Bob's 1986 Daytona Turbo Z C/S: rebuilding a 2.2 liter turbo engine
by Bob O'Neill. Updated 3/4/08.
In December 1985 I purchased a standard Daytona. But what I really wanted was the Turbo Z with T-tops and the C/S handling package. Twenty years later I found the perfect project car. On the way to the Chrysler National Car show at Carlisle in 2006 we stopped by Madison Heights, VA where Wayne had found the car for me. Wayne AKA Hogtownhustler on the Allpar.com Daytona forum, is a friend that I've chatted with over the years on the forums and have visited a few times. He found this car and thought it would be perfect for my project. When I saw the car I knew he was right.
This engine was apart when I purchased the car. So this article will concentrate on the proper assembly of the engine with some additional information about my goals for the car and what roles the engine plays.
The car has 121,000 miles on the clock. This is not a great deal of miles on one of these 2.2 Turbo engines. The problem was that the owner had blown the head gasket. Once it was discovered that the head itself had a crack between the combustion chamber and the water jacket, the head was left off the block and parked outside in the elements for most of a year. The car was not badly affected by this but the engine block was. In the first generation Daytona there is a hood 'grill' which allows air in through the hood. It is my guess that this was installed is to help cool the turbo. There was a modification to the induction of the first generation Daytona which was available from Direct Connection. It was an intercooler which was mounted just above the valve cover and intake manifold. This would position it just below the grill. The theory was that the air which flowed through the grill would cool the intake air as it passed through the intercooler.
In addition to air, the grill allows rain to fall through the hood and onto the engine when the car is left out in the elements. Because the head was off the car rain collected in the cylinders. Cylinders #2 and #3 were badly rusted. Had this not happened it may have been possible to simply hone the cylinders for the rebuild. Because of the rust the cylinders were bored to the minimum over size and replacement pistons will be used.
The Engine Rebuild
Before I can discuss the engine rebuild I think it is important to understand my goals for this car and therefore the engine. This project car will be a show car and as we know, show cars which are driven must have a bit more guts than stock. It is an unwritten rule that just sounds right to me.
In 1986, the Daytona Turbo Z was equipped with a 2.2 liter turbocharged engine. This is a non intercooled turbo 1 engine and uses a suck through throttle body. This engine delivers 141 hp and 170 lb-ft torque.
Then, in 1986, Dodge installed the 2.5 liter engine in the Daytona for the first time. This is the engine which is in my standard Daytona. In comparison with the 2.2 turbo, the 2.5 TBI produces 100 hp and 135 lb-ft torque. The difference in performance between the 2.5 and the 2.2 is not really huge so I felt it necessary to plan the rebuild of the 2.2 so it would produce more than the stock 141 hp. The goal for the 2.2 turbo engine is 200 hp with 230 lb-ft of torque.
To properly rebuild an engine it is very important to pay attention to the details. Details such as the clearances between the bearings and the crankshaft journals as well as the clearances between the pistons and cylinder walls and the rings both in the grooves of the pistons and the rings end gap in the cylinder. There are other clearances which are also important and I'll mention these when I get to that part of the engine rebuild.
The Block, Pistons and Rods
The block was bored to the minimum over size as this was all that was necessary to clean up the rust and straighten the bores. This increased the bore of the cylinders from 87.5mm (3.44 in) to 88mm (3.46 in) or .5mm (.020 in) over size. The pistons used for this rebuild are the turbo 2 cast pistons and were manufactured by Mahle. Mahle is the company who originally provided the pistons for these engines. There is a slight difference between the turbo 1 pistons and the turbo 2 pistons. While the wrist pin is the same diameter in both engines the turbo 2 pistons use a floating pin where the turbo 1 pistons were press fit to the rod. Also in the 1986 turbo 1 engine used a lighter weight rod and weighed 659 grams. Since my goal for this engine is to make 33% more power and torque I decided to use the turbo 2 rods. These rods are heavier but stronger in the area where they connect to the crank shaft. The turbo 2 rods weigh 699 grams each and have more material in areas which are under stress in higher horsepower applications. The rods used in this rebuild were fitted with new bushings which were matched to the wrist pin. They were also modified to permit an 'extra' oiling hole in the small end and permits more oil to be supplied to the pin. The turbo 2 pistons also have oiling holes on the underside of the boss which supplies oil to the pin where it connects to the piston. Because the turbo 2 pistons are not press fit they require a snap ring to keep the pin in place. In addition to the rework of the rods I weighed each one and machined them to insure they were each within one gram of each other. Once this was completed they were shot peened to insure strength especially where the machine work was done. It is my hope that this extra step will help with rotational balance. I know the crank was in balance and during the internal components preparation I weighed each piston. Each piston weighed exactly the same, so when they are attached to the rotating balance should be really close.
