VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Re: Engine Bottom Noise - Thread Closed

To Bill Barker Moderator:
I have followed that thread with great interest, but as a human being I am bothered by the way the thread was closed. A lot of accusations were made by people who believe that they are right. Both sides of the engine rebuild have stated a case. Somewhere in the middle is the truth. Was the engine rebuilt right? One side says yes and states the case of several engine overheats. The other side says no - and has shells with no oil grooves to back up his side. At this point I don't see why a candid discussion did not follow instead of the thread being closed. I still wonder why the engine overheating was not stated earlier in the thread and I would love to know why the rebuilder used ungrooved shells. We all have different opinions which is what makes us human. But Rush Limbaugh said it best when he stated " Lead by example - Facts Matter, Truth Counts and Wrong's not Right - EVER - Think About It". I feel sad that this forum could not be used to bring both parties together to resolve the problem - with some give and take on both sides, instead of just closing the thread after allegations are made. Are we not Adults? Can we not reason? If we would just communicate instead of ASSUME - we can all resolve problems and enjoy this wonderful hobby. It saddens me to see the thread abruptly closed instead of real discussions continuing to resolve the problem and maybe someone will be man enough to utter those scary words " I'm Sorry - I made a Mistake - what would you like me to do to make amends" in regards to both the engine and the accusations:( :( :( :( :( :(

HI MOEDIP, THANKS FOR THE REPLY AND COMMENTS. AS TO MY ENGINE OVERHEATING PROBLEM, WELL HERE IT IS, FOR THE FIRST ONE HUNDRED FIFTY MILES AND SEVERAL HOURS RUNNING THE ENGINE IN MY GARAGE, I HAD A HEAT PROBLEM FROM THE ENGINE BEING NEW. THE TIMING WAS SET RIGHT ,AS I NEVER TOOK THE DISTRIBUTER OUT UNTIL AFTER THE MILES AND HOURS OF RUNNING THE ENGINE IN THE GARAGE. THE ONLY REASON THE DISTRIBUTER WAS TAKEN OUT WAS BECAUSE I BOUGHT A BETTER ELECTROLOCK FROM SKIP GEAR WHICH CAME WITH THE DISTRIBUTER. AFTER THE MILES AND RUNNING THE ENGINE, THE HEATING PROBLEM COMPLETELY WENT AWAY AND NOW RUNS AT THE RIGHT TEMP. THE PART OF HAVING TROUBLE TURNING THE ENGINE OVER NOW, IS BECAUSE THE TIMING IS TO FAR ADVANCED. THANKS DON :) :)

Great! - we have a start! OK - Pre68dave - is it normal for your rebuilds to run hotter than normal for the first few hours because of engine tightness? How high should should he have allowed the temp to climb before shutting the engine off to avoid damage to the aluminum pistons? Or is it normal to run hotter at first? Was he advised of the repercussions to the pistons from the higher heat? Has any one else had a newly rebuilt motor run hot from the get go because of tightness? Doesn't advancing the timing too far cause higher engine heat? How hot is too hot? I'm trying to broker some peace here - so please respond.

The last two engines I have done were test run on a rolling frame that is fitted with exhaust, gas tank, battery and radiator. The first two or three times they were started they began to overheat and were shut down. After that there was no problem. Both engines have Egge aluminum pistons, neither was converted to insert rod bearings.

OK - so how hot is too hot (what temp does the engine have to go to ) that the egge pistons will collapse like Don's?

Fellas,
I too was a bit disappointed in stopping the thread. However, I understand that people will write their thoughts without taking into account that it might not be read the way it was intended. We must all try to think about who is going to read what we write and will they be in the same frame of mind as the writer. When I feel that I am possibly getting into a sticky situation, I have the BOSS read what I have written in an attempt to not irritate readers. It works most of the time. I am sorry and appologize if I contributed to any irritation or misunderstanding.

I feel that someone, maybe moedip or Donald, could take the total information on the engine and write an article. It should be when the engine has been fully evaluated and fixed. It may help someone else avoid similar problems.

It is normal for newly rebuilt engines to run a bit hot for the initial run period. I rebuilt a '32 engine with 0.060" oversize aluminum pistons (NORS) about 30 years ago. As I remember it ran a bit hot for a while even with a modern replacement cellular radiator core. We allowed +0.002" fit to compensate for the higher expansion of the aluminum vs cast iron block. It was in the normal range for modern engines though maybe a bit higher gap. With the lack of full cylinder cooling on the early Chev 6 cylinder blocks the pistons will run a bit hotter than full jacketed blocks.

