OK backing up a bit...
O/S = Oversize Valve head...
This isn't the still to be put together 198 long rod motor... this is the original build I put together for the duster back in 2001, that evolved with a change to dutra duals and the Hpak one summer....
Original problem was I ended up with a nasty 'miss' on the highway doing the speed limit... did a compression test and found the #5 cylinder to be fairly low, compression wet test didn't bring the number up...leakdown test could be heard plainly through the rear back tail pipe...
Teardown revealed that 1) there was a hair size burnline across the exhaust guide face, and 2)the #5 exhaust valve guide was loose (about 3/16" lower than it's buddies in the neighboring cylinders....
So I figured this was as good a time as any to finally pitch the stock valves for the set of SI stainless vavles I had bought a few years back...
The machine shop found on autopsy that 2 more exhaust guides were a bit loose (#2, and 3)... so I had those replaced, had opted to put stainless seats put in for the exhaust seats (I'm pretty sure that the original hardened seats wouldn't have been hardened after a grinding...)
At first I had thought it was a vacc. leak, but doing the usual checks showed I had put the 'stack' together correctly with no leaks. My theory at this point is: #5's rings were OK, but failed to seal due to the exhaust valve...now with the new head #4 had better sealing and the rings were almost ready to go on that one.... condition of the bore were a bit smooth with a little faint indication that they had crosshatching at one time, the lip of the bore barely has any ridge in the cylinders.....
I'm currently mulling over my options...
#1) Beater Valaint get me to work fine but has the 'old suspension' random shuffle, then engine is fresh.
#2) Hpak Duster's suspension, gear box and tires are all new/refurbished and it hugs the road good...but the engine has a dead hole...
#3) I have the time to pull the duster engine do a rehone and re-ring and see what happens...
#4) If I had a third vehicle and a couple of weekends(I have had some offers am still thinking about it). I could pull BV's engine...put the duster head and Hpak setup on it...drop it into the duster (I think the cam in that build would be happier and the cast crank would love the revs in the 'pak' zone...)...that way I can do the things that need to happen to the BV (suspension rebuild, steering box rebuild, swap to disc brakes and the 8.25" rearend, and drop in the refreshed Duster engine...)
-D.Idiot
|
