LilJayV10

iTrader: (5)

I don't know if this is the best place for this post or not. On my 406 I am using the AFR 195 eliminator heads and an Air Gap RPM intake. I am using the 1205 intake gaskets that AFR recommends.

In the never ending quest to get my car running right. My intake leaks on 5-7 cylinder. I replaced them about a month ago and when I sprayed carb cleaner on it the idle wouldn't change.

The idle started getting higher and higher. Today I sprayed carb cleaner on it and the engine vacuum shot way up and smoothed out. So yeah it's leaking again.

The block was cleaned up to almost zero deck height. The heads are new as is the intake. I didn't think the block was resurfaced enough to require the intake being cut. I think if the intake was cut the problem would be worse.

There is a 1205 gasket that is a little bit thicker and is reinforced with metal, I don't know if or why that would help me.

I have re torqued the intake bolts many times. When I put the gaskets on this time I used the gasket shelack(sp?). It looks like the intake doesn't have enough material around the top of the runner to seal. I will post a picture later.

Any suggestions? It's tough to tune a carb with the intake leaking.

Thanks for any help.

Jason

Damon

It's possible the intake needs to be machined a little. As the block is decked the heads get closer together. That pushes the intake UP relative to the heads and could possibly cause a problem like this.

While you've got the intake off lay a straight edge across both intake mating surfaces. I had a brand new out of the box Performer RPM a few months ago with one intake flange so far out it was rediculous- like somebody got drunk before they put it in the milling machine (out by .025"), yet the pass. side was straight as an arrow. They're still mass-produced parts and mistakes can be made.

Not a bad idea to check the heads as well while you're at it.

F-BIRD'88

try this too

LilJayV10

iTrader: (5)

I will try that. If I have time I am going to take it off tonight. I was hoping to take it to the track saturday. Hopefully I can get it back together by then

327_TPI_77_Maro

iTrader: (8)

Usually zero decking a small block chevy, with flat tops, means taking 20-40 thou off the deck. What type of gaskets are you using, and do they have molded in silicone beads? Mr. Gasket and Felpro race gaskets have molded silicone beads, that will give you more squish than a stock auto parts store paper gasket. If that doesn't work, sounds like the intake is going to have to be cut.

LilJayV10

iTrader: (5)

The intake is warped. I took it to the machine shop and they ran a straight edge across it w/ a feeler gauge. Right where it was leaking he could slide the feeler gauge in. How much I don't know. He checked the other side and it was out too but not as much. They are going to resurface it and I should have it back tomorrow. He was actually suprised the intake was off. He said edlebrock stuff is normally pretty good.

I am using a felpro 1205 intake gasket w/ the silicone bead around it.

I hope this takes care of it.

F-BIRD'88

Once the manifold is straightened out you won't need any RTV around the intake ports at all. Just a little around the 4 water ports and a bit in each of the 4 corners of the china wall, unless you are using the RTV as a china wall gasket. MR. Gasket makes some intake gaskets with the same size ports as a 1205 but the gasket is thicker.

LilJayV10

iTrader: (5)

I don't use RTV around the intake ports. I did try that gasket sheclack(sp?) It's a small brown bottle with an indian on it. That's the first time I have ever used it. I normally just use the RTV on the china wall's.

The guy at the machine shop suggest to use a stock style intake gasket. He had one and it was the same size as the 1205. He measured it and it's about .090 thick. It has the metal ring around the ports. I don't know which would be better.

Damon

Yep, that was about my level of shock when I found the same thing with my brand new Eddy intake a couple months back!

LilJayV10

iTrader: (5)

I got the intake back on today. The machine shop said they had to take .08 off the driver side. The first pass the grinding stone didn't even touch the runners.

I put it on and was messing the with carb trying to set the idle. I checked for vacuum leaks and YUP, it's leaking again.

I checked it when I first started it and it wasn't leaking. After it ran for about an hour I checked it again.

Dammit. Should I just get a new intake or try a different gasket?

