289 compression numbers

Discussion in 'Ranchero Tech Help' started by cbolt, May 8, 2019.

  1. cbolt

    cbolt In Overdrive SILVER MEMBER

    Messages:
    590
    Location:
    Palm Coast, FL
    I just ran a compression test on my newly rebuilt 289 (347 stroker now) and got around 180-190 per cylinder. This seems high to me. The engine has been punched .030 and I installed SpeedPro flat top pistons if that would make a difference.

    Reason I am doing all this is my newly rebuilt engine developed a valve train tap after only about 400 miles so I figured I did something wrong and need to diagnose it before calling the job complete.

    Along with valve noise the engine also has significant hesitation at various speeds and rpm's. I initially chalked this up to the mechanical fuel pump eccentric drive was moving on the cam due to the roller timing gears being thicker than the original equipment and the dowel not fully engaging the eccentric, causing fuel starvation. I fixed that issue with a longer dowel, but the hesitation has remained and the valve noise began.

    Needless to say I am removing the intake as I type this (coolant draining now) to inspect the pushrods and lifters. I did a pushrod check yesterday and they seem to be straight on the side making the valve noise.

    Yeah, that's the long version, but I do need to know about the compression test results. It seems to be too high and I have not seen numbers like that from any other engine I have rebuilt. I have never experienced an issue like this on a rebuild either. Its pretty discouraging really. $@#%$#@&
     
  2. TestDummy

    TestDummy In Maximum Overdrive SILVER MEMBER

    Messages:
    22,358
    Location:
    C'Ville
    I wouldn't worry about that. It's more important they are the same than the actual pressure. That's what I've been taught. Your rings and valves seem to be in order.

    From Haynes.

    A compression test reveals the condition of your engine's valves, its valve seats, and piston rings and whether these parts are wearing evenly. Healthy engines should have compression over 100 psi per cylinder, with no more than 10 percent variation between the highest and lowest readings.
     
  3. Basstrix

    Basstrix In Maximum Overdrive BRONZE MEMBER

    Messages:
    1,184
    Location:
    Phoenix, AZ
  4. grebaba

    grebaba In Third Gear

    Messages:
    207
    Hi
    A little more info on your build would help.
    What heads are you using? What is your chamber volume, what size valves ,type of exhaust, type and CFM of carb-or injectors if used.
    Your compression sounds good.
    How did you break in the engine on startup? Did you use ZDDP additive in your oil.
    I think you have a few areas to check on your hesitation problem.
    Could be bad carb, stuck chock or pull off. Distributor could need to be recurved. Timing could be off .
    I suspect that you could have a flat lobe on your cam if not broke in correctly or you could have a stud that is pulling out of the head if your cam has to much lift. It could be a bad ball assembly in your rocker arm.
    Let us know what you find and good luck.
    Greg
     
  5. cbolt

    cbolt In Overdrive SILVER MEMBER

    Messages:
    590
    Location:
    Palm Coast, FL
    I used the stock heads and just had them gone through by the machine shop. They replaced the valves, seats, seals, etc but as far as I know they are likely stock 289 heads with stock 289 vavles. Exhaust is also stock. I stuck with the stock manifolds over headers. The carb is a 600 cfm edelbrock 1406 I think. I purchased a kit from Jegs consisting of cam, lifters, intake, carb, which are supposed to be a matched set. I broke in the engine as I have done in the past... keeping the rpm's fairly consistent at 2k until the engine warmed up. I used a vacuum gage to set the mixture and timing. So far the engine has only seen 3k rpm's once.

    Oh by the way, my low cylinder was 180, my high just short of 195. I would say if high compression isn't an issue my valves and rings and whatnot seem to be in order.

    Thing is initially the engine ran fine. I was careful to keep the rpm low, not lug the engine, etc. but have only around 400 odd miles, not even to the initial oil change. The car began hesitating, then flat out not running on my way to get the exhaust done properly. After coasting to the side of the road I raised the hood and noted no fuel in the filter, so all the missing, hesitating, and progressively worse running I believed to be the fuel delivery issue which I have since solved. The hesitation and valve noise have not gone away. I will say that the valve noise is intermittent. Yesterday I drove around the neighborhood and the noise went away. Today I drove a bit further and the noise remained during the entire trip. My initial thought was exhaust leak since the noise went away yesterday after warm up. So, I did the old soapy water trick and didn't find any exhaust leaks.

