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Offline Wittsend

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Re: blow by
« Reply #30 on: September 27, 2014, 12:23:55 PM »
For sure I would use a screw in gauge. They typically have a hose. I position the hose in a way I can see the gauge when cranking. Depending on the engine it takes 3-6 revolutions to get a full compression reading. Watch the gauge and see when it stops rising. It won't go higher.  Get the right gauge (if you haven't already) and do the test again.

 Assuming the rings are the issue, it would seem that the plugs would show evidence of oil fouling or contamination.  And I guess this is what is baffling.  You have very low compression, but no smoking.   You have evidence of seals and gaskets weeping, but can't detect an abundance of crank case pressure unless you "get on it."

  Did you build the engine yourself,  or did someone build it for you. If you built it, what is you background and experience? What grit did you use for the wall finish? Was a hone plate used. What was the piston to wall clearance. I'm assuming forged pistons - they require more clearance that need to be warm to work properly. What is the ring width and end gap?  This would all be helpful to to getting to the bottom of the problem.

If it is truly a blow by issue then something is wrong with: Piston to wall clearance, piston rings - upside down, or broken, wall finish that damaged the rings.

If it is simply a crankcase pressure issue then somewhere the engine is not venting the crankcase properly.  A thought comes to mind.  What are the valve clearances (or are they hydraulic)?  I've heard of improperly set valves that never seat and the potential exists that pressure (possibly) could be going up the valve stems.

Offline 65ShelbyClone

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Re: blow by
« Reply #31 on: September 27, 2014, 04:10:55 PM »
Did you try a wet compression test too? Add about a teaspoon of oil to the cylinder and if compression comes up substantially, then ring seal is a problem.

I would expect to see at least 180psi with your build, cold or not.
'72 Runabout - 2.3T, T5, MegaSquirt-II, 8", 5-lugs, big brakes.
'68 Mustang - Built roller 302, Toploader, 9", etc.

Offline bad bean

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Re: blow by
« Reply #32 on: September 27, 2014, 04:22:16 PM »
Should I run motor till 180 degrees, going to pull several test checking o ring. How much psi with 284/544 110 lobe separation.

Offline 65ShelbyClone

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Re: blow by
« Reply #33 on: September 27, 2014, 04:55:37 PM »
Testing it at operating temp isn't going to tell you anything new.
'72 Runabout - 2.3T, T5, MegaSquirt-II, 8", 5-lugs, big brakes.
'68 Mustang - Built roller 302, Toploader, 9", etc.

Offline bad bean

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Re: blow by
« Reply #34 on: September 27, 2014, 05:51:20 PM »
Motor work done by others, I put it together. I am not professional builder but have put many motors together. Ring gap is 18-20.I put rings at top and second are over pin 180 from each other oil ring is at 11 and 7 o'clock. Motor runs good plugs a little sutty but that could be cold plugs or only driveway running. I have only drove it around the block. It's not tagged yet to really put time on motor but won't to get bugs out first. Someone said to run and put rubber glove at pcv. Haven't done that yet. Still not sure if gauge was wrong will do test again to be sure. Just hoping to find solution without having to year it down. Not sure if I'll have time if can't find problem. Thanks guys looking for any input.

Offline bad bean

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Re: blow by
« Reply #35 on: September 27, 2014, 11:34:31 PM »
The rings are 1/16,1/16,1/8.:-hydraulic lifters.I did not check piston to wall.something that might be my problem.would I not hear some skirt .slapping.mayb e not .

Offline 74 PintoWagon

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Re: blow by
« Reply #36 on: September 28, 2014, 07:52:41 AM »
Was the cylinders honed for the particular ring type??, maybe cylinders got a little hot on break in and some rings distorted seen that a few times..
Art
65 Falcon 2DR 200 IL6 with C4.

Offline bad bean

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Re: blow by
« Reply #37 on: September 28, 2014, 08:52:27 AM »
No certain hone done. Motor did get warm during break in 240 degrees, fan had quit for some odd reason.

Offline 74 PintoWagon

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Re: blow by
« Reply #38 on: September 28, 2014, 09:39:30 AM »
Different type rings require different hone machinist should have asked what rings you were using?, if water was 240 cylinder walls were hotter, a comp test should tell.
Art
65 Falcon 2DR 200 IL6 with C4.

