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Discussion Starter #1
Has anyone successfully changed the 4.1 in an 87 deville to 4.9????
Are there a lot of changes needed??? Seems like I have seen one person that changed from 4.1 to 4.5 without a lot of modifications
 

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djcalaska said:
Has anyone successfully changed the 4.1 in an 87 deville to 4.9????
Are there a lot of changes needed??? Seems like I have seen one person that changed from 4.1 to 4.5 without a lot of modifications
A 4.9 engine running off the 4.1 injection system is not going to run very well. To make it run correctly, you would either have to run the 4.9 with a carburator, an aftermarket fuel injection system such as megasquirt or find a donor car and transfer all the electronics over. It would be a really neat project and with the 87 being shorter and smaller, it would be a quite a hot-rod.

Try reading the first thread on this list for a lot more information.
 

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'98 Buick Regal LS - '91 Caddy Seville - '87 Caddy Seville!
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My '87 Seville runs with a TBI 4.5 liter that replaced the original 4.1 liter engine. To make that swap work, you have to use a 4.5 liter out of either an '88 or '89 with the TBI system. The MPFI engines from 1990 on up will not work out unless you're up for a lot of work like Edahall said.

To make a good swap from 4.1 liter to the 4.5 (TBI) liter, the following must be done:

Swap intake manifolds. You could probably get away with using the 4.5 liter manifold, but for optimal performance, I would use the most original euiptment to make the ECM play right. I'll let everyone know if the 4.5 liter intake can be used without any trouble once I finish my '86 Deville.

Everything else that was on the 4.1 liter should be used. This will help keep everything in check as far as sensors and such go.

That said, you can do one of two things for fuel to make up for the larger displacement of the new engine. You can either use the original TBI setup from the 4.1 liter, or you can opt for an adjustable fuel pressure regulator and set the fuel pressure up by about 10-15%.
 

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Discussion Starter #4
sorry about taking so long to get back to you. I thank you for the advice. The engine I have now has been bored to 4.5. My understanding is the block of the 4.5 is the same as 4.1. If the block of the 4.9 is the same as the 4.1 then I thought I might be able to use external 4.1 parts and make hook ups as original. Do need to find out if the fuel supply would be adequate. will have to stay with TBI.
 

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It would require far, far more work to go from an HT to the 4.9 in that car.

Simply isn't worth it. If you want a 4.9, get a '91-'93 DeVille, better car then the '87 anyway, and you already get the 4.9. They are cheap.
 

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Discussion Starter #6
Thanks Illumunia... That is exactly what I have figured... Have to much money in parts to just trash the car... Rides better than new and had started having upholstry redone... Painting was coming around.. It just rides so good... That 4.1 is garbage and my best option is probably going to the bored 4.5.. changing top and keeping as close to 4.1 as possible..From what I understand the head job may be more complex than what I want to get in too.
 

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Perhaps the main reasons to trash the 4.1 liter block is because of the lack of the roller cam system. You might be able to make the change to roller cam on the 4.1 liter, but there's more math involved than you would want to get into and it still might not work...

Here goes:

I'm not too sure on it, but the retainer for the roller lifters in the 4.5 and 4.9 liter blocks will fit the 4.1 liter lifter carrier, as the correct bolt patterns for a retainer are also on the 4.1 liter lifter carrier. But that means that you'd have to swap either a new set of lifters with the correct cam (for the 4.5 liter), or figure a way to get used ones into a lifter carrier that might not work with rollers...This might be a bad idea, thus I would avoid it unless someone (me perhaps) tries this method out with success.

Therefore, because I'm not sure of the exact differences in the lifter carriers, I would go for the 4.5 liter block that already has the roller lifters and associated hardware ready to go.

Remember this rule to keep everything on the safe side when swapping to a 4.5 liter:

Engine can be the 4.5 liter (block, heads, pistons, grease stains, crank, cam, everything else internal), but everything external should be from your original 4.1 liter. That would include the intake...

Anyway you go about it, let us know and we'll try and help you through it.
 

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The 87 HT4100 blocks were early castings of the 4.5 liter. They already have the roller cam hold downs, but they aren't drilled. One way to check if an 87 HT4100 block is a 4.5 casting is the reinforcing ribs on the sides. The 4.5 block has the vertical and triangular reinforcing ribs, the transverse 85 86 4.1 just had the triangular ribs and the RWD 4100 didn't have any at all. I would just get a reman 4.9 and swap manifolds and valve covers and run it on the TBI system, if the manifolds are same size of coarse (they should be).
 

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caddeville said:
The 87 HT4100 blocks were early castings of the 4.5 liter. They already have the roller cam hold downs, but they aren't drilled. One way to check if an 87 HT4100 block is a 4.5 casting is the reinforcing ribs on the sides. The 4.5 block has the vertical and triangular reinforcing ribs, the transverse 85 86 4.1 just had the triangular ribs and the RWD 4100 didn't have any at all. I would just get a reman 4.9 and swap manifolds and valve covers and run it on the TBI system, if the manifolds are same size of coarse (they should be).
Since I still have my original 4.1 liter block, I can say for sure that the lifter retainer can in fact be attached to the HT4100 lifter carrier. It has the bolt holes and everything. And mine is from an '87. However, I still would advise against swapping lifters to an engine that didn't use a another type in the first place. If you're going to rebuild an HT4100, then do it by the book: you'll find that the replacement parts should be of better quality for such a rebuild.

