Minimum cylinder wall thickness

Rocky rotella says in his book .125 is the minimum wall thickness. Does this apply to the thrust side?
Does block filling up to the water pump holes change the minimum thickness?
Thanks  

hi i am probably not the one for your answer however i know a bit about this and a lot about overheating. first of all are you referring to filling the block with concrete for drag racing? i would not know this then. i havent read his book however if you are talking about block thickness using water then it has to do with heat transfer and cylinder cracking or distorting from heat or cyl head bolt torque. the heat warping might be reduced some with concrete but probably not the potential warping from head bolt torque or overheating.  like i mentioned though i am probably not your guy for concrete fill info.

seems like an unusual question, why are you interested in this?

what exactly are you building?

how much hp?

thanks  

Not building anything at the moment. More out of interest. Rocky is referring to .125 wall thickness without block fill. It seemed to thin to me. I was wondering if using block fill means u can actually run thinner cylinder wall thickness  

not in my limited experience with it plus the hp increase gained by running a slightly larger bore for racing is hardly worth the potential problems it can cause. early pontiacs love to run hot due to water passage design.  

Cylinder wall thickness really does not play into how hot an engine runs "old wives tale #99"
90% of the heat is transfered in the cylinder head and top of cylinder.
i would not loose sleep over .125  

hello pmd400

mb68bird has graciously posted that i am wrong. my apologies for giving you this information.

mb68bird is clearly saying that one can bore their pontiac [or other] motor out to .060 or more and it wont overheat. this is good news to me and everyone here and i'm sure they all appreciate this revelation. it means that when you drive your car in the summer with the ac on and your radiator vomits up the water and your temp gauge now reads hot in traffic where neither did this before prior to the overbore, then it is simply a faulty gauge and radiator cap. no problem easy fix.  

Hey, guys, hope I can clarify this for you.

When considering very high performance applications (as the book's title suggests) the recommended minimum nominal cylidner wall thickness of a stock Pontiac block should meausure no less than .125 inches (or 1/8") with an ultrasonic thickness tester. Keep in mind this is after final boring. Original thickness can vary, and that's why some blocks should only be taken out .030 or .040, while others may be able to got .090 or more.  

While some have successfully run their cylinder walls thinner, I don't recommend it, especially if a long-stroke crankshaft is used. Thinner cylinder walls can distort under the side load pressure exerted as the piston travels upward from the bottom of the bore. Block filler can help solidify the block's bottom end, making it more rigid, but block filler should never be used to replace metal in the cylinder walls.  

You can't condemn an engine running hot to just because of overbore.  

My 400 is bored .060 over and it runs steady at 190 degrees (in the summer in Texas).  I have always heard a Pontiac 400 can go .060 over without any issue.  I don't think I just got lucky!  

hello goatwool

i/m gonna erase my suggestions for your carb problem now "lol". your comment isn't completely useful unless you include more info. it would be helpful to know the info below.

obviously you can get away with .060 on some motors with thick enough cylinder walls. that's not the point here.


turn your ac on and sit and idle when it's 100 degrees out, what happens then?

do you have ac?

do you have aluminum heads and headers?

do you have a bone stock radiator and fan?

one can not intelligently discuss this topic with those who think they "know" what they are talking about but really don't. i never argue i let the facts argue for me. keeps me out of the loop that way. i'll just enjoy reading others comments re this no matter what they post if there any.

thanks  

Hey Barnett, erase away!  As far as the boreing .060 over -

My car has factory air - I use it all the time during the summer and it does get over 100 in Texas.  The temp will fluctuate between 190 and 200 but has never gone above 200.

I'm running factory CI heads.

The radiator is original but I have had it recored.  I'm also running the factory thermal clutch fan.

Enjoy your Holley!  

goatall  

hello goatall

You still have not answered my questions in sufficient detail, perhaps you could have someone explain them to you.

What happens when you sit for 10 minutes with the ac on in 100 degree heat?

How many rows does your radiator have in it?



Erase away”, sarcasm, really? Seems a little unnecessary, unprovoked and   undeserved. Seems like an immature reply triggered by a defensive response.I had  mistakenly assumed I was dealing with mature people here. My questions were not intended to trick or trap you. They were just for my info and others here that might benefit from it. I have no “hidden” agenda my point is very clear.

Neither m68bird or you have answered my original question. That makes it look to everyone like neither of you have a reasonable answer. Since you have no response to it maybe you can try this simple following test instead to prove me wrong.

Call jaspers engines at 812-482-1041 or any other professional engine rebuilder and tell them you have a 1966 ford 289 block you want bored out to .060 with their 1 year warranty. Tell them it didn’t overheat before and your radiator is stock and the rebuild will be also. Once they stop laughing [if they ever do] ask them if they will also do that on a 1967 or newer ford 390 that you have too. Was that no they said in between gasping for air? How about a 1969 chevy z28 302, maybe an early 327. Try a 318 chrysler, perhaps even a 350 pontiac. Maybe you’d have better luck with a 6 cylinder. Hello, are they still there? Did they hang up yet?

Oh by the way don’t forget to also ask them what the purpose is for the” overheating detector” they install on every rebuild.

Once you get a reply from them [providing it is pg rated] please accurately post what they said including the person’s name you spoke with and their shop number. This way others here can verify the info if they want to.

The physics don't care who made the motor, they applies equally to all of them.

I’ll be waiting for their response’s.  

Wow - you are a piece of work!  Conversation is over!  

Agreed, the conversation is officially over, as of now.,. it will not escalate, because I won't allow it.
IF, you guys wish to banter, use the PM feature.,. please and thank you.

 
When The Flag Drops,,,



The Bull Chit Stops,,,


P. Engineer, Engine Builder