Remove and replace intake manifold gaskets/seal
I can't believe we don't have a tech tip on removing the intake manifold and resealing it to stop oil leaks. I'd like the short version of a good procedures to accomplish this. The Helms is good, but usually there is a better way. We're talking 92 LT1. :flag :flag :flag
|
Re: Remove and replace intake manifold gaskets/seal (Strick)
(Here ya go) Get to the intake first. Remove. Clean all surfaces well. Assuming the surfaces are in good shape. I use just a little weatherstrip adhesive to hold the gaskets in place. The writing will be up and more than likley the rear water jackets will be restricted with just a small hole in the gaskets. Put the front and rear gaskets in a small can and fill with lighter fluid. Use a good grade silicone and run a bead along the front and rear of the block where it meets the intake. Install the intake and torque to spec. Last but not least - light the can of fluid and burn the supplied front and rear gaskets to a crisp. They are useless. :thumbs:
|
Re: Remove and replace intake manifold gaskets/seal (Strick)
I just emailed you a file that I wrote and send to guys on sealing the intake manifold.
It was written primarily with the L98 in mind (also engines that have coolant circulating through the intake), but works equally well with other types. Let me know how you make out. Jake |
Re: Remove and replace intake manifold gaskets/seal (autotech)
(Last but not least - light the can of fluid and burn the supplied front and rear gaskets to a crisp. They are useless. :thumbs: Thanks, I'll be doing this soon. I especially like that last tip! :lolg: |
Re: Remove and replace intake manifold gaskets/seal (autotech)
Put the front and rear gaskets in a small can and fill with lighter fluid. Last but not least - light the can of fluid and burn the supplied front and rear gaskets to a crisp. They are useless. :thumbs: Hey Jake, put the article you sent me in the C4 Tech Tips. Your dimple idea is cool. :thumbs: [Modified by Strick, 9:11 AM 2/2/2004] |
Re: Remove and replace intake manifold gaskets/seal (JAKE)
Jake,
Can you please post the article you wrote ? I'm in the process of installing a new manifold on an L98 right now and have some questions, maybe the article will help out. Thanks ! |
Re: Remove and replace intake manifold gaskets/seal (Strick)
http://www.firehawk.org/article.html?ID=1336
Ken Collings knows his LT1s. Hey Strick, how's that new clutch coming along? What happened, take off your bell housing and see all that oil? Same happened to me. I'm going to be doing the intake gasket when it warms up here in Detroit. By the way guys, I don't think there is a rear and front gasket for the lt1 intake manifold. I think GM used sealant, surface is not flat enough for a gasket. Problem lies with the egr pipe coming to close to the intake after it leaves the passenger side exhaust manifold and wraps around the rear of the engine- where the oil leak develops. Jake, can u post your steps? Hatz [Modified by djhatz, 8:53 AM 2/3/2004] |
Re: Remove and replace intake manifold gaskets/seal (djhatz)
dj, I have the clutch & flywheel off and inserting a new rear main seal just for preventive maintenance. No I didn't have a lot of oil inside, but there was some from the first oil leak I had which killed the disc and over heated the flywheel from slipping. These beam plates will make it so much easier to reinstall the C-beam bolts.
