Stuck with a HT4100? I have the solution!
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HT4100 4.1, 4.5, 4.9 Discussion, Stuck with a HT4100? I have the solution! in Cadillac Engine Technical Discussion; Okay, after lots of thorough research and experiences, I have come to a final solution to the HT4100 problem. By ...
  1. #1
    try2playJAY's Avatar
    try2playJAY is offline Cadillac Owners Member
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    Exclamation Stuck with a HT4100? I have the solution!

    Okay, after lots of thorough research and experiences, I have come to a final solution to the HT4100 problem. By problem, I mean it's instability, lack of power, etc. Now I know you all really want some solution to make the engine perform better, go faster, accelerate, etc, and here it is..... ready......This solution completley solved my problem. This will consist of 3 steps, like so:
    1-Remove Radiator Cap and hold
    2-Drive a new car under the rapiator cap
    3-Replace the Radiator cap

    This is actually what a local hick mechanic told me when I personally asked him about these poopy engines. Boy, I really thought he knew some underground, secret modification of something! Got ya!!!

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    peteski is offline Cadillac Owners Enthusiast
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    Re: Stuck with a HT4100? I have the solution!

    Hmmm...

    What did you expect?! It is a 20 year old car which was manufactured at the tail of the 2nd gas crisis. It was made this way on purpose!

    It is a fairly large car and if tuned up properly it gets decent gas milage. Now, now, it is the 80's technology, not some 21st century high tech engine.

    Treat it as an antique, not a pocket rocket.



    Peteski

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    Re: Stuck with a HT4100? I have the solution!

    if you were looking for a race car, an early 80's eldorado was a terrible choice. the car is meant for cruising at average law abiding speeds. I love my car, despite the slowness. The ht4100 isnt really that bad of an engine. Ive had zero problems with the engine, which is more than i can say for the rest of the car. Definately not the worst engine ive driven. If you take care of teh thing, and get a competant mechanic to set it up, theres no reason to complain. I changed my spark plugs, ignition cables, distributor, and removed the cat (dont need them for cars this old here), and got a new exhaust and bam my car drives almost the speed of a regular car.

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    SolidGoldsteen's Avatar
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    Re: Stuck with a HT4100? I have the solution!

    Yeah, so far in the first month (almost) of owning my cadi: it's not that bad of an engine. The wiring is a little messy, and the emissions crap sucks, but it's better than some of the newer engines with super-expensive sensors and crap like that.

    The HT4100 is actually nice to work on, and seem to be well built. I like it. It actually has HEI, and digital EFI, which is pretty cool for an old school 4.1 liter engine considering the era it was built. The transmission sucks, but that's a whole 'nother thing.

    I am pretty sure there is a way to get more horsepower out of this engine. Look at the V6, it has more horepower, but less ft/lbs. and 2 less cylinders. If you bored the block a size or two over, fitted some high compression pistons, and found a port injection intake that would fit.... you could make some nice power, and improve the power-band. Maybe you won't get the rev's needed for HP, but that could be fixed with the right amount of $$$

  6. #5
    The Ape Man's Avatar
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    Re: Stuck with a HT4100? I have the solution!

    Actually, many HT4100 radiator caps were covered with brown gook form engine oil whipped up with antifreeze. To complete the job you would have to throw the cap away also.

    There are some folks out there getting good service from these engines. They probably go to church every Sunday.

  7. #6
    Stoneage_Caddy's Avatar
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    Re: Stuck with a HT4100? I have the solution!

    if your HT4100 runs ....its a good engine ...look how old the damn thing is ...its 20 years old......you dont see many nikasil vega engines anymore ...and i sure didnt in 1995 when that engine was 20 years old ...im sure thats what try2play means ....i think he realizes this engine is good ....but wanted to bring up that story up for some comic relif...

    ive seen real crap over the years .....ill go out on a limb and say the 4100 isnt one fo them ...but it sure isnt at home in a big car ....

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    SolidGoldsteen's Avatar
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    Re: Stuck with a HT4100? I have the solution!

    Dude, no church, and Stoneage_Caddy, Mine will surely be dead when it's 20. It's just that the PO put in a new long block a few years ago.

    I bet it would fit in my BMW 2002, and with that much torque, that little 2000 pound car would slingshot. But anyways, whether he was purely joking I doubt it. It's a Cadillac, not a BMW. I think the player needs to pay to play.

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    The Ape Man's Avatar
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    Re: Stuck with a HT4100? I have the solution!

    If not for the HT-4100 I would have not been able to get so many nice clean low mileage early 80's Cadillacs cheap to transplant reliable power trains into.
    Great engine when you look at the big picture.

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    D'Elegance is offline Cadillac Owners Fanatic
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    Re: Stuck with a HT4100? I have the solution!

    hey my HT4100 has 225,000 miles on it, never even had a complete rebuild just head gaskets, its kinda slow but it does move if you get on it and the gas mileage is actually still pretty good

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    Re: Stuck with a HT4100? I have the solution!

    HAHAHAHA - and look at your title... "horrified HT4100 Owner. LOL

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    Re: Stuck with a HT4100? I have the solution!

    I have the 4.5 which must have totally different characteristics. The car was rated at 155HP but has tons of torque. I would say that my STS is anything but slow. Also I have 215k on it and the engine has never been worked on, doesn't smoke, make any noise and will put serious rubber on the road.



    Quote Originally Posted by D'Elegance
    hey my HT4100 has 225,000 miles on it, never even had a complete rebuild just head gaskets, its kinda slow but it does move if you get on it and the gas mileage is actually still pretty good

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    Re: Stuck with a HT4100? I have the solution!

    Allow me to compensate for my lack of explaination. I don't actually HATE the HT4100, I'm just unsatisfied with the pairing of the engine and car itself. Big, heavy car; ineffecient, weak engine-spells disaster. I do like the way the engine is laid out (except the spark plugs) and the engine compartment is very spacious. I love the body of the mid-80's Eldorados, very low profile, for that year. If I do actually put in a Olds 4-something of a GM 350-400 I'll be supremely satisfied with the car.

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    The Ape Man's Avatar
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    Re: Stuck with a HT4100? I have the solution!

    Yup. It is true that the poor HT4100 was worked to death in a 3850 Lb vehicle. They made too much power for their displacemant also.
    Imagine a 368 DEFI with overdrive and a proper final gear ratio. That would have been the ticket.
    Too bad someone incorrectly figured that the demand for RWD vehicles would be non-exisitant in the 80's.

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    Re: Stuck with a HT4100? I have the solution!

    Jay, the 4100 is not inefficient. You're looking at horsepower, which is making you confused.

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    peteski is offline Cadillac Owners Enthusiast
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    Re: Stuck with a HT4100? I have the solution!

    Quote Originally Posted by try2playJAY
    Allow me to compensate for my lack of explaination. I don't actually HATE the HT4100, I'm just unsatisfied with the pairing of the engine and car itself. Big, heavy car; ineffecient, weak engine-spells disaster..
    Again, this was the early 80s right after the gas crisis. I'm sure that this and the CAFE requirement had something to do with this.

    If Bbob was reading this thread, I'm sure he would have a good story about why HT4100 was used in a big Caddy.

    It is not a disaster: I really like my sluggish Eldorado! It handles so badly (but extremely softly) that if it had a more powerful engine, I woudl have wrapped around some pole by now...

    Thing positive: Having a low power engine in a big car probably puts very little stress on the transmission. That should it make last pretty long! And think of all the highway speeding tickets you'll avoid!

    Peteski

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