Offline amc49

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Re: blow by
« Reply #39 on: September 28, 2014, 07:17:27 PM »
WAS ENGINE BORED FOR OVERSIZE PISTONS??? Then MUST have been honed or totally messed up there. You CANNOT competently assemble motors and not know if hone done/not done if rings are changed, death lies there and totally unacceptable. The start of a major FU. Not trying to be an butt or insult anyone, but it needs to be said. I would be dogging the person who did the machine work there for more information. If not bored at all then you get into the nightmare of what kind of condition the cylinder walls were in to begin with, not knowing if honed just doubles that nightmare with all kinds of bad possibility. The rings (especially moly, even worse if double moly) MUST have correct break-in wall finish or they are junk as soon as started up and run five minutes. You don't get another chance after that without new rings/walls.

There will be no exact compression number since cam timing alone advance/retard can greatly affect that, all I know is true 12/1 needs well over 200 psi, I'd be expecting like 220-230+ on a well sealed motor. Even more (250+) if the motor truly setup to get the advertised compression, i.e., decked correct for the application and proper cc head/head gasket thickness, the compression can range off a full point by simply throwing in pistons that say they are this or that number, not nearly that simple. Catalog advertised compression numbers are worthless without the motor set up to spec called for there.


Offline bad bean

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Re: blow by
« Reply #40 on: September 28, 2014, 08:35:16 PM »
I didn't say that compression was 12.1 I merely stated that trw piston 12.1,60cc heads 210 runners,motor bored .030, they told me I would be fine for Moly rings.no decking needed..015 piston to deck height, gaskets .041 compressed.com pression should be about 10.5-11.1.a fire notch was cut in piston for plug clearances.I don't do machine work so I'm relying on them.only thing I noticed was the cross hatching.cylin der felt smooth.

Offline dick1172762

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Re: blow by
« Reply #41 on: September 29, 2014, 12:38:32 PM »
Also do like they teach you in A&P school. After you run the compression check, shoot some motor oil in the spark plug hole on the low cylinders and recheck the compression again. If the reading goes up its the rings. If there is no change its the valves.
Its better to be a has-been, than a never was.

Offline amc49

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Re: blow by
« Reply #42 on: September 29, 2014, 02:57:14 PM »
And yet asking how much psi without telling any of that.......... .(chuckling to self) Major omissions like that are why you are here now.......... Just now finding out about the overbore after I mentioned possible not being bored issues twice. Your lack of attention to detail is death playing with a specialty engine like this, the same lack (and resultant damage) would be likely to be expected on the engine itself. No insult intended again, just the facts ma'am.

Rubber glove on pcv, that one's borderline stupid. As in on the OTHER side of that border.

'I didn't say that compression was 12.1...'

Au contrere mon frere. reply #10 says...

' I'm running high compression about 12.1...'

'they told me I would be fine...'

Oh boy, if I had a buck for every time I've heard THAT one......you ALWAYS doublecheck the work. Say piston-to-wall is too tight and you seize piston to gouge aluminum then that ringset is stuck from metal flow and your blowby. Seen that plenty of times with fresh boring, the incompetence is usually worse with the louder the shop crows about how good they are.

Look here, all the flogging in the world not gonna do a thing until you real world either trip over better compression numbers or make them happen by more work. The motor is dead at those low numbers, 100 psi is the point at which cylinder is considered to be not contributing to power even if it is working. A bang up trick ignition (MSD) might fire it but no power because power comes from gas expansion, ergo, COMPRESSION.

In reference to OP issue you must baffle pre-pcv and I'd look at adding more breather as well.

Offline Wittsend

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Re: blow by
« Reply #43 on: September 29, 2014, 03:26:31 PM »
".........ru bber glove on pcv, that one's borderline stupid."

I'll take the hit for that one. He had stated that it didn't seem like there was a lot of air coming in /out of the oil filler cap. There seemed to be doubt in his mind that he was able to detect it  I told him to put a rubber glove over the PCV hose as a way of telling (visually) just how fast there the crank case pressure was building - if at all. It wasn't meant to be any kind of a definitive test, just a way of observing that which he was struggling to perceive.

