LilJayV10

iTrader: (5)

Has the intake been milled? What intake gasket do the heads call for? I am most familiar with felpro.

LilJayV10

iTrader: (5)

Do you know the intake isn't sealing? Have you sprayed carb cleaner over the intake gaskets to see if the motor speeds up or smooths out?

lowridetractor

iTrader: (2)

i'm unsure if it is milled or not. seems like it is. there is a huge gap between the heads and intake. the heads call for 1206 gaskets. which don't even come close to sealing.

LilJayV10

iTrader: (5)

I would see if you could get another intake to try.

When you say the gaskets aren't close to sealing what do you mean?

What do they look like on the cylinder head?

By the pic it looks like the intake isn't wide enough. However if the intake gaskets are wrong or to tall it can look the same way.

Do you have any pics of the intake off?

lowridetractor

iTrader: (2)

no pics of intake off. but it looks as if the intake isn,t wide enough. i had my edelbrock eps on and it lined up good.

LilJayV10

iTrader: (5)

You might have answered your own question.

lowridetractor

iTrader: (2)

what would make it too short tho?

Air_Adam

Have you ever had the heads off? Were the locating pins for the heads present in the block?

lowridetractor

iTrader: (2)

yes i put the heads on and the pins were there. and another note to i just remembered is i had to get a shim kit for the dizzy.

LilJayV10

iTrader: (5)

If its been milled.

Air_Adam

Yep.. if the intake port faces have been milled, the manifold itself gets narrower, which means it will drop down between the heads more than it should.

scamaro355

man i have the same problem with my dart heads and stealthram.... curious to see what u find out

lowridetractor

iTrader: (2)

uncool! i have never seen one of these intakes before. and i really wanted to use it. looks like i gotta hurry up and finish gasket matching my eps. thanks guys.

pancherj

I have had problems with intakes sealing in the past...so I'll pass on the checking method that was given to me:

1) Bolt intake down with one gasket on one side only. Use a standard thickness gasket (usually around .060").

2) Visually check the gap at the opposite side (intake to cylinder head). Is it even from top to bottom? Check the gap at front and back wall with feeler gages. Is it even? What is the thickness (needs to be at least 1/16th of an inch or more)?

3) If your gap on the side you just measured is more than the thickness of the gasket you used, you will need extra thick gaskets. I have seen .09" and .125". If the intake is bottoming out on the end walls, you will need the ends of the intake faced. If the gap isn't even from top to bottom, you will need the intake flanges angle milled so the gap is even.

This has seemed to work for me. Just remember, never trust anyone else's work...always verify for yourself before bolting it down!

LilJayV10

iTrader: (5)

I remember that the stealth ram had some problems sealing on certain heads. I have seen some people weld a bead above the ports then have the intake resurfaced. There was a thread about it but it's been a long time.

evilstuie

I realise this is a ridiculously old thread, but I'm having a similar problem with a set of second hand AFR heads.

They were used in a sprint car and had a lot of porting work done to them. Bolted them on to my 400 block along with a HSR intake, and had vacuum issues when trying to tune.

Vacuum with 10.8comp and XR270HR cam was around 10-12"hg. After a bolt got into the motor and the cylinder cracked, i tore the thing apart, sent the block to a shop to get sleevded and the other cylinders honed, replaced pistons, rods, rings, lifters and put a XFI280 cam in there.

Now it won't idle under 1300rpm, long starts, backfiring on start, hesitation, and the vacuum only reads 5-6"hg.
Checked all other sources for leaks and nothing, so I'm assuming either the head surfaces were milled at an angle to clean them up after the bolt damage when they were surfaced, or when they sleeved the block they surfaced just the one side or just around the sleeve and made it uneven.

The other post-build factor to this, is when i bolted the intake down, the bolts were rather difficult to get in, where I used to wind them in by hand most of the way, I only got about 1/3rd in before i had to use the wrench, and the angles weren't the same.

The first build may have been block/heads, but with the work done it feels like either they stuffed up and made it worse...
Or they did it correctly, but exaggerated the problem I already had and created a larger vacuum leak with the intake ports not lining up.

Does this sound possible?
I'm going to do what has been suggested here tomorrow, and i've bought a digital angle tool of ebay to determine if the angles are different on each side, or if they're both out, and then check the intake as well.

88305tpiT/A

iTrader: (2)

8 year old thread.. nice.

In your situation, if the motor will idle, I would do a smoke test.

