pishta
I know I'm right....
How long does it take? stock Iron rings, 240 grit dingle ball clean up to uniform gray on parallel glazed cylinders. procedure? Just on my beater Mazda.
ring break in time
- Thread starter pishta
- Start date
-
pishta
I know I'm right....
did the rings, gaps 120 degrees apart per FSM, reconditioned head w/valve job 500 miles ago, new head gasket...get it all put back together and I got 5 inches of vibration on my vacuum guage...Fuc-------!!! :-( cylinder drop shows me #3 is not hitting. Dont have a leakdown tester yet.
circlepilot
Well-Known Member
You did get the rings "right side up," didn't you? I'm sure you got the right diameter rings? Just because you have a "fresh head" doesn't mean there is not a valve train problem. When you get a hold of the leak down tester, you should find out really quick where the problem is. Valve problems...air noise either in the exhaust system or in the intake manifold. Ring problem...air noise in breather.
Norm
67Dart273
Well-Known Member
If you are talking about all iron rings, almost zero. Should be nearly a short drive. You don't want the cylinders too "slick." (Old school crosshatch)
So far as gap, you could intentionally line them all up and it should run better than you describe. I vote valves or some other problem.
So far as gap, you could intentionally line them all up and it should run better than you describe. I vote valves or some other problem.
I get a laugh out of these idiots that put a freshly bored engine on a dyno for 30 min with WOT pulls & claim the rings are now 'broken in'. Broken might be the right word in this case, as the intense heat generated from friction from new surfaces getting acquainted might anneal the rings.
There is no set time for rings fully breaking in, but 2000 miles is a good number. Driving at 50 mph, it would take 40 hrs. Use mineral oil, then switch to your oil of choice.
And an 'in tune' driver you will notice the difference.....The engine feels more lively because it is making more hp from better ring seal & reduced friction.
There is no set time for rings fully breaking in, but 2000 miles is a good number. Driving at 50 mph, it would take 40 hrs. Use mineral oil, then switch to your oil of choice.
And an 'in tune' driver you will notice the difference.....The engine feels more lively because it is making more hp from better ring seal & reduced friction.
TT5.9mag
Two atmospheres are better than one
Nope. To anneal cast iron it has to heated much hotter than combustion temperature and remain there for 1-2 hours then cooled slowly. You ain’t getting to that temperature in a running engine. I’ve put a bunch of engines that have had minutes of run time on them, (just enough to do idle timing and carb adjustments) on the dyno and they go through a short dyno break in and then to wot pulls. And they typically come off the dyno leaking down between 3-6%. Load breaks the rings in. Period. Pat Musi was asked once how he breaks an engine in. Look up what he builds if you don’t know. He said “we start em and put em at 8500 rpm in the burnout box”.
pishta
I know I'm right....
no, I have 120 psi. only down ~20% from the others. but I got no fire, I pull the plug wire and I see a healthy spark to a new plug but the idle does not change. I cant imagine a bent intake valve but dang it if I got a crank speed 5 inch deflection on my vacuum gauge at idle. Only last week did I tell my self "man, I've never seen a gauge do that" while looking at the cheater sheet for a vacuum gauge reading.. and now I'm witnessing it. I sure hope its a friggin intake manifold issue. Taking this chain driven OHC head off requires you to pull the friggin water pump! Ill let you all know what the cylinder pressure test reveals. All valves are .012 per spec hot. Cant really tell if one is lower as they are not comparable with a straight edge unless you take the head bolts/valve train off.
Rat Bastid
Dunamis Metron
If it takes 2000 miles to get the rings in the engine is junk.
All rings today, even the most cheap assed rings you can buy are either belt lapped or barrel lapped.
Ring break in time is near zero. You might see a 1-2% reduction in blowby from initial start up until the 4th or 5th pull. Because the rings are in.
The days of long break in times for rings is decades past.
If the rings aren’t in in a short run in time the engine is junk.