I had tried it once when my Chevy 283 powered Studebaker was showing 150 PSI on the gauge, the valves had both new O-Ring and umbrella seals, the valve stems didn't feel "too loose" and yet it was smoking quite a bit.

Offline amc49

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Re: blow by
« Reply #44 on: September 29, 2014, 03:33:16 PM »
My bad as well, I get rambunctious over this stuff and have a tendency to say things I shouldn't thus creating problems. I have no desire to actually rip or insult but I sure seem to go there enough. My apologies to all. It just seems that people should think a little more and that certainly includes me. Chalk it up to my lack of patience as I age, not my strong point. Stupid old man we'll say.

Offline bad bean

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Re: blow by
« Reply #45 on: September 29, 2014, 10:56:54 PM »
Sorry that I didn't give full description.So me people forget the reason people are on this post is to get answers.I'm just looking for advice. Not wanting to year a fresh motor apart. If I'm over looking something.Got another gauge doing test tomorrow. If leaving out anything you need to know to help please ask.

Offline bad bean

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Re: blow by
« Reply #46 on: September 29, 2014, 11:46:14 PM »
I did state that it was high compression my bad.my mind is rambling so not getting things always correct.like I stated moments ago.looking for advice not ridicule.I want to thank all again for input.hope I get good compression reading so I give good news before I tear it down.

Offline bad bean

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Re: blow by
« Reply #47 on: September 30, 2014, 03:55:24 PM »
Did another check on compression. This time the cylinders were 125 except the number 6 hole was 110 put a drop off oil it then went to 125. Not sure if overlapping of valves or rings making low or is that OK cylinder pressure. Can or will rings seat after running for some time. I know that someone said that it could be the best they will show after few minutes. Now I have  to figure out about leaks.

Offline amc49

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Re: blow by
« Reply #48 on: September 30, 2014, 04:28:23 PM »
I get 170-180 psi on 9/1 engines all day long.......... .............. .............t he rings will seal to show that in five minutes, the last bit takes a bit longer say hour. Drag race motors go to the strip and max power expecting max compression after the 20 minute cam break-in.......................I certainly did it enough.

There is no night vs. day point at which the cylinder is dead but 10 psi higher it's not, the 120ish mentioned is still pretty much dead for an engine like that.

Could be crap gauge, the cheaper ones can be pretty ratty, I learned early on to get a good one and I'm cheap, cheap. It don't work there.

Offline dick1172762

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Re: blow by
« Reply #49 on: September 30, 2014, 05:54:02 PM »
Well sooner or later you've got to live with it or pull it out and fix it right. In the old days with chrome rings, we would put bondamy in to the cylinders to seat the rings. Those day are over thank God. Guess you can do like the Brits over across the pond, and drive it till it breaks, and then you know what was wrong with it. Or you could do like we did on dragsters back in the 60's and wrap rags around the breathers to catch the oil. That trick was also good to play mind games with the car in the other lane. That and adding a quart of oil as you staged the dragster. But none of this is going to help you one bit. Pull it out and give us a break please.
Its better to be a has-been, than a never was.

Offline bad bean

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Re: blow by
« Reply #50 on: September 30, 2014, 06:22:53 PM »
Last I checked didn't ask anyone in particular to put there two cents in. If you don't want to answer stop reading. I just needed help not smart @$$. Must be wrong site to seek help.

Offline Reeves1

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Re: blow by
« Reply #51 on: September 30, 2014, 06:37:41 PM »
125 lbs too low for 12:1 comp.

My B2 engine (that was returned ready to blow up - long story) had 10.35:1 pistons & had 170 lbs.

Try another gage. Some oil in each cyl.

As I mentioned, gaskets are cheap. If I were you I'd pull it & do a detailed inspection (after trying another gage).

Offline bad bean

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Re: blow by
« Reply #52 on: September 30, 2014, 08:16:54 PM »
Thanks thats all I'm asking. They are rental gauges not a good gauge. But that's all I have for now. Pistons are rated 12.1.I think I'm at 10.5-11 according to sites when I enter specs. How much do you know about over lapping and could that cause low psi.

