HT4100 FAIL!

[Ohio57-62Sedan]

Okay here are my thought's on this if it was my car I would do a swap... 307 or 350 old's ...  part's are getting harder to find for the swap but a good shop or a good mechanic can do the swap and make it look factory.. As for the 4100 I would do a rebuild myself it not that bad of a job.... Jasper has a special department for rebuilding 4.1, 4.5 & 4.9 .  here are a couple pictures that I took when touring the plant...

[Ohio57-62Sedan]

the site wont let me post the pictures I'll try latter

[Rusty Shepherd CLC 6397]

What do you get when you go there?  I just get a home page, a single diagnostics page with a few links I did not try, a links page with nothing special on it, a blank contacts page, and a swap page with a dead link.   

I've never seen any more on that page than is currently there (although I think the links that don't work now did at one time) and I've never understood why since it's supposed to be the source for HT4100 problems..  At the very least, I would have expected a thorough discussion of the engine, its inherent problems, and ways to repair and improve it.  When I first clicked on the diagnostics link, I thought there would be topics like diagnosing and fixing engine knock, but instead it has an explanation of computer error codes that deal with a lot of non-HT4100 issues like air conditioning.

[Ohio57-62Sedan]

Rusty what do you want to know about a 4100 ?  give me a code number and I'll do my beat to help you out... there is no such thing as a quick fix for a knocking motor...

[nycnftm]

Thank you all.  I think I will try to sell the rear e/g kit on eBay and try to get a few bucks for what's left.  Thankfully the the 04 Accord runs fine.

[76eldo]

The links page worked for me.

Here is the direct link to the message board:

http://autos.groups.yahoo.com/group/HT4100exchange/

Brian

[76eldo]

The swap page used to go to the Eldo Country site.  The domain name on that site has changed, but it is still around. Cory's site is still intact, but it is now:

Main Site

http://www.radar58.com/

Cadillac link:

http://www.radar58.com/eldo/index.html

And, the complicated engine swap...

http://www.radar58.com/eldo/swap.html

I had a 45K mile 80 Eldo that sat for years, but the motor ran well.  I took all of the parts i could get off of that one, and have them stored away.  I tried to give the car away so that the 368 could be swapped into an HT4100 Eldo, but no one wanted it, and I needed to get it out of my driveway, so it went to the crusher.

If you read Cory's page on the 403 swap, you will see it's not a one weekend job, and not a job for someone that isn't a tinkerer.

There are no direct bolt-in swaps to replace a 4100 and have everything work properly without a lot of mods, but every so often someone posts something about a small block Chevy or an Olds motor being a "bolt-in" swap, like they have done it.  If that was true, almost every 4100 car would have a different drivetrain.

OK, next guy to chop up my posts and re-quote it, I wish you a big red oil stain on the driveway.   

Brian

[TJ Hopland]

Cool to see the Eldocountry is still around. 

I was going to say maybe the HT4100 site was powered by a 4100 and it done blew up 

[Rusty Shepherd CLC 6397]

Rusty what do you want to know about a 4100 ?  give me a code number and I'll do my beat to help you out... there is no such thing as a quick fix for a knocking motor...

Thanks, I appreciate the offer, but I'm actually pretty well versed in HT4100 problems having owned one and known the details of the trouble of three friends who had them as well as reading posts on this board.  I was thinking of someone who was considering buying an HT4100 car and after hearing that they sometimes can prove somewhat problematic (note my phrasing to try to avoid upsetting those very few members who have had good service from them),go to the site looking for specific internal engine problems and cures.

[Dave Shepherd]

During my time as a field troubleshooter for Cadillac, the HT4100 was a non stop repair issue, multiple cam failures which led to torn up cranks and bearings, intake manifold and valve cover leaks, common, underpowered for the larger cars they were installed in. Good gas mileage, yes. Intake valves getting heavily carboned up causing them to stick in the valve guides at higher rpms causing valve float and severe loss of power. Yes this is all rote and general knowledge by now, any 4100's still running have been rebuilt or repaired some way by now.  BTW I was wrong in my post above, the 4.5 only will replace a fwd 4100 as a drop in.

[Johnny]

any 4100's still running have been rebuilt or repaired some way by now. 

Except mine, with 30K miles.