We never had any piston slap problems with the engine during several thousand miles of operation. But as written in the other thread I have a '31 engine (original cast iron pistons) with 0.004+" gap and taper that clunks a bit at idle speeds. It is guiet at higher speeds. Since it was considered temporary replacement to the original and time was a bit short to get it back in operation we put it back together knowing that it should have been bored. It is still clunking and running after ~ 1500 hard miles.

I look forward to getting additional information from all involved. That way we can all learn something.

"I look forward to getting additional information from all involved. That way we can all learn something" AMEN!
I really believe that if both parties in this fiasco will both start communicating and really try to understand the other's viewpoint that they will come up with a resolution to the problem somewhere in the middle. But both have to bend a little. Here's hopin'
WHAT DO YOU SAY GUYS?
Pre68dave - will you weigh in? Are you willing to at least talk about a solution ?
Chevy - if you are certain in your own mind that you did not run the engine hot enough to damage the piston - would you be willing to send it to Egge for evaluation as to cause of failure?
Pre68dave - if the piston comes back as defective manufacture - would you be willing to do the necessary repairs under warranty?

I'm sticking my nose in - and I hope I don't get it chopped off!!! and pre68dave knew he could do it - or he wouldn't have taken the job. Somewhere something went wrong. :confused: I leave the ball in both of your courts.

Hi Folks, I have been following the thread also and hoped it would have continued. I had my engine rebuilt and it overheated from the get go. I was told that it was because everything was nice and tight and it would go away. It would shoot up too boiling in just a few minutes after the start. after fooling around with it,checking the timeing, I temporarily in stalled a 3 core radiator from a chrysler (brand new out of the box) it did the same thing, boiled over instantly. At that point in time I decided to check the radiator for hydrocarbons and found that I had more exhaust in the radiator than out of the tail pipe. At that stage of the game I checked the compression (w hich was good in all cylinders) and decided to change the head gasket....it didn't help any. I then removed the head and sent it back to the machine shop to check over and we found all the valve seats leaking. The head was junk so they started looking for another and in the meantime I sent the water pump out to be rebuilt. When the head came back ( a 33 head that I wasn't told about) I installed it and the same thing boiled over just like before. Removed the engine and sent it back to magnaflux the block.....Oops have to go will get back shortly with the fix..hang on

If this continues I think blame should not be placed on any one person.At this point we do not know for sure what the problem is.The pistons will have to to be removed and analyzed and then it still will be spectulation as to what happened.To get so hot as to do damage, an engine would need to have the water boiled way or driven a long distance while very hot.Think we should all cool it for now until more facts are known. :cool2: :cool2: :cool2:

I agree with Chevy Nut particularly since overheating was never a part of the issue from what Donald has been saying. And, somehow things got misconstrued at the end of the last thread that his pistons were collapsed, which at this point, is definitely not the case. I think that we should wait until all of the details are in from Donald, and since it is his engine, and his money that is invested, it is up to him what he does next, if anything, or how he is going to pursue the problem with his new engine and the engine rebuilder in the forthcoming weeks.

Sorry about that, but when you have to go you go Anyway when I got the engine back and installed guess what, the dam thing was still overheating..hooked it up to the wrecker and went back to check for hydocarbons again...it had dropped quite a bit but I was not a happy camper. It was not boiling like before but it ran on the hot side. I left it running up on the wrecker and came home...still not boiling but running in the normal range which was an improvement. Lowered the car on the driveway and it would start to heat up..lift it up and it would cool down. At that point in time I said hell " I'll just run it with small wheels in the back or just big ones in the front" I finnaly got in touch with a Chevy Garu and he came down to check this engine over and had me remove the head one more time to check it out and found #5&#6 cyl's were running very hot. Removed my rebuilt water pump and started to check the large plug in the block and the water pump and the fix was the impeller on the pump was to far away from the housing. He brought the pump to his shop and corrected the clearance of the impeller and the car has been fine since. He stated that I had a good flow of water but not enough volume. I'm running it with the original radiator and have put about 300 miles on it and most of it was this summer in 90 degree weather and it runs nice and cool, even idling.

Over the years I have overhauled a few 216 engines and never had one run hot after the work. If the work is done right it should fire up and run as it did before. Hit the starter and it should run. If you have to tow or push it to start it, its way to tight.

Lets talk about shim stock fot the bearings. When I overhauled a unmolested chev engine I always found several shims on the rods and mains. The brass and the silver colored ones and if I remember correctly the brass were the thicker of the two. Maybe I haven't payed much attention to the engines I've worked on but I have never seen shims on an insert bearing.