There is one more thing about the block which should be mentioned here. This would be the oil pump. I did replace the oil pump even though the unit which was originally installed didn't appear to have excessive wear. I didn't see any logic in not replacing it since the replacement is 'new' and should be good for the life of the new engine. There is however one issue which I felt I needed to address. This is the oil hole in the block. The hole in the block is round and angles away from the oil pump. The oil pump's output is oval and appears to be slightly off center, so I adjusted the oil galley hole in the block to better match the mating hole in the pump. It has been mentioned that this can return otherwise 'lost' horsepower at higher RPM. It is only a few as in two to five but if this simple modification helps flow the oil better then it's a no brainer.
Check out the picture and notice the oval hole. I took a grinder before the block went to the machine shop to be cleaned and ground out this hole to match the oil pump output. I can see how horsepower could have been lost here. The original hole was round like I said and it angles away from the pump. It's not perpendicular to the output of the pump. So, the pump would make pressure and have to force it into the galley. With this modification there is far less force needed to put oil into the galley.
Before beginning the assembly, the block must be cleaned and the thread holes cleaned as well. The way to insure that the thread holes are cleaned is to use a thread chaser of the proper size. I didn't have a thread 'chaser' for the head bolt threads so I made one. Let me explain why. The thread chaser doesn't cut new threads it simply cleans them to remove junk which may be on the threads. This junk can prevent the proper tightening of the bolts. I couldn't use a tap because it cuts threads. So I did the next best thing. I took an old used head bolt and using a Dremel tool with a cutting wheel I cut four grooves parallel to the bolt through the threads. Then I cut a bit more at the 'bottom' of the bolt.
Once I did this, I oiled up the hole/chaser and using my hand only I threaded it into each bolt hole all the way to the bottom to 'chase' the threads. The reason to chase the threads is to remove the grit, machining dust or anything else that may be in the bolt holes on the threads. Using oil on the threads helps to lump contaminates together so when the chaser is unthreaded the contaminates are removed from the threads. If I noticed any hole that seemed to be especially dirty I chased it till it was clean. This step helps to insure that when the head bolts are tightened they will be uniformly tightened to the proper torque specification.
Once the threads have been chased on each head bolt hole the flatness of the decks should be confirmed. The flatness of the block should actually be done prior to building short block in case it needs to be returned to the machine shop. But if the shop did their job right, they would have checked the flatness of the block's deck would have been checked and the block decked if necessary. To check it, use a straight edge which you know to be straight. A good quality carpenter's square will work fine. Using a feeler gauge to measure, put the straight edge across the decks at a diagonal and straight. Take your measurements between the cylinders between the straight edge and the deck. Any warping of the deck will be evident if the measurements exceed .020". Mine was flat and there was no measurement more than .010".
The Assembly
The clearances between the parts are critical if you want to make the power and reliability goals set for an engine. If the clearances are too tight things will bind and will wear out with a bang. If they are too loose the same thing can happen. To insure that the bearings have the right clearance measurements are taken before final assembly.
The following are the required clearances for a 'new' engine. This information was pulled from the Factory Service Manual (FSM). While I was researching this I discovered some discrepancies in the information. Some of these discrepancies can be explained as simple typographical errors. But upon careful examination of the specifications I did some further research. It appeared to me that some of these specifications were very tight. I noticed that even the Plastigage didn't come in a size which would measure less than .001". Some of the specifications in the FSM called for as little as .0004". The following table compares information I pulled from the Factory Service Manual and from a popular Turbo Dodge web site.
