HT 4100 Engine Question


#1

The 4.1 liter engine in many mid 80’s Cadillacs … I’ve read good and bad about this engine. I am considering purchasing an 85 with this engine. Does anyone have information about the engine? Good points/bad points? Recommendations? Thanks


#2

I didn’t mind the power seats one bit. The 4.1 could be OK. The computer for the engine used to cost about a hundred dollars. The rocker arm support can break but it is easily fixed by the owner. The new ones aren’t threaded so you drill the holes out to 11/32 and use 5/16 bolts with self locking nuts. I actually don’t remember the exact sizes but you get the idea. The bolts go in upside down and some of the bolt heads will get in the way of installation. Grind away part of the bolt head after it is installed on the support if it gets in the way. I used a body grinder for such non-precision work. I didn’t try countersinking the support and using screw type heads but I wouldn’t rule it out. The damn thing ran! The oil pump pickup tube has an O-ring seal. If you have an oil light coming on at idle, take it down (bolted, so it’s easy) and check for the O-ring because somebody forgot to install it when they took the thing apart. The oil pan on the Deville comes down with ease. The engine oil is supposed to be thick. Straight 30 or even straight 40. If the guy before you was running 5W-30, you may have to change the lifters due to low oil pressure. These aren’t major problems if you have done this kind of work before. The brakes don’t work especially well. If you are driving and the engine goes to fast idle, has no power, cruise doesn’t work, stalls, or runs really awful all at once, change the computer.