Get the motor idling and get cig or something else that smokes lit and see if you can find where the vac leak is.

The other way of doing this is with propane, where instead of smoke you wave an unlit propane torch around the motor to find the vac leak. when you get close the idle speed should go up since the propane will actually bring the F/A ratio up. Never sat right with me having propane just running unlit like that for any length of time though so I usually use smoke to see where it gets sucked in.

evilstuie

that test will only work though if the leak is on the top of the intake runners yes?

If the angle has changed and it doesn't crush seal at the bottom of the intake, then i won't see any change.

88305tpiT/A

iTrader: (2)

It will work if there is a vacuum leak anywhere downstream of the throttle blades.

If the leak is from the intake runners to the valley of the motor, you still need to smoke test to see if the front or rear china walls of the block are sealed. If the arent, you've likely found your leak(s). If the are, now you can check the PCV system to see if the engine block is under vacuum. Do this by plugging the breathers on the valve covers and putting a vacuum gauge on the oil pan dip stick. If it pulls vacuum - yeah your intake isnt sealing to the heads.

evilstuie

Genius mate.

I'll give this a try.

That will at least save me breaking a perfectly good gasket on a hunch.

evilstuie

So I made a smoke machine, but it didn't really smoke, and I couldn't check it with the motor running as the vacuum leak is so bad the engine won't idle or run on it's own.


I've taken the intake off and took a look at the gaskets.
Although the engine has only run for maybe 20 minutes, they didn't look like they had crushed at all.

The bolt holes didn't look like they lined up that well and the gasket was soaked in fuel from when I disconnected the fuel rails just prior to unbolting the intake.

Before I did that I soaked the fuel up with some cloths, so the fuel was able to travel through the gasket before undoing the bolts.

I removed the RTV sealant from the coolant passages and china wall edges, and the intake and place it back on after cleaning the surfaces.

It seems to fit correctly, but the china wall only has 0.048" gap when I measure it with the intake sitting on the heads with no gasket.

Does that sound right for a stock block?
Is there anyway to calculate the deck height from that?

Anyway, I put some of the blue gunk you can buy for checking bearing clearances on, and just smeared it on.
First attempt there was nothing on the intake, so i put the blue stuff on a bit thicker, and got some random bits of blue in spots, but nothing to definitely find a low or high side, left/right or back front.

Any other ideas I can try?

Oh also, I measured the head angles on the intake ports:
Left Front:54.28
Right Front:55.15
..Left Back:54.26
Right Back:55.14

pancherj

Put a gasket on one side and bolt the intake on that side. Measure the gap on the other side. It sounds like you need extra thick intake gaskets. Consequently, This will push the intake up some and make the China wall gap a little bigger (although the .048 isn’t a huge concern).

evilstuie

What should the china wall gap be standard?

The new gaskets are procomp and about 0.10" as opposed to the felpro 1205's that were meant to only be 0.060" so that should help.

If my chinawall gap is bigger than it should be, should I maybe use the stock chinawall rubbers, and coat both sides with RTV to help strengthen it and fill it?

pancherj

.048” is just under 1/16”... that is tighter than stock, so the rubber gaskets won’t fit. Follow my suggestion. If you bolt manifold to one side with gasket and measure gap on opposite side, it will tell you if .10” is too thick, too thin or just right. Measure in a few spots to make sure gap is fairly even.

evilstuie

OK.....
So here are some measurements firstly:

The right side are measured with a gasket on the LHS, left measure with the same gasket on RHS. Bolted down and tightened but not torqued to spec.

Clearances:
..Front left Cylinder to Intake- 0.020"
Front right Cylinder to Intake- 0.081"
...Rear left Cylinder to Intake- 0.030"
.Rear right Cylinder to Intake- 0.066"

..China wall Front Left to Intake- 0.090"
China wall Front Right to Intake- 0.083"
...China wall Rear Left to Intake- 0.083"
.China wall Rear Right to Intake- 0.078"

Angles:
..Front Left Cylinder: 34.85
...Rear Left Cylinder: 34.86
Front Right Cylinder: 35.15
.Rear Right Cylinder: 35.15

Then the observation that was missed this whole time.
On the china wall at the front, the left cylinder head edge is 0.035" higher than the wall.

On the back right section of the block, the head sits 0.035" lower than the china wall.

The other 2 edges line up correctly.

