1980 RX-7, with a V8?

If it has to meet the same requirements for smog as it did in the mustang, then it won't pass in the 7.

Even if it would pass, just go through the motor. A set of pistons and rings can't be much, and could be done in a day.

Saving work to speed up a project does neither!

You might be able to find a later model Explorer engine in a junk yard for about $500 that would drop in too.

The last few weeks I have been pretty busy. Any free time that I have had has been spent on trying to make progress on the project.

I decided it would be foolish to not take the time and rebuild the engine now. And with that I must also add the original budget is shot. While I am not too happy to endure this cost now, I know it is for the best. As I began to take the engine apart I could see several things that were going to haunt me if I hadn’t. Water pump, intake manifold, timing cover and rear main seal all beginning to leak. The connecting rod bearings are all showing wear. And most of the cylinders the cross hatching is all gone.

My trouble cylinder, #8, as anticipated shows the most wear. The piston rings have shaved enough material off the cylinders wall that there is about a 0.008”=0.010” lip at the top of the cylinder. I have not put my hands on a bore gage to accurately measure the diameter, but it appears to have been a standard 4.000” bore. I took a digit caliper and measured the bore at the top of the cylinder and it measures 4.00”. I have judged the wear of 8-10 thousands with a feeler gage up against the lip. So with my fingers crossed I am hoping to have it bored out at 20 or 30 over.

During disassembly I got in a fight with the timing cover.

One of the water pump/timing cover bolts broke off during water pump removal. At first I thought the bolt had seized in the block, but when I tried to slide the cover off I realized the bolt had actually became part of the timing cover (rusted). I tried to drill it out, but eventually the drill went a little off center and went through the cover. At that point I just went a little on the wild side. I will have to add this to the cost of the rebuild now.

What’s on my agenda? When I get a chance I want to clean the block deck and check it for straightness and condition. I am keeping an eye out on Craigslist and EBay for an affordable set of GT40 heads from an Explorer (anybody have some for they want to sell?). I am attempting to call around to machine shops in the Sacramento area for price quotes on cleaning and boring the block; decking the block (in case its needed); replace connecting rod bolts and realignment of the caps (I figure best to address these bolts before they become a problem); pressing piston pins; install cam bearings, and cost of cylinder head work (clean, resurface, valve guides and grind). If anyone has any recommendation on a machine shop in the Sacramento area it would be helpful.

At this time I plan on purchasing an engine rebuilt kit from Summit. A kit from Federal that come with about everything included hypoeutectic pistons is about $330. Additional items I plan on getting are new fasteners (most the fasteners did not look in great shape), water pump, alternator/air pump bracket (found that mine was broken from a previous alternator replacement), timing cover, shorty CARB legal headers and a new clutch (there is more to list but these are the larger items).

Hopefully I can get the block to a machine chop within the month. I am doing my best from stalling out on the project.

Tough break, but you will absolutely be glad later that you took the time to do it right the first time. It shall be mighty!

Yes, a wise decision

I was able to pick up a new set of "super stock" rods off eBay for $90 with free shipping from Speedway Motors for my build. They are actually late model Explorer rods.

I did a junk yard run for a Explorer intake set for $60 too.

I don't know where the fuel lines are at in a RX-7 but you can get some fuel rails that have the connections at the passenger front or drivers rear.

GPz11 thanks for the heads up on the rods. I was only going to replace the rod bolts because I figured they were a little tired and there is no point putting all the money into the engine and watching it go BOOM! The ARP rod bolts are nearly $80 on their own plus add the fees to press them in and realign the caps I'll be well beyond the cost of these new rods. Thanks again, I think I will be going with these.

Question. If I replace the rods will I need to rebalance the rotating assembly? I know it never hurts but wondering if it would a necessity?

rebalance?no definitely not.id check the rods big end for round just in case(torqued) but after that you can smack em in...but heres what I do.get a digital scale that reads to 3 dec points,measure all and shave to bring em all down together.the I beam rods I have in a 351W race motor all read within .75 grams of each other,all came on the build sheet.the rods big and little ends have balance pads for this purpose,just sand them to get down to "spec"

YoloRX7 wrote: GPz11 thanks for the heads up on the rods. I was only going to replace the rod bolts because I figured they were a little tired and there is no point putting all the money into the engine and watching it go BOOM! The ARP rod bolts are nearly $80 on their own plus add the fees to press them in and realign the caps I'll be well beyond the cost of these new rods. Thanks again, I think I will be going with these.

stock 91 and up ford rods are junk anyways--the casting codes will read either C8OE or F1SE on Ford 302 rods...the C8 are 1968 pattern and are forged, while the F1 or 1991 thunderbird (S code) are powdered cracked metal.all factory rod bolts are weak and stretch under prolonged high rpm use

