Intake gaksets blowing out....

I have a 406 SBC, 13:1, fairly radical cam (697 lift, 290 dur), solid roller, Dart block, heads. Motor runs very strong, and has gone 9.80's in a Vega, with 1 850 carb. I recently bought it, and proceeded to replace the intake with a Pro Dominator Holley tunnel ram w/ 2 660's. Again...this motor runs very strong, but blows out the front and rear intake seals as soon as I do a test burn out in my parking lot. I have breathers to the headers for crank case pressur evac. I have replaced the intake gasket 3 times....same situation. The intake looks good....like new....I picked it up from a fairly reputable seller at a swap meet......there are some of those. The motor is 23 degree. Is it possible that this intake was modified for an 18 degree application? Do you even have to modify the intake for that? Thanks in advance for any input.

i did re work a blower intake for pro heads the ports need to be re work by welding ports .i think what you have going on is that you need to lose the rubber end seals and use only RTV and you engine is not breathing and it going to find a way to vent your headers do not have the egr check valves in or they are junk try running it with your header hook up on start the car un hook it off your breather and if there is EX pressure pumping up your hookup hose then your egr valves can be bad

I have used RTV only.....I always do, but when this happened twice, I used the cork gaskets that come with the 1206 Fel Pro kit w/ RTV over them. Still blows out. I will check the egr valves as you suggested, but everything was fine until I changed intakes. Now, I'm wondering about the oil pan capacity. I bought this motor fully assembled, and was told by the previous owner that it was a 7 qt. pan, excluding the filter. Maybe he was wrong, and I over filled this thing. I need to find the mfg. of the oil pan, and confirm the capacity....I would imagine too much oil + high volume pump might = blown intake seals. Thanks.

the egr is a ez check and have had them go bad .your engine could be way over fill i never done that but could add to what you have going on but this is ez to tell the oil presure go s all over the place i have need told . was thinking the first thing that happens is you push oil out the dip stick if not vented good if you have a dip stick . did you do a comp check on the engine i never use RTV on any end gaskets they have a way to squirt out

use the 3-M (yellow) weatherstripping.

I did a compression check......150 -175lbs. I have used RTV many times before without any problems, but it's worth a try. I guess I will try the cork gaskets that come with the Felpro intake set....I'm not familiar with the 3-m yellow weatherstripping. Is that just a material you pick up at the hardware store, or is it specifically for gaskets? Thanks.

Forget about using ANY type of cork/rubber gasket that comes with the gasket package. Throw them away.... just use straight 3-m weatherstripping you can pick it up at Autozone or pretty much any where. Racers use it a lot

How big is the gap, it could be parts not matching correctly.

The gap appears to be between 1/16" and 1/8". I would think that's pretty normal. Thanks for the tip on the 3-m weatherstripping.

If this started with an intake change it probably is the intake. Or you could have damaged the motor doing the burnouts. Or you have to much crankcase pressure. Either to much blow by or not enough venting.

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Originally Posted by BigTruckDriver

use the 3-M (yellow) weatherstripping.

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yellow is good for rubber or cork but i never try to build a 1/8to 1/4 bead with yellow death your better with RTV yellow death as not much body to it the omc type M is much better the 3m yellow for rubber and cork if you have a boat yard round you that sells OMC

dont get it:confused:

yellow 3m cement is runny has no body to it to use just to fill a gap .rtv is better to fill gaps with out a gasket then yellow death is.3M to glue gaskets it is ok but not as good as it use to be. OMC type M is alot better for cement for rubber and cork gaskets

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Originally Posted by BigTruckDriver

dont get it:confused:

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i guses i did not get it till i look at it better you are talking about a 3m Wether Strip and is yellow .what i was thinking 3m weather strip yellow cement:( i sorry i will now go to my room:D

i too thought they are talking about 3M 1300 vinyl adhesive. AKA 'monkey snot' It is a GOOD gasket adhesive, but I have never heard of it being used for gasket replacement as is silicone.

[QUOTE=Mikej;342322]If this started with an intake change it probably is the intake.

I have to keep coming back to this, also. I've changed dozens of intakes, using cork, rubber, rtv, without problems. I guess the thing to do is to remove it, clean it up, and take it to a qualified machine shop to check it out. I am convinced that the crank case evac tubes are working, and if it had a hole in the piston, broken rings, etc. the motor would not be running properly. Thanks.

Blows the seals out or sucks them in???

Do you run a vacume/pressure guage hooked into your valley???

do you have mufflers on the car??? Crankcase evac won't work with mufflers, you'll just pressurize the crankcase instead

do you have your intake hooked up to vacume your crankcase??? My tunnel ram engine would pull a strong vacume at idle and the headers evac system would then take over and pull 18-20 inches in the traps at 9500rpm

[QUOTE=lodilobo;342414]

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Originally Posted by Mikej

If this started with an intake change it probably is the intake.