If jake doesn't post soon, I'll post what he sent me. It's interesting. |
Re: Remove and replace intake manifold gaskets/seal (Strick)
Put the front and rear gaskets in a small can and fill with lighter fluid. Last but not least - light the can of fluid and burn the supplied front and rear gaskets to a crisp. They are useless. :thumbs: It's been cold down here so the fire will be needed for heat. :lolg: :rofl: :lol: :lolg: Hey Jake, put the article you sent me in the C4 Tech Tips. Your dimple idea is cool. :thumbs: [Modified by Strick, 9:11 AM 2/2/2004] Jake |
Re: Remove and replace intake manifold gaskets/seal (JAKE)
Ok then I will step out and be the stupid one. All I can find is your tip on lifter lash adjustment. Under the cross generation section of tech tips. Where is this one at? :leaving:
|
Re: Remove and replace intake manifold gaskets/seal (Strick)
Fixing a Leaking Intake Manifold One of the most common leak spots on both the BB and SB Chevy engines is the end seals of the intake manifold, followed by valve covers and then timing chain. Guess you could throw in rear main seal too. Here's the way I've been doing it for years and have prevented leaks in the intake. Remove the intake and thoroughly clean all the gasket sealing surfaces, I mean clean!!! No traces of gasket or silicone, or oil is acceptable. Use a coarse grit sandpaper to scrub down both ends of the block and the underside of the intake. Use a degreaser or carb cleaner to make sure all traces of oil or silicone are removed. Now take a fine point punch and hammer and punch a series of dimples on both ends of the block and on both ends of the manifold. You will end up with maybe 30 or more dimples on each end when you're done. They should be positioned about 1/8 to 1/4 inch apart. You don't have to go deep, but make sure you've got dimples that you can catch with your fingernail. Be careful not to place the punch so close to the edges that you chip the block or intake material. It's kinda hard to chip it but there's no need to get closer than say 1/8th inch. Now with every mating surface clean, clean, clean, use your finger to put a very THIN layer of silicone sealant around each intake port and water port on the heads. Place the intake gaskets in place and gently press the gasket into the sealant. Be sure to use silicone sealant that's "sensor safe". Fumes from the other kind can kill the 02 sensor. I use VersaChem # 613 Super Blue Silicone; comes in a 4 oz tube. It has about 1/3rd more silicone than some other brands. Other brands work just as well, just be sure it's 02 safe. Auto- Zone, O'Reilly's, Pep Boys, NAPA, etc., all sell the good stuff. Any sealant the oozes out into the port area is to be wiped away with your finger. Now do the same thing to the intake gaskets; place a very thin layer of sealant around each intake port and water port on the gasket, even those with the sealant rings on 'em. Smooth it out with a wetted finger tip (wetting your finger keeps the sealant from sticking to your finger, but it's still kind a messy). When your finished you'll have a thin layer of silicone sealant on both sides of the gasket. Keep the sealant about 1/4 inch from the port entry. If you apply it thinly it won't squeeze into the port to obstruct airflow. If a little does ooze into the airway, well if that small amount of airflow restriction is enough to cause you to lose the race or hurt your power you have some much more serious deficiencies. Using a thin layer minimizes the chance of any leak. Now the critical part: RUN A CONTINUIOUS BEAD ABOUT 3/8 INCH thick, maybe even a hair thicker, along both end seal areas. Make sure the bead extends onto the head and that it is continuous with no gaps and as few hi/low places as possible. 1/4 inch bead is too small. CAREFULLY SET THE INTAKE MANIFOLD IN PLACE ON THE HEADS WHILE THE SEALANT IS STILL WET. SIT THE MANIFOLD STRAIGHT DOWN - DO NOT ALLOW IT TO SHIFT FRONT TO BACK. Some guys like to wait for the sealant to skin over, but I've found you get a better seal by setting everything in place with it wet. Proper alignment can be done by looking through one of the intake manifold bolt holes and visually align it with the threaded hole in the head as you lower it in place. Remember, straight down. Take your time and do it slowly. All the intake bolts should have been cleaned before you started the gasket installation. Cleaned of any old sealant and crud. I use Anti-Seize on my threads just for insurance against vacuum leaks; and it's especially important when using aluminum heads to prevent the manifold bolts from seizing. Chasing the head bolt holes is a good idea but this can cause some crud to fall into the lifter valley unless you take precautions to really cover it well and pick every little