Offline 74 PintoWagon

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Re: blow by
« Reply #53 on: September 30, 2014, 10:16:36 PM »
Should do a leak down on it..
Art
65 Falcon 2DR 200 IL6 with C4.

Offline bad bean

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Re: blow by
« Reply #54 on: September 30, 2014, 10:38:52 PM »
Borrowing one from friend he said to do leak down as well.had someone else say same thing in earlier post.didn't have one til now this will let me know where problem is upper or bottom would much rather find problem on top than bottom removing head is nothing compared to doing while motor.

Offline 74 PintoWagon

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Re: blow by
« Reply #55 on: September 30, 2014, 10:49:23 PM »
Well good luck, hope it's an easy fix.
Art
65 Falcon 2DR 200 IL6 with C4.

Offline dick1172762

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Re: blow by
« Reply #56 on: October 01, 2014, 10:33:26 AM »
Last I checked didn't ask anyone in particular to put there two cents in. If you don't want to answer stop reading. I just needed help not smart @$$. Must be wrong site to seek help.
      I don't want to stop reading this post because its like a good story, but we can't turn to the last page to see the outcome. I've learned all kinds of good stuff on here, buts its all coming from other people. Ever possible thing that could be wrong has been talked about over and over and all say to pull it out. Sorry if you don't like that idea but it will happen sooner or later.
Its better to be a has-been, than a never was.

Offline Wittsend

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Re: blow by
« Reply #57 on: October 01, 2014, 10:52:31 AM »
      I don't want to stop reading this post because its like a good story, but we can't turn to the last page to see the outcome. I've learned all kinds of good stuff on here, buts its all coming from other people. Ever possible thing that could be wrong has been talked about over and over and all say to pull it out. Sorry if you don't like that idea but it will happen sooner or later.

That is likely the case, but since he now has access to a leak down tester I think there is one last thing to see here. You know, kind of like the doctor sees the X-Ray, then a CAT Scan, then (and where we are at now) a MRI.

  Stranger things happen. My daily drive (Mazda Protege) was throwing P-300 codes (Multiple Random Misfire).  Couldn't figure out why.  And, it often happened when the A/C was on. I attributed it to the A/C clutch engaging, - and momentarily slowing the engine.  This went on for about 6 months. The car developed a slight tick sound at idle (only). I looked everywhere and could not find the source. Eventually the tick took on every aspect of a rod knock.  Eventually I found the problem.  A loose balancer that was spinning fore/aft on the crank shaft within the key clearance (that was increasing constantly). This was throwing off the Crank Position Sensor  The bolt was "stiff" in the treads and thus felt tight so I assumed the balancer was tight.  So, sometimes disastrous symptoms  (rod knock sound) have simple solutions (tight the balancer bolt).

Offline amc49

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Re: blow by
« Reply #58 on: October 01, 2014, 11:22:54 AM »
You're doing the same thing all over again, asking about overlap (but no mention of how much) but only half-framing the question setup........s eems to me some of your grief is self induced by vague questions with no information to frame any possible answer that makes sense, and then answer not liked. You give incompletely, you get back incomplete.

Looking at overlap is looking at the issue backwards, the compression effect is from intake closing point not opening point, just that the two are linked mechanically since cam is not DOHC.

I built a 304 AMC using 8.5/1 pistons and heavy chamber work with biggest hydro stick (IIRC 234I-244E @ .050", .550" lift) I could find and still had 140 psi with maybe true 8/1 compression.

BBC with true adjusted 12.5/1 and huge overlap roller and 300psi.

You are not going to make up for that huge difference with overlap alone. Overlap has nothing to do with the OP blowing out of seals either. That is from leak across the rings, the engine is an air pump and will pump up the crankcase as fast as the cylinder if leaking.

Offline bad bean

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Re: blow by
« Reply #59 on: October 01, 2014, 01:32:21 PM »
I'm not denying that there is blow by from rings. And that oil is getting by some seals. Other sites have stated that motors can go many miles before rings seal. I'm not saying many thousands just hundreds of miles. Since motor only has maybe 1hr run time. I know that people on this site say it should happen quickly. With test for leak down will let me know where from. Not sure but some sites say that cylinder pressure of 180 gives you over 12.1 compression.