Greetings from Bulgaria!!! Recently i'm building an abf engine for the hillclimb championship... So .... I'm using wossner pistons cr13:1,Fcp forged rods,cat cams 292° ,12.45 lift...the bore has been changed to 83.5... I was having issues with the oil with my old motor so i need an advice of keeping the wngine lubricated and in one peace... And also the biggest issiu ...valve to piston clearance Sorry for my english.... The high pressure path of the oil from the block to the head is 6 mm so i drilled a M10 thread in the block and put a (bolt)with a hole 1.5 mm....i have read somewhere that the head doesn't need that much oil when you are using solid lifters.... So i continued stopping the oil to the head,the holes in the head that feed the lifters are going to be sealed off....thread m5... My question is....is this the right way to go??????? And continuing with the valve to piston issue..... When engine is at TDC....i have 5.1 mm to the piston....the camshaft shoul be fitted at 3.55mm...it is looking like there will be no issue with the clearance...but what about when you try to put it in 4.5(asking for more power at the dyno)...my last set up was running at 4.5mm at TDC with 303°cams... So a big question now???? Should I grind the seats of the valves an extra 1mm amd put a shim under the sprigs or pocket the brand new pistons I will try uploading some pictures of the build.....and thanks in advance to the people who will help......Help me fight the Hondas....
Hi there. From my experience there is no need to seal off the Hydro oil feeds or reduce the flow. Yes it runs high pressure with solid lifters, and probably wastes some power, but sealing off the return does not seem a good idea to reduce the power consumption. To me it seems to make the pump work harder. I would not offer advice how to reduce the pressure or flow, as I've not done it myself, but they run fine just left the same as with hydro lifters, I can tell you that for sure. You must pocket the pistons if the clearance is too tight, that is the way to do it. I run Wossner 82.5mm 9a pistons (in an 8v tall block) and 296 cams with 12.5mm lift and 3.65mm on both @ TDC and have around 2.47mm clearance at TDC with the cams advanced to where the power is. What pistons do you use, looked like Wossner? I believe the valve cutouts in mine are standard (but the pistons were secondhand), but hey look factory. The piston crowns have been machined to adjust the compression, but this does not affect the piston clearance - actually I took the pistons out after this picture was taken to machine them, after I measured the cylinder and head volumes to get the compression. This was my first temporary build before fitting the proper cylinder head and cams. ot easy to see the valve marks, but there were some small ones. What head gasket? This engine makes 247bhp, not quite a Honda beater on the dyno but it goes ok, more development to come.
These are almost identical specs I have on my ABF. 13:1 Wössner pistons with 292° CatCams. The engine shop that built my engine also machined down the valve pockets in the pistons. Technically I could be able to also run the 299°cams since I have enough space now. CR is down to 12.8:1 but since I want to drive it as street car with 102 octane it is enough. If you want to keep the higher CR then I would just shave the head a little bit more. I would also not touch the oil feed of the lifters. What exactly was happening to the old engine?