piece of whatever that may fall into the valley. Hand start all the intake bolts and slowly torque them down following the correct bolt sequence shown in any of the GM books that apply to your engine. This can be tricky because the TPI intake calls for a peculiar torque sequence. You may be able to get away with the old tried and true cross pattern, but why take the chance. I guess GM had good reasons for the recommended sequence shown in the Shop Manual. Torque them down in very small increments, 5 lbs at a time is what I use. I have to make more passes, but you're only dealing with 12 bolts so what's the big deal, right? PUT A TORQUE WRENCH ON THEM TOO. There's no substitute for proper torque. Too much and you can distort the manifold and/or pull threads; too little and the manifold bolts will loosen when it goes through heating and cooling cycles. Wait about an hour or preferably longer, then go back and re-torque the manifold bolts again. Letting manifold sit for an hour or more will allow the gasket to take a set. This "set" has the effect of loosening the bolts. On occasion I've had to re-torque them a second or even a third time. The more compressible or thick the gasket, the more it will compress and need to be re-torqued. Be sure to torque all the bolts in place while the silicone sealant is still wet. Resist the temptation to wipe away any sealant that may ooze from between the intake and block/heads. If you're so inclined, you can cut it away with a very sharp razor blade after waiting for it to FULLY cure - about 24 hours. The dimples in the block and manifold will give the sealant something to bite into and you'll be leak free until you decide to change cams, then ya gotta do it all over again. Do Not, Do Not use the end seals that come with the new intake manifold gaskets. If you do you've got better than a 50/50 chance of having the same leak again in time. Like many other things, there's always more than one way to do something, but I've used this technique on many, many engines with complete success. Hope this helps, Jake BTW, I use the dimple technique on the blocks of BB Chevys between the cylinders that don't have head bolt holes to give the head gasket something to bite into also. When you're running 14.1 CR without "O" rings you need all the help you can get. [Modified by JAKE, 12:37 PM 2/5/2004] |
Re: Remove and replace intake manifold gaskets/seal (JAKE)
Sorry! I thought for sure I'd posted that some time back. Guess I didn't.
I just posted it now though; with a couple of little additions. I've become a little reluctant to post tips like those because there's always someone to come along to criticize/disagree and then offer an alternate way of doing it. Example, setting lifter preload: One guy advocated doing it with a dial indicator. Most of the tips I give now are through private emails. My fighting days are over; I've become a devout pacifist in my old age. Fightin's too stressful. LOL Hope it helps though. Jake [Modified by JAKE, 1:43 AM 2/4/2004] |
Re: Remove and replace intake manifold gaskets/seal (JAKE)
I can vouch for the procedure that Jake has. I used it 2 –3 years ago and it was invaluable, works like a charm and still leak free! Thanks again Jake! :thumbs: :thumbs: :thumbs:
|
Re: Remove and replace intake manifold gaskets/seal (Jake)
Well,Jake ,I HAVE to disagree with you or at least add my cents...you didnt include one very important PART when redoing the intake,you never mentioned the BEER!This is defintely a 12 pack job!
:D :jester J/k buddy...thats a great write up and its probably the best Ive seen.Chilton or Haynes,or even the GM manuals couldnt pay you enough to re write their books. :cheers: |
:lurk:
|
Originally Posted by Strick
(Post 1546360334)
I can't believe we don't have a tech tip on removing the intake manifold and resealing it to stop oil leaks. I'd like the short version of a good procedures to accomplish this. The Helms is good, but usually there is a better way. We're talking 92 LT1. :flag :flag :flag
Doesn't seem to be a real big job.But it would be nice to have some info or maybe a sticky .:thumbs: |
Originally Posted by JAKE
(Post 1546383998)
Fixing a Leaking Intake Manifold