The following table compares information I pulled from the Factory Service Manual and from a popular Turbo Dodge web site.
Turbocharged engine specifications
by Bob O'Neill. Updated 3/4/08.
In December 1985 I purchased a standard Daytona. But what I really wanted was the Turbo Z with T-tops and the C/S handling package. Twenty years later I found the perfect project car. On the way to the Chrysler National Car show at Carlisle in 2006 we stopped by Madison Heights, VA where Wayne had found the car for me. Wayne AKA Hogtownhustler on the Allpar.com Daytona forum, is a friend that I've chatted with over the years on the forums and have visited a few times. He found this car and thought it would be perfect for my project. When I saw the car I knew he was right.
This engine was apart when I purchased the car. So this article will concentrate on the proper assembly of the engine with some additional information about my goals for the car and what roles the engine plays.
The car has 121,000 miles on the clock. This is not a great deal of miles on one of these 2.2 Turbo engines. The problem was that the owner had blown the head gasket. Once it was discovered that the head itself had a crack between the combustion chamber and the water jacket, the head was left off the block and parked outside in the elements for most of a year. The car was not badly affected by this but the engine block was. In the first generation Daytona there is a hood 'grill' which allows air in through the hood. It is my guess that this was installed is to help cool the turbo. There was a modification to the induction of the first generation Daytona which was available from Direct Connection. It was an intercooler which was mounted just above the valve cover and intake manifold. This would position it just below the grill. The theory was that the air which flowed through the grill would cool the intake air as it passed through the intercooler.
In addition to air, the grill allows rain to fall through the hood and onto the engine when the car is left out in the elements. Because the head was off the car rain collected in the cylinders. Cylinders #2 and #3 were badly rusted. Had this not happened it may have been possible to simply hone the cylinders for the rebuild. Because of the rust the cylinders were bored to the minimum over size and replacement pistons will be used.
The Engine Rebuild
Before I can discuss the engine rebuild I think it is important to understand my goals for this car and therefore the engine. This project car will be a show car and as we know, show cars which are driven must have a bit more guts than stock. It is an unwritten rule that just sounds right to me.
In 1986, the Daytona Turbo Z was equipped with a 2.2 liter turbocharged engine. This is a non intercooled turbo 1 engine and uses a suck through throttle body. This engine delivers 141 hp and 170 lb-ft torque.
Then, in 1986, Dodge installed the 2.5 liter engine in the Daytona for the first time. This is the engine which is in my standard Daytona. In comparison with the 2.2 turbo, the 2.5 TBI produces 100 hp and 135 lb-ft torque. The difference in performance between the 2.5 and the 2.2 is not really huge so I felt it necessary to plan the rebuild of the 2.2 so it would produce more than the stock 141 hp. The goal for the 2.2 turbo engine is 200 hp with 230 lb-ft of torque.
To properly rebuild an engine it is very important to pay attention to the details. Details such as the clearances between the bearings and the crankshaft journals as well as the clearances between the pistons and cylinder walls and the rings both in the grooves of the pistons and the rings end gap in the cylinder. There are other clearances which are also important and I'll mention these when I get to that part of the engine rebuild.
The Block, Pistons and Rods
The block was bored to the minimum over size as this was all that was necessary to clean up the rust and straighten the bores. This increased the bore of the cylinders from 87.5mm (3.44 in) to 88mm (3.46 in) or .5mm (.020 in) over size. The pistons used for this rebuild are the turbo 2 cast pistons and were manufactured by Mahle. Mahle is the company who originally provided the pistons for these engines. There is a slight difference between the turbo 1 pistons and the turbo 2 pistons. While the wrist pin is the same diameter in both engines the turbo 2 pistons use a floating pin where the turbo 1 pistons were press fit to the rod. Also in the 1986 turbo 1 engine used a lighter weight rod and weighed 659 grams. Since my goal for this engine is to make 33% more power and torque I decided to use the turbo 2 rods. These rods are heavier but stronger in the area where they connect to the crank shaft. The turbo 2 rods weigh 699 grams each and have more material in areas which are under stress in higher horsepower applications. The rods used in this rebuild were fitted with new bushings which were matched to the wrist pin. They were also modified to permit an 'extra' oiling hole in the small end and permits more oil to be supplied to the pin. The turbo 2 pistons also have oiling holes on the underside of the boss which supplies oil to the pin where it connects to the piston. Because the turbo 2 pistons are not press fit they require a snap ring to keep the pin in place. In addition to the rework of the rods I weighed each one and machined them to insure they were each within one gram of each other. Once this was completed they were shot peened to insure strength especially where the machine work was done. It is my hope that this extra step will help with rotational balance. I know the crank was in balance and during the internal components preparation I weighed each piston. Each piston weighed exactly the same, so when they are attached to the rotating balance should be really close.
