The Chrysler Minivan Fan Club Forums banner

1991 3.3 Rebuild

5151 Views 140 Replies 9 Participants Last post by  donchicago48
My 91 Grand Caravan spun a rod bearing at 235,000 miles and 31 years. As luck would have it, I was 200 miles from home. I rented a UHaul Truck and Tow Dolley and towed the wounded vehicle home.
I began disassembling the engine in preparation for removal immediately. I found that the #4 rod bearing had spun and the#4 piston was hitting the cylinder head. All the other main and rod bearings looked fine.
The engine block had very little cylinder wall wear, about .003" - .004". There were no perceptible ridges at the tops of the cylinder walls. I decided to rebuild the engine myself except for machine shop operations.
Once the engine was out of the vehicle, I finished stripping the block of all parts and removed all the freeze and oil plugs. The camshaft and roller lifters were visibly worn. The pistons showed some skirt wear and the oil rings were fairly caked with oil deposits.
I pressure-washed the block and once all the oily grime was gone, I prepared it for an Electrolysis bath (see youtube) to clean the water passages. It did a great job of cleaning up all the invisible parts of the block. After about 48 hours of Electrolysis, I pulled the block out of the bath, pressure washed it again and treated it with WD40 Blast. I cleaned all the block threads with Taps and prepared to send it to a machine shop for cylinder boring and main bearing line boring (if needed).
Since there was only one 1991 block used for both 3.3 L and 3.8 L engines in 1991, I decided to have the block bored to 96 mm (3.780"). I found a set of 2007 3.8 L 96 mm bore flat top EUM Silvalite pistons that would work with my 3.3 L crankshaft and stock 6.18" rods. These pistons have 1.261" compression distance, the same as stock 3.3 L dished pistons. This engine will now be a 3.5 Liter engine with 9.7:1 compression.
I purchased a reground 3.3 crankshaft and matching main/rod bearings from Crankshaft Supply in Minneapolis, MN for $175. They provided fast shipping and excellent customer support. I recommend them highly. They provided a return shipping tag and refunded the $75 core charge quickly.
I found a reconditioned rod on ebay that was an exact replacement for my #4 Rod. It weighs almost exactly the same as the rest of the rods and has same forging number. I will weigh both ends of the rods and adjust weights as needed after the rods are reconditioned and fitted with new rod bolts. The new pistons will weigh more than the original ones, so the crank will need balancing.
I originally planned to use Hastings Moly Rings, but they could not ship before Christmas. Summit Racing customer support was excellent and arranged to cancel order from Hastinngs and refund my purchase price quickly. I found similar 1.2mm/1.5mm/3.0mm Moly Rings from Mahle on Amazon.
I ordered a new 3.8 L 4th Gen Cam, new lifters, valves, valve guides, valve seals, push rods, and rocker arms. I have not found new valve springs and will continue looking for a suitable replacement.
I will recondition the cylinder heads myself after the machine shop cleans and surfaces them. I also drilled and retapped the rocker shaft bosses for larger, longer bolts in order to help prevent rocker shat boss breakage. In the future, I may get later model cylinder heads, Intake and exhaust manifolds, and larger throttle body and air filter box.
See less See more
  • Like
  • Wow
Reactions: 3
1 - 20 of 141 Posts
How bout some pics? Sounds like you’ve got quite the project going.
Today I visited a wrecking yard that had a couple dozen Chrysler minivans. I did not find a 1998 Mosel with a 3.8 L V6. I want to get the intake manifold and throttle body. I did find a 1992 Dodge Caravan. I got the Body Computer module and the hood release. However, this was a bare bones model. I'm not sure if the BCM will work on my Grand Caravan.
I will go back and keep looking for an early 3.8 L van with a larger Throttle body and manifold.
I am thinking about getting an entire top end of a later model 3.8 with heads, Intake, Air Box, exhaust manifolds, and etc.
Hear are a few photos;
Automotive tire Camera accessory Street light Cameras & optics Gas
Automotive tire Gas Vehicle Auto part Motor vehicle

ĥ
Wheel White Automotive tire Bicycle part Motor vehicle
Camera accessory Coin Camera lens Automotive tire Nickel
Font Gas Rectangle Auto part Electric blue
Automotive tire Camera accessory Bicycle part Auto part Automotive wheel system
Motor vehicle Automotive tire Bumper Automotive exterior Gas
See less See more
7
  • Like
Reactions: 3
  • Like
Reactions: 2
Here is a 1991 3.3 L V6 Throttle Body compared to a later model 1998? 3.8 L Gasket.
I picked up the Cylinder Heads and several Aluminum Alloy parts from the machine shop today. The engine block is getting final cylinder honing today. The Crankshaft will go to a shop that does engine balancing next week.
I will concentrate on the Cylinder Heads next. I will do a 3-angle valve job with all-new valve guides, valves, valve springs, and keepers. I will have to send the intake valves out for back-cutting.
Rectangle Font Auto part Composite material Automotive exterior
Automotive design Automotive tire Font Automotive exterior Gas
Machine Auto part Gas Metal Plastic
See less See more
3
  • Like
Reactions: 4
W-O-W.