One of the most common leak spots on both the BB and SB Chevy engines is the end seals of the intake manifold, followed by valve covers and then timing chain. Guess you could throw in rear main seal too. Here's the way I've been doing it for years and have prevented leaks in the intake. Remove the intake and thoroughly clean all the gasket sealing surfaces, I mean clean!!! No traces of gasket or silicone, or oil is acceptable. Use a coarse grit sandpaper to scrub down both ends of the block and the underside of the intake. Use a degreaser or carb cleaner to make sure all traces of oil or silicone are removed. Now take a fine point punch and hammer and punch a series of dimples on both ends of the block and on both ends of the manifold. You will end up with maybe 30 or more dimples on each end when you're done. They should be positioned about 1/8 to 1/4 inch apart. You don't have to go deep, but make sure you've got dimples that you can catch with your fingernail. Be careful not to place the punch so close to the edges that you chip the block or intake material. It's kinda hard to chip it but there's no need to get closer than say 1/8th inch. Now with every mating surface clean, clean, clean, use your finger to put a very THIN layer of silicone sealant around each intake port and water port on the heads. Place the intake gaskets in place and gently press the gasket into the sealant. Be sure to use silicone sealant that's "sensor safe". Fumes from the other kind can kill the 02 sensor. I use VersaChem # 613 Super Blue Silicone; comes in a 4 oz tube. It has about 1/3rd more silicone than some other brands. Other brands work just as well, just be sure it's 02 safe. Auto- Zone, O'Reilly's, Pep Boys, NAPA, etc., all sell the good stuff. Any sealant the oozes out into the port area is to be wiped away with your finger. Now do the same thing to the intake gaskets; place a very thin layer of sealant around each intake port and water port on the gasket, even those with the sealant rings on 'em. Smooth it out with a wetted finger tip (wetting your finger keeps the sealant from sticking to your finger, but it's still kind a messy). When your finished you'll have a thin layer of silicone sealant on both sides of the gasket. Keep the sealant about 1/4 inch from the port entry. If you apply it thinly it won't squeeze into the port to obstruct airflow. If a little does ooze into the airway, well if that small amount of airflow restriction is enough to cause you to lose the race or hurt your power you have some much more serious deficiencies. Using a thin layer minimizes the chance of any leak. Now the critical part: RUN A CONTINUIOUS BEAD ABOUT 3/8 INCH thick, maybe even a hair thicker, along both end seal areas. Make sure the bead extends onto the head and that it is continuous with no gaps and as few hi/low places as possible. 1/4 inch bead is too small. CAREFULLY SET THE INTAKE MANIFOLD IN PLACE ON THE HEADS WHILE THE SEALANT IS STILL WET. SIT THE MANIFOLD STRAIGHT DOWN - DO NOT ALLOW IT TO SHIFT FRONT TO BACK. Some guys like to wait for the sealant to skin over, but I've found you get a better seal by setting everything in place with it wet. Proper alignment can be done by looking through one of the intake manifold bolt holes and visually align it with the threaded hole in the head as you lower it in place. Remember, straight down. Take your time and do it slowly. All the intake bolts should have been cleaned before you started the gasket installation. Cleaned of any old sealant and crud. I use Anti-Seize on my threads just for insurance against vacuum leaks; and it's especially important when using aluminum heads to prevent the manifold bolts from seizing. Chasing the head bolt holes is a good idea but this can cause some crud to fall into the lifter valley unless you take precautions to really cover it well and pick every little piece of whatever that may fall into the valley. Hand start all the intake bolts and slowly torque them down following the correct bolt sequence shown in any of the GM books that apply to your engine. This can be tricky because the TPI intake calls for a peculiar torque sequence. You may be able to get away with the old tried and true cross pattern, but why take the chance. I guess GM had good reasons for the recommended sequence shown in the Shop Manual. Torque them down in very small increments, 5 lbs at a time is what I use. I have to make more passes, but you're only dealing with 12 bolts so what's the big deal, right? PUT A TORQUE WRENCH ON THEM TOO. There's no substitute for proper torque. Too much and you can distort the manifold and/or pull threads; too little and the manifold bolts will loosen when it goes through heating and cooling cycles. Wait about an hour or preferably longer, then go back and re-torque the manifold bolts again. Letting manifold sit for an hour or more will allow the gasket to take a set. This "set" has the effect of loosening the bolts. On occasion I've had to re-torque them a second or even a third time. The more compressible or thick the gasket, the more it will compress and need to be re-torqued. Be sure to torque all the bolts in place while the silicone sealant is still wet. Resist the temptation to wipe away any sealant that may ooze from between the intake and block/heads. If you're so inclined, you can cut it away with a very