Show and tell

[mytmouz]

Well I've got to pull me engine and do a tear down inspection. Give your opinion as to what's wrong, and when I get it out we will see. :( I've got an iron block/aluminum headed small block. It has head studs which are sealed, oringed heads/reciever grooved block, copper head gaskets that were retorqued after the 2nd heat cycle. (six passes now). The block is partially block filled. When I dropped the pan to fix an oil leak, I noticed water dripping between the # 4 piston skirt and the cylinder wall. When I rotated the crank to look in the bottom of the cylinder (it was at the bottom of the stroke) water ran out of the header when the exhaust valve open. It did not run hot (over 180) at any time and the water was not mixed with the oil. What's your guess? I'm going with a cracked cylinder as that's the way my luck goes.

[zipper06]

Well Neighbor,
Either way it doesn't sound good. I thought you had a Dart lillte "M" blk in the truck, which at 4.125 bore should never crack.
Which ever way it goes let us know.

Zip.

[davis419b]

If the block was a Dart it probably would not have grout in it. I bet it is a GM 400 and i am going with a cracked cylinder wall. I have had it happen in the 10 tears i ran a 377 sbc,

[mytmouz]

It's factory GM, sorry I left that out. However it turns out, I'm gonna go aftermarket this time. *$@# budget racing. :lol:

[jaykz1000]

yep i had a 509 block ran it for 2 years had cometic gaskets on it always thought they leaked some over night... so i just drained the radiator after racing and went on with it ... then i had to take engine apart one day and found i had a hair line crack in one of the cylinder walls toward the lifter bores... it was about 3 inchs long... u could barely even see it ...been runnin it like that for 2 years .lol thank god it wasnt on the thrust side.. prolly tore up everything heck i ran compression and all on this engine many times and it was fine... i have had many 350 block crack and u can tell when they did be a wide crack...

[knova70]

I guarantee it was cracked at the steam hole,usually the top one and after it cracks from the stress of the head stud and cylinder pressure,then the crack starts to run down the cylinder wall,after taking my 400 apart for the same reason that was what it was,and it cracked on every top steam hole but only 2 cylinders were cracked,and this was a virgin block with only about 30 passes on it,it was maged before it was machined,but thats what I get for using a stock block! went to a bowtie aluminum block as of now hope this one doesn't crack?

[jaykz1000]

my holes where plugged and then decked

[knova70]

they still will crack,doesn't matter what you do to them,just personal experience.

[jaykz1000]

never said they wouldnt just statin that they can crack any where anyway...

[bjuice]

have the heads had any work done to them ?..i have seen over agreesive port work done where the exhaust valve bowl developed a hair line crack..you could not see by looking at it...i did a backyard pressure test..DAWN dishwashing liquid and a air pressure hose...showed right up.

it did not run hot..when the motor got warm the crack in the heads would expand and leak fluid into the #8 cylinder..after it sat for a while the cylinder would fill up...

if there was any epoxy work done to the heads it could have come loose...SO DO NOT PUT ALL THE EGGS IN THE BASKET ON THE BLOCK BEING BAD AT THIS POINT..

brian

[mytmouz]

Heads were pressure checked before this install, no leaks on the other motor they were on, bjuice. Maybe I'll get lucky and it will be something else. I'm probably overdue for a block problem, as I've run em at .060 and never had a problem. :lol:

[mytmouz]

I believe I'm gonna get lucky. Pulled the heads, cylinders are beautiful. Looks like the problem is gonna be in the seat of the # 4 exhaust valve. :shock:

[davis419b]

.060 over on a GM 400 is a disaster waiting to happen ! I ran GM 400 for years and when .030 got loose i got another block. Never blew one up!

[mytmouz]

:? Well, the head checked out OK. Pressure checked OK. Checked for warpage, OK. Block looks perfect also. Any ideas?

[bjuice]

when you said the head checked out ok..what was done to check the head...was the vales taken out and bowls,etc checked.. ? Mine also checked good on the initial rounds of pressure checks but after much closer with the inspection ( with dish washing liquid) we saw the tiny bubbles coming from the crack in the bowl itself.
it was seeping so slowly that it would pass the Pressure checks.... bit would eventully seep enough water into the cylinder once the head got hot........if your heads have had any port work at all i would start where the work was done..

One thing for sure its soming from the heads or the block ..lol :D :D ..

i would really look close at my heads before i got into the block...

Terry my hairline crack was so small it was almost undectectable.

just telling you how i would handle if it were my motor.

hope you find it.

also what brought you to conclusion the problem was in the exhaust seat valve #4 ?


thanks brian

[mytmouz]

Yep, the valves were removed, my head guy waited to reassemble them after I looked at em. The reason I thought it was the #4 exhaust port was water stains in the port going out to the header. I believe now that the valve was open, and the water was backed up past the valve. Good ring seal. :lol: The shop I use is a locally known shop and one of the areas best tuners is next door. The engine builder at the shop and the tuner guy in separate conversations said it was probably a gasket sealing issue and told me the method they used, practically identical. A thorough search of the block once more and swapping the heads from side to side is next.

[sg6085]

You need to pressure check those heads in hot water, have seen the presure test fine till up to temp. Good luck though hope it is a gasket problem.

[mytmouz]

Yeah, good suggestion. However, this leak was while it was sitting on the trailer so I'm hoping I'm good. Finally got my head gaskets yesterday, what i get for buying local. Maybe in a week or so i'll have it back up. Thanks.

[mytmouz]

Well, my buddy and I triple checked everything and put it back rogether today. Brought the engine home and started getting it ready to drop back in. When I get an extra set of hands I'll get it in and we'll see.