On my cmc speedster I am going to remove my dual port intake manifolds to check for vacuum leaks. What are the steps to remove the manifolds without dropping the engine? Are there any tin pieces that can easily be removed to gain access? Finally, gaining the easiest access to the manifold nuts should I work from above or jack up the car and work under the engine?
this is from my ongoing saga of idle not dropping rpms.
Thank you,
Renfrance
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What you need is a 1/4” drive u-joint or one of these.
and a thin wall, 12mm deep socket (and hope the PO used the proper 12mm nuts rather than the more common 13mm ones.)
$9.95 3/8” and 1/4” combo on Amazon.
NEIKO 00239A Flexible Extension Bar Set | 2 Piece | 1/4" x 6" & 3/8" x 8” https://www.amazon.com/dp/B001...oding=UTF8&psc=1
I would disconnect the cable from the carb first to make sure the carb isn't hanging up somewhere and lube all moving linkage. If the idle drops while woking it by hand then you have a problem with the cable or foot pedal. If it still doesn't drop then you can check it for a vacuum leak by get the motor to idle while spraying carb cleaner, brake clean or starting fluid at the manifold and see if the motor rev's while spraying. If it does rise you then have a leak. If not you have a bind in the cable or pedal. Pulling the engine is not as hard as you think. You will have a harder time trying to remove the manifold while it is in the car. Once you drop the motor you can leave it on the jack and get to the manifold easier. Make sure to check both sides for the leaks before you start to remove the engine.
Good luck
@Butcher Boy posted:I would disconnect the cable from the carb first to make sure the carb isn't hanging up somewhere and lube all moving linkage. If the idle drops while woking it by hand then you have a problem with the cable or foot pedal. If it still doesn't drop then you can check it for a vacuum leak by get the motor to idle while spraying carb cleaner, brake clean or starting fluid at the manifold and see if the motor rev's while spraying. If it does rise you then have a leak. If not you have a bind in the cable or pedal. Pulling the engine is not as hard as you think. You will have a harder time trying to remove the manifold while it is in the car. Once you drop the motor you can leave it on the jack and get to the manifold easier. Make sure to check both sides for the leaks before you start to remove the engine.
Good luck
His problem has already been diagnosed: idle was set high at 1200 and distributor was advancing. Idle was set high because he's not running on all 4 cylinders. Which is why he's been advised to remove the manifold to check for an intake leak.
Manifolds can be held on by 13mm, 12mm, 11mm, or 10mm nut size. They are all used and all available. On the motor I just built, I used JayCee, they are stainless flanged nuts with a 10mm wrench size.
@DannyP posted:Manifolds can be held on by 13mm, 12mm, 11mm, or 10mm nut size. They are all used and all available.
... there are also 3/8 head flange nuts, just to really complicate things.
To answer all the questions, in order:
Q: "What are the steps to remove the manifolds without dropping the engine?" A: There are no real tricks. While you are doing this, you'll look to passers by as if you're having a torrid love affair with your car. Mothers will shield the eyes of the innocents as you hump the back end. You will enjoy the whole thing significantly less than other people will think you are. You'll personally feel like you are standing on your head in the engine compartment, but without the aid of your hands. Hopefully you're small, and double jointed. Remove your belt before you start, and wear pants without a button or snap - or just go ahead and scratch the back fenders with an awl to get the whole thing out of the way ahead of time.
Q: "Are there any tin pieces that can easily be removed to gain access?" A: Sadly, no - but wouldn't that be cool?
Q: "Finally, gaining the easiest access to the manifold nuts should I work from above or jack up the car and work under the engine?" A: it's your call, but working from above is how everybody does it. To work from the underside you'll need to jack up the car, take off the wheels, get everything out of the way (exhaust, etc.), take off the surround tin, and see if it's any better than making love to your car from the top side. You may have better luck down there. At a minimum, you'll waste a half-hour figuring out it's no better.
To answer the questions you didn't ask:
Put a wadded up paper towel sheet in each manifold throat before you start anything. Don't let stuff fall down into the engine. You can thank me now or later. I accept PayPal.
Make sure you don't lose the (aforementioned randomly sized) nuts as you take them off. It's ridiculously easy to do. If they drop down, you'll lose them in the tin or fins of the head and forever worry that you dropped them down the ports. This is all part of the fun.