NudeHemidude
Well-Known Member
Could it be a bad plug? Swap a spark plug from a good cylinder and see if things change.
pishta
I know I'm right....
new plug(s) and I even swapped cables AND plug into good cylinder. Cylinder pressure test didnt point to anything leaking anywhere (crankcase, intake, nor exhaust) Another 2 suggestions from the all knowing internet: Holley says ignition issue , while Vac Visual: Quick Guide to Vacuum Gauge Readings - OnAllCylinders says valve guides.....Maybe as I got new rings and now its higher vacuum is highlighting the old valve guides? I had a valve job done <1000 miles ago on this head (milled, valves ground...) not sure if he touched the guides. F it, these are press in guides with a hammer according to the FSM so Ill spend $25 on all 8. Could not hurt, Ill learn to hammer a guide in and I got 5 months to complete this truck. Really dont want to use the old head but I got it just in case. What effect will a smaller exhaust port have on overall driveability? I know the W2/Wx had a dinky looking exhaust port but they flowed like a ****.
Charrlie_S
Well-Known Member
Slant six heads have the guides as cast into the head. The only way to fix them is to:
1) bore over size, and use press in liners
2) use a Bronzewall liner that looks like a "helicoil"
3) Old school knurl the guide
pishta
I know I'm right....
This is on a Mazda B2000 so they do drive in with a hammer. They are only $2.50 a piece (ID is already finish reamed) so I'm gonna try and replace them myself. This diagnosis makes sense as the closed valves sealed up fine, it was the lean mix in #3 from the bad guides that would not light off, theoretically...... I even put a Mallory HD coil on it and almost put a Hi-6 box in to see if I could force it to fire but I didn't want to hack the Hi-6 harness for this POS.
pishta
I know I'm right....
Rapid Vibration at Idle
If the needle vibrates rapidly between 14 and 20 inches of mercury, but then steadies as rpm increases, you may be dealing with worn valve guides. How fast the needle vibrates is telling of how many valve guides may be worn. (Like all of them!!!)
67Dart273
Well-Known Member
Pishta, I think you are on the wrong track. A guide, in my view, would have to be so bad that you could easily wobble the valve in there by hand and see it, before it would leak enough to not fire. I think you have another issue, like an intake leak, etc.
"I aint there" so just some wonderings...........
1....This efi or carb? That alone could open up all sorts of stuff. Again, vacuum, intake, etc leak
2...You ever run a leakdown? Even if you don't have one, you can put air into a cylinder, either make a fitting from a plug or you can buy cylinder/ air fittings cheap OR----remove the schrader from your compression tester and use it to inject air
3... You can easily make a leakdown tester from a compression gauge, an air regulator, and a few pipe fittings. You really only need one gauge. I'm assuming you have a hose type compression tester with a quick disconnect setup? Put the gauge on the downstream side of the orifice which you can make, and set it by unplugging the hose, which blocks airflow by closing the connector, and set the gauge for either 80 or 100. Then screw the hose into the cylinder at TDC and plug the hose into the made tester.
Your "path" is air hose--regulator--tee. One branch of the tee gets a quick connect nipple to fit your compression gauge, the other tee branch gets an air coupler to fit your compression gauge hose. Figure a way to fit the will be orifice between the regulator and tee. Drill it for .040" or close as you can, or find a jet like Holley about there, and braze / solder it in It will not be "aircraft accurate" but it will give you comparable results.
Is there ANY chance you are misreading the spark situation. Any chance there is some sort of distributor / cap/ wire problem that you are missing? Timing? Firing order?
Any chance the cam is flat?
You can bounce the valves by tapping with a hammer and a piece of wood, and that will give you a clue "if they are sticking."
Take a really REALLY good look at the intake system. Stick an unlit LP torch in there around that port and see if "anything"
"I aint there" so just some wonderings...........
1....This efi or carb? That alone could open up all sorts of stuff. Again, vacuum, intake, etc leak
2...You ever run a leakdown? Even if you don't have one, you can put air into a cylinder, either make a fitting from a plug or you can buy cylinder/ air fittings cheap OR----remove the schrader from your compression tester and use it to inject air
3... You can easily make a leakdown tester from a compression gauge, an air regulator, and a few pipe fittings. You really only need one gauge. I'm assuming you have a hose type compression tester with a quick disconnect setup? Put the gauge on the downstream side of the orifice which you can make, and set it by unplugging the hose, which blocks airflow by closing the connector, and set the gauge for either 80 or 100. Then screw the hose into the cylinder at TDC and plug the hose into the made tester.
