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I had a set of aluminum assault heads to me sbc 400 drilled for steam holes. I put them on and now coolant is seeping into my oil!!! When I drain my oil I can see a constant drip of coolant. What could've possibly happened?
 

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Did you use sealant on the head bolts?
Was the block checked for cracks?
Were the steam holes drilled correctly?
Correct head/intake gaskets ?
Correct placement and tightening of intake ?
 

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Did you use sealant on the head bolts?
Was the block checked for cracks?
Were the steam holes drilled correctly?
Correct head/intake gaskets ?
Correct placement and tightening of intake ?
Add to this...Correct torque sequence on head bolts??

Were head bolt washers used??

Did you retorque/check head bolts after a first run and cool cycle??
 

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Discussion Starter #4
Did you use sealant on the head bolts?
Was the block checked for cracks?
Were the steam holes drilled correctly?
Correct head/intake gaskets ?
Correct placement and tightening of intake ?
I didn't use any sealant on the head bolts.
Yes the block was checked.
Yes the correct head/intake gaskets where used.
And yes the heads where torqued down in the correct sequence.
 

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Discussion Starter #5
Add to this...Correct torque sequence on head bolts??

Were head bolt washers used??

Did you retorque/check head bolts after a first run and cool cycle??
No washers where used.
And no I didn't torque the head bolts after the 1st run. After the 1st run is when I discovered the milky oil. I have 0 clue if the steam holes where drilled wrong. How can I check and see?
 

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Sealer on the head bolts is mandatory on the SBC, they all go into the water jacket and coolant WILL come up through the threads around the bolt if it isn't used.

Teflon paste pipe sealant, or Black or Copper RTV Silicone is what I've always used.

Head bolt washers are mandatory on aluminum heads.

Here's what you need, if you don't already have them, Head bolts, one thread longer, does not include washers: Performance Head Bolts, Chev SB, One Thread Longer - Competition Products and hardened washers: Hardened Head Bolt Washers, 34 Pcs. - Competition Products

Competition Products is a real good source, good prices, good quality.

On the drilled steam holes in the heads, what size drill was used, how were they located, and were the upper set of holes drilled at the correct 30° angle to the head surface??
 

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Don't forget, the head bolt holes in the block need to be cleaned with the proper thread chaser or a tap, and then washed and dried(Brake Cleaner works good for this).
 

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NEVER use a tap on the head bolt holes as they remove metal which gives them a chance to strip when you torque the heads ,Only use a thread chaser ,it does not remove any metal Only cleans the threads,you ask how to check if it was drilled right ,lay the head gasket on the head with 4 corner bolts dropped in to hold gasket from moving the gasket should match the holes drilled in head 2 on each side approx. 7/32 hole in gasket should be slightly Larger than hole in head ,keeps if from causing bubbles ,steam pockets ,Also when heads are drilled SLIGHTLY chamfer the holes ,if engine is completely torn down also chamfer the head bolt holes you get a true torque if they have ben retourqued a few times on the flat surface of the block the threads WILL raise above deck giving a false torque readind and causing a gasket leak . cjamfering will get them back below deck.:thumbup:

GM ,,Chevrolet makes an excellent thread sealer ,White.
 

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No washers where used.
And no I didn't torque the head bolts after the 1st run. After the 1st run is when I discovered the milky oil. I have 0 clue if the steam holes where drilled wrong. How can I check and see?
Bolts going into the block need sealer even when they come with Teflon on them it's still a good idea to add some paste plumbers pipe sealer with Teflon. This is because this stuff has about the same friction coefficient as engine oil which is what GM torque ratings for these bolts are spec'ed with and it seals really well. This is also needed for the intake to head bolts as some of them enter the cooling system and some into the internal oily ares. So using sealer keeps coolant and oil from pooling on the intake around these fasteners.

Any bolt or nut that clamps onto aluminum needs a washer between it and the aluminum. Not any washer but a hardended washer that will not bend under the load put on it. Aluminum left without a hardened washer deforms under the clamping load which allows the fastener(s) to loosen.

Some of these aftermarket heads also take longer than stock bolts, I haven't used Assualt heads but here's a set of bolts that KMJ carrys with a note about this <<< SBC Extra Long Cylinder Bolt Set Aluminum Heads Small Block Chevy Afr | eBay >>>. So check out what you need against a stock head for bolt lenght a lot of these aluminum heads and especially the import ones are at least a tenth inch taller than factory heads needing a longer bolt.

Sealant also goes under the hardened washer and under bolt head for both a seal stopgap measure and to eliminate torque between these pieces and these pieces to the head.

