specs http://www.v8buick.com/showthread.php?240635-401-buick-nailhead-engine-torque-spec
Planed by a machine shop instead of gaskets or goo. Keep in mind that virtually all stainless steel bolts are about as strong as hardened peanut butter. About the same as "Grade 2" hardware store junk. If the bolts seem to be loosening all the time, I'd pull one out for inspection--I bet it's necked-down from stretching.
You can either have a machine shop resurface them for you or do like I do,,, I have a BIG flat file that i use and then check them in the middle with a straight edge....untill I get them flat..... then sandblast them and then port match them and the heads,,,,by taking a set of exhaust manifold gaskets and using the gaskets as a template to outline the ports on the heads and the manifolds.... then grind the ports to the scribed lines,,, next drive a nail into the wall and hang the gaskets on the nail for use the next time....DONT PUT THEM ON YOUR ENGINE...:Brow: next, chase the threads in the heads and buff the bolts and coat the the bolt threads with anti seize compound.... reinstall the manifolds after,, you coat them with what ever coating you want on them.... When you install the manifolds ,,get all the bolts started ,, then,, tighten them by hand, starting in the middle and working to both ends... tork them the same way... middle to both ends.....WITHOUT GASKETS,,,,and ,,, if you did it all right , you will have zero exhaust leaks....:Brow:
The stainless facts https://www.kimballmidwest.com/cata...r Primer - Stainless Steel By Guy Avellon.pdf W
No,,,, RJ,,,, the heads are big enough that they do not warp with time and usage...besides the water jackets keep them cool.....Just clean them good before you put the manifolds back on..... the exhaust manifold gaskets are directional,, so be sure you have them lined up the same way before you start marking and cutting......
X2 - I am always suprised when folks buy a stainless kit off ebay and wonder why the bolts break. Of course it always depends on what you are buying. ARP sells grade 8 SS bolts: "A face centered cubic arrangement of atoms Stainless Steel 300 series is not heat-treatable. But heavy reduction (power dumping), in the cross section, during forging causes a dramatic increase in strength. This is the process ARP uses to make 304 Stainless Steel reach 170,000 psi UTS." - Bill
The tube in the exhaust manifold supplies hot air to the choke. The choke has a vacuum passage in it, so it pulls air thru the tube from the exhaust manifold. The other end of the exhaust manifold tube (in the rear) should be connected via another steel tube that goes to the very top of the carb....that ensures that only clean, filtered air gets heated and passed to the choke.
Hum...... i'm a little confused. Not sure I quite understand everything. Here are two pics with some questions on it. I assume the brass nipple should connect directly to the choke air tube. But then it will in time clog it up with exhaust dust and stuff I assume. So are you saying a first tube goes from the brass nipple to somewhere and then a second tube goes to the choke on the carb ? How are they linked ? Is my set up (with tin box held on manifold) stock or an aftermarket add on ?
from the factory , there was a tube in the manifold and a smaller tube inside of that tube....the smaller tube goes up to the carb choke nipple......
What a UTS you ask ? [video=youtube;HVjbf-dHjW0]http://www.youtube.com/watch?v=HVjbf-dHjW0[/video] Sorry --- just a bit of humor I couldn't resist. Carry on ou:
The tube in the exhaust manifold.... it goes THROUGH the manifold, it will not have exhaust gas in it. It's purpose is for clean air to enter the rear of the tube, get heated by exhaust AROUND the tube, and supply that heated air to the choke on the carb. The housing/cover on your manifold looks like an aftermarket repair kit. It'll work, but it may suck in some dirt which will find it's way to the vacuum passage in the carbs choke housing, and clog it. The original design would draw filtered air in from the tube connected at the top of the carb. If you have a Buick Chassis manual, it may have some pictures.