I once owned a 1994. Not sure if I would go the extent you have after having a 4th gen with SnG seats. Plus the 4th gen handles so much better on the road vs feeling like the 1994 was just a box with wheels.

I too did the 3.8L TB swap onto my 3.3L engine. It was plug-n-play, nothing special.

Got to say, I love your build log here. Keep telling us more as you go along and the pixs are excellent!
I once owned a 1994. Not sure if I would go the extent you have after having a 4th gen with SnG seats. Plus the 4th gen handles so much better on the road vs feeling like the 1994 was just a box with wheels.
Really? Your 2006 handles so much better than your 1994?

I owned a 1991 for over twenty years and I own a 2006 for over three years. I liked the way my 1991 handled. Here are some comparisons from my experience. Some of this may be subjective.

1991 is better.

- Visibility out sides
(side windows and pillars design)

- Visibility out back
(rear window design)

- Parking
(smaller size & window/pillar design)

- High speed cornering
(less weight)

-Looking thru side mirrors close up as in seeing the parking lines
(side mirror design)

2006 is better.

- Visibility out front
(large windshield)

- Turning circle
(1991 = 41 ft 2006 = 37.7 ft)

- Tire feel
2006 = 15 inch 1991 = 14 inch

-------------------------
- Braking and other handling is about the same in both vans in my opinion.

- My 06 has more power because I had the 3L in my 91 and I have the 3.3 in my 06.

-Both vans are SWB with front disc rear drum brakes.

-Both vans have the 4spd auto.

-Glad I have removable seats instead of stow n go.:cool:
-------------------------

- My 91 had high back front buckets.
-My 06 has low back with headrest front buckets.
Not sure which are more comfy but I like the door and seat armrest better on the 06.

Both vans have the basic instrument cluster and I like the 06 a lot more. But if both vans had the deluxe cluster – more gauges on the 91.

-------------------------

Like I said some of this may be subjective. If anyone wants me to compare other stuff ask away.:)

Mopar-Mofun
Please share your experience in comparing and mention stuff like engine size, brakes, tires, wheelbase ext.
See less See more
  • Like
Reactions: 3
W-O-W.

I once owned a 1994. Not sure if I would go the extent you have after having a 4th gen with SnG seats. Plus the 4th gen handles so much better on the road vs feeling like the 1994 was just a box with wheels.

I too did the 3.8L TB swap onto my 3.3L engine. It was plug-n-play, nothing special.

Got to say, I love your build log here. Keep telling us more as you go along and the pixs are excellent!
Circuit component Rectangle Font Electronic component Electronics accessory

My search for Connecting Rod Bolts took me to ARP. I gave their tech support my Rod bolt dimensions. They recommended part no. 145-6002, which fits various Big Block Chrysler V8 engines from 1957 - 1978. The bolts are about 0.100 longer than the 3.3 V6 bolts. They have just enough threads to work on the 3.3 rods. The ARP bolts are significantly stronger than the OEM 3.3 L V6 bolts
See less See more
  • Love
Reactions: 2
Really? Your 2006 handles so much better than your 1994?

I owned a 1991 for over twenty years and I own a 2006 for over three years. I liked the way my 1991 handled. Here are some comparisons from my experience. Some of this may be subjective.

1991 is better.

- Visibility out sides
(side windows and pillars design)

- Visibility out back
(rear window design)

- Parking
(smaller size & window/pillar design)

- High speed cornering
(less weight)

-Looking thru side mirrors close up as in seeing the parking lines
(side mirror design)

2006 is better.

- Visibility out front
(large windshield)

- Turning circle
(1991 = 41 ft 2006 = 37.7 ft)

- Tire feel
2006 = 15 inch 1991 = 14 inch

-------------------------
- Braking and other handling is about the same in both vans in my opinion.

- My 06 has more power because I had the 3L in my 91 and I have the 3.3 in my 06.

-Both vans are SWB with front disc rear drum brakes.

-Both vans have the 4spd auto.

-Glad I have removable seats instead of stow n go.:cool:
-------------------------

- My 91 had high back front buckets.
-My 06 has low back with headrest front buckets.
Not sure which are more comfy but I like the door and seat armrest better on the 06.

Both vans have the basic instrument cluster and I like the 06 a lot more. But if both vans had the deluxe cluster – more gauges on the 91.

