CALLING ENGINE GUYS/GALS

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MOPAROFFICIAL said:
As I said, run it...then test again, probably fine.
That's a rough cross hatch and itll take some run time is all.
It wouldn't be a bad idea to have the heads gone through though.
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I have a set of X's fresh from the machine shop. Hoping to use them when the block gets machined.
 
dadsbee said:
Takes 2 hours of balls to the walls flying to seat the rings in a lycoming. Prior to that you'd never get anything on a compression test leak down. If I leave any airplane all winter without touching the prop(read turning the engine), there will be one cylinder that only reads 45 to 55 / 80 on a leak down due to the minor rust the open valves on that cylinder get over the Winter. Either stake the valve (read hit with a hammer) or run the engine and leak down will be 75 to 78/80 again. Can't see this situation being any different with an un-run car engine. Those rings don't seat themselves sitting in there...
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I don’t know why the Lycoming would take 2 hours to seat rings. I can’t think of an automotive engine that takes more that 3-4 pulls on the dyno to get the rings in. If it takes more than that, ring seal is compromised and you can never get it back.
 
Rat Bastid said:
I don’t know why the Lycoming would take 2 hours to seat rings. I can’t think of an automotive engine that takes more that 3-4 pulls on the dyno to get the rings in. If it takes more than that, ring seal is compromised and you can never get it back.
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Maybe load related? Rings always seat quickly with lots of load. WOT pulls on a dyno or burnouts always work great.
 
CFD244 said:
Man, I'm taking a beating here.......The engine was pulled about 8 years ago by the owner. A running engine with 75k on it. The plan was to throw it back in after the bodywork was done, but they decided to do a "little" on it before they put it back in......The cyls were de-glazed, the valves were lapped, the rings were changed, and the oil pump was replaced. He made no claims that the engine was "re-built". They eventually gave up on the project with tons of metal and body work left, which is what I have now.

I bought a leak-down tester, and thought I'd play with it. When I found the results, I simply asked if "break in" would change the crappy results that I got.......Now I've got guys telling me that I have a "piece of ****" etc.

Of coarse, I am eventually going to do the engine up completely, but after spending thousands on the rest of the car, I was hoping to drive it for a year or two then go balls deep over the winter with the engine.

I am planning, however, to tear it down before running it to make sure that nothing done will compromise the future of this engine. A set of gaskets and some plastigauge will be cheap insurance.

Thanks for everyone who responded to the question. Lots of great replies, some, not so much.
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Is that the original engine from the car? If that's the case, finding usable a garden variety or a later hydraulic roller cam 318 for cheap (if that's possible at your location) and using the 340 intake, carb, and exhaust manifolds may be the best option for now, providing you could get into one for minimal investment. That would allow you to use and enjoy the car some while buying time for the 340 until you can go through it and check things out or send it on out for rebuild. At least enough to make sure that there aren't greater issues at hand or that if any moly assembly lube has been used that it hasn't drawn moisture and corroded the crank journals and that everything is at proper torque spec. The real question that needs to be answered here is "Was the engine gone through and put back together with the intention of the prior owner to keep the car and get it back together and if so so did they do it with enough competence for it to run reliably without risking major damage?" "And what was wrong that merited them going through it to start with?" A quick indicator is seeing if the rocker arms and shafts have been changed or if they are the original ones off the engine with the rocker shaft holes egged out on the bottom. If it's the original shaft and it's off of the head, pull the end bolts and spray some carb cleaner from one end to the other to see if it has been cleaned inside. Look around at the places dirt and sludge hide and see how clean things are. That's going to let you know a whole lot about what you can expect. And as noted, if you do elect to get into it just to clean and reassemble then a dial bore gauge and some Plastigauge will let you know if you need to wait until you can machine it or go ahead and run it. If this were a 318 or 360, I'd give give it the bare minimum and let the budget build fly. But all the checking, cleaning, gaskets, and probably a usable donor 318 is going to be less than replacing a 340 block.
 
