Can anybody identify this piston and it's compression ratio

Discussion in 'Street/strip 400/430/455' started by VET, May 29, 2023.

  1. VET

    VET Navy Vet, Founders Club

    Here's what I know, BUT not the compression ratio, this is a mystery. It could be 11 to 1?

    I was told, they look like Pistons that were sold by Kenne Bell years ago.
    I checked their Website, but it's not listed.

    Please let me know if anybody has information on this piston, I need to know the compression ratio.... Thank you in advance....


    These pistons are what is in my Buick, however, I can't find any information on this particular piston design. Can't find compression Ratio. I'm referring to the piston on the left side of the picture.
    I know it's this piston because I had borescope pictures taken of my pistons, they are identical to the picture below (left side pic).

    Piston on left is the Federal-Mogul hypereutectic alloy cast piston (.030 over) according to the article.
    I have searched all over the internet for this piston, I'm sure this is an old design that is no longer continued.

    The previous owner of my Buick bought this car in 2015. Don't know how soon he changed out the pistons.

    I know the original engine builder and he said he installed the pistons (10.5 to 1) like the Stage 1 engine had. I'm guessing the 10.5 to 1 pistons are also aftermarket clones of the original Buick pistons. Could be the piston design on the right side of the picture below?

    He built the base engine to Stage 1 specs including the larger valves. This engine has it's original intake and cast-iron headers, 750 Qjet and was bored .030 over.
    It's a matching numbers engine.


    FYI: On the right is a Speed Pro L2353F forged piston. Black on the skirt of the forged piston is the new anti-scuff coating.

    If this piston as I suspect, is a high compression model, I hope the 510 lbs of Torque is still retained. VET (Navy)



    [​IMG]
     
  2. Max Damage

    Max Damage I'm working on it!

    A piston in itself cannot tell you the compression ratio. You would need more info about the motor, like the deck height, heads, etc.
     
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    VET,
    None of your pictures are visible. If you e mail the picture you want to post (my e mail is in my signature), I'll post them for you.

    Here's the bottom line, unless you are willing to take a head off and measure everything, you'll never be sure of what the compression ratio is. Pistons may be rated at a compression ratio, but that does not mean they will produce that compression ratio in any engine. Aftermarket pistons typically sit below the deck at TDC. This is certainly true of pistons that were produced years ago.

    I highly doubt whether you have anywhere near to 11:1. It is more likely that it is 9.5:1 or so.

    I have a 1998 Kenne Belle Catalog. These may be the pistons,

    CCI_000003.jpg
     
  4. VET

    VET Navy Vet, Founders Club

    Larry, you found it, it's the piston that says 455.
    Piston part# KB50015 - .030".

    It says compression 9.5 to 10.5.

    I realize I don't have the numbers I need to correctly identify the compression ratio.

    I will not strip down the engine to determine that fact.

    I have to say, this piston design is very different to the original 1970 Buick design.

    I wonder how good this piston design is? Since it's not manufactured anymore.
    The previous owner of my car had tons of detonation and over heating issues.
    So i'am trying to find as much information as I can to take the mystery out of this car.

    I have spent a lot of money resolving the detonation and over heating issues.

    So far the shop has made excellent progress. Seems the detonation issue is resolved.
    The over heating is going very good too. The only issue is the shop installed a HD clutch fan and now the fan roars when engaged. Way to loud. So either it's defective or it's normal for the HD model.

    I might have to reinstall the original clutch fan. The water temp never exceeded 190 degrees but the engine mechanic started worrying it might reach 200 or higher on an August hot day, especially with A/C running.

    My only other option is to add a duel electric fan setup.

    I have spent almost 19 months trying to figure out what the previous owner did to the engine, because it's been modified from the original engine build that John Chamberlain did back in 2012.

    The previous owner purchased the car in 2015.

    Thank you very much Larry.
    I hope the compression is a SAFE 9.0 to 1.

    All the mechanics have assumed it has 11.0 to 1 and have recommended I add octane booster.

    I now feel pretty confident I don't have to do that. Even 10.0 to 1, I should be able to use pump gas, 91 or 93 octane.