    Prior to that I cut the top off an old valve cover to watch the valve train in action and attempt to adjust the rockers with the engine running. The modified valve cover worked great, but I could never adjust the noise out of the valve train, nor was I able to isolate which valve/lifter was making the noise. Everything seemed to be working as advertised.

    It has me scratching my head.

    I'm going to rip it back apart and find out what happened. I think the flat cam lobe could be the culprit, but being an intermittent problem perhaps not.

    I'm no Smokey Yunick, but I have built several engines and have never had one fail.... until now.
     
  6. LSChero

    LSChero In Maximum Overdrive PLATINUM MEMBER

    Messages:
    2,075
    Location:
    Area 6 NV
    Some of 67 windsor heads had small quench chambers 49.2>63cc.Iam running gt40 heads 58cc with stock forged flat tops 165 average compression.Check your casting# see what you have.https://www.enginelabs.com/engine-tech/engine/reference-ford-ohv-cylinder-head-casting-numbers/
    I would check static valve lash again,inspect push rods,rocker arms before tearing into to far.Did you replace stock rockers with roller style?
    May just have a weak lifter.My crappy proform rollers still sound like a solid lifters..Stethoscope is a good investment to pin point noises!
     
  7. grebaba

    grebaba In Third Gear

    Messages:
    207
    If the noise stopped for one trip I would not think it has a flat lobe. It sounds like a lifter that isn't pumping up or you might just have a rocker that won't adjust because of wear.
    The Hesitating is more then likely related to the dry carb. If it ran completely dry then if there was any small bits of trash in the float bowl then it would be pulled into the jets, metering valves ect. and clog up the carb.
    I would try to borrow a known good carb and see if that doesn't fix the hesitating problem.
    I tend to think you are having a valve train problem with the ticking noise. How loud is it? Can you hear it with the hood closed and in the drivers seat?
    Seems funny to me that it won't adjust out. LSChero is right about checking the valve train and using a stethoscope, they are a great help in finding noise.
    Greg
     
  8. grebaba

    grebaba In Third Gear

    Messages:
    207
    I just reread your post about using a vacuum gauge to set your timing.
    I have used that method for years but you will find that you can be out 4 or 5 degrees when you check it with a timing light.
    I would get a timing light and check it first thing and see if this doesn't help.
    They only times I use a vacuum gauge to set timing is when there is a missing timing pointer on the engine.
    Greg
     
  9. cbolt

    cbolt In Overdrive SILVER MEMBER

    Messages:
    590
    Location:
    Palm Coast, FL
    Greg, I am missing the timing pointer to my engine. Additionally, the new crankshaft/balancer/pulley that goes with the balanced set has TDC mark on the passenger side whereas my engine hits TDC when the marks on the balancer are on the drivers side, so that all goes out the window without timing tape, if that makes sense. (Long story about 3 or 4 bolt 28oz balancers) I will say that after the carb was adjusted I was getting about 22hg on my vacuum gage and the needle was rock steady, so I was pretty happy with that. My most recent check, yesterday after the issues arose, has the needle at around 19hg. I didn't look into that yet either.

    All the rocker studs were replaced by the machine shop, and are brand new. When I had the engine running and was adjusting the valves from there I could tighten each one until the car started idling poorly, back them off until they made noise, but never was able to adjust any single rocker to eliminate the noise. It was consistent throughout that process.

    You can see why I am stumped.

    To answer the question about the hesitation, I believe the car was beginning to hesitate prior to the carb running dry. Again, I attributed the hesitation to the fuel delivery problem at the time. Looking back it could very well be junk in the carb, but I really have trouble with that as the carb was brand new. Still, that's a great idea about borrowing a carb. Ill see if I can find one and slap it on there. At least it will eliminate the carb as the culprit... or determine the carb is causing the hesitation.