Once you pull the manifolds off, you won't be able to reuse the gaskets. It's very likely that some will stick to the head, and some to the manifolds. As soon as you get it off and take the pictures, stuff wadded up paper towels into the intake ports on the heads. You'll need to scrape the gasket material off the head and you don't want that stuff falling into the ports. You'll think (or say) bad words about the guy who decided that studs were a better idea than bolts when you are trying to clean the gasket material off the heads around the aforementioned studs. This is normal.
Scrape the gaskets off, but don't scratch the soft material of the heads or manifolds. Once you have them both clean, you'll want to make sure the manifold sealing surface is flat. Get a sheet of 220 grit wet-or dry and put it on flat surface, gritty side up. Sand the manifold sealing surface in a figure 8 until you see sanding marks across the entire surface.
You'll need to cut new gaskets because the stock ones are too small for modified heads. I've got a secret way to do this, but you'll likely have a few (many?) posts between now and then, and I'll catch you when you're ready.
You'll likely hate yourself by the time you get to this point. You may wish your father had never met your mother, and that they'd never gone for that ice cream cone back in the day. You'll question your worth as a human, your vehicular proclivities, and the choices that brought you to this point. You will contemplate arson, and may consider immolation as an option. You'll go through the stages of grief (I suspect you may be at denial right now) until you come to accept that this is inescapable - that there's nobody within 4 states that will do it for you, that the interweb is no help, and that there's a reason this little leg of the vehicular evolutionary tree is a dead-end, not unlike the Neanderthals.
With luck, you'll get it back together and it'll work. But if it goes like things generally do the first time around, you'll get a second chance to go around the horn. Remind yourself that this is all part of the fun. If you feel like shooting yourself or the car, just go inside and have a cold beverage.
There is always a tomorrow, until there isn't. At that point, you won't care about your idle speed or potential vacuum leak.
Perfect description, Stan!
Per Gordon's suggestion long ago, I put Chapstick on my carb gaskets. They don't stick and they can be reused. I think he later updated his recommendation to use something else.
I got the "Chapstick" idea from the legendary George Brown and it really works well, but unless you have a LOT of seasonal allergies 
you may not have a tube kicking around, so I also use regular automotive grease. I have a BBQ marinade injector (looks like a YUGE! medical syringe) filled with grease and just shoot a bead along the gasket.
I don't go nuts with it - I just use enough to moisten the gasket to get it to soften a tiny bit. That means I smear the grease (or chapstick) on both sides, covering all of the surface, and then let it sit for 30 minutes or so to moisten the gasket material. After the setting time, I wipe off the excess and install. Seals things right up and works like a charm. Been installing manifold gaskets that way for a looooong time.
@Gordon Nichols posted:I got the "Chapstick" idea from the legendary George Brown and it really works well, but unless you have a LOT of seasonal allergies
I don't go nuts with it - I just use enough to moisten the gasket to get it to soften a tiny bit. That means I smear the grease (or chapstick) on both sides, covering all of the surface, and then let it sit for 30 minutes or so to moisten the gasket material. After the setting time, I wipe off the excess and install. Seals things right up and works like a charm. Been installing manifold gaskets that way for a looooong time.
Got that tip from you guys a long time ago and works like a charm. I've used a little grease also. It helps seal well and prevents everything from sticking together.
@Stan Galat posted:... there are also 3/8 head flange nuts, just to really complicate things.
To answer all the questions, in order:
Q: "What are the steps to remove the manifolds without dropping the engine?" A: There are no real tricks. While you are doing this, you'll look to passers by as if you're having a torrid love affair with your car. Mothers will shield the eyes of the innocents as you hump the back end. You will enjoy the whole thing significantly less than other people will think you are. You'll personally feel like you are standing on your head in the engine compartment, but without the aid of your hands. Hopefully you're small, and double jointed. Remove your belt before you start, and wear pants without a button or snap - or just go ahead and scratch the back fenders with an awl to get the whole thing out of the way ahead of time.
Q: "Are there any tin pieces that can easily be removed to gain access?" A: Sadly, no - but wouldn't that be cool?
