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Thread: Engine running awful

  1. #11
    Member Justin335's Avatar
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    I am thinking that the bottom end I have is the short rod and not the 88 long rod like I was told when I bought it is there a way to tell from looking at the complete engine ? The engine was set up with a stock 86 model cylinder sleeved to a 310 and the newer style piston in it 88 and it had no spacer plate I’m thinking I might have the spacer plate on an 86 motor and it not support to have it would that make it read a low compression rate

  2. #12
    Senior Member american opel's Avatar
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    if you put a lr piston on a shrot rod crank the piston skirt will hit the crank and not turn over..if you have a longrod crank and put a shortrod piston on it the piston will stick out of the cylinder 1-2mm's.if you have a sr crank and a sr piston the piston will be down in the cylinder about 3mms..all have same stroke.

  3. #13
    Member Justin335's Avatar
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    When I switched the top end I left the hard on the cylinder so I wouldn’t have to get another head gasket I’m pretty sure my piston is too far down in the cylinder with the spacer I assumed it was a long rod because I was told it was an 88 engine I put the piston ttdcand stuck a pencil to the top of piston and went to the outside of the head where the plug screws in and measured the pencil and came up with 40 mm

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  5. #14
    Member Justin335's Avatar
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    I’m thinking spacer needs to come out but I’m not sure which crank is in it guess it’s time to tear it down and see what is going on with it

  6. #15
    Member Justin335's Avatar
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    Tore it down and had ka4 on rod from google I c it is an 86 short rod for a cr so I don’t need the spacer I don’t think
    american opel likes this.

  7. #16
    Member scrappy's Avatar
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    As long as you have the short rod piston to go with the oem ka4 short rod crank you don't need the spacer plate. As stated before if you put a LR piston on the SR crank the skirt will hit the tins before it gets to bdc. There's about 5mm difference in rod lengths which is the reason for the .190" spacer when using the SR piston on the LR crank. The piston's are easily identifiable by SR having a "half moon" cut out on the bottom of the intake side & no window & the LR piston has a full skirt on intake side with a window instead of the cut out... Another good thing to do would be a leak down test, it should hold 6psi for 6 minutes.

  8. #17
    Senior Member acecarlos's Avatar
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    A bit of confusion posted..."if you put a LR piston on the SR crank the skirt will hit the tins before it gets to bdc"....only true for an OEM cylinder NOT re-sleeved to 293CC...as the OP states he has.

    If you have a re-sleeved OEM cylinder with a 293 Sleeve, aka 310 (72-73.5MM Bores), then the piston will be an 85-86 style, not 87-89. If it's a long rod, it will need a 3/16" spacer plate plus two OEM base gaskets. If it is a short rod, no spacer plate is needed.

    Best way to determine is remove the head, and see if the outer edges of the piston are flush or within -1MM to '0' of the top of the cylinder at TDC....if you have a short rod with spacer plate installed you will easily see if it's to far below deck at TDC. Basically these 293's are set up for the 85-86 style piston outer edges to be Flush with cylinder deck at TDC.

    Carlos
    Last edited by acecarlos; 12-23-2019 at 11:15 AM.

  9. #18
    Member scrappy's Avatar
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    Quote Originally Posted by acecarlos View Post
    A bit of confusion posted..."if you put a LR piston on the SR crank the skirt will hit the tins before it gets to bdc"....only true for an OEM cylinder NOT re-sleeved to 293CC...as the OP states he has.

    Carlos
    What I posted is 100% accurate & there is no confusion. I basically reiterated what American opal stated about piston & rod combo's. Your right that a 72mm piston is the same design as the oem piston for the short rod crank since long rod piston's are only available up to 68mm.
    Last edited by scrappy; 12-24-2019 at 04:27 PM.

  10. #19
    Member Justin335's Avatar
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    I am having a firing issue with my r hopefully someone can help me with I am getting no spark and sometimes intermittent spark I read some forums and did ohm test and here are my results stator was 217- pulse generator was 112- primary side of coil I could not get a reading it just said 0 and secondary coil side I was getting 3.5 so I'm thinking it is the coil because everything else is within spec I think. I also put a test light on the plug end of the coil and was getting a verry faint light flashing so I am assuming that means the pulse generator is working properly it is a nology coil I hate to go buying parts if it's not likely the coil so I need a little help from some of you that know more about it thanks with the coil lighting test light still has no spark

  11. #20
    Senior Member The Norm's Avatar
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    Check to see if you have a good ground. If you go online to service honda you can get a brand new oem honda coil.
    bdt=pos!

    Current: Hybrid Engineering 391R
    Hybrid Engineering 310R (super 310)
    Hybrid Engineering 265R
    Hybrid Engineering 250R


 
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