    Great you hoard old tech info, really helped me out. Vet.
     
  5. VET

    VET Navy Vet, Founders Club

    Max, I agree with you 100%.
    Read the response I wrote to Larry, you will understand where i'am coming from.

    Than you for your response and help, I appreciate everybody in the forum, I've been given a lot of help. Regards Vet (Navy).
     
  6. Max Damage

    Max Damage I'm working on it!

    With regard to the cooling, the regular fan clutch is likely fine. The HD ones are noisy.

    If you have a modern big tube aluminum 2 core radiator, that is good too.

    Also, running the highest octane fuel you can get is reasonable in these cars. Even with my very mild stock 1968 cars, they like the highest octane they can get, and just start/shutoff and run better with fuel that is above 92 octane.
     
  7. VET

    VET Navy Vet, Founders Club

    Thanks Max, I will have the shop reinstall my regular clutch fan. The HD model is really load. Just to prove my point and to deter any push back from the shop mechanics, I bought a Decibel meter. Just to prove to them, it's a lot loader, to the point, it's useless to play the radio just driving 60 mph.

    As for cooling, my car has the HD Stage 1 radiator, so I'm sure that is good to go. Not sure if it's original, I wouldn't think so, it's been 100% restored.
    Thank you for your help and advice. VET (Navy)
     
  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Piston.jpg
    There is your piston picture. It has valve reliefs for cams with more duration/lift. It is likely that the compression is somewhere around 9.5:1, unless the block was decked so the piston was at zero deck. Then the compression could be over 10:1, but not 11:1. The only way to know would be to remove a head and measure.

    If you have resolved the detonation problem, that is the most important thing as Hypereutectic pistons do not tolerate detonation very well. As far as engine temperatures go, the stock radiators were barely adequate IMHO. A modern 2 core aluminum radiator with 1 1/4" tubes will vastly out perform the stock radiator. That being said, 190-200* is not overheating, in fact it is representative of what these cars ran at back in the day. If the engine runs more than 10* over the thermostat rating, there is a deficiency in the system. 100* over ambient temperatures is the absolute maximum temperature an engine should run with a proper functioning cooling system. The HD fan clutch moves a lot of air, the noise is normal for them. If you find it objectionable, just go to the stock thermostatic clutch.

    https://www.rockauto.com/en/catalog...79763,cooling+system,radiator+fan+clutch,6812
     
  9. Jim Weise

    Jim Weise EFI/DIS 482

    Well, that's a a first.. never heard anyone complain that the fan roars too much... Is it a centrifical clutch deal that runs all the time or something? I have had HD thermostatic fan clutches on various hot rods and tow vehicles for decades.. they roar for a couple seconds when started, and then only when they are needed.. aka when the air coming off the radiator heats the bi-metallic spring enough to engage the fan.

    In a properly regulating system, you can hear the fan clutch cycle on an off as your driving, if ambient temps and driving conditions dictate. But most of the time you hear nothing, as the fan is just freewheeling.

    Never had much use for the stock fan clutches, they usually engage after the temp is higher than I am comfortable with.

    If they cheaped out and put a centrifugal fan clutch on it, tell them to install the proper HD thermostatic fan clutch.

    On the other hand, if it is a thermostatic fan clutch, and it roars all the time, then two possibilities exist..
    1. The fan clutch is defective.. east to identify this one.. car should start, fan should roar for a second, and then quiet down.. it's a very noticeable change.. you should not hear it roar again until everything is good and hot, and it's needed.

    2. Your build is putting out a ton of heat, and you need that massive, noisy airflow, this most likely will be from one of two things.. not enough timing advance, or a lean condition with the carb, especially when cruising at steady throttle. Assuming of course that all the coolant system components are functioning properly.

    Taking off a heavy duty fan clutch in favor of a stock one, is going backwards in my opinion. I have to believe that they put a non-thermostatic one on it.. Easy to tell.. see if there is a bi-metallic coil spring on the front of it..

    Thermostatic..

    [​IMG]

    Centrifugal..