I think break in will change the results. Quite dramatically. I said that in my first response. I'm sayin it now. I never said you had a POS. A lot....and I mean a LOT of the engines I've built through the years had cylinders that looked just like yours and they turned out good. Some better than good. Is that type cylinder finish textbook correct? No. I've always had to do what my budget will allow. I don't have the luxury of doing all of the correct machine work on builds most of the time with my budget. I'm not going to take food off the table so that my block can have a perfect bored and honed finish, when I know good and well that it'll be "just fine for what I'm doing" as it is. I'm glad there are people blessed enough in this world that can afford to do it all and do it dead right. That's just not in the cards for me. It's not for a lot of people, so they do the best they can with what they have. One man's piece of ****, is another man's nice engine.
 
One more area to be inspected would be, did the guy use a rubber? hose pieces on the con rod bolds through the dis/assembly procedure. The # of cranks I see that have been dinged is just head shaking.
 
I called it a POS. I have a 'reassembled' POS 318 like that in the 1/2 ton. It has been in there for 15 years and 3 different owners. I'm going to fire it up in a few minutes and get a pizza. When I get back to the house with the pizza that ol' 318 is still gonna be a POS. It won't be anything but a POS until we tear it down and build it correctly. Long live my POS.
 
yeah what he said. if its a numbers matching motor, throw a donor in like Nicks Garage...

Garrett Ellison said:
Is that the original engine from the car? If that's the case, finding usable a garden variety or a later hydraulic roller cam 318 for cheap (if that's possible at your location) and using the 340 intake, carb, and exhaust manifolds may be the best option for now, providing you could get into one for minimal investment. That would allow you to use and enjoy the car some while buying time for the 340 until you can go through it and check things out or send it on out for rebuild. At least enough to make sure that there aren't greater issues at hand or that if any moly assembly lube has been used that it hasn't drawn moisture and corroded the crank journals and that everything is at proper torque spec. The real question that needs to be answered here is "Was the engine gone through and put back together with the intention of the prior owner to keep the car and get it back together and if so so did they do it with enough competence for it to run reliably without risking major damage?" "And what was wrong that merited them going through it to start with?" A quick indicator is seeing if the rocker arms and shafts have been changed or if they are the original ones off the engine with the rocker shaft holes egged out on the bottom. If it's the original shaft and it's off of the head, pull the end bolts and spray some carb cleaner from one end to the other to see if it has been cleaned inside. Look around at the places dirt and sludge hide and see how clean things are. That's going to let you know a whole lot about what you can expect. And as noted, if you do elect to get into it just to clean and reassemble then a dial bore gauge and some Plastigauge will let you know if you need to wait until you can machine it or go ahead and run it. If this were a 318 or 360, I'd give give it the bare minimum and let the budget build fly. But all the checking, cleaning, gaskets, and probably a usable donor 318 is going to be less than replacing a 340 block.
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IQ52 said:
I called it a POS. I have a 'reassembled' POS 318 like that in the 1/2 ton. It has been in there for 15 years and 3 different owners. I'm going to fire it up in a few minutes and get a pizza. When I get back to the house with the pizza that ol' 318 is still gonna be a POS. It won't be anything but a POS until we tear it down and build it correctly. Long live my POS.
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Lmao
 
You can do a leakdown test a number of ways and get different results. When you get a low number, you have to take a step back and think about the why of it.
Most testers will ask for a very low regulated pressure; I have seen as low as 30psi. That is IMO, nonsense. The idling cylinder pressure will be many times that, and at WOT the pressure will rise to perhaps 800psi or more, so why would the tester manufacturer specify such a low test pressure? IDK, but I've never tested at less than 80psi.