Thats my two cents worth, if its worth that and looking forward to the fix on Don's car :rolleyes: :rolleyes:

WOW, WHAT A GREAT SUBJECT ALL ABOUT ENGINE PROBLEMS, MY ENGINE IS ONLY ONE OF PROBABLY ALOT OF OTHER ENGINE PROBLEMS. I THINK PRE68DAVE IS A VERY GOOD MECHANIC AND NO BLAME IS DUE HIM ON MY ENGINE. AS I STATED BEFORE WHEN I BOUGHT THE CAR, THE 32 ENGINE HAD A 31 HEAD ON IT, SO I FOUND A 32 HEAD AND HAD IT REDONE. THE ENGINE HAD 31 RODS, SO I FOUND 32 RODS AND HAD THE MACHINE SHOP DO INSERTS IN THEM. THE ENGINE WAS SIXTY OVER, SO I HAD THE MACHINE SHOP RESLEEVE THE CYLINDERS BACK TO STANDARD. THE ENGINE HAD 31 ROCKER ARMS, SO I FOUND A 32 ROCKER ARM ASSEMBLY AND HAD IT REWORKED. I NEVER EVER WORKED ON A CAR OR ENGINE BEFORE AND IM REALLY A GREENHORN WHEN IT COMES TO THE MECHANICAL THINGS. IM LEARNING EVERY DAY????? I HEARD THAT ALUMINUM PISTONS WAS THE BEST WAY TO GO, SO I CALLED EGGE IN CALIFORNIA AND ORDERED A SET OF STANDARD ALUMINUM PISTONS AND A SET OF CAST IRON RINGS. WHEN THE MACHINE SHOP STARTED ON MY ENGINE I TOOK THE PISTONS TO HIM AND HE ASKED, WHERE DID YOU BUY THE PISTONS AND I SAID, EGGE? WELL HE SAID, THAT IS THE WORST PLACE TO BUY ALUMINUM PISTONS. ANYWAY THAT IS WHAT IS IN MY ENGINE. MY ENGINE DID BOIL OVER SEVERAL TIMES WHEN I RAN IT IN THE GARAGE, AFTER RUNNING ONLY A SHORT TIME. AFTER 150 MILES OF RUNNING AND HOURS RUNNING IN THE GARAGE, IT RAN COOLER. THE ENGINE ALSO HAD A 31 DISTRIBUTER IN IT AND I TOOK IT OUT AND SKIP GEEAR SOLD ME A BEAUTIFUL RESTORED 32 DISTRIBUTER AND ELECTROLOCK, WHICH I INSTALLED AND HAVE NOW GOT IT TOO FAR ADVANCED, THIS IS WHY I HAVE TROUBLE GETTING THE ENGINE TO TURN OVER GOOD WHEN TRYING TO START IT ANOTHER WORDS ITS LIKE TRYING TO START A NEW ENGINE AFTER IT GETS HOT, THEY DONT WANT TO TURN OVER VERY WELL. I HAVE HEARD SEVERAL DIFFERENT COMMENTS ABOUT EGGE PISTONS GIVING PROBLEMS, AND ALSO PEOPLE WHO SWEAR BY THEM. MY PISTONS ARE NOT COLLAPSED AND AS IT STANDS NOW, NUMBER SIX PISTON AND NUMBER TWO PISTON ARE THE TWO PISTONS THAT APPEAR TO BE GIVING PISTON SLAP. I DO NOT PLAN ON TAKING THE ENGINE OUT OF THE CAR OR EVEN PLAN ON TAKING THE HEAD OFF THE ENGINE AT THIS TIME. IM PUTTING THE ROD INSERTS BACK IN AND I WILL HAVE BETWEEN .001 AND .002 CLEARANCE. PRE68DAVE IS A FRIEND OF MINE AND HE HAS DONE MANY MANY CHEVROLETS AND HIS WORK AND REPUTATION, I WILL STAND BY
I WILL PUT THE ENGINE BACK IN RUNNING ORDER AND DRIVE THE CAR. I WILL ALSO LOOK FOR ANOTHER 32 BLOCK AND PARTS TO GO WITH IT AND HAVE ANOTHER ENGINE BUILT UP , FOR MY CAR DOWN THE ROAD OR JUST HAVE IT FOR DISPLAY. I HAVE HAD FOUR EMAILS FROM OTHER GUYS WHO HAVE READ THIS WHOLE SERIES THAT YOU GUYS HAVE MADE GREAT COMMENTS ON AND THEY ALL HAVE SAID THEY HAVE LEARNED THINGS ABOUT CHEVY ENGINES AND WHAT TO DO AND LOOK FOR. I DONT THINK ANY OF US SHOULD PICK ANYONE APART, BUT WE SHOULD TALK ABOUT ENGINE PROBLEMS AND FIXES, WHICH WILL BENEFIT EVERYONE, AND NOT HURT ANYONES FEELINGS, THAT IS WHAT THIS CHAT SITE IS FOR. THATS IT FOR NOW, MY FINGERS ARE STARTING TO BLEED FORM HEN PECKING THIS KEYBOARD? THANKS DON :) :) :) :)