    [​IMG]

    JW
     
  10. VET

    VET Navy Vet, Founders Club

    Jim and Larrry. thank you so much for your help and
    guidance.

    Right now I'm feeling an overload of technical information. I've had a load of Buick guys on the forum Trying to to help me and
    I really appreciate it very much. Right now, it's confusing as to know which way I should proceed.

    I know you and Larry are on top of Buick engine builds and I know Jim you are a top line Buick engine builder. I will take your and Larry's advise and guidance.

    Let me start with Larry, the block deck has not been milled down, at least John C said he doesn't have this done because most of his customers what to see the block ID number (I assume for resale value) which in the case is the 455 SR number, which is still on the block. I know that can be replaced (counterfeited) with the right letter stamp. I'm a machinist and I'm 100% sure I could do that.

    For Jim, your questions.
    if it is a thermostatic fan clutch, and it roars all the time, then two possibilities exist.
    (1) The fan clutch is defective. east to identify this one. car should start, fan should roar for a second, and then quiet down. it's a very noticeable change. you should not hear it roar again until everything is good and hot, and it's needed.
    My answer - I'm sure it roared from the get-go. So, it appears it's defective. However, I need to check it again. I didn't know the procedure as you have outlined it.

    (2) Your build is putting out a ton of heat, and you need that massive, noisy airflow, this most likely will be from one of two things. Not enough timing advance, or a lean condition with the carb, especially when cruising at steady throttle. Assuming of course that all the coolant system components are functioning properly. My answer - I have a 160 degree thermostat installed. When the Buick was driven with the regular clutch fan, the water temp never exceeded 190 but the engine mechanic was fearful it might go higher because it was not a super-hot day and I'm not sure if he had the A/C running. I guess he erred on the safe side and recommended a change to an HD fan.

    Here are the current timing specs - -11° initial at 800rpm, (no vacuum advance, only mechanical)
    -34° @2800rpm, (no vacuum advance, only mechanical).

    These specs were done about a month ago. The MSD distributor failed and the shop had to buy another one and also added the MSD coil to the setup. I didn't get timing specs the second time around, so I can't confirm if the timing specs are the same as before.

    Just so you know, this engine has been screwed with a lot, after John C built this engine. In fact, the previous owner included all the repair receipts when I purchased this car. Had I had known all the mechanical issues with this car, I may have not bought it.
    The consignment dealer never told me about all the problems the owner had. Makes me wonder why the owner sold this car for less than what he paid for it.

    The previous owner had over heating problems, detonation issues (they go hand in hand with each other), distributor rebuilt (still wasn't right), installed pistons that the original engine builder didn't install. I came very close to having the engine rebuilt, reason I didn't is because I had a compression check done and the numbers came out very good.
    Had a leak down done and again great numbers. So I decided not to rebuild the engine.

    Because the compression numbers are higher than I expected, I assumed I had high compression pistons in the Buick.
    My only experience with engines are a 327 small block chevy, 11 1/4 to 1 compression. I never got this high of a compression level as I have with the BB Buick engine. Big surprise for me.

    See below specs on my Buick 455.

    Thank you both for all your help, I can't express enough of my gratitude, you both have been super helpful. Regards VET (Navy)

    Here are the specs:
    COMPRESSION CHECK–

    •dr/s:
    #1—180
    #3—185
    #5—180
    #7—175

    •pa/s:
    #2—180
    #4—185
    #6—180
    #8—180

    ———LEAKDOWN———-
    •dr/s:
    #1—95/100
    #3—92/100
    #5—94/100
    #7—90/100


    •pa/s:
    #2—90/100
    #4—92/100
    #6—93/100
    #8—90/100





     
  11. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Read this,
    http://cochise.uia.net/pkelley2/DynamicCR.html

    And a quote from the above,

    "Dynamic compression ratio should not to be confused with cylinder pressure. Cylinder pressures change almost continuously due to many factors including RPM, intake manifold design, head port volume and efficiency, overlap, exhaust design, valve timing, throttle position, and a number of other factors. DCR is derived from measured or calculated values that are the actual dimensions of the engine. Therefore, unless variable cam timing is used, just like the static compression ratio, the Dynamic Compression Ratio, is fixed when the engine is built and never changes during the operation of the engine."