So I'm pretty sure that is the problem, the $64,000 question though is.... how the F*(& do I fix it?
Do I need to get both heads milled on the intake port side?
Os it possible to loosen the head bolts and move it slightly to correct it? I know the bolt heads have a slightly thicker spot that lines up the heads so I didn't think it was possible, but this seems to be a pretty big problem to fix to me....

Any ideas?

The intake is a Holley Stealth RAM, in case it's possible to mill that to suit.
Currently the bolt holes line up pretty well. I slightly elongated them, but it was the tiniest amount I took off, I couldn't really even see the hole change shape.

Also without gaskets, the intake sits firmly, no rocking by pushing on any corner of the intake.
Here's a high res image of the front china wall:
https://imgur.com/6fYSBZK

and the back one:
https://imgur.com/VWNtmBI

NoEmissions84TA

iTrader: (1)

Then the observation that was missed this whole time.
On the china wall at the front, the left cylinder head edge is 0.035" higher than the wall.

On the back right section of the block, the head sits 0.035" lower than the china wall.

So then you are saying that 1 head is not sitting on the block correctly.
The head is located by the 2 pins in the deck surface.
Something has to be amiss there.

evilstuie

Nope, I'm saying I think both are wrong. :/

Both heads have the dowel pins in the block and all the head bolts are in and aligned correctly to the block.

But 2 corners of the heads to block are level, as in, the edge of the head where the angle changes, is flush with the block.

On the other two, the front left and back right, The left front sits 0.035" high, and the opposite head and the back sits 0.035" low on the right.

NoEmissions84TA

iTrader: (1)

I follow you, but WTF???
So your heads and/or block have been milled crooked.


What if you swapped the heads side-to-side?
Do you think that might change anything?

Jorlain

iTrader: (4)

The obvious answer would be that the head is somehow located wrong or something along those lines. But, from what you say, sounds like that's not the issue. Is there any chance that one head has been milled but the other hasn't?

I don't know how viable it is, but you might be able to get away with running one thicker gasket on the right hand head, and a thinner gasket on the left.

pancherj

They make cylinder head dowels that will offset the head... but hat seems like treating the symptom to me. The block was probably zero-decked and the machinist never checked the China walls. Two thicker gaskets would push the intake up, but slightly misalign the ports and bolt holes. The other option is removing the engine and taking the block, heads and intake to a competent machinist. If this is just a daily driver, I would be tempted to go the thicker gasket route.

Jorlain

iTrader: (4)

To clarify, I meant using a thicker intake gasket on the short side, and a thinner one on the taller side.

Using different height\thickness head gaskets wouldn't sit right with me personally.

NoEmissions84TA

iTrader: (1)

Just to clarify guys: (as I read this)

Then the observation that was missed this whole time.
On the china wall at the front, the left cylinder head edge is 0.035" higher than the wall.

On the back right section of the block, the head sits 0.035" lower than the china wall.

But 2 corners of the heads to block are level, as in, the edge of the head where the angle changes, is flush with the block.

On the other two, the front left and back right, The left front sits 0.035" high, and the opposite head and the back sits 0.035" low on the right.

evilstuie

Yes that's correct.

NoEmissions84TA

iTrader: (1)

This is soooooo messed up.
The only thing I can come up with is that someone installed offset cylinder head dowel pins.
Anyone else have any good ideas?

Jorlain

iTrader: (4)

Wait. What? I'm so confused. How can that happen!?

NoEmissions84TA

iTrader: (1)

I'm still wondering if swapping the heads side-to-side might make things "straight"?

Jorlain

iTrader: (4)

I'm eager to know myself.

evilstuie

I thought about that, but then the edges would just be on the reverse side, because the other 2 ends line up with the china wall perfectly.
So if I swap the heads and reverse the orientation, it's just going to move the issue yeah?

NoEmissions84TA

iTrader: (1)

Maybe, maybe not. This is just so effed up.
I think it that will be costly to make it correct.
At this point, why not try the swap? It can't get any worse.

evilstuie

I'll try the thing gasket one side, thick gasket the other first, as that's the easiest to do.
That will at least confirm if I'm on the right track if the vacuum and KPA improves.

To swap the heads I have to undo the rockers, remove the pushrods, then clean up the heads, and the block without getting any crap in the motor, buy a new set of head gaskets, and then reset all the valve adjustments again, and that's if it fixes the problem.
Just more money spent fixing something I didn't break.

