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:suspense: I've seen second generation HT4100 motors mentioned in a previous story but no info.
Does anyone know what the improvements in these would be if any? I would like to keep my 85 fwd coupe deville when the motor goes. Would this be the way to go? Jimbo [email protected]

 

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1991 Deville / 1989 BMW 635csi
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they are pretty much the same thing except maybe better gasket material. They definatly use steel timing gears instead of the nylon gears used in earlier versions. That also adds and extra 5 HP. I would go for it, but try to find a used 4.5 first to save some money and get a little more power. Remanufactured engines are cheaper and also use steel gears and better gaskets.
 

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I'm not sure if the 4100 can be classified by generations - it was undergoing constant development throughout it's use. The first installations in '82 were hurry-up affairs, because of the V-8/6/4 debacle in 1981. These were traditional inline placements in RWD cars for which considerable re-engineering was required. The 4100 was designed from the ground up as a transverse engine for the smaller FWD cars due in the mid 80s.

Most of the improvements made over the years were responses to conditions that caused the early 4100s to self-destruct. Better gaskets were part of that, but primarily Cadillac tried to resolve the issues resulting from blending the aluminum block with cast iron heads. I remember reading something about the head bolts and block threads being upgraded to prevent corrosion and loosening of the bolts.

By late '86 and throughout '87, the 4100 was the best it was going to get. It still had problems, but I frankly think this engine has gotten a bad rap. Yes, a lot of them went to the junkyard with 50-60-70 thousand miles, but there are also a hell of a lot of 4100 equipped Cadillacs still out there on the road with 150-200k on the clock. Go to eBay autos and see how many 1982-87 Chryslers there are available, or for that matter, full size Buicks or Ponitacs, compared to the number of Cadillacs of the same vintage.

The key to an enjoyable long life with a 4100 is simply this: do your maintenance, and don't drive like an idiot. Change the anti freeze with the GM sealant every year or two (FLUSH WITH FRESH WATER ONLY! NEVER EVER USE ANY KIND OF COOLANT FLUSH PRODUCT ON A 4.1). Change the oil based on the severe service schedule.

BTW - if you think Cadillac has a lock on troublesome engine designs - check out www.dontbuyone.com to read the suffering of poor saps who bought the Chrysler 2.7 V-6. It's enough to make you run out and hug your Cadillac.
 

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1992 Cadillac Sedan Deville
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noahsdad said:
I'm not sure if the 4100 can be classified by generations - it was undergoing constant development throughout it's use. The first installations in '82 were hurry-up affairs, because of the V-8/6/4 debacle in 1981. These were traditional inline placements in RWD cars for which considerable re-engineering was required. The 4100 was designed from the ground up as a transverse engine for the smaller FWD cars due in the mid 80s.

Most of the improvements made over the years were responses to conditions that caused the early 4100s to self-destruct. Better gaskets were part of that, but primarily Cadillac tried to resolve the issues resulting from blending the aluminum block with cast iron heads. I remember reading something about the head bolts and block threads being upgraded to prevent corrosion and loosening of the bolts.

By late '86 and throughout '87, the 4100 was the best it was going to get. It still had problems, but I frankly think this engine has gotten a bad rap. Yes, a lot of them went to the junkyard with 50-60-70 thousand miles, but there are also a hell of a lot of 4100 equipped Cadillacs still out there on the road with 150-200k on the clock. Go to eBay autos and see how many 1982-87 Chryslers there are available, or for that matter, full size Buicks or Ponitacs, compared to the number of Cadillacs of the same vintage.

The key to an enjoyable long life with a 4100 is simply this: do your maintenance, and don't drive like an idiot. Change the anti freeze with the GM sealant every year or two (FLUSH WITH FRESH WATER ONLY! NEVER EVER USE ANY KIND OF COOLANT FLUSH PRODUCT ON A 4.1). Change the oil based on the severe service schedule.

BTW - if you think Cadillac has a lock on troublesome engine designs - check out www.dontbuyone.com to read the suffering of poor saps who bought the Chrysler 2.7 V-6. It's enough to make you run out and hug your Cadillac.
Are you sure the 4.1 was redone for the FWD Cars? I am pretty sure it is the same engine, just transverse.
 

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SilverFleetwood85 said:
Are you sure the 4.1 was redone for the FWD Cars? I am pretty sure it is the same engine, just transverse.

Thanks for catching that. After re-reading my post I realize I could have been clearer on that point.

No, the 4100 was designed for the FWD cars. The alterations took place so they could adapt them to the RWD cars in the early installations. The oil pan, bell housing drill points in the block, and the belt driven accessory mounts were changed to accomodate the fore-and-aft arrangement.

I read somewhere on this group that a RWD engine cannot be swapped into an FWD car, or vice-versa. Otherwise, you're right, internally the engines are the same.
 

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94 Fleetwood Brougham
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Chrome valve covers: Early
Finned Aluminum: Late
Source: Cadillac dealer
 

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The HT4100 was developed for use in the second generatrion of downsized Cadillacs due out in 1984, but were not released until 1985.

The blocks used for the longitudinal applications (RWD and FWD 1982-85 Sevilles and Eldorados) and the transverse applications were differant. The castings themselves were differant, primarily in the oil filter areas.

Right from the getgo, they were a die cast aluminum block and cast iron heads. No HT4100's were ever manufactured with aluminum heads.

Improvements were made pretty much from the beginning, the most significant was gasket technology, and solid instead of split head dowels. The intake manifold gaskets and bolts were revised. Later gasket sets had spring loaded washers and revised torque specifications. Head gasket materials were also changed.

Distributor drive gears were also revised to adress premature distributor gear wear. All transverse HT4100's used the steel timing gears as well.

Main bearings, particularly #1 were revised to adress main bearing knocks. They incorporated greater eccentricity to prevent crank float when the engine warmed.

The block and head castings remained the same throughout the production runs, except that the 4.9 blocks received extra ribbing. This was incorporated into all new replacement 4.5 and transverse 4.1 blocks with the targetmaster engine program.

If you are looking for a good replacement, search out a car that had the engine replaced with a GM Targetmaster in the early to mid 90's. These engines incorporated all the updates mad to the engines during their production runs.

The spring loaded intake manifold gaskets are a good indicator, but you will need the invoices from the job to actually prove it being done as there are no real for sure fire ways of telling.

Mike
 
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