Donald,
If my experience is any indication, the engine will run as long as we do (1500+ miles and counting). Cathy's firetruck does not sound too good when idling slowly but runs well and hasn't stopped yet. A little piston slap is not good but also not likely to cause major problems immediately. If you don't like to hear the piston slap get a big pair of ear muffs or turn up the radio. If I think that someone will get concerned I just increase the idle speed a bit and the clunking sound goes away. Besides those aluminum pistons will not hammer as bad as our cast iron ones do.

Well, I wasn't going to extend a thread unnecessarily, but I've also received some emails (and phone calls)... all of them postive about me closing the previous discussion.

The first message in this thread says "A lot of accusations were made by people ..." and that, my friend is precisely why I closed it down... the discussion originally started as a positive one with lots of helpful comments about how to resolve a knocking engine noise... As the discussion moved on to page 6, some of the discussions got off track in solving the problem and instead shifted to a more personal discussion based on NO evidence at all. I concur with Moedip that these then become accusations, and that's the kind of stuff that we don't need here.

So, I shut that one down in hopes of getting the TONE of the discussion back on track.... (re-read my closing note if you missed it.)

Another consideration is that the thread had already gone on for 6 pages and it would be easier on our system if we limit them and move on when the topics are sufficiently covered.

Now... for future reference... the previous discussion was closed, BUT I also said that Don should come back to us when he's got more information about "facts" that would be useful to everyone. Two postings above this one, he's done that!! Thanks Don. So, the discussion now continues again, but focused back on the issues at hand and void of the unsubstantiated "accusations" that were begining to show up.

By the way, as "one of the moderators" for the 29-32 forum, I also emailed one of the other moderators as soon as I had shut the thread down.... we are ALL trying to make this a positive and informative place where Chevy lovers can chat and chew. And as a moderator we all have to do what we think is best in this regard. In retrospect, I'm still comfortable with what I did and I see no need to apologize. Prior to my posting here, this thread re-started in just the positive vein that I had hoped it would.

If anyone would like to dialogue further, please feel free to email me directly anytime. I display my email on my Profile page just for that purpose. If you want to hold a public discussion on the duties and responsibilites of the Moderators for VCCA Chat, please post a NEW thread in the <Suggestions> forum and keep these year group ones focused on the cars. Thanks... and let the productive discussions continue!

After all of the discussions on the pros and cons of the Aluminum piston I went back and read the section of my 1927 and 1928 National AA and AB repair manual about the "new" aluminum pistons introduced in the AB engine, It is an interesting piece about the difference in fitting Aluminum Vs/ Cast iron pistons and the method used to prevent the heat tansfer from the head of the piston to the skirt, and what they did to eliminate piston slap in the new engine.

Dang man!!! Ya gonna keep us in suspense or tell us what they said!??!?!?

Mr. Barker was right when he closed the prior thread. Enough was said to help start diagnosing the engine and it was getting "off track in solving the problem".

Helping a guy guess-a-diagnosis of an engine problem is one thing: trying to do a "chat forum" trial to fix blame, or bring people together, is another. Both the engine owner and the rebuilder were able to read all of our suggestions and opinions. Let them decide what to do next.

It was Moedips quote of the Radio Politician that got me thinking about the "truth" of what may the real root of the problem. Both Radio Politician and me come from a State that has the motto "Show Me". What this means is that regardless of what you 'say' it comes down to Showing -The -Proof. A radioshow hosts' idea of the "truth" is usually defined by them as whatever comes out of their mouth: in radio talkshows they don't show proof...they rely on the listeners "faith".

"Lay your hands on the radio and believe in me" .....reminds me that ALL of what I see and hear on this VCCA "forum" may, or may not, be a representive of "truth". I think its best not to judge any individual by "alledged facts" in any forum. I take all these "forum truths" with a grain of salt.

Dons' motor......Well, we can't see that real engine unless we stand right in front of it and even then it comes down to the "tail of the tape" as to what a good mechanic can measure and view the "possible and probable" cause of the problem.