    Oh, and I have already drained the coolant and removed all the plugs, wires, cap, etc. in preparation for removing the intake, which comes off tomorrow.

    What I think would be useful is a dial indicator and someone who knows how to set it up to measure total lift on each valve. I am hoping a physical inspection of the lifters will reveal the issue.

    LSChero, I did check the static valve lash again when I inspected the pushrods for true. It seemed fine as did the pushrods, but I didn't check them all... only the ones from the area the noise was coming from. (Lazy me!)

    My initial thought was a bad off the shelf lifter, factory defect or whatever, or perhaps the block wasn't sufficiently cleaned and some debris got into a lifter causing it to fail.

    A mechanics stethoscope may be a good investment as well. Ugh!
     
    Last edited: May 8, 2019
    andrewok1 likes this.
  10. andrewok1

    andrewok1 In Maximum Overdrive SILVER MEMBER GOLD MEMBER

    Messages:
    3,428
    Location:
    ocala ,florida
    wow , troubles at 400 miles it sure was sounding good at the Round UP , sorry to hear this Jim
     
  11. grebaba

    grebaba In Third Gear

    Messages:
    207
    Since you have it all ready tore down I would check both sides of the valve train all though I am beginning to believe it isn't there.
    Chasing harmonics is all ways fun. I have cars come in with a knock or tick that seemed to be coming from one place but found it is came from a completely different area.
    The thing is if you don't find a bad lifter or worn ball in the rocker [be sure to measure all your pushrods for length] then you will have to put it back together and check it with a stethoscope to narrow it down.
    Sometimes a tick turns out to be a bad fuel pump or is coming from the Distributor and you would swear it is in the valve train.
    On the timing pointer you can make your own and just buy a new timing tape to get in the right place.
    We have found about 1 in 15 new carb's to be bad out of the box. Any brand, it doesn't matter all though some are better then other's.
    Greg
     
    cbolt likes this.
  12. cbolt

    cbolt In Overdrive SILVER MEMBER

    Messages:
    590
    Location:
    Palm Coast, FL

    This car has been trouble from day 1. I should have predicted the rebuild would also be difficult. I always follow the instructions, go by the book, etc. to the letter. Fixing airplanes taught me to check and double check everything. Every torque value, every clearance, etc. I keep racking my brain to see if I can remember any step I overlooked. Near as I can figure, I must have done something wrong. Ill figure it out eventually. In the meantime any suggestions or ideas, or stories of other people and their experiences are more than welcomed.
     
  13. cbolt

    cbolt In Overdrive SILVER MEMBER

    Messages:
    590
    Location:
    Palm Coast, FL
    Harmonics. I really hadn't considered that. Ill check both sides while the intake is off and see what I can find out.

    Looking back, I didn't change any of the ignition system. Plugs, wires, and distributor cap were changed but the rotor, coil, and ignition module came with the car when I bought it. Not that those items would cause a valve tap, but perhaps contribute to the hesitation. I did read the cap and wires out with a multimeter, and they are all good from a continuity standpoint.

    That's discouraging about new carbs being bad at that high percentage. This has been my first experience with Edelbrock parts. I know folks who swear by the brand.
     
  14. cbolt

    cbolt In Overdrive SILVER MEMBER

    Messages:
    590
    Location:
    Palm Coast, FL
    Hey LS, would a weak lifter cause hesitation as I described? It is possible I have two problems and not just one. A noisy valve train, and a hesitating engine.
     
  15. pmrphil

    pmrphil In Overdrive GOLD MEMBER

    Messages:
    879
    Hesitation is quite often caused by a lean stumble, adjusting the carb for highest vacuum WILL make it right on the lean edge, maybe too lean? Try fattening up the mixture until the engine is slowing down a hundred RPM, or even a bit more.
    What rockers are on it? Did you replace the pushrods with the same length, or just install what's "supposed" to be in there? 289's can have 3 different lengths from the factory.
    A leaky lifter will tick intermittently, but won't cause a hesitation. Did you use a known "break-in" oil on your initial start up? What weight oil is in it now? Pressure (hot) at idle and at RPM?
    Make a new pointer and get the timing part eliminated from the mix - you already probably know that, though.
     