LilJayV10

iTrader: (5)

I let it sit for a couple of hours and went and started it. It idled pretty good. Went and drove it. When I got back it was idling at 1500 or so. I could spray carb cleaner and the engine vacuum would go up and the AFR would level out. Just like it did before.

I have had brake rotors in the past do something similar. I would turn the rotor and they would be true. Put it on the car and drive it. When the rotor would get hot it would warp again. I have never had this problem with an intake.

Damn car. It's been one thing or another with it. I need a beer.

Damon

Take out the bolts a couple at a time and look down to the threads in the head. Are they reasonably centered at the bottoms of the holes in the intake? If not, it's possible you're bottoming the intake against the bolts and not crushing the gasket. Had a Weiand intake a few years back the holes were simply drilled in the wrong spot. Port match was perfect, bolt pattern match was not.

LilJayV10

iTrader: (5)

Whats the best way to measure the angle of the intake?

Since I am taking it off..AGAIN...i am going to check it. I should have checked it last time but I thought for sure I had found the problem with the warped intake.

LilJayV10

iTrader: (5)

I measured the angle of the heads and the intake today. Both are 145 degrees.

I used a ruler and a feeler gauge(not super scientific I know)to check intake and it doesn't seem warped. It got dark and I didn't get a chance to check to see if the heads are straight. I am going to get a real straight edge tomorrow.

I tried the stock gaskets that are a lot thicker but it still leaked. I can have it on and off in about 1/2 hour so I figured what the hell.

I put sat the intake down without any gaskets and it looked like everything lined up.

I am out of ideas.

Damon

You need it to line up properly WITH the intake gaskets in place. Double-thick ones could be making your problem worse with the decked block.

This is a tough one to do over the internet without actually seeing it. We're talking about a few hundredths of an inch possibly making all the difference.

LilJayV10

iTrader: (5)

I lined it up with and without the gaskets. With the felpro 1205's and the stock type. I know it's tough trying to figure it out on the net. I appreciate your time and ideas.

Everything "looks" fine and looks like it lines up. The bolt holes line up and the intake sits down fine.

The angle of the intake and the heads are the same. Is there something else I should be measuring?

Thanks again.

Jason

Damon

When I discovered my intake was whacked it was almost by luck. I had it laid on the engine with no gaskets. It sat low enough that it was sitting flat on the front and rear china walls of the block. For whatever reason I pushed down on one corner- it went "clunk". Odd. So I checked some more and found I could rock it corner-to-corner along one of the diagonals pretty bad. Not only was one intake flange not flat, the whole damned intake was "twisted" like it was warped or something right out of the box.

I realized I was dealing with something as crooked as a dog's hind leg, so I just boxed it up and sent it back rather than trying to machine it back into spec.

LilJayV10

iTrader: (5)

I checked the heads and they are straight. I checked the intake and it's straight also.

I was looking at the gaskets and I think I might have found it. Someone suggested it before I don't remember who.

It looks like the bottom of the gasket is compressed a lot more than the top. I can see it on the 1205's and the thicker style stock gasket. On the stock gasket with the wire ring around the port. It's compressed on the bottom but not on the top. You can see where the intake pressed against it but didn't have enough force to collapse the ring and make a seal.

I guess the intake needs to be ground at a little different angle? We are probably talking about several thousands of an inch.

Damon

That sounds like the kind of issue you would run into if your heads had been angle-milled a fair bit. But yours are new out of the box.......... hmmmmm. You got me man. I got nothing for you on that one.

Could you borrow a known-good intake from a friend just to see if it will seal up? Just to eliminate the intake as the problem.

five7kid

iTrader: (14)

Put a carpenters square across the manifold port surfaces. They should be at a right angle to each other.

Damon

Huh? Don't think so. They aren't 90* to eachother. They're more like 110*. The intake port flange on the heads is "laid back" about 10* from being truly perpendicular to the block deck.