    A higher compression engine combined with a smaller cam will have higher cylinder pressures.
     
  12. VET

    VET Navy Vet, Founders Club

    Larry, I just read what you sent me, I feel like I just when back to school at a high level, Ha.

    Ok, I get it now, DCR and cylinder pressure are very different indeed. Thank you for this info.

    The only engine I have every built (with a very engine experienced friend) was a 327 built to a 1964 Corvette 365 hp specs.
    The reality is, we cloned the factory specs. in 1971, this engine was a high compression very well designed and built engine.

    We knew we had a high rpm engine, the 365 hp engine came with a solid lifter cam (30/30).
    What we added was at the time very new, an Offenhauser low profile tunnel ram intake manifold with a single 4 barrel Holley 650 double pumper, which at the time was the first double pumper that Holley came out with. It was also a Spread bore design.

    The Offenhauser was a clone of the 1969 Camaro Z28 CanAm racing manifold. The big difference was, the Offey was a split manifold design, you could run a single, double four-barrel carbs or 3 duce Weber setup. I ran the single carb setup.

    Amazingly, it got super gas milage if you stayed on the primaries (which was very difficult to do).

    The only other adds was a Mallory ignition system and Headman headers and a T-10 4 speed.
    A little trick my buddy did was to install a 409 chevy mechanical fuel pump, bolted right on the 327, and gave me a lot more fuel pressure at the top end.

    I didn't have to do a lot of calculating, since I copied what Chevy had built. The intake was the biggest hurtle.
    I tried all types of carbs and only the Holley 650 double pumper worked, and it worked fantastic.

    This engine was installed in a 1956 Belair. Many years ago, it was the fastest car in my town. I got a big kick out of beating BB cars.

    Check out the manifold, super cool, I got a lot of WoW looks when I opened the hood. Still looks bad ass.

    A little history, hope you enjoyed the read. Again, thank you both for the great help and tech information.

    I hope to have my Buick run with the Pure Stock guys. VET (Go Navy)

    [​IMG]


     
    Dadrider likes this.
  13. VET

    VET Navy Vet, Founders Club

    To Jim Weise,

    Follow-up on the HD Clutch fan ordeal.

    I went over to the shop and spoke with the Servicer Manager about which type of fan clutch they installed in my car.

    He said he didn't know and would have to ask the mechanic and let me know tomorrow, since the mechanic was not around.

    I printed off some of your response to me and also the two pictures that identify the Thermostatic clutch fan from the Centrifugal clutch fan and gave them to the Service Manager who told me he would give them to the mechanic.
    I guess I will find out what they have to say in 24 hours. They are suppose to take the Buick out for a test drive.

    I also told him I bought a decibel meter to measure the roar of their HD clutch fan, his eyes got big and said really!!!

    I told him I wanted to prove to him and his mechanic I wasn't making up this issue. That my car now, sounds like an airplane not a car.

    I've had some issues in the past with this company, so this is not something new to me. I will say, the Service Manager has been very good about issues that have to be corrected or mistakes on their part, I will not pay for.

    It's too bad I don't live close to your shop. It's really difficult to find top notch Classic auto shops and mechanics that do super work.

    A lot of the "difficult" auto work is farmed out I found out months later.
    Thank you for your help. I will keep you in the loop as to how this issue is resolved. Vet (Navy)




     
    Dadrider likes this.
  14. VET

    VET Navy Vet, Founders Club

     
  15. VET

    VET Navy Vet, Founders Club

    To Jim Weise,

    Taking your advice, I contacted Todd Miller this morning and told him I will be purchasing one of his recommended Thermostatic clutch fans.

    I sent Tood's recommended clutch fan to the shop that is working on my car and instructed then to purchase Todd's product.

    This should cure the loud noise problem. Thank you very much for your help and guidance with this annoying issue. VET (Go Navy)
     

Share This Page