I have to keep coming back to this, also. I've changed dozens of intakes, using cork, rubber, rtv, without problems. I guess the thing to do is to remove it, clean it up, and take it to a qualified machine shop to check it out. I am convinced that the crank case evac tubes are working, and if it had a hole in the piston, broken rings, etc. the motor would not be running properly. Thanks.

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well did you check the crank case evac ? and like jerry said you can not run that setup with EX with muffs i know it will not work no matter how big of a ex you have as for a machine shop looking at your intake they are not going to tell much from just the intake they would need the engine to make sure it fit right and has the same angle has the heads. the part of the intake your blowing out just is not a big deal less you have some pressure in the crank case it coming from some were you need to check were it coming from the end rails are the dumb part of the intake if you have some gap for rtv or gaskets it will work i cut and fitted and built intakes this parts of the intake is not very critical longs as when the intake is tq down you have gap on the china walls of the block so the intake gaskets seal the ports and not hold in up with no gap the intake bottoms out

this wasn't just an intake manifold swap---it was a vechicle swap---different everything
anyone running a crankcase evac should have a vacume/pressure guage plumbed into the valley--tells a lot of what is going on


on a more serious note-----if you are blowing the gaskets OUT, you have a serious problem in that all that pressure is acting as a head of pressure that your oil system must overcome----for example----30 lbs of crankcase pressure, 40 pounds of oil pressure equals 10 lbs of lubrication!!!!!!

We pull over 20 inches of crankcase vacume at 10400rpm----we could run without a oil pump!!!!!

for those of you who want a better product than rtv---try right stuff by permatex, available at Napa---a little more expensive , but lives up to its name

No exhaust system on the car....open headers only. But, I didn't know that the evac hoses to the headers would not work with mufflers. In fact, I have a similar engine, sbc421 c.i., 13.5:1, solid roller w/ .765 lift in another vehicle that I have mufflers on, and am using the same evac system. Have had no problems.... similar, but stronger motor. Should I be knocking on wood as I type this?

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Originally Posted by lodilobo

No exhaust system on the car....open headers only. But, I didn't know that the evac hoses to the headers would not work with mufflers. In fact, I have a similar engine, sbc421 c.i., 13.5:1, solid roller w/ .765 lift in another vehicle that I have mufflers on, and am using the same evac system. Have had no problems.... similar, but stronger motor. Should I be knocking on wood as I type this?

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well i have tried using a evac system on a 462.468 .548. 572. 632. with a 3.inch 3 1/2 and a 4 inch with a X pipe EX it just did not work on my 50 chevy or my GTO and it was not for lack of trying:whacked:

so have you checked crankcase vacume/pressure yet???

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Originally Posted by jerry clayton

so have you checked crankcase vacume/pressure yet???

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WHO ?:whacked::3dSMILE:

lodilobo----

I have not put any type of gauge on the crank case pressure, but I have blown air through the breathers and lines to determine that they are functioning. While excessive crank case pressure may be the source of the problem, I did have a severe crank case pressure problem with a sbc a couple years ago. However, the difference was, that it would constantly blow out oil pan and timing cover gaskets.....not intake gaskets. I am in the process of removing the intake, at the moment. I suppopse I could put the original intake back on the motor, and check the results. If the problem is corrected, that tells me 2 things....the new intake has problems...and never buy an intake at a swap meet.

Even if you find the intake don't fit, that doesn't solve the crankcase pressure issue

Jerry....I'm not sure there is a crankcase pressure issue. This vehicle....as it sits....with the exception of the intake, and switched from trick flow rockers to harland sharp, ran 9.80's and never had that problem before.

its got that problem now if its blowing out the seals

I have already done the compression test......close to 180 in every cylinder. I will know shortly if the problem is the new intake, or something else. I'm betting on the intake.

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Originally Posted by lodilobo

I have not put any type of gauge on the crank case pressure, but I have blown air through the breathers and lines to determine that they are functioning. While excessive crank case pressure may be the source of the problem, I did have a severe crank case pressure problem with a sbc a couple years ago. However, the difference was, that it would constantly blow out oil pan and timing cover gaskets.....not intake gaskets. I am in the process of removing the intake, at the moment. I suppopse I could put the original intake back on the motor, and check the results. If the problem is corrected, that tells me 2 things....the new intake has problems...and never buy an intake at a swap meet.

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if you blow thru the hose at the valve covers that not going to tell you that the check valves are bad you need to know at ex pressure can not get in the engine this needs to be check on the other end

Intake update.... replaced the intake with an intake I had lying around....Super Victor....used Felpro 1206 agsket w/ black RTV for front and rear seal. Engine is up and running......haven't had any indications of it leaking. The intake I removed shows nothing....to me, anyway.....that it has a problem. I won't be using it again, though. Thanks for all the input and ideas that you guys provided.