[Dave Shepherd]

Not to be argumentative here, but a lot of this work was done within the warranty period, which would be hard to detect on your car. Some did make it through though.

[Wayne Womble 12210]

Except mine, with 30K miles.

And my `87 Deville at 300K miles. Opps, I did change the intake gasket as a precaution at 110K though.

[Rusty Shepherd CLC 6397]

the 4.5 only will replace a fwd 4100 as a drop in.

And only a transverse HT4100, not a longitudinal FWD one as in the '82-'85 Sevilles and Eldorados.

[Johnny]

Not to be argumentative here, but a lot of this work was done within the warranty period, which would be hard to detect on your car. Some did make it through though.

Not true, since I ordered my car, and I am the original owner, and I know the complete history of the car.  The only work that has been done on the car, is a new electric antennae, new tires, and new belts and hoses. 

[Ohio57-62Sedan]

No brake pad's Johnny?  is she metal to metal

[Guidematic]

 I think I should have become involved with this discussion earlier on.

The HT4100 site you mention gas really not changed since it was posted. The HT4100 chapter of the CLC is in somewhat of a limbo. Derek Sherwood started it, then sometime later left the club. But, there is a very vibrant and helpful Yahoo group, called the HT4100 Exchange, up and running that was the offspring to this that I started for the purpose of helping those with these engines.

http://autos.groups.yahoo.com/group/HT4100exchange/

There are 2 basic versions of these blocks, the longitudinal and transverse blocks. The longitudinal blocks were used in the 82-85 RWD deVilles and Fleetwoods, and the 82-85 Eldorados. They were available only as the HT4100. The transverse blocks were used on all the rest FWD Cadillacs. In 1988 they were enlarged to 4.5 litres, then in 91 to 4.9. The longitudinal and traverse blocks are not interchangeable.

The 4.5 was an overbore of the HT4100. They used removable wet cylinder liners, so to make a 4.5 out of a 4.1 can be done by simply exchanging the liners. The 4.9 was made by stroking the 4.5. The crankshaft cannot be used in the 4.1 since the nose is much shorter.

Early HT4100's suffered many failures. The most common was head gasket and intake gasket failures. They then also suffered distributor gear and camshaft failures. Many of the cam failures were caused by leeching of coolant from the head gaskets which compromised the oil's ability to lubricate the lobes. The head gaskets failed because of migration on the block. This was caused by split dowels used to locate the heads. Later engines had solid dowels and better gasket material which eliminated this problem.

Intake manifold gaskets also failed, and this was the most common cause of large amounts of coolant getting into the oil. This was repaired by revising the washers on the bolts, the gasket material and revised torque specifications.

They developed main bearing knocks as well. Many early 4.9's also suffered from this. When the engine got hot, clearance in the #1 ans #5 bearings increased so that the crank would move around causing a knock. This generally occurred under light acceleration. The fix was a bearing with increased eccentricity.

Other problems I have seen is the plastic on the timing gear on the camshaft come apart. This gets sucked into the oil pickup screen and starves the engine for oil causing potential catastrophic failure. This usually occurs on a long highway run. But this problem is by no means unique to the HT4100.

Reports of block porosity is a myth. But GM did and does recommend the use of the cooling system supplement tablets. And the coolant MUST be changed on a bi-annual basis, regardless of mileage. Put in 2 of these pills at that time.

I hope this addresses, once again, some of the common questions and myths about these engines.

Now, on the original problem, I would first find out where the coolant is going before I condemn the engine. If you are driving the car and just adding water as it goes down, you are only making the problem worse. Have you looked at the oil? The knock may be caused by the old main bearing issue I mentioned. Or by the coolant oil mix tearing away at the bearing material.

But, in any event, you will be spending upwards of $1,000 on the repair, if not more. A rebuilt engine will cost many times that, but will eliminate the problem, and that would be my recommendation. A swap to another type of engine is a very labour intensive job and will run you into even more, unless you can do the work yourself. Then there is the time involved the "shake down" all those little problems that arise from such a conversion.

Mike

[Dave Shepherd]

I think I should have become involved with this discussion earlier on.

