Well it look like time for a top end on DCP Engine. The current top end has right at 37 hours on it. I did munch a reed a while back and had notice some performance issues nothing major though. I'm starting to feel better to where I can get back to the garage and play. As most know I had taken back four piston that for one reason or anther had some issues. So I thought to my self why not play with them. So I built a new top end using one of the pistons. I opped to run it a .0035 clearance, Yes I know that's to dam tight and I do not recommend it to anyone to do so. DO NOT try that at home please.
As always I air test the
Engine before disassembly and found a air leak at the main seal clutch side. Easy fix just pull it, polish and reinstall. Then precede to remove the top end and put back together. I will not bore you with a bunch of details other then this is an experiment with a high CR and a tight bore, after all I have three more pistons to play with. I did leave the static timing alone since the DCP already has it altered. I felt this would be a good base line for the octane involved or change in octane that is. I want to study the LPP effects with the altered timing according to octane. Sorry BLA BLA BLA. I thought to my self why not so I went for it. I will need to get an EGT to help me in re-quards to the octane since I can use it to gauge the effects on higher octane and detonation. Since the high CR will lower the EGT reading from a lower CR Engine using the same fuel I thought it might just come in handy for that reason. This of course if the thing to seizure up on me. You may ask why so tight. I want to see what the effect on the rings and it's pressure will have based on the end gap and a few other things.
A few note to start with the base line static pressure level is 172 before the Engine had ran and after it warmed up (first heat cycle) it went up to 181. Again an experiment on assembly to get the rings to seat quicker. The heat cycle water temp was 105 degrees when the test was done. With the high CR and octane in the machine the Engine temp came up quick. This could be for a few other reasons as well so it will be something I will keep my eye on as I go. I have been working on heat transfer from the piston crown and have seen some success so far. I have a piston pic where the under side of the crown is pretty dam good for a piston ran for 37 hours at high rpm. I will compare this to the now higher CR piston and evaluate.
Any way thought I would share some playing around pics of the build, nothing great just normal stuff.