Q: "Finally, gaining the easiest access to the manifold nuts should I work from above or jack up the car and work under the engine?" A: it's your call, but working from above is how everybody does it. To work from the underside you'll need to jack up the car, take off the wheels, get everything out of the way (exhaust, etc.), take off the surround tin, and see if it's any better than making love to your car from the top side. You may have better luck down there. At a minimum, you'll waste a half-hour figuring out it's no better.
To answer the questions you didn't ask:
Put a wadded up paper towel sheet in each manifold throat before you start anything. Don't let stuff fall down into the engine. You can thank me now or later. I accept PayPal.
Make sure you don't lose the (aforementioned randomly sized) nuts as you take them off. It's ridiculously easy to do. If they drop down, you'll lose them in the tin or fins of the head and forever worry that you dropped them down the ports. This is all part of the fun.
Once you pull the manifolds off, you won't be able to reuse the gaskets. It's very likely that some will stick to the head, and some to the manifolds. As soon as you get it off and take the pictures, stuff wadded up paper towels into the intake ports on the heads. You'll need to scrape the gasket material off the head and you don't want that stuff falling into the ports. You'll think (or say) bad words about the guy who decided that studs were a better idea than bolts when you are trying to clean the gasket material off the heads around the aforementioned studs. This is normal.
Scrape the gaskets off, but don't scratch the soft material of the heads or manifolds. Once you have them both clean, you'll want to make sure the manifold sealing surface is flat. Get a sheet of 220 grit wet-or dry and put it on flat surface, gritty side up. Sand the manifold sealing surface in a figure 8 until you see sanding marks across the entire surface.
You'll need to cut new gaskets because the stock ones are too small for modified heads. I've got a secret way to do this, but you'll likely have a few (many?) posts between now and then, and I'll catch you when you're ready.
You'll likely hate yourself by the time you get to this point. You may wish your father had never met your mother, and that they'd never gone for that ice cream cone back in the day. You'll question your worth as a human, your vehicular proclivities, and the choices that brought you to this point. You will contemplate arson, and may consider immolation as an option. You'll go through the stages of grief (I suspect you may be at denial right now) until you come to accept that this is inescapable - that there's nobody within 4 states that will do it for you, that the interweb is no help, and that there's a reason this little leg of the vehicular evolutionary tree is a dead-end, not unlike the Neanderthals.
With luck, you'll get it back together and it'll work. But if it goes like things generally do the first time around, you'll get a second chance to go around the horn. Remind yourself that this is all part of the fun. If you feel like shooting yourself or the car, just go inside and have a cold beverage.
There is always a tomorrow, until there isn't. At that point, you won't care about your idle speed or potential vacuum leak.
Loved this Stan; this is poetry and funny too! Now could you go on about your secret on cutting custom head gaskets? 
@Michael McKelvey posted:Per Gordon's suggestion long ago, I put Chapstick on my carb gaskets. They don't stick and they can be reused. I think he later updated his recommendation to use something else.
yeah but then when u kiss the old lady she says"U taste like carb gasket" kinda breaks the mood
You gentlemen do understand that the head is over 300*F at that juncture, correct? The melting point of Chap-Stik, et al, is considerably under that point.
I've tried it all - Chap-Stik, Never-Seize, grease, spit, Curil T, Brylcreem, Burma-Shave, and various elixirs from all the usual suspects. The Never-Seize you have on your shelf comes the closest to doing what you want. The Curil T worked OK as well. I used a high-temp gasket spray from Permatex last time. We'll see next time.
... but it's important to remember that this joint gets hot - like, "muffins just out of the oven" hot. If you heat up a joint enough it's going to start to break down the gasket, or make it rock hard. I've often thought that a nice copper or steel gasket would be perfect here, but you'd have to figure out how to cut them for your individual ports.
It was Danny P. who was the first one to push me away from the CB Performance "thick-n-squishy" black gaskets that will disintegrate and glue themselves to the head every time you attempt disassembly.
way back when we used that black permatex stuff,,does not come off the hands..almost has to wear off.smells good too..
I don't remember what it is but I think I have some magic stuff from a tube between the manifold and head and no gasket. I have Chapstick on the gaskets between manifold and carb and between carb and air cleaner.