sharp razor blade after waiting for it to FULLY cure - about 24 hours. The dimples in the block and manifold will give the sealant something to bite into and you'll be leak free until you decide to change cams, then ya gotta do it all over again. Do Not, Do Not use the end seals that come with the new intake manifold gaskets. If you do you've got better than a 50/50 chance of having the same leak again in time. Like many other things, there's always more than one way to do something, but I've used this technique on many, many engines with complete success. Hope this helps, Jake BTW, I use the dimple technique on the blocks of BB Chevys between the cylinders that don't have head bolt holes to give the head gasket something to bite into also. When you're running 14.1 CR without "O" rings you need all the help you can get. [Modified by JAKE, 12:37 PM 2/5/2004] Sticky :D |
6 & 1/2 years old the dust is so thick I can't see to read
|
Originally Posted by JAKE
(Post 1546383998)
Now with every mating surface clean, clean, clean, use your finger to put
a very THIN layer of silicone sealant around each intake port and water port on the heads. Place the intake gaskets in place and gently press the gasket into the sealant. Be sure to use silicone sealant that's "sensor safe". Fumes from the other kind can kill the 02 sensor. I use VersaChem # 613 Super Blue Silicone; comes in a 4 oz tube. It has about 1/3rd more silicone than some other brands. Other brands work just as well, just be sure it's 02 safe. Auto- Zone, O'Reilly's, Pep Boys, NAPA, etc., all sell the good stuff. Any sealant the oozes out into the port area is to be wiped away with your finger. Now do the same thing to the intake gaskets; place a very thin layer of sealant around each intake port and water port on the gasket, even those with the sealant rings on 'em. Smooth it out with a wetted finger tip (wetting your finger keeps the sealant from sticking to your finger, but it's still kind a messy). When your finished you'll have a thin layer of silicone sealant on both sides of the gasket. Because I note none of the silicones I've looked at say fuel resistance, I was reluctant to (and did not) do this step. Instead, I placed the thin layer around the water ports ONLY and let it setup/glue to the heads overnight. Nothing went on the other side of the gaskets. I did use the touted "Right Stuff" sealer to seal the China walls. I also used the dimpling method described here. I debated the issue of using silicone (or other sealer) on the intake. I also pointed out that the injector squirts its fuel slightly below the intake-to-head seal where little (if any) fuel would come in contact with the gaskets. The couple of people who were adamently against the use of sealer were so emphatic, that I conceeded to that option. Had I found silicone to be fuel resistant, I would have gone the other way. I'm still not convinced it's harmful, but I am convinced that good intake gaskets look "substantial" enough that I see why some people believe thats ALL that's necessary to seal your intake. Plus, when I removed the old gaskets, GM didn't appear to use anything like silicone that I could find. |
GEEZZZ! You went back to 2004 to dig this up?? What's up with THAT! Motivation?? Is it because I questioned your LSA claim in another thread?? Seems that way to me.
More to the point, Here's one example: A big, beautiful photo of an engine builder applying SSS to the intake gaskets intake ports appears in one of the Performance Building the SBC Vol. II(or some such wording) manuals which dates well over a decade ago. This is "Old School" stuff which we "Old Guys" have known and been doing since Hector was a Pup. My advice, Try not to get too anal over this stuff - over-thinking, overly concerned, overly this and overly that. Suspecting faults and flaws when none actually exist. Too stressful doing things that way. Either follow the procedure I posted or don't'; no skin off my nose if you don't. BTW it's also posted as a STICKY on LS1LT1.COM and a few other Forums (Third Gen/CamaroZ28/others) as well and I regularly get feed-back on how well it works and grateful thanks from the Forum members. One Forum Administrator emailed me asking my permission to cut and paste it to HIS Forum after he came across it on a competing Forum - naturally I consented. So your concerns are unfounded. As I wrote, (what was it six years ago?), there's always someone who comes along and disagrees or whatever. Never fails - sooner or later. Either accept the procedures or don't. My only goal is to try, as best I can, to help others - HELP being the operative word. As I regularly say, feel free to do as you please. Jake |
All times are GMT -4. The time now is 01:34 AM. |
© 2024 MH Sub I, LLC dba Internet Brands