An engine sitting for years will have little to no oil on the cylinder walls. IMO, where your test would fail would be from lack of oil on the cylinder walls and lack of oil in the ring lands, which provides the major sealing.
This is the same reason why a gas-flooded engine is hard to restart; all the oil has been flushed into the oilpan, and there is very little cranking cylinder pressure being produced. Simply pulling the plugs and cleaning the gas out, then injecting some oil, then cranking it to distribute that just-injected oil onto/into the ringlands, then blowing out the excess, then re-installing the cleaned plugs, almost without exception will get it running again. Without oil sealing the rings to BOTH the cylinder walls AND the lands, the pressure HAS to be low; it cannot be otherwise.
Additionally; at rest, no matter where the engine stops, there will never be more than two to perhaps four valves that are on the seat. When an engine sits for long periods of time all those open valves are gonna grow hair, and it takes fire to burn it off. Or mechanical help. As long as that fuzz is on there, the valve will Not seal. and this is excuse #2 for a low LD test results.
You had the right idea in removing the valve gear, but you didn't follow it thru, or at least you didn't mention doing so.
Doing a LD test at 80psi or more, with the valve gear off, will blow the piston to the bottom. Read your tester. Then tap each of the valve stem pairs of the cylinder being so tested several times with a small hammer, to pop them off the seats. When the valve slams back onto the seat, it will crush the oxidation, then the next tap will allow the 80psi to blow the rust out. After a few taps, of each pair, the pitch of the sound will change as the valves begins to seal again. Pop the pair a few more times to burn the sound into your brain, then move to another pair. Then repeat the LD test. Finally inject some oil into all the cylinders and starter crank her, with the plugs out, to lube the rings and blow out the excess.
Now you can do a proper LD test. And you can see the progression in the results as the cylinder begins to seal.
However, the least worn part of the cylinder is at the bottom, and you will get the best results down there, which, with ball-honed or stone-deglazed cylinders, may not be accurate. So it behooves you to do a final LD test, with the piston at TDC.
However, at 80psi this is/can be dangerous. If you just dump 80 in there all at one time, the piston is not likely gonna stay at the top, and it's gonna take a very long bar to keep it there. On a 3.91 bore, 80 psi is a force of 960 pounds. If the piston moves, and you get caught off-guard it can flip that bar hard over in the blink of an eye, with plenty of force to break bones.
To prevent that, I installed a ball-valve and a restriction in the air line. With this I can control the amount of air entering the cylinder without changing the regulator setting, and therefore have lots of time to reposition the bar to keep the piston at exactly TDC, even as the chamber is filling.
At the top of the bore, on a previously used engine, the worn area is neither round nor straight nor perpendicular to the axis of the cylinder. So the LD test is gonna give you another set of numbers. Eighty psi will blow some of the sealing oil down, but the number you finally get, will be representative, so live with it, or bore it.

BTW-1
In Smokey Yunich's book, Power Secrets, he says that if he had an engine with over 4% LD, he didn't have a race engine anymore. I can tell you that at 2%, I have had incredible results. Results that FABO members flat-out deny are possible. In this case I don't mind being insinuated or even directly called, a liar.
BTW-2
In addition to my Hotrod 367;
I have a dingle-balled and re-ringed original-bore/original pistons, 1973 Smoggerteen, that is still great fun to drive. with 3.55s, a 904, headers/dual exhaust/ and an old TQ on a small-port intake. Ima guessing it is pushing 250,000 and more miles on the short (but not the rings). I have had this engine since the mid-70s.
BTW-3
It's just too bad that the heads are already off.
If it was mine; I would clean it up and install new gaskets, but tighten to only 80% of spec, (which IIRC is 95ftlbs). I would repeat the LD test as described above, to see what you really have. If the engine is not heat-cycled, the gaskets should be fine; I know the FelPro .039s would be.
BTW-4
it is possible to assemble a freshly bored engine, and check the leakdown before installing it, and get a really really small number. I wouldn't install my engine any other way.