It is always wise to retorque several times after building and running aluminum and iron have very different rates of thermal expansion the head when hot will not only be pulling up on the fastener but spreading them apart which bends them. Don't trust gasket manufacturer advertising when they say no retorque is necessary, my expereince says maybe, and you're betting big bucks on that maybe. If you don't chase these things a few times especially on import castings which probably aren't hardened to T5 or T6 even though they claim to be. So a soft aluminum casting will deform more when it presses against the fastener head which loosens the fasthener when things cool off because the head has flowed away from the force of the fastener allowing it to become undertorqued from where you set it originally. Aluminum work hardens so it won't do this forever, but don't be surprised if you have to go back 3 or 4 times before the material settles down. First retorque comes soon figure 3 to 5 heat and cool cycles. Second may be about 10-15 cycles. Third may be 25-30 cycles the forth may be a check with no adjustment needed. It's good to peek now and again after that but it should be stable from there out. you want to to keep coolant out of the threads especially where water is conserned as this will form rust. I know I sound like overkill on this subject but I like to also coat the female threads so the fastener pushes a bead of sealant ahead of it. I try to stay away from sealers like RTV as this stuff cures to a solid and any that gets loose in the cooling or lubrication system has the potential to cause a lot of trouble.

The head gasket on these things should be MLS, stainless faced composition or stainless and graphite composition GM sells a couple thin ones (.028), copper with a built in O ring if you're not going to O ring the head or block. Steel shim in one layer even rubber coated is iffy with aluminum they work but tend to etch the aluminum around the edges of the combustion chambers from the difference in movement between the aluminum and ferrous parts of the sandwich. Flat copper with elasomeric coatings can be good if the compression isn't over 10 to one and there is no blower of laughing gas but these need really straight surfaces and careful attention to bolt torque.

Especially where aluminum heads are concerned I like to run a number 10 wire as a ground from a non structural bolt hole that does not penetrate into coolant or oily spaces with an aluminum bolt and plane steel with a thin coat of antisize on the threads to form a ground path for each head and the intake to the chassis or battery for the ignition and any sensors atteched to the heads or intake. This is seperate from a starter ground which should be on the block close to the starter so high amp currents of the starter aren't looking for grounds through sealer coated fasteners, electronic modules or sensors. Given all the insulating goo on the part attachment fasteners which isn't conductive, the use of seperate grounds and bonds insures there is a sufficient current carrying capacity to ground. This is really important if you're using a capactive discharge ignition as that will find a ground path through something and if it's an ignition module that can get expensive to replace not to mention a tow in the middle of the night from the middle of nowhere.

Bogie
 

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Discussion Starter #10
NEVER use a tap on the head bolt holes as they remove metal which gives them a chance to strip when you torque the heads ,Only use a thread chaser ,it does not remove any metal Only cleans the threads,you ask how to check if it was drilled right ,lay the head gasket on the head with 4 corner bolts dropped in to hold gasket from moving the gasket should match the holes drilled in head 2 on each side approx. 7/32 hole in gasket should be slightly Larger than hole in head ,keeps if from causing bubbles ,steam pockets ,Also when heads are drilled SLIGHTLY chamfer the holes ,if engine is completely torn down also chamfer the head bolt holes you get a true torque if they have ben retourqued a few times on the flat surface of the block the threads WILL raise above deck giving a false torque readind and causing a gasket leak . cjamfering will get them back below deck.:thumbup:

GM ,,Chevrolet makes an excellent thread sealer ,White.
Could the heads have drilled too deep???
 

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Just a note,,you didn't mention you may already have them,, but with my Amiminum heads I had to get longer head bolts and hardended washers ( ARP ) has the correct length also I had to get longer pushrods .250 exaust .125 on intake I am using roller rockers and cam ,you might want to measure your pushrods and see if there centering valve stem . zoom in picture you can see the type head bolts I used . but that don't mean that is all you can use , hope this helps:thumbup: last photo is before I changed heads .

in first photo notice the sandwiched copper head gaskets.
 

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Could the heads have drilled too deep???


Not likely there is an empty space behind where the head is drilled ,it would have to almost had to be deliberate to drill to far,,if the heads are still off check to see if threads are pulled up slightly if so yhey will be hard to seal if not try sandwiched copper or S/S embpsed Felpro designed for aluminum heads and a steel block ,also gasket should be for a 4.185 bore ,the stock bore is 4,125 ,if .030 over it will be 4.155 ,gasket will skwish when torqued
I have used 4.185 fel pro 1010 -4.100 ,, very successfully ,for years
 

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Could the heads have drilled too deep???
It would be obvious if that happened, that would require drilling clear through to the topside of the head, between the Intake rocker arms.