@Stan Galat That motor I just built:
The gaskets that came with the CB heads and port-matched manifolds are hard and a bit more than 1/16" thick, call it 3/32". They, of course, must be hand cut. You didn't think they would come pre-cut to fit the CNC ports, did you? I did think that maybe they would, but that was pretty wishful. The gaskets are definitely NOT the squishy ones.
I don't know why you'd want to soften the gaskets. If both surfaces are flat, you want to pull the manifolds in square, straight, and tight. And then you want them to stay tight. If the gaskets squish, you WILL get leaks later.
Anyway, since Stan isn't giving up his secret, here's the way I do it.
I use some decent printer paper for patterns. Card stock is too hard, and cheap paper too thin. I press and tape the paper to the manifold. Then shade the paper with pencil lead. The pencil is almost flat on the paper, I don't use the point. You'll rip the paper a couple times, then get the hang of it. You'll shade a good area, but there will be a fine dark line to denote your pattern. I do the inside of the manifold, the outside edge, and the stud holes. I cut them out with scissors and an X-Acto knife. Make sure you mark your patterns L and R or 1-2 and 3-4 and which side is UP.
Then, move your patterns to the actual gaskets and trace where you're cutting with the point of a sharp pencil. Last time I did this, I used a Dremel 1/2" drum sander. Check fit, you may have to trim the outside of the gasket to fit in the intake recess.
I assembled them dry. The CB manifolds and heads were machined dead flat, and the flanges are very thick and sturdy. There will be no leaking, looseness or rocking on this set. I used JayCee's 10mm flanged SS nuts. I did put a touch of Never Seize on the threads due to Stainless steel touching regular steel studs.
Here's how I do it:
Choose your gasket material - I really have tried everything from Yamabond flange sealer to the CB gaskets. Best is somewhere in between. Gaskets are made to take up the imperfections in sealing surfaces, so the thinnest gaskets that seal properly are probably the best. I'll leave it for you to decide how flat you feel your sealing surfaces are. Any gasket dressing I use is to facilitate removal, not to soften the material or to take up imperfections. I really am keenly aware of the temperatures involved.
I start by laying the port-matched manifolds on a sheet of gasket material, sealing surface down. I trace the outside of the manifold onto the gasket with a sharp pencil or mechanical pencil. I mark the exact center of the mounting holes. I then cut the outside of the gaskets with a sharp scissors, and punch the mounting holes with a special, larger bore office-style hole punch I bought on Amazon. I check these rough gaskets to make sure everything (especially the holes) line up.
Then I bolt the gaskets to the manifolds using 5/16 x 1" or so bolts and nuts. If everything is right, the gasket will be perfectly flat against the manifold. I then take an exacto knife and make a plunge-cut into the center of one of the ports. I work my way in a circular motion creating a spiral cut until I get to the edge of the port, at which point I use the wall of the port as my guide to make a nice, clean cut around the entire inside perimeter of the port. It's almost impossible to overcut the gasket like this, and if I do it right, there's nothing hanging in the port. If I'm satisfied, I move to the other port and do the same thing.
I then mark the gasket with a mechanical pencil - head or manifold side, and which direction it goes, etc.
I'm not super-good at freehanding with an exacto-knife, and doing it like this means I don't have to. You've got to watch that you don't start carving into the aluminum of the port, but if you're slow and reasonably careful, you can do a really nice job really easily. The gaskets take about 5 minutes and come out nearly perfect.
That's my secret. Your mileage may vary.
This is awesome! Thank you Stan!
Ah, Stan, how I have missed your precise wisdom and experience, so eloquently expressed. I really have nothing to add other than: been there, done that. With variations on the theme you and Gordon have presented. So far, I've only done it once. And I can put in a plug for the 10mm head size nuts. These really help. Have not used the flexy extension as shown, but have made great use here and in many other tight spots with what I think are called wobbly extensions. Where the corners of the male extension ends are rounded off some. Cute trick and they really work.
X2 on the wobbly extensions. I have 11mm nuts on there and the wobblies seem to work as well as anything - Nothing's great.
I've always thought that it is a lot harder to get in there and clean off the flange surface on the heads from the old gasket than it is to get a wrench in there to tighten the manifold nuts properly. It's always sumthin.....