Your "path" is air hose--regulator--tee. One branch of the tee gets a quick connect nipple to fit your compression gauge, the other tee branch gets an air coupler to fit your compression gauge hose. Figure a way to fit the will be orifice between the regulator and tee. Drill it for .040" or close as you can, or find a jet like Holley about there, and braze / solder it in It will not be "aircraft accurate" but it will give you comparable results.
Is there ANY chance you are misreading the spark situation. Any chance there is some sort of distributor / cap/ wire problem that you are missing? Timing? Firing order?
Any chance the cam is flat?
You can bounce the valves by tapping with a hammer and a piece of wood, and that will give you a clue "if they are sticking."
Take a really REALLY good look at the intake system. Stick an unlit LP torch in there around that port and see if "anything"
Last edited:
pishta
I know I'm right....
Just read this and yes, I took a Propane torch and waved it around that intake port gasket and nothing. Did a pressure test and no audible leaks above the other 3 cylinders. Still getting 120-130 psi compression out of that #3 hole within 10% of the other 3. Can't wobble the valves in new head as the valves seal is a polyloc thay i cant readily remove and would artificially support the valve in a crap guide. Carbed, common plenum up to the last 2 inches. Replaced plug, checked ohm/swapped wire, changed coil, cap has no wear visible on #3 contact, looks identical to the other 3, rotor is as new as cap <500 milea and they ran great until I put this newer head on. I pulled the guides out of the old head (that ran fine) and all 8 are perfect. No wobble, no wear, look like ther were replaced before I got this head as they are not OEM. All 8 will almost support the valve on the air pressure the tolerance creates if you plug the end with your finger. So I know the old head was good, it just didn't have the right port shape, not a deal breaker but I don't know of how long the Mickey mouse adapter plate I made out of aluminum will seal a square head port to a round manifold port. New head gasket, New rings....I have 4 new bronze intake guides on the way. Just seems crazy that this port won't frigging light off while.all the other will with the same readings on the compression tester and 2 new intake gaskets. Manifold not cracked, removed twice and checked each time. Power brakes work off #4 and even that one is hitting. Flummoxed! Will pull head again this Saturday, I hope #3 intake is wobbling......will advise
pishta
I know I'm right....
Here are the old guides coming out, easy peasy to replace, cheap ($3-5) too. Ill call it preventive maintenance if new bronze ones don't fix it. These are finish honed from the box so no additional reaming needed. Now I got 8 spare valves too.
pishta
I know I'm right....
Pulled all the guides out the troubled head and #3 Intake was shot. Valve was worn under the limit and the guide was .006 off the max limit. a few of the exhaust guides were at or over the limit too but those valves were fine. The old guides were knurled and must have been reamed too large or may be to small as #3 had some bad scoring. Good thing is that I have 8 exhausts to choose from and 3 are under .004 of a .008 max valve stem deflection. Still waiting on guides......:-(
Hope the seats don't need cut much again, if the knurling & reaming were somebody's half-assed repair, the seats may have been cut/ground in a spot that'll be non-concentric with fresh guides....which should also be checked.
Further to my comments in post #7.
These come Race Engine Technology magazine, a British Bi-monthly magazine. If you want to know to adjust your carb, buy Hot Rod magazine. If you want to know how the race winning Indy Chev Ilmor engine was designed, buy RET magazine.
There is a 13 page article on Nascar engines & upcoming changes.
One comment about engine performance caught my eye: 'Our engines actually run better on the second hit [ second of two 500 mile races ]....our engines go & race 500 miles & come back & actually run better than they did before they left.'
These come Race Engine Technology magazine, a British Bi-monthly magazine. If you want to know to adjust your carb, buy Hot Rod magazine. If you want to know how the race winning Indy Chev Ilmor engine was designed, buy RET magazine.
There is a 13 page article on Nascar engines & upcoming changes.
One comment about engine performance caught my eye: 'Our engines actually run better on the second hit [ second of two 500 mile races ]....our engines go & race 500 miles & come back & actually run better than they did before they left.'
pishta
I know I'm right....
My *** they are finish honed! Maybe the cast iron ones don't hourglass when pounded in but the bronze ones sure did. Waiting on an adjustable reamer now in the mail.
-