I'm thinking your use of stock bolts with no washers and no sealer is the culprit.....no sealer on bolts would make torque wrench read incorrectly, as would not having washers under the bolt head as the heads will dig into the aluminum. Both these things will cause you to not reach full torque and clamp load on the gasket. Not to mention leak water up around the bolt up under the valvecover.

Seal the bolts, use washers(and oil between washer and underside of bolt head) to get threads sealed and correct torque load on the gasket. New gaskets too of course.

Fel-Pro #1010 head gasket listed in above post won't work for .030" overbore 400, too small gasket bore(to close to bore size) and no steam holes.
 

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Discussion Starter #14
It would be obvious if that happened, that would require drilling clear through to the topside of the head, between the Intake rocker arms.

I'm thinking your use of stock bolts with no washers and no sealer is the culprit.....no sealer on bolts would make torque wrench read incorrectly, as would not having washers under the bolt head as the heads will dig into the aluminum. Both these things will cause you to not reach full torque and clamp load on the gasket. Not to mention leak water up around the bolt up under the valvecover.

Seal the bolts, use washers(and oil between washer and underside of bolt head) to get threads sealed and correct torque load on the gasket. New gaskets too of course.

Fel-Pro #1010 head gasket listed in above post won't work for .030" overbore 400, too small gasket bore(to close to bore size) and no steam holes.
All this information is very good help! I will try this! ! !
 

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Not trying to bump heads with anyone the Felpro qasket 1010 is Designed for the 400sbc it has a pre flattened stainless steel flame ring around cylinder bore as you can see in the picture it DOES HAVE SREAM HOLES' .041 thickness

Also can use 1004 same gasket with wire amd with Steam Holes difference is compressed thickness the 1004 is .039 also pictured Go to JEGS or Summitt web sight they give Pictures discripion and intended use

or just type in 400 chevy felpro gasket ,they will be a complete list of gaskets:D
click on pictures below
I am sure you already know but thes print o seal gaskets are Stamped ,This side up .
 

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intake gaskets

I had a set of aluminum assault heads to me sbc 400 drilled for steam holes. I put them on and now coolant is seeping into my oil!!! When I drain my oil I can see a constant drip of coolant. What could've possibly happened?
This doesn't sound like a head gasket issue to me. Its most likely a leak at one of the coolant passages on the intake gaskets thats leaking coolant into the valley. Drain the coolant and pull the intake, you should be able to see if one or more of the four coolant passages is leaking by evidence of coolant at that corner of the valley. Make sure to use sealant on the bolt threads as well as on the coolant passages. IMHO Nolan
 

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. Also, lay intake on heads/engine without gaskets and make sure the intake and head mating surfaces are milled at the exact same angles... that the intake doesn't bottom out on the engine block before it hits the heads...

. Can also get leaks from rocker stud threads into coolant and intake ports on some heads...
 

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One of the common(just one of many in thin casting 400's)issues was the blocks cracked starting from the steam holes.....................................
 

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Not trying to bump heads with anyone the Felpro qasket 1010 is Designed for the 400sbc it has a pre flattened stainless steel flame ring around cylinder bore as you can see in the picture it DOES HAVE SREAM HOLES' .041 thickness

Also can use 1004 same gasket with wire amd with Steam Holes difference is compressed thickness the 1004 is .039 also pictured Go to JEGS or Summitt web sight they give Pictures discripion and intended use

or just type in 400 chevy felpro gasket ,they will be a complete list of gaskets:D
click on pictures below
I am sure you already know but thes print o seal gaskets are Stamped ,This side up .
Went to Summit Racing site, typed in "chevy 400 fel-pro gasket" as you said,.....and they say #1010 has pre flattened copper fire ring and NO steam holes..... says designed for '86-91 Corvette aluminum heads... Link from Summit site :
http://www.summitracing.com/parts/fel-1010/overview/make/chevrolet

So where are you finding reference to this gasket having steam holes???
 

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Discussion Starter #20
. Also, lay intake on heads/engine without gaskets and make sure the intake and head mating surfaces are milled at the exact same angles... that the intake doesn't bottom out on the engine block before it hits the heads...

. Can also get leaks from rocker stud threads into coolant and intake ports on some heads...
Before pulling the heads, I've noticed the #4 spark plug was wet! After draining my (milky) oil I can still see water dripping out the drain hole! I've ordered the new head bolts with washers. Now about those #1010 head gaskets...they have no steam holes!
 
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