Us folks on the this forum can't usually even see real "evidence" in these post; and posting "truth" is even trickier.

Don has made his engine decision with the help of our "opinions"...so Good Luck Don and I hope it all works well!

I got to go now because of I just got an e-mail that will make me rich! A lady in Nigeria will trust me to deposit 30,000,000 dollars in my bank account! All I have to do is give her my account number and we will split the 30,000,000. How lucky can I get?

Hey MrMack, I am with Bill. What did they say to prevent the piston slap? By the way I have Egge pistons in my 31. I have to admit I have not read every line of this thread but other than the noise what problems come with piston slap?

Piston slap over time will damage and cause excessive wear to the cylinder wall and the piston,.
The 1928 aluminum alloy piston was cast with an "Invar strut" the Invar strut was cast into the piston because the Invar alloy had a very low heat expansion index. Since Aluminum has a higher expansion index than cast iron the former alloy pistons could not be fitted as close to the cylinder walls when they are cold, and they would slap the cylinder walls, then at operating temp they would fill the cylinder and the slap goes away. the Invar Strut was supposed to keep the skirt from expanding so much due to the lower heat transfer rate and therefore it could be fitted closer to cylinder diameter at room temperature. The piston head was also sawn all the way around to keep the heat transfer low on the outer surface of the head to the skirt. Now does that seem logical? at least in theory?

Now everybody with aluminum pistons should not panic if they have a little piston slap when the engine is cold.The cast iron pistons also could make noise if a little loose.If noise goes away after the first five minutes there is nothing to worry about.The replacment pistons usually don't have the steel Invar strut and have a T slot cut in the skirt instead this is old technology but acceptable and they will make a little noise when cold.Should be most apparent under slight pull.The 1953 Power Glide engines often had piston slap with steel strut and all that is why they changed,in 1954,to pistons with off set pins to equalize the thrust of the piston on the cyl. wall to eliminate noise.The off set pin ment the wrist pin was not centered in the piston but slightly of to one side.Piston slap was also found in the 50-52 Power Glides with iron pistons and standard high limit .001" oversize pistons were installed or Recam piston expanders were sometimes installed.It was a spring type "wedge" that was inserted between the wrist pin boss and piston skirt to expand the piston.Due to the quite hydralic valve lifters in the PG engine other noises were more easily detected......And piston noise is still with us today,As an example the Chev. 3.1 & 3.4 engines.If people complain pistons with tefflon coated skirts are installed to cushion the slap.The ones that don't complain go on to drive them 100,000 plus miles with no problem.

Gene, that is very true, Some of the 5300 engines in the 2001 Surburbans and Tahoes were brought in for service due to piston slap complaints, with very few miles on them, I don't know if GM really got to the bottom of that can of worms. (Maybe the Teflon coated pistons as a solution?) Other engines of the same production runs are so quiet you can't hear them running if the A/C is off. I guess those that wear a cell phone duct taped to their ear and those with megawatt music? blasting out the 4 or 5 speakers don't notice it, just the listeners for noise group does.

The engines I mentioned for an example are only an few of what I have seen over the years.There has been problems like this on most makes.The pistons used in many current engines have very short skirts,Many extend only about 2" below the rings.This is done for low friction for fuel milage but it ends up giving the piston less bearing area to keep the piston from rocking.This is what modern technology is all about.

OK, now I will sound even dumber. What does piston slap sound like? I have overhauled a few in my life but I don't believe I have ever heard piston slap. Is it like a knock, or something else? I know it is hard to describe a sound but give it a try if you will. :confused: :confused:

Gene, Modern Technology, does that mean you engineer a engine and a car for what comes out of the tailpipe rather than what comes out of the driveshaft? I think that is so.

I think maybe it sounds kind'a like k-slap, k-slap,k-slap? not so much like tic, tic, tic or bang, bang, bang?

Matt,Piston slap in a stock 216 with iron pistons will sound like a slight ping when under pull and will go away as engine warms up.With aluminum pistons it sounds like an old Plymouth,which was the king of piston noise.First if it is so bad you can hear it at idle when cold it will stand out over normal tappet noise but as MrMack said it will be a clap .If heard under a pull it will be a little deeper noise like a heavy ping.There again it should go away as engine warms up.Advancing the timing will make it a little louder as it puts a little more thrust on the piston.Noises are the most difficult things to try to describe as we all use different descriptons.Also various types of pistons will have slightly different noise characteristics......Ths was as difficult as answering Don's original question on bottom engine noises....And yes if only one piston is making noise it can be shorted out.If you understood this your lucky