At least if the gaskets work enough I can drive it down to the shop and show them what they've done and tell them to fix it.

evilstuie

Maybe it's the flu talking, but swapping the heads would fix the china wall alignment issue if they didn't touch the block deck and just milled the heads and then checked them only one way.

But the clearances on the intake port to head surface would still be different either side.

Jorlain

iTrader: (4)

As the diagram above indicates, though, I don't think the thin\thick gasket will work. I think I was misreading the situation and thought that one head was sitting higher than the other one on both ends, not just one.

evilstuie

That's the truly weird f**&ed up thing, the head/china walls joins don't match up, but the clearances from the mating of the intake to heads does, at least in that the front and back of each side are within 0.010" of each other.

I just went to the nearest auto shop and bought some copper gasket spray, permatex hardening sealant, 0.040" gasket paper and some super glue.

I'm going to use the thick gasket on the larger clearance head (0.100"), and make a 0.040" one for the other side. When I install it I'm going to put a thin line of the hardening sealnt around each intake port, place a bit of superglue on the center areas of the head to hold the gasket in place, and then lightly spray the gasket with the copper spray and place it in place.

While it's setting, I'll run another thin line of sealant on the top side of the gaskets, and a thick bead of RTV sealant along the china walls and the head/block corners. Then I'll drop the intake on, make sure all the bolt holes line up and the gaskets haven't moved, and then finger screw all the bolts in, then torque in 5lb increments in sequence till i get up to 25lb.

If it still leaks after that, I'll know it's beyond my abilities and remove the motor and drop it off at the shop that screwed it to fix. If they don't then I'll take it to small claims court for everything from the diagnosing time, parts, labour, to the fuel money spent driving it back to them.

NoEmissions84TA

iTrader: (1)

I don't think that the thinner gasket you make from gasket material will be stiff enough to stay in place long term - it will probably shift. I suggest using an actual .060" intake gasket on the "thin" side, but you could make the .100" gasket thicker by adding gasket material to it on it's back (head) side.
You might even want to not add material to the entire length of the gaskets, so you can end up with gaskets that are thicker at whichever ends need the added thickness to compensate for the crookedness of your heads and/or block.
Before you torque the intake in place, look at the bolt hole alignment to see if the holes need to be elongated so as to not prevent the intake from seating all the way down.
1 other suggestion is to only torque the intake down evenly to only maybe 10 ft/lbs and leave it that way overnight for the sealants to dry/harden. Then torque it down the rest of the way the next day.

Good luck.

evilstuie

Yep, sounds good.
I'll do it this afternoon and leave it overniight at 10ft/lb torque and finish it off tomorrow.
At the very least if there's no vacuum or kpa change I know I'm chasing my tail, but if it improves, even if only for a minute or two, I'll know I've at least identified the problem and where my leak is, so it won't be a total loss.


I called the engine shop and the guy said he didn't do it, it was the other guy and to call back later, so I'm pretty sure they'll just deny everything and say it was already like that.

evilstuie

Well it's all done, mostly.

Torqued everything up except the inner bolt on the right hand front coolant passage is spinning in place.

This is most likely the result of some of the thread material breaking off the bottom of the underside of the head, so there's no enough material to grab onto.

Not sure what I can do there, but I'll keep any eye on the oil and see if there's any water getting into it.
I thought of putting some loctite on the bolt, but not sure what to do there.

Everything feels good, but I'll find out tomorrow when I fire it up.

I had a quick go this afternoon to fire it up, but the dizzy wasn't set right, but I'm pretty sure everything else is ready to go.
Once its running I'll know pretty quickly if the vacuum issue is resolved, better, or worse.

NoEmissions84TA

iTrader: (1)

Install a stud in that hole with red Loctite and use a nut and AN washer (3/8" hole with a small outer diameter).
Try to have the stud grab all of the remaining threads that it can.

Below: SAE vs AN flat washer

evilstuie

Awesome.

I've ordered the stud and washer and should arrive this week.

NoEmissions84TA

iTrader: (1)

Good. Hopefully the remaining threads in that end hole in the head are enough to hold the stud securely.
Loctite those threads only, not on the nut.
If it ever has to come apart again, you want the stud to stay in the head and the nut to remove easily.
I don't know if the stud you ordered has any coatings to help prevent corrosion, but a smear of anti-seize on the threads for the nut would not be a bad idea.

evilstuie

Yeah will do.
I think there's enough thread there. It will hit about 5ft/lb and hold, its only spinning at 10ft/lb.