Bad Cylinder head or gasket?

[wayne petty]

ok.. those look like the right gaskets for the 882 heads....

its just the port size on the intake thats smaller...

can you take a look next time you go out.. and see how much material is surrounding the ports in the gaskets... on the intake side...  see is there is any way it could leak vacuum through the gap...

i have taken to gluing the intake gaskets to the heads 20 to 30 minutes before i drop the intake on...   with 3M or permatex black super weather strip adhesive..   using some short 3/8 bolts and washers to hold it in place while it starts to dry...    this way . it does not slip when you drop the intake on..

the end rails are cleaned with brake cleaner..  as i use black or grey ultra silicone instead of a end rail gasket..

i am very careful when i put the bolts in..  plug the distributer opening with a shallowly stuffed in rag .. tape or a cap plug to prevent intake bolts from falling in.. while the distributer is out..    stuffing a rag deep will cause it go dig into the sealer on the rear rail...

after you get all the bolts in.. but before you tighten any..  you have to drop the distributer in..  make sure it will fit all the way in..

start with the center 4 bolts.. X pattern..   once you have those snug.. but not torqued..  pull the distributer back out.. tape the hole and start the big X pattern on the intake bolts...    a little tighter at a time..   going around and around.. checking the tightness at least 3 times after you reach final torque...   this way.. you know the intake is down tight..  ( vortec owners be careful the torque on vortec manifolds is small)

i use the super weather strip to glue the water passage area to the face of the heads...  

grey ultra or  black to seal the upper half to the intake.. and for the end rails..   i like the grey ultra as it hardens harder..

[Rob]

Update;  HUGE (and I mean Gi-normous) crack at the top of the combustion chamber!  I pulled the other head to check it before deciding what way to go;  it's cracked too (small, coming off plug area).  I think I'm going to go with new after-market heads (anyone have any experience with the Summit 72cc P/N SUM-152123  http://www.summitracing.com/parts/SUM-152123/ )?

Sigh

[wayne petty]

first thing i posted.. was .. a 50 percent chance of a crack...

i hate being right .. sorry...


got pictures??


i will try not to make any more cracks...


for others...   i have found that taking the valve core out of a compression tester hose... and rigging it so i can hook it to shop air... full pressure...
using a remote starter switch  to position the pistons being checked at TDC.. and charging the cylinder...  the engine might turn... just reposition it..  look for changes in the coolant level in the radiator filler neck...

it a sure fire test to verify a cracked head or blown head gasket..



and you still have one non cracked 882 head for trading or sale...  that is a very popular head... so don't trash it...  some head rebuilders will actually repair the cracked head for installation on reman motors... or to see in an exchange head type of sale...  when done right.. you cannot tell its ever been repaired...    i know..i have seen a few come back from the welding shop..   they went as far as using a needle scaler to duplicate the  combustion chamber surface..

one last thing....    do you have any kind of set up for checking deck height of the pistons below the deck.... i would really like you to set up a something and measure each piston...      if you have one ... like the one that had the broken chamber that is down a few thousands.  you might want to check the rod and the piston... make sure they were not damaged by hydraulic lock...

[zzford]

Rob, if you need to replace both heads, I see that Summit has assembled Vortecs for approx. $20 apiece more than what you were looking at. Granted, you'd have to replace the intake manifold, but you'd be looking at a very substantial increase in power.

[Rob]

Rob, if you need to replace both heads, I see that Summit has assembled Vortecs for approx. $20 apiece more than what you were looking at. Granted, you'd have to replace the intake manifold, but you'd be looking at a very substantial increase in power.

I was looking at those, but the additional cost of the intake, plus I'd have to change all my Alt/AC brackets etc,  starts to add up.  The additional HP would be nice, but for my application (cruzin around town) the smaller chambers (72 vs 76 cc) would give me a bit more compression, and I can keep the costs down a bit by using the pieces and parts I already have

Thanks

[wayne petty]

as a side note...


did anybody ever see one of these intake bolt pattern drill fixtures

http://www.bhjproducts.com/bhj_content/products/cylinderhdtooling/mdf_vdf.php

 snip

Cylinder Head Intake Drilling Fixtures
BHJ's Vortec and Magnum Cylinder Head Intake Drilling Fixtures
allow quick and accurate drilling and tapping of Chevrolet Vortec
and Mopar Magnum heads. Finished heads allow installation
of a standard S.B. Chevrolet intake
manifold onto Vortec heads, or the
"LA" Mopar intake manifold to be
installed onto Magnum heads. The
operation can be done on a bench top in 30 minutes or less using a
hand-held drill.
Both Drilling Fixtures include one precision-manufactured Fixture Plate
with interchangeable Drill and Tap Guide Bushings, a 5/16" Drill, a 3/8"-
16 Tap and necessary Mounting Hardware. Only a 3/8" hand drill and a
tap handle are necessary to complete the job.


i would think that some engine rebuilders and cylinder head shops might have one..


i wonder if the summit heads can be drilled by them..

[Okiedokie]

Since I have been dealing with head problems also I have been following your post Rob. I have noticed that Herbert Cams advertises aluminum SBC Chevy heads with name brand componants for $799.00 a pair with free shipping. Anyone have any knowledge of that product?

[Crosley.In.AZ]

Since I have been dealing with head problems also I have been following your post Rob. I have noticed that Herbert Cams advertises aluminum SBC Chevy heads with name brand componants for $799.00 a pair with free shipping. Anyone have any knowledge of that product?

Sound like Pro Comp heads.  There have been problems with the castings  and valve train parts installed.  Herbert may be using different valve train  parts.

The casting problems I read about included too thin of walls in some areas , the valve spring pockets collapsed ,  the decks were thinner than most aluminum heads offered

[Rob]

first thing i posted.. was .. a 50 percent chance of a crack...




got pictures??

I hilited the big crack with a marker, because is doesn't completely show up on the original picture with my camera, the 3rd pic is the 2nd head, smaller crack coming off where the plug comes in