    Basstrix likes this.
  16. cbolt

    cbolt In Overdrive SILVER MEMBER

    Messages:
    590
    Location:
    Palm Coast, FL
    I followed the recommendation when adjusting the mixture.... max vacuum then back rich 1/4 turn. It ran good initially. I am probably not describing the hesitation correctly. It isn't just when I accelerate, it is when running steady throttle as well. The engine kind of hiccups without any backfire... hard to describe.

    Rockers are stock. Pushrods (and rockers) are the same ones I took out. I checked them at the time and didn't see an issue. All pushrods were straight and equal length. All the rockers looked fine. I didn't magnaflux them or eddy current them, but they didn't show any abnormal wear.

    I used dinosaur oil for my break in, nothing special. I have never had an issue doing that in the past so I saw no reason to put any special oil in for the break in period. Its 10-40. I don't have an oil pressure gage, but noted the rockers had sufficient oil flow at idle (while adjusting the rockers with the motor running)

    I have to purchase timing tape first. The balancer has the mark on the wrong side, making the pointer useless without the timing tape.

    I think I am dealing with two separate problems which manifested themselves at the same time, which is what you are suggesting too pmrphil.

    Tomorrow I will try to get the physical inspection done and see if I can spot any abnormalities. My thought is if it is making noise, it will show wear somewhere... a shiny spot or something on the metal.
     
  17. pmrphil

    pmrphil In Overdrive GOLD MEMBER

    Messages:
    879
    A hiccup without any backfire I would think ignition issue.
    My reason for asking about break in oil is because oil manufacturers have reduced the amount of additives (zinc, phosphorus, sulfur, etc.) that are necessary for the break in AND extended life of a flat tappet style cam, including rockers and pushrods. I am seeing more and more oil related lifter/cam issues, plus overall wear issues because of this. ALL pushrod type engines are susceptible to failure without some kind of "help" in the oil department nowadays.
    Your timing can be set by simply static lining up the mark with the original tab location, then just file a new mark corresponding to a new "zero" indicator, and you're off!!
     
    cbolt likes this.
  18. beerbelly

    beerbelly In Maximum Overdrive SILVER MEMBER

    Messages:
    1,820
    Location:
    Portland OR
    I agree with Phil about the break-in oil, and the internet is full of info about it. My friend ordered a 2027cc VW engine built at SCAT, and they shipped it with Brad Penn break-in oil. They wouldn't warranty it without it.
     
  19. colnago

    colnago In Overdrive

    Messages:
    591
    Location:
    Ridgecrest, CA
    I'd say your hesitation is a misadjusted accelerator pump on the carb, or a torn accelerator diaphragm. When you tap on the accelerator, it's not giving the engine the extra juice that it needs to accelerate.

    On the timing, get a pointer and a piston stop, and make your own marks.

    Joseph
     
  20. cbolt

    cbolt In Overdrive SILVER MEMBER

    Messages:
    590
    Location:
    Palm Coast, FL
    A complete inspection of the lifters, pushrods, and rockers was negative. All the pushrods are true and same length, all the lifters are brand new looking and show no signs of wear, and all the rocker surfaces to include the tops of all valves look fine. My next step is to turn the engine by hand and measure each lifter for total travel. In this way I can check the cam lobes for any wear causing the lifters to not fully travel in their lifter cylinders. If that test shows no cam lobe wear ill be replacing the lifters. Oh, and there were no signs of any leaks. Everything I can see is clean and looks like it should. In other words there was no obvious evidence of what was tapping. Nothing scored, nothing shiny that shouldn't be, that kind of stuff.

    I don't have a carb to drop in, so I will be opening this one up to inspect the needle and seat area for debris. Ill have to try this same carb again after a cleaning without a known good carb in hand, and hope for the best. Along with the carb cleaning I will be replacing all the ignition components that were not changed during the rebuild, specifically the coil and module.

    After all that is complete I will be trying again, this time with a stethoscope in hand. Wish me luck!
     

Share This Page