-------------------------

Like I said some of this may be subjective. If anyone wants me to compare other stuff ask away.:)

Mopar-Mofun
Please share your experience in comparing and mention stuff like engine size, brakes, tires, wheelbase ext.
My 1991 Grand Caravan LE came with 15" alloy wheels. It had HD suspension and a towing package with trans cooler, etc. I put a 1999 Grand Caravan Rear Axle in it with 2007 Disc Brakes and an aftermarket adjustable proportioning valve and aftermarket Rear Sway Bar. I put on 17" X 7" alloy wheels with 215/60R17 tires. I changed the front Sway Bar to a 1-1/8" bar. I removed the load-sensing rear brake proportioning valve. The van now has KYB Front Struts and KYB adjustable Rear Shocks. I retained the original multi-leaf Rear Springs. The 1999 Axle has a bracket for a link that prevents lateral axle movement when cornering. The 1999 monoleaf springs would not provide as much lateral stiffness as the 1991 multileaf springs. I may have a bracket for the link fabricated and welded to the chassis in the future just to see if it improves handling. I would have to relocate the left rear brake line to clear the bracket. As it is, the rear ride is a bit harsh on rough roads when the van is not loaded.
See less See more
  • Wow
Reactions: 2
Oh yeah I forgot My 1991 had the factory tow package
-Front Stabilizer Bar
-Heavy Duty Suspension
-Trans Cooler
-Hitch / Wiring

My 2006 has the regular suspension but gen-4 vans 2001–2007 come with transmission coolers.
Another thing I love with my 2006 is the sliding doors on both sides.
Oh yeah I forgot My 1991 had the factory tow package
-Front Stabilizer Bar
-Heavy Duty Suspension
-Trans Cooler
-Hitch / Wiring

My 2006 has the regular suspension but gen-4 vans 2001–2007 come with transmission coolers.
Another thing I love with my 2006 is the sliding doors on both sides.
I bet the tow package made the ride so much better. The 1994 was miserable for a tight u-turn, crosswinds on the highway felt like the van was going to tip over and hard to keep on the road, it sat much higher than the 2006, the 1994 was lack luster for power as a V6 loaded with passengers.
Yes, your points on the visibility are a huge plus.
My 2006 with the crappy DaimlerChrysler single leaf rear suspension cost savings had to be beefed up with Dayton Add-A-Leaf and the Monroe coil over shocks to bring it back to the level of the 2001 thru 2004 models.

OK, let's let the OP keep going in his build blog here. This really has my interest going. (y)
  • Like
Reactions: 1
After further careful review, these rod bolts will not work. The threaded area is too short to provide adequate torquing margin. The search continues for new rod bolts of any kind that will work.
  • Wow
Reactions: 1
I bet the tow package made the ride so much better. The 1994 was miserable for a tight u-turn, crosswinds on the highway felt like the van was going to tip over and hard to keep on the road, it sat much higher than the 2006, the 1994 was lack luster for power as a V6 loaded with passengers.
Yes, your points on the visibility are a huge plus.
My 2006 with the crappy DaimlerChrysler single leaf rear suspension cost savings had to be beefed up with Dayton Add-A-Leaf and the Monroe coil over shocks to bring it back to the level of the 2001 thru 2004 models.

OK, let's let the OP keep going in his build blog here. This really has my interest going. (y)
"Crosswinds on the highway felt like the van was going to tip over and hard to keep on the road" You're right I forgot about that as I didn't drive much in those situations. Yeah the tight U turns as I mentioned earlier Turning circle
(1991 = 41 ft 2006 = 37.7 ft)


OK, apologies for the slight hijack - let's let the OP keep going in his build blog here. :)
Train Gas Engineering Auto part Nut

I visited the Machine Shop today. My block was in the Sunnen Honing Machine.

Attachments

See less See more
2
  • Like
Reactions: 3
View attachment 68876
I visited the Machine Shop today. My block was in the Sunnen Honing Machine.
Motor vehicle Font Auto part Automotive super charger part Metal
See less See more
I picked up the Cylinder Heads and several Aluminum Alloy parts from the machine shop today. The engine block is getting final cylinder honing today. The Crankshaft will go to a shop that does engine balancing next week.
I will concentrate on the Cylinder Heads next. I will do a 3-angle valve job with all-new valve guides, valves, valve springs, and keepers. I will have to send the intake valves out for back-cutting. View attachment 68785 View attachment 68786 View attachment 68788
Automotive tire Gas Motor vehicle Engineering Wood

Removing old Cam Bearings with 8MileLake tool.
See less See more
  • Like
Reactions: 2
1 - 20 of 141 Posts
Top