The HT4100 site you mention gas really not changed since it was posted. The HT4100 chapter of the CLC is in somewhat of a limbo. Derek Sherwood started it, then sometime later left the club. But, there is a very vibrant and helpful Yahoo group, called the HT4100 Exchange, up and running that was the offspring to this that I started for the purpose of helping those with these engines.

http://autos.groups.yahoo.com/group/HT4100exchange/

There are 2 basic versions of these blocks, the longitudinal and transverse blocks. The longitudinal blocks were used in the 82-85 RWD deVilles and Fleetwoods, and the 82-85 Eldorados. They were available only as the HT4100. The transverse blocks were used on all the rest FWD Cadillacs. In 1988 they were enlarged to 4.5 litres, then in 91 to 4.9. The longitudinal and traverse blocks are not interchangeable.

The 4.5 was an overbore of the HT4100. They used removable wet cylinder liners, so to make a 4.5 out of a 4.1 can be done by simply exchanging the liners. The 4.9 was made by stroking the 4.5. The crankshaft cannot be used in the 4.1 since the nose is much shorter.

Early HT4100's suffered many failures. The most common was head gasket and intake gasket failures. They then also suffered distributor gear and camshaft failures. Many of the cam failures were caused by leeching of coolant from the head gaskets which compromised the oil's ability to lubricate the lobes. The head gaskets failed because of migration on the block. This was caused by split dowels used to locate the heads. Later engines had solid dowels and better gasket material which eliminated this problem.

Intake manifold gaskets also failed, and this was the most common cause of large amounts of coolant getting into the oil. This was repaired by revising the washers on the bolts, the gasket material and revised torque specifications.

They developed main bearing knocks as well. Many early 4.9's also suffered from this. When the engine got hot, clearance in the #1 ans #5 bearings increased so that the crank would move around causing a knock. This generally occurred under light acceleration. The fix was a bearing with increased eccentricity.

Other problems I have seen is the plastic on the timing gear on the camshaft come apart. This gets sucked into the oil pickup screen and starves the engine for oil causing potential catastrophic failure. This usually occurs on a long highway run. But this problem is by no means unique to the HT4100.

Reports of block porosity is a myth. But GM did and does recommend the use of the cooling system supplement tablets. And the coolant MUST be changed on a bi-annual basis, regardless of mileage. Put in 2 of these pills at that time.

I hope this addresses, once again, some of the common questions and myths about these engines.

Now, on the original problem, I would first find out where the coolant is going before I condemn the engine. If you are driving the car and just adding water as it goes down, you are only making the problem worse. Have you looked at the oil? The knock may be caused by the old main bearing issue I mentioned. Or by the coolant oil mix tearing away at the bearing material.

But, in any event, you will be spending upwards of $1,000 on the repair, if not more. A rebuilt engine will cost many times that, but will eliminate the problem, and that would be my recommendation. A swap to another type of engine is a very labour intensive job and will run you into even more, unless you can do the work yourself. Then there is the time involved the "shake down" all those little problems that arise from such a conversion.

Mike

Mike great post, I didn't want to list this littany of issues,( I was stuck trying to keep up with this stuff back in the day,) for fear of scaring and/or insulting any present owners, they did run well when they ran but the problems never ended. I was on the other side of  coin stuck running around NYC trying to keep them going!

[Guidematic]

Yes, the issues continued well into the 90's on earlier engines that did not get the upgrades, or were not replaced outright with the Targetmaster engine. I remember dealing with main bearing knocks, failed intake gaskets and distributor gear wear in the 90's on HT4100's while I worked at the dealer.

But, the problems were fixed one by one, and if you have one of the Targetmaster engines, you have one with all the issues fixed. The 4.5's were also not all immune to some of these issues. Failed intake gaskets and the odd distributor gear failure were seen on some of the early engines.

But, I have an '88 Eldorado with the 4.5 and it is a great engine. I have not had one bit of trouble with it at all. It has plenty of power and is great on gas. It runs so smooth and quiet you can't hear it, unless you stuff your foot into it. Then it sounds like a nicely tuned 327.

Mike

[Johnny]

No brake pad's Johnny?  is she metal to metal

Nope, no brake pads either.  With under 30K miles, in 24 years, it gets limited use, and most times its "highway" driving.  But since you mentioned it, I was going to have the brakes checked before Summer.

Since you mentioned it and to be completely honest, I guess I should mention that the following items have also be replaced:

Tires
Windshield Wipers
Battery
Rear Speakers
The TCC
Spark Plugs

But as far as the engine, nothing has been done to it, other then changing the spark plugs.