Air_Adam

I think Damon is right (wow... I'm actually NOT going with what Five7 said... this is rare!) The heads are not milled square with the block - as in, the intake mating surface is not ground 90* to the deck surface IIRC, its slightly less than that, so the port surfaces on the manifold will be a bit more than 90* to match correctly.

five7kid

iTrader: (14)

Okay, I'll double check that.

Air_Adam

I took a snapshot of a chunk of a SBC dimension diagram I have - I marked the intake port grind angle in the pic with the red arrow. It is ground 10* off of a square 90*. Enjoy!

LilJayV10

iTrader: (5)

Do you mean that I should have my intake ground 10 of of a square 90? Sorry that I didn't follow your post.

LilJayV10

iTrader: (5)

I guess the intake does need ground. I tried a new intake and gaskets today and it still leaks. I can't find anyone in town that knows what the **** they are doing. It's a god damn small block chevy people. ****!

Air_Adam

Ask around the local car clubs, especially racers or muscle car clubs. They can tell you who to talk to.

LilJayV10

iTrader: (5)

I am going to talk to another machine shop in town next week. So what was the 10 degrees from 90 post? I am still lost about that one.

Air_Adam

If you look at the cylinder head, as its shown in the diagram - if you put a square across the deck surface of the head, then the angle up on the intake side is not 90*, but 80*. You can see it in the picture.

LilJayV10

iTrader: (5)

I took the new intake to another machine shop along with the gaskets. They milled 20 thousands off the bottom side of it to make it sit down deeper in the engine.

I test fitted it with and without gaskets and everything looked great.

Still leaks.

JohnyP

iTrader: (3)

my computer didnt load everyone elses comment so i edited this that sucks though i would of just sent it back in the first place

LilJayV10

iTrader: (5)

I have tried two intakes.
I have tried a felpro 1205 and 1266 gasket and a stock gasket
I am using permatex gray on the end rails

I am using the right torque sequence.

I have worked on cars fors years. I know how to put an intake on. However there seems to be something wrong with this setup.

Either the block was decked wrong or something. I am really close to getting rid of it.

JohnyP

iTrader: (3)

then i would try just re machining the block...i mean if thats the case (didnt mean to offend u) then its obviously not your teqhniqe your intake or your heads so that leaves the block........maybe there lies your problem

Air_Adam

What you should do, is drop the intake on, without any gaskets or anything - just drop it in place, and take pictures, and post them here. If we can see exactly whats going on, then we might be more help to you.

89RsPower!

Wow I feel your pain man, I'd be losing it by now, something so simple screwing you up...

LilJayV10

iTrader: (5)

I will take some pics soon. I appreciate the help guys. It just doesn't make any sense.

LilJayV10

iTrader: (5)

Tried to get it to seal again. I used RTV this time and still leaked. I am going to pull the engine out and put my 305 in it so I can drive the car. This is ridiculous. I haven't had a chance to get any pics of it.

PaceFabricating

HUMM this is really odd, Something is wrong, witch we now. But need some pics to really look at this. angles to the pass side and drivers side on the heads is equal right?

Confuzed1

iTrader: (4)

LilJay - Sorry to hear you're STILL having problems with that 406....but you're talking crazy stuff now. Put the 305 back in?!? Because of a vacuum leak? Are you serious? Hard to believe RTV didn't seal it though - I'll ask the stupid question then,,,you did put a nice thick ugly bead around every port just for testing purposes right??
Man, I'd even try yet another intake, another carb - pull both heads and replace them before I'd do that.
I know you're seriously frustrated - I've been there and got the T-shirt...but don't give up!! You'll figure it out!!

