Engine Carnage

Rick Parker · #1 (**permalink**) 08-15-2010, 01:23 AM

There hasn't been much discussion about lash caps over the years on this forum. I have always used lash caps in my 289. Originally I believe it was because it helped prevent the ends of the stems from becoming worn from the roller tips. They fit on the end of the valve stem, the rocker arm roller tip contacts the lash cap. There is a minute hole in the cap to allow oil in & out from between it and the valve stem end. I am using Ferrera valves throughout. I recall that I had to have all the ends of the lash caps that fits over the stem surface ground to reduce their length a few thousandths, so they would not contact the valve locks or keepers, so far no problems.

RICK LAKE · #2 (**permalink**) 08-15-2010, 04:15 AM

bobcowan Bob letting the motor over rev on a down shift is like banging one on a rev limiter. You may want to work on rolling on and off the throttle to stop this kind of major rpm change. Keeper broke off in the retainer and cause the damage you see. As far as the motor, unless it is cracked, it can be rebuild with a .015-.30" over bore of the cylinder. Need to have the machinist do a sonic test to see how thick the walls are. Might be easier to have a sleeve installed in the bore and keep this block for a spare or street motor. IMO racing days are over for any block with this kind of damage. I would replace, get a junk yard block or buy new and repair this one.
Are the retainers steel Bob?? Jerry has the correct ideas on lash caps, He did leave out the load of the rocker pushing down on the valve being spread out.
What valves where in the heads? Ferra's? If good top of the line parts are used, valve caps shouldn't be needed. You want to lighten the valve train , not add more weight. The other question is what oil system are you using? What pressures are you running at? It is possible that there is not enough oil getting to the top of the motor and overheating the parts. The parts are not blue in color BUT too hot for normal driving. You may want to replave the retainers and locks with stronger retainers ( lighter if possible too ) and new locks. The head can be welded and repaired. This is the fun of racing. Rick L.