There is one more thing about the block which should be mentioned here. This would be the oil pump. I did replace the oil pump even though the unit which was originally installed didn't appear to have excessive wear. I didn't see any logic in not replacing it since the replacement is 'new' and should be good for the life of the new engine. There is however one issue which I felt I needed to address. This is the oil hole in the block. The hole in the block is round and angles away from the oil pump. The oil pump's output is oval and appears to be slightly off center, so I adjusted the oil galley hole in the block to better match the mating hole in the pump. It has been mentioned that this can return otherwise 'lost' horsepower at higher RPM. It is only a few as in two to five but if this simple modification helps flow the oil better then it's a no brainer.
Before beginning the assembly, the block must be cleaned and the thread holes cleaned as well. The way to insure that the thread holes are cleaned is to use a thread chaser of the proper size. I didn't have a thread 'chaser' for the head bolt threads so I made one. Let me explain why. The thread chaser doesn't cut new threads it simply cleans them to remove junk which may be on the threads. This junk can prevent the proper tightening of the bolts. I couldn't use a tap because it cuts threads. So I did the next best thing. I took an old used head bolt and using a Dremel tool with a cutting wheel I cut four grooves parallel to the bolt through the threads. Then I cut a bit more at the 'bottom' of the bolt.
Once I did this, I oiled up the hole/chaser and using my hand only I threaded it into each bolt hole all the way to the bottom to 'chase' the threads. The reason to chase the threads is to remove the grit, machining dust or anything else that may be in the bolt holes on the threads. Using oil on the threads helps to lump contaminates together so when the chaser is unthreaded the contaminates are removed from the threads. If I noticed any hole that seemed to be especially dirty I chased it till it was clean. This step helps to insure that when the head bolts are tightened they will be uniformly tightened to the proper torque specification.
Once the threads have been chased on each head bolt hole the flatness of the decks should be confirmed. The flatness of the block should actually be done prior to building short block in case it needs to be returned to the machine shop. But if the shop did their job right, they would have checked the flatness of the block's deck would have been checked and the block decked if necessary. To check it, use a straight edge which you know to be straight. A good quality carpenter's square will work fine. Using a feeler gauge to measure, put the straight edge across the decks at a diagonal and straight. Take your measurements between the cylinders between the straight edge and the deck. Any warping of the deck will be evident if the measurements exceed .020". Mine was flat and there was no measurement more than .010".
The Assembly
The clearances between the parts are critical if you want to make the power and reliability goals set for an engine. If the clearances are too tight things will bind and will wear out with a bang. If they are too loose the same thing can happen. To insure that the bearings have the right clearance measurements are taken before final assembly.
The following are the required clearances for a 'new' engine. This information was pulled from the Factory Service Manual (FSM). While I was researching this I discovered some discrepancies in the information. Some of these discrepancies can be explained as simple typographical errors. But upon careful examination of the specifications I did some further research. It appeared to me that some of these specifications were very tight. I noticed that even the Plastigage didn't come in a size which would measure less than .001". Some of the specifications in the FSM called for as little as .0004". The following table compares information I pulled from the Factory Service Manual and from a popular Turbo Dodge web site.
The following table compares information I pulled from the Factory Service Manual and from a popular Turbo Dodge web site.
Turbocharged engine specifications
New part clearance |
---|