JohnyP

iTrader: (3)

lol well if you ever sell your 406 ill buy it....honestly man ive been following this thread for a while something seriously just doesnt add up...like we have all said take a ton of pictures so we can see wtf is going on and help out. thats got to be a huge pain in the ***....you have tried everything possible with the intake and you said the heads are fine so that again leaves the block but i dont know how that wouldnt be solved by what you have tried so far..even if it was bad you still tried stuff like rtv that should of temporarily made a small difference to show you...im sorry bro i really am GL keep your head up youll figure it out...

mattsv8_03

iTrader: (2)

this is just my opinon but i dont know af any dual plane intake that has a high enough port to lign up with afr 195s. the only edelbrock ive seen with a tall enough port to offer a good seal is the super victor. wich is what i run with my afr eleminator 210s. wich uses a 1206 gasket. but not too much diff.

CamarosRUS

I feel your pain...trust me. I have thought many times over the last 3 years "why did I ever that perfectly running STRONG 305..."

Stick with it though, this is more than frustrating since you have pursued every avenue it seems.




This also makes me wonder since there have been a couple mentioned screwed up Edelbrock intakes. I just bought an Performer RPM Air-Gap for my third rebuild hopefully this one is straight.

My block is decked .015 and my heads have been milled...so I'm sure I'll be right with ya in a couple weeks man!

CamarosRUS

HAHA....I decided to check out my intake after hearing a couple of the screw ups in this thread and guess what?







My dizzy boss is not milled straight but downward towards the drivers side at around a 15 degree angle. Don't think the dizzy would seal too well like this huh?
Sorry for the huge pics and hi-jack but I figured a couple of you would get a kick out of it.

Edelbrock

JohnyP

iTrader: (3)

no but id like to see that shot with a credit cared,numbers facing us...please be careful with thumb position that is key its a better level....lol j/k man but that is funny...

CamarosRUS

Yea I actually had my credit card out at first then was like "ummmm, lets use the Kroger card instead"


Pretty crappy though isn't it? After reading this thread and then seeing what mine looked like; Edelbrock needs to get their ish together.

LilJayV10

iTrader: (5)

Obviously this thread is old. I didn't realize how old till now. I ended up taking the 406 out of my car and putting the stock 305 back in it so I could drive it. I was so mad at the engine I put it in a corner and didn't look at it till a few days ago.

I took it to another machine shop and told the the problem. They had a "jig" made up to check the angle of the intake. It was pretty cool.

In the front the jig sits like its suppose to and you can't move it. When you put it on the rear there is almost 1/8 of an inch difference. The heads are farther apart at the rear of the engine than the front. Which explains why the rear ports leaked worse. The engine is no longer square.

I am not happy but I am not surprised. I had exhausted all other options. They are going to take some measurements from the crank center line next week to get an exact number.

Looks like the block was decked wrong.

flaming-ford

iTrader: (7)

Unbeleivable........ that realy sucks buddy hopefully you can find a way to correct this.

btw about the dizzy hole they are all angled like that, i'm sure you know this by now though.

LilJayV10

iTrader: (5)

When I got there I asked the guy if it was possible to deck the block wrong. He said someone would really have to be trying to do it. After he checked it with the jig he said there is a good possibility.

Unless the brand new AFR heads are all jacked up. I have no other idea. I am sure I will need a new block.

LilJayV10

iTrader: (5)

I know this is an old thread and I stumbled across it. To put some closure in this thread.

The machine shop that decked the block screwed it up. Bad! They were suppose to zero deck it. The heads are further apart in the back than the front. The pistons sit down in the hole anywhere from .005-.022

I have since junked the block and found another. I have been working on my 00' Firehawk and have put this project on the back burner. Hopefully next year it will get a solid roller cam and some new AFR heads with a super vic intake.

Thanks for those who replied and yes they can deck a block wrong.

lowridetractor

iTrader: (2)

ok here is what i have. 70's 350 block std. bore. speed pro .125 domed pistons.dart 215cc iron eagle heads. comp cams 280h cam. high-tech torque-link intake. edelbrock 750 carb.

the problem is i think the intake is not sealing for obvious reasons. what do you think would cause this? the intake milled for a zero decked block? the gaskets that are in there are mr.gasket 1/8 inch thick. thats the only ones that would be even close to sealing.