My father in law says I need to do a compression test on my new BBC before trying to start so I can konw if I have the piston rings in the right position.  I argued with him saying you cant do that on  a fresh motor and why?  Is this unheard of, I have never done it in the past or konw anyone who has done to a fresh enigne.  One other question, If you re-use head bolts to you put silicon on the head bolts? lock tight? or what? or should I just get a new set?

Oh yea, I forgot about the white crap.  I did not think silicon or even lock tight sounded like a good thing.   

I does not seem right to be cranking and cranking on a fresh engine for almost no reason at all.   

A compression check before wont hurt anything, but unsure if it will provide any good feedback other than knowing it has compression and a good starting point for monitoring break in progress..

And a big negatory Ghost Rider on the silicone on the head bolts, use either ARP thread sealer or the white crap from Permatex with PTFE, I think it is the 14D formula (can't remember right now)..

Silicone really screws with the torque value and does virtually nothing to seal water.....

These are just my opinions and subject to flaming  

GT

A'ight.  Now you farted in my fruitloops.  

I would like to respectfully disagree

That permatex stuff blows.  I lost a motor because of it.  Thread sealer that didn't seal threads.  I used it with new CLEANED arp studs, and nice clean block threads.  It leaked water into the oil on 3 studs under the valve cover.  It's pipe dope.  Pipe dope is for pipe threads...the tapered ones.  

Silicone does nothing to seal water?  Toyota used silicone to seal water pumps to engines for years...only silicone, no gaskets.  It seals against water just fine.  

I use black silicone most of the time, and I've never once had an issue.  I prefer the toyota FIPG, but I'm starting to like the loctite black stuff too.  Permatex has never impressed me, but it seems their ultra black is better than it used to be.  

About torque values...you could piss on the bolt and it would screw with torque values...or rather, the relationship between bolt tension and the torque used to achieve said tension.  Silicone, loctite,....or hell, maybe even TEFLON (ptfe, for those that don't know) will all act as a lubricant.  Teflon just happens to be one of the better ones out there....about the only thing that can stick to it is itself.  Even though silicone has the viscosity, I would guess that Teflon would screw with torque values as much or mores so than the teflon.  If you're using studs though...that's a moot point.  

A'ight.  Now you farted in my fruitloops.  

That permatex stuff blows.  I lost a motor because of it.  Thread sealer that didn't seal threads.  I used it with new CLEANED arp studs, and nice clean block threads.  It leaked water into the oil on 3 studs under the valve cover.  It's pipe dope.  Pipe dope is for pipe threads...the tapered ones.  

Silicone does nothing to seal water?  Toyota used silicone to seal water pumps to engines for years...only silicone, no gaskets.  It seals against water just fine.  

I use black silicone most of the time, and I've never once had an issue.  I prefer the toyota FIPG, but I'm starting to like the loctite black stuff too.  Permatex has never impressed me, but it seems their ultra black is better than it used to be.  

About torque values...you could piss on the bolt and it would screw with torque values...or rather, the relationship between bolt tension and the torque used to achieve said tension.  Silicone, loctite,....or hell, maybe even TEFLON (ptfe, for those that don't know) will all act as a lubricant.  Teflon just happens to be one of the better ones out there....about the only thing that can stick to it is itself.  I would guess that Teflon would screw with torque values considably more than most others.  If you're using studs though...that's a moot point.  

I thought you said you didn't like Froot Loops...

You took me pretty literal on the flaming part.....Easy turbo..

I have never had an issue using PTFE on threads in Chevy builds....Ever. I recently picked up a bottle of the ARP stuff (it was a gimme  ) and this stuff is similar in texture (not same)...

This is the SPERMatex crap I was speaking of...  http://www.permatex.com/products/Automotive/thread_compounds/a_thread_sealants/auto_Permatex_High_Temperature_Thread_Sealant.htm

Not the plumbers paste chit...  

As for silicone, if you get silicone on a "blind hole" the chances for a hydraulic are greater than if using a paste....Silicone in itself is a horrible product for sealing against water for a few reasons. One, it does not "meld itself" well to bare metals and can be rubbed off with an oily thumb, two, water can penetrate between the bare metal and the sealant if under extreme pressure...RTV be different, but still use caution when using it on water type jobs...


EDIT; Silicone also has no rust proofing properties whatsoever...

Also, some silicones are different than others, the stuff you are talking about is NOT silicone, it "contains" silicone. It is actually RTV. A good RTV (Room-Temperature-Vulcanizing)  has properties similar to an epoxy.

The problem lies with silicone NOT being anaerobic (able to cure without the presence of air) which makes them undesireable for thread sealing, the do not cure leaving them way too gooey and prone to failure..on the other hand, RTV uses compounds more complex than me to enhance this curing characteristic....Still can and has been proven to alter torque specs in lab tests, but maybe not on the scale seen with the stuff we see...(Speaking of extremely large fine threaded equipment) I think it has to do with the curing taking place while being torqued because it gets "sticky"...Where as PTFE remains pretty much the same resistance until it fully cures, which in some cases is 4-6 hours.

Not trying to shake your apple tree, just taking the opportunity to support my comment....

I do this sort of stuff for a living, I bet I have over $1500 in sealers and compounds in my service truck, there is literally a sealer for every purpose...It's actually a little insane... I use about 2oz. of Red Loctite 271 in a month....

Ever seen yellow Teflon tape? Smaller molecular structure than the old white stuff and totally petroleum resistant....Which is why it is used on natural gas piping....

GT

OK...now you get all technical.

I'll clarify, I was referring to RTV when I said silicone.  That was a mistake.
The rest of it makes sense and I agree with you...except that PTFE permatex stuff.  I've still got the tube of it I think....same like the one you linked to.  It's crap.  Mine never cured....at all.  I even squirted some on the work bench and after a week, still un cured.  Maybe that was my problem...or thiers, I dunno. 

It almost sounds like you got a bad batch....

The paste crap does not totally "cure" in the presence of air, but in the non presence of air (anaerobic)  but it still should have skinned over and been able to pick it up like a booger...

One thing I did forget to mention, when using this stuff, "less is more" if you know what I mean...

BTW, this is the same crap that GM uses on all there crate motors, it just has a GM label on it...   http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=22434

I was a Chrysler then later a GM tech for three years when we had a drought, nobody was boating, soooo..

No harm no foul brother...See ya 

GT

Wait...are those the GM crate motors that come with a stopleak tablet in each side of the block water pump passages to seal up leaks?     I worked for GM too....

LMAO...

Yep, same ones...Ever try to get the Bars Leaks to stay in a marine engine? 

GT

We just tested Nordies mew motor, 132-135 accross the board. I think he checked gain after he ran it and was still in the 135 range. We're lookin more for a variance from hole to hole.. He has a Hyd cam and we had the inner springs out.

Wait...are those the GM crate motors that come with a stopleak tablet in each side of the block water pump passages to seal up leaks?     I worked for GM too....

LMAO...

Yep, same ones...Ever try to get the Bars Leaks to stay in a marine engine? 

GT

    WTF,   You know after reading about all this sillycone and such on head bolts, I'm about ready to toss my BBC into the back yard and just buy a blower manifold for the BBF.  Where else is this Cheby going to ooze fluids from ? 

 Whats next, JB weld for head gaskets ?