MV8 Thanks again. I pulled both heads because I thought they both needed help with regards to exhaust manifold bolt holes. As it turned out the one was still acceptable in that I only lost a couple of threads. Below that, the threads were in good shape. It was a good thing as the intake valve seals were shot and needed changing anyway. Easier to do off the engine than while on the engine. I also had planned on replacing both head gaskets along with all gaskets and seals on general principle. I think I'll skip the porting. I am not building a hot engine, just a comfortable cruiser. If it gets another 20K or 30k miles I'll be thrilled.
Yesterday I borrowed a spring compressor and removed all the valves. The seats were in better condition than I expected. I wire wheeled the valves to clean them up. Then tested a few valves and seats by hand lapping them. It took maybe a minute or two of hand lapping with the suction cup on a stick method. Most of the time was spent reattaching the suction cup. The seats turned out great as did the intake valves. The exhaust valves were a bit more pitted and did not clean up with a short lapping. The valve guides appear to be in good enough nick to keep them as is.
Attachment:
lapped valve.jpg
I still don’t know why the #1 exhaust valve was leaking while the other 5 supported over 155psi compression. Perhaps the buildup on the valve stem was the root cause? Or maybe a lifter was collapsed. I’ll dig into the latter in the next couple of days.
Today, just for S&Gs, I took out one of the exhaust valves from a Fiero head and it was in about the same pitted condition. I tried lapping it using the drill clamped to the stem. I gave it the ol’ college try but it had minimum effect. That seat looked good, the valve had a long way to go. Time to either buy new exhaust valves or have them dressed.
I dropped off the exhaust valves at the automotive rebuilders for a quick face grinding. I took along the bad head and they thought it could be saved economically. Economically means about ½ hour of labor. I’ll find out for certain in a couple of days.
I tested the oil pump output as MV8 suggested. An 8mm socket fit well on the pump shaft. I used a speed handle as suggested and got very little oil flow. I tried both CW and CCW rotation. Then I tried a drill to drive the socket. Still nothing to speak of. I thought I was screwed. Then I looked on the floor and it was covered with oil. I forgot that I had removed the gallery plug next to the oil filter, planning to attach a gauge. DUH! I plugged that and ran another test. I got a gusher at the #6 cyl tappets followed by #4,#2,#1,#3 and #5, in that order. Each one was progressively lower flow to the point of the last cylinder, #5, was barely flowing by the time I had to stop pumping. Oil on the 2-4-6 side was pooling up and about to run over the engine block.
_________________
Chuck.
“Any suspension will work if you don’t let it.” - Colin Chapman
Visit my ongoing MGB Rustoration log:
over HEREOr my Wankel powered Locost log :
over HEREAnd don't forget my Cushman Truckster resto Locostusa.com/forums/viewtopic.php?f=36&t=17766
Login
Register
FAQ
Members
Now on to cleaning and prepping valve train parts for reassembly. I hate being this far in and using dirty used parts. I at least want to clean those used parts up a bit. Time to put this puppy on the engine stand to save my back.