EDIT
I do not mean to imply that you need less than 4% to have a decent driver. I'm just saying that it is possible to get to less than 4%. I''ll bet there are plenty of driver's out there at 10% LD. The think is this; on a GOOD day, a good low-mileage 318 might make
135psi CCP at sealevel at 4% leakage. Which means, That at zero LD, the pressure would be ;
135/96%= 140psi.. If you had one at 10%leakage, that would then be
140 x 90%= 126psi
So then from 135 to 126 may not seem like much difference, but giving the Wallace calculator a workout, I see that at 8/1 Scr and 900ft elevation, that amounts to a V/P index of 114.
At 126psi, the V/P is equivalent to what you would get at 2700st elevation with still 8/1 Scr, or
a drop in Scr to 7.5, which at 900ft equates to a V/P of just 106 .
106/114 equates to a V/P loss of 7%, and so a loss of performance of that same 7%, at WOT beginning at stall rpm, and diminishing with rpm to break even somewhere north of 3000 rpm with the stock cam.
This translates at part throttle to always having to press the gas pedal harder than what would be possible with a higher VP. And of course that also sucks gas mileage.
All in all, low cylinder pressure is a bad thing. As is large Leakage.
Large leakage also means combustion pressure is gonna blow into the pan. When the engine cools of, water that came in thru the carb as humidity will now condense in the pan, forming acids with the blow-by, that are then gonna be in the oil, ready to be pumped all thru your engine on the next warm-up cycle, where they attack anything not made of iron or steel or rubber. Not to mention that the PCV is sucking it all up as it turns to vapor.
And almost finally, most of this scenario happens in the first inch of ring-travel.
And finally; in that last inch, the ring gap shrinks and grows by 3.1416 times the change in bore size. So if your bore at 1" down is 3.910 and at the very top just under the ridge is 3.917, that is .007 , and so the gaps are changing .022! and while they are doing that, they are scrubbing the ring-lands, wearing both the rings and the pistons.
So no, you do not have to target 2% or even 4% Leakdown, but you can clearly see the problems at 210% which, intuitively, does not seem like much. But from the engine's point of view is huge.


Read about VP here; V/P Index Calculation
 
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Did a quick measurement of one of the cylinders...... .020 oversized from the factory with .0005 out of round, and .004 taper. Crank and rod bearing looked good but I didn't bother measuring it. Emotionally wiped after this thread so I slammed it back together, pushed it to the back of the shop, and said F@#k it. I'll have to re-evaluate where I am with this build.:(
 
IF IF it were me Troy, I would teardown, have a shop check block and crank and if all checks out start reassembling. Rebearing if need be obviously. :thumbsup:
 
Yeah, not race engine specs, but not terrible. What kind of piston to wall clearance do you have? I’m along with 4speedragtop, maybe even with a torque plate hone back to round. The main thing is just to know running it is not a high risk endeavor, and what you would feel comfortable running with.
 
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Garrett Ellison said:
Yeah, not race engine specs, but not terrible. What kind of piston to wall clearance do you have? I’m along with 4speedragtop, maybe even with a torque plate hone back to round. The main thing is just to know, and what you are comfortable running with.
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No race engine for this guy. I think Mopar hit a home run with the 340. The LA's could run without oil LOL.
 
Before you did anything else you should have squirted oil in the cylinders and tried it again. Fresh parts and machining won't do much to contain air without the help of oil.
 
EDIT to post #61
I do not mean to imply that you need less than 4% to have a decent driver. I'm just saying that it is possible to get to less than 4%. I'll bet there are plenty of driver's out there at 10% LD. The thing is this; on a GOOD day, a good low-mileage 318 might make
135psi CCP at sealevel at 4% leakage. Which means, That at zero LD, the pressure would be ;
135/96%= 140psi.. If you had one at 10%leakage, that would then be
140 x 90%= 126psi
So then from 135 to 126 may not seem like much difference, intuitively , but giving the Wallace calculator a workout, I see that at 8/1 Scr and 900ft elevation, that amounts to a V/P index of 114.
At 126psi, the V/P is equivalent to what you would get at 2700ft elevation with still 8/1 Scr, or
a drop in Scr from 8/1 to 7.5/1, which at 900ft equates to a V/P of just 106 .
106/114 equates to a V/P loss of 7%, and so a loss of performance of that same 7%, at WOT, beginning at stall rpm, and diminishing with rpm to break even somewhere north of 3000 rpm with the stock cam.
This translates at part throttle to always having to press the gas pedal harder than what would be possible with a higher VP. And of course that also sucks gas mileage.
All in all, low cylinder pressure is a bad thing. As is large Leakage.
Large leakage also means combustion pressure is gonna blow into the pan. When the engine cools off, water that came in thru the carb as humidity will now condense in the pan, forming acids with the blow-by, that are then gonna be in the bottom of the oilpan, ready to be pumped all thru your engine on the next warm-up cycle, where they attack anything not made of iron or steel or rubber. Not to mention that the PCV is sucking it all up as it turns to vapor.
And almost finally, most of this scenario happens in the first inch of ring-travel.
And finally; in that last inch, the ring gap shrinks and grows by 3.1416 times the change in bore size. So if your bore at 1" down is 3.910 and at the very top just under the ridge is 3.917, that is .007 , and so the gaps are changing .022! and while they are doing that, they are scrubbing the ring-lands, wearing both the rings and the pistons.
So no, you do not have to target 2% or even 4% Leakdown, but you can clearly see the problems at 10% which, intuitively, does not seem like much; but from the engine's point of view is huge.

