Anecdotal info on failed bottom ends after top end rebuilds/upgrades.
 

In another amusing, now closed post this "wive's tale" was brought up. I'm in my '70's and can attest to how this wive's tale grew legs ... because it happened, a lot.

The fact is increasing the valve sealing via a valve job along with guide rebuilding on a car with excessively worn rings usually emphasized the failing compression by increasing blow-by and oil consumption and a wive's tale "My motor never smoked or used oil before I had the heads done" was born. Yeah, it did, but they just never paid attention to it until they re-did the top end and just couldn't admit they wasted their money on a worn-out engine because that would be stupid.

As if that wasn't bad enough, inexperienced backyard builders would combine the cylinder head work (surface seats/valves and replace or knurl the guides) with an opportunity to install a performance camshaft and matching springs along with a four barrel intake upgrade on their 2 Bbl low compression, worn-out econo-motor.

The old, worn motor was RPM limited (protected) by it's original 2 barrel carb that ran out of juice and old valve springs that floated the valves just north of 4,000 rpm. With the upgrades, the motor would rev past what was a safe upper RPM limit for
its condition and well-worn crappy cast pistons with excessive clearance would rock in their bores, rod and main bearings became oil-starved at high rpm due to excessively worn clearances and of course crappy low-performance cast rods would get stressed as the bearings got hot. The continued abuses eventually would cause some combination of spun bearings, cracked piston skirts and broken rods. Motors got grenaded and the old wive's-tale was perpetuated.

So true !

Yes sir. Then head to the junk yard.
Lather. Rinse. Repeat.

The high mileage 2 bbl motor conversion and down fall.

Install bigger cam and many times with more lift then there’s either enough retainer to guide clearance for or too much lift for the coil bind spec of the factory springs.

Install 4 bbl man and carb, IE , call upon the worn rings to seat up the added cylinder pressure .

Leave in the 40 psi pimp with its 5/8” pickup tube.

Along with not enough oil pressure leave in the factory Moraine 200 series bearings where as the factory 4 bbl motors had the far better 400 series bearings.

Now let’s float the valves at only 4500 and introduce the valves to the pistons ,

This I am guilty of 45 years or so ago.

It’s a win win for the junk yard !

But the engine in question wasnt a 2bbl, it was a HO (insert year, cid & code here) that had good oil psi etc etc. The main thing with that example was that the engine was never really driven after that or abused at high rpms, it started knocking in the driveway after the heads were rebuilt. Compression wasnt raised to cause detonation, if anything they might have had a .003 clean up that wont change the comp anywhere near enough to do damage. Highly unlikely the rebuilt heads caused the bottom end to fail on that engine.

I do agree the bottom end was fubar'd & on its last leg to begin with, and that 2 gallons of ATF, 2 different times probably didnt help the situation, but the rebuilt heads didnt "cause" the bottom failure.

Don’t you guys know the bottom end failed because the truck was at Mount Everest elevation!!! Sheez !

It failed because he's running a crank case full of transmission fluid in it. That for sure scored bearings and cylinder walls running it for any length of time, and he said he did that more than once.
Then tears it down for a head rebuild and claims it killed the short block because a knock suddenly appeared? Yeah ok lol

Did he say that ? I missed that part.

I am still trying to find out how you get a "following" when you have done nothing in the Pontiac world besides endlessly babble and screw up PMD engines.

Oh yeah, the discourse on it was quite comical.

Not “sure” if Lou had an opinion on USING transmission fluid, purchased at Walmart on sale the prior week when it was raining, or he stayed on the periphery taking pictures of the sunset.

Man I’m gonna miss those posts. LOL

I've had a number of Subarus. I've had the head gaskets done on 3, as new as a 2016. On EVERY one, they used oil after a top end rebuild.

The 2016 had 76k miles, popped HG due to oil leak on the top of pass cylinder head. At 83k miles, it was using 2 quarts of oil between oil changes after the HG replacement.

I've had a number of Subarus. I've had the head gaskets done on 3, as new as a 2016. On EVERY one, they used oil after a top end rebuild.

The 2016 had 76k miles, popped HG due to oil leak on the top of pass cylinder head. At 83k miles, it was using 2 quarts of oil between oil changes after the HG replacement.

I think this dude's threads are like a wreck on the highway when everybody slows down to look at the wreckage. I gave up on his threads 'cuz they take up too much time to look at and ruining a good 428 is too hard to read about. My brother has made good money off dudes like him when they have some myth they believe is the holy grail of engine repair and "shock" they have to have my bro "rescue" them.

Overheating a Subaru couldn't possibly
have a detrimental effect on ring seal.

Here’s one for sale on Facebook marketplace $6500 .00 forged pistons .030
Over with forged H beam rods. Same code numbers as Mike’s 428.

https://www.facebook.com/share/WKPuX...ibextid=79PoIi

A shot of the block and for sale add, including crank

Let’s see now, in terms of any motor how could overheating and blowing a head gasket a long with possible coolant getting into the cylinder(s) effect ring seal and valve guides. :-)

My post was not specific to that particular thread, but was intended to address the wive's tale of the top end rebuild causing bottom end failures in general. The engine you reference had its own set of issues and possessed dubious build quality long before it's owner started monkeying with it. I would suggest also his accounting of a motor's condition is not something I would take to the bank.

I put that Facebook marketplace add up, only because Mike thinks his motor is worth allot of money, just kind of showing him, kind of what they go for. The one thats for sale is about 1/2 hour from me.

Subarus are famous for using oil. Everyone I know with one says that.