Before anyone wonders why my statement has changed from earlier, I stopped by my garage this evening to for some other parts and had a look as I remembered this thread...

As for swapping the 4.1 liter intake onto the 4.9 liter engine, it ain't gonna work out at all! You'd have to swap the 4.1 liter heads to the 4.9 block because of the slight but very important intake runner alignment and water passages due to the MPFI specifications of the entire setup. If you attampt to place a 4.1 liter intake onto 4.9 liter heads, the very first time that engine fires up it will leak water into some portion of the oil passages from the lack of correct alignment.

Rule number one-million for an 4.x series swap: from the cylinder heads on up, a MPFI engine and a TBI engine will not interchange!

The best method that still stands for this swap, as it is very easy and the least in time consumption, would be to swap a TBI 4.5 liter in and everything else should work out just fine.
 

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A guy on ebay was sellin a reman 4.9 and said just swap out the intake and valve covers for a 4.1/4.5 swap. Looks like he was wrong. Thanks for the info. If my engine blows (god forbid), i'll install 4.9 with tranny, with all electronics (just computer right?). I have access to many complete donor cars.
 

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caddeville said:
A guy on ebay was sellin a reman 4.9 and said just swap out the intake and valve covers for a 4.1/4.5 swap. Looks like he was wrong. Thanks for the info. If my engine blows (god forbid), i'll install 4.9 with tranny, with all electronics (just computer right?). I have access to many complete donor cars.
Yes, my answer is that the guy on Ebay ( :hmm: ) is wrong. Unless I'm proven wrong by someone else or if I try and mix parts during my next rebuild and prove myself wrong, then I'll change my answer. Until then, I stand by my previous statements.

And if anyone would like to question further, just look at the intake manifolds from the MPFI and the TBI engines: there's a lot of changes between them, therefore, they are not interchangeable. If anyone needs further explanation, please ask me and I'll set the record straight.

For your car Caddeville, you might as well save up for a 4.9 liter powered car if you really want one. It's just way too much work to swap those engines (trannies need swapped too should you decide to use the ECM) for what is going on.

That said, I still stand by my statement where I said that you should be able to interchange heads, oh, say, from a TBI 4.5 liter to a 4.9 liter block. Have the compression ratio raised a little, get the correct timing, and play with the fuel pressure for the TBI unit (an adjustable regulator will be needed for that), and you'll have a TBI powered 4.9 liter engine that should run better than the 155 horses that a TBI 4.5 liter runs...
 

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I will most likely then end up making a TBI running 4.9, i really like the taillights and the shape of the whole car on the 87 88 devilles, plus my caddy has a custom flake paint job (july 2006), custom sound system, wheels, etc. I'd rather do an engine change than buying a whole different car even though i can pick one up a wrecked one for 250$ with low milage. Such as i did with mine.
 

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caddeville said:
I will most likely then end up making a TBI running 4.9, i really like the taillights and the shape of the whole car on the 87 88 devilles, plus my caddy has a custom flake paint job (july 2006), custom sound system, wheels, etc. I'd rather do an engine change than buying a whole different car even though i can pick one up a wrecked one for 250$ with low milage. Such as i did with mine.
Well then, here's what you need to do:

a.) Get one (1) 4.9 liter engine,
b.) Get one set of TBI 4.5 liter cylinder heads,
c.) Take set of said heads to a machine shop...

Have the following done to heads:

1.) Decked to a 10.0:1 compression ratio (maybe even 10.5:1),
2.) Have the valves redone with a 3-angle valve-job,
3.) If you have the extra cash, a port-polish job with intake matching done.

Now we go back to what you need:

d.) A TBI intake manifold. The 4.1 liter intake should work, I will be experimenting with a 4.5 liter intake with a 4.1 liter ECM,
e.) An adjustable fuel pressure regulator...

Once you have all of this, rebuild the entire engine. Have new bearings placed into everything. Rods. Mains. Cam bearings...All of them...

Once done, you should have a fine running TBI unit that puts down around 180-plus horsepower...
 

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All of this info will come to use very soon, thank you very much. Once my lifters fail, i will definatly do this swap. It'll be one unique engine when done. Call it HT4700.
 

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Discussion Starter #15
Before this nightmare 87 I had a 88 deville with 144,000. Never had problem 1 with that car or engine.... it definately had more go than the 87.. If the mounts on the 88 4.5 are the same as the 87 4.1 then swap should be easy enough... I paid someone on the first engine change, this time I am going to do myself...Last time car came back missing pieces.....
 

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I have another question. What is the main difference between the roller camshaft and the flat tappet camshaft? Like, what would happen if you would try to use roller cams with a flat tappet camshaft? I'm just curious.
 
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