Read about VP here; V/P Index Calculation
 
CFD244 said:
Did a quick measurement of one of the cylinders...... .020 oversized from the factory with .0005 out of round, and .004 taper. Crank and rod bearing looked good but I didn't bother measuring it. Emotionally wiped after this thread so I slammed it back together, pushed it to the back of the shop, and said F@#k it. I'll have to re-evaluate where I am with this build.:(
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Those numbers are not bad. I'd have the block honed with torque plates to where the hone just starts to scratch the low spot. Make sure they torque the main bolts to spec while you are at it. Buy a good set of file to fit rings. Get a good valve job, knurled guides are fine with me. Call it done. and enjoy!
 
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Killer6 said:
Nope. Bores look like rusted poop honed in the hopes of a dingleberry revival, valve seats wide as the Grand Canyon, piston crowns fairly crater-pitted, I haven't pulled out the Sunnen roller knurlers to "save" a guide in 25 yrs. Too many real guide restoration choices to excuse that these days.
Choice #1) drop it in, hook it up, light it, say it magically seals & You get lucky.
Choice #2) take it to a trusted shop & have it done right.
Choice #3) enjoy choices 1&2 and spend more quality time with Your ride.
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He said "poop" and "dingleberry" love it...:)
 
It depends on what you are expecting to see, an "Overhaul" and a "rebuild" are two different things...I won't even get into the term "blueprinting ". th epoint is, ppeople will machine everything off the bat while others will measure hone and rering, hand lap vales etc. others port heads while others just clean 'em up measure guide slop and go . neither is right or wrong it depneds on how you are running it. if you do car shows to the tune of 2 thousand miles a year, a overhaul may do the job. Flat out racing you may want to blueprint the engine. there is no need to sink thousands into machine work on a car show cruise engine UNLESS it actually needs it. And even then Id drop in a crate engine if it was more cost effective.
 
Treblig said:
I see cross hatching in the cylinders so how could they be worn?
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A bit of previous pitting behind the crosshatching. Also the valve seats look a bit wide. Probably touched up at some time without narrowing them. My 289 Ford seats look the same. The ld method was to knurlize the guides. They actually wear quicker. You could put cast iron guides in or bronze. I would check valve length and look at either new Hemi or LS valves. They are lighter and you then use the lighter beehive or conical springs and retainers. Hemi valve stems are 5/16 while LS are about 0.003" larger diameter at 8mm. Then it is to find a compatible spring.
Was the leakdown done at TDC? As the bores are worn a bit and looks pretty dry, ring end gap at TDC would let the leak be high. A bit of oil.on the cylinders would show if that is the problem.
 
3 words: Vice Grip Garage. Watch about 5 episodes on YouTube where he jump starts a 50 year old car, does an oil change and drives it 900 miles with no smoke. Give those bores a chance.
 
Brooks James said:
Fix it right so you can enjoy cruising instead of working in it.

Prior
Preperation
Prevents
Piss
Poor
Performance
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Gotta go with Brooks here. A numbers match engine for the car and you have it apart this far. Pull it apart and inspect it now. Even if you have to take the block to a reputable machine shop to check the block out. The heads definately need a proper rebuild. Better now in the offseason than tossing it together and finding out in the spring that it has to come out for surgery.
 
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