YoloRX7 wrote: The last few weeks I have been pretty busy. Any free time that I have had has been spent on trying to make progress on the project. I decided it would be foolish to not take the time and rebuild the engine now. And with that I must also add the original budget is shot. While I am not too happy to endure this cost now, I know it is for the best. As I began to take the engine apart I could see several things that were going to haunt me if I hadn’t. Water pump, intake manifold, timing cover and rear main seal all beginning to leak. The connecting rod bearings are all showing wear. And most of the cylinders the cross hatching is all gone. My trouble cylinder, #8, as anticipated shows the most wear. The piston rings have shaved enough material off the cylinders wall that there is about a 0.008”=0.010” lip at the top of the cylinder. I have not put my hands on a bore gage to accurately measure the diameter, but it appears to have been a standard 4.000” bore. I took a digit caliper and measured the bore at the top of the cylinder and it measures 4.00”. I have judged the wear of 8-10 thousands with a feeler gage up against the lip. So with my fingers crossed I am hoping to have it bored out at 20 or 30 over. During disassembly I got in a fight with the timing cover. One of the water pump/timing cover bolts broke off during water pump removal. At first I thought the bolt had seized in the block, but when I tried to slide the cover off I realized the bolt had actually became part of the timing cover (rusted). I tried to drill it out, but eventually the drill went a little off center and went through the cover. At that point I just went a little on the wild side. I will have to add this to the cost of the rebuild now. What’s on my agenda? When I get a chance I want to clean the block deck and check it for straightness and condition. I am keeping an eye out on Craigslist and EBay for an affordable set of GT40 heads from an Explorer (anybody have some for they want to sell?). I am attempting to call around to machine shops in the Sacramento area for price quotes on cleaning and boring the block; decking the block (in case its needed); replace connecting rod bolts and realignment of the caps (I figure best to address these bolts before they become a problem); pressing piston pins; install cam bearings, and cost of cylinder head work (clean, resurface, valve guides and grind). If anyone has any recommendation on a machine shop in the Sacramento area it would be helpful. At this time I plan on purchasing an engine rebuilt kit from Summit. A kit from Federal that come with about everything included hypoeutectic pistons is about $330. Additional items I plan on getting are new fasteners (most the fasteners did not look in great shape), water pump, alternator/air pump bracket (found that mine was broken from a previous alternator replacement), timing cover, shorty CARB legal headers and a new clutch (there is more to list but these are the larger items). Hopefully I can get the block to a machine chop within the month. I am doing my best from stalling out on the project.

I just saw on speedmasters site that a 347 kit with crank,H beam rods and hypereutectics is $480...that's a steal when you need to get a crank machined,buy rods,pistons etc

Fwiw: I had my rotating assembly balanced. All the parts were at the machine shop anyway and I wanted a smooth running engine. Possibly overkill but worth it.

In reply to GPz11:i built 2 347s for a father/son team...dads is a 65 GT350 replica,also went with MSD EFI.juniors is a 68 Cali Special, carbed. dad's got balanced ($400) and junior's didn't.both use 28 oz imbalance...cant tell the difference on either at 6000+ rpm.its a personal "feel" thing but on street motors I don't bother,especially with modern rotating assemblies from Eagle etc

I got an estimate today on machine work.

For the block: bore, hone, deck, clean and cam bearings= $400

Press rod bolts and resize rods = 125

Cylinder heads: clean, deck, check for cracks and compete valve job = 265 (forgot to ask if that was both heads. He knew I was doing an engine rebuild so I hope that is both).

Budget keeps going up.

Thanks for the info. I like the sound of new rods. It would be half the cost of replacing bolts and resizing.

Sorry there for the lack up updates but not much has changed. My 2 other hobbies have been keeping me busy (family & garden). I have mostly doing a lot of research the last 6 weeks or so. I won an eBay auction last week for some GT40 heads. $355 w/ free shipping. Fingures crossed they will be in good shape and want require much work. I have decided on a machine shop to use. Looks like around $1200-$1300 for hot tank, bore, deck, line hone, press new cam bearings, freeze plugs, grind crankshaft, balance and press pistons over.

I have been going back and forth on a couple of decisions. One is hypertetic/forged pistons. I think I am going hypertetic. Saves me $200, and weight. Being I am mostly doing a stock rebuild I think this will be okay. The second decision I am still undecided on. The machine shop is advising me to stick with the connecting rods I have rather than go with the super stock rods. They suggest using these and replacing the rod bolts with ARP bolts ($195). They advised you just don't have any garantys the refurbished rods will have fitment issues or damage/deformations form prior use.

Any thoughts? Hypertectic or forged? My current rods or refurbished super stock rods?

With luck I will have the block and crank dropped off at the machine shop this coming week.

Love the project, and I'd like to weigh in on my opinions:

Hyperutectic(sp?) all the way. I went down that wormhole once. As I recall, Forged expand more, and slap when cold, and this can make your knock sensor unhappy. Or do they expand less? Anyway, I was very unhappy with my N/A, forged piston, expensive street engine.It slapped itself to an early grave. For serious boost or power, maybe go forged. A mildly built 5.0 in this car will be spectacular. Try to build torque over horsepower.

The same K.I.S.S. principal applies to o stock rods. If you want to get fancy, get a postal scale, and balance them while apart, along with the pistons. Thank you for viewing my opinion.

The connecting rods I mentioned are brand new, not reconditioned.

I also have a GT40 / Explorer lower intake all cleaned up and painted if you are interested. I'll take $50 plus shipping from Chicago. Also have some BBK underdrive pulleys for a Fox Body 302 too.

https://chicago.craigslist.org/wcl/pts/5498054226.html

There is a note at the that states they are reconditioned. I read past it several times before I noticed. It wasn't until I actually went to Speedway Motors website did I finally catch it. The only thing they speak of in their reconditioning process is new bolts are installed. Their item is description is kind of misleading because they open with the statement "new ford motosports forged rods."

Huh, that wasn't there when I got them.

If the machine shop installs new rod bolts, they'll have to recondition them too.

A quick update since I have not made a whole lot of progress.

Work has not been cooperating with me to get the engine too the machine shop. I am hoping maybe Friday I can work it out.

I think I need to replace the flywheel. Someone must have been trying to do some burnouts riding the clutch because there seems to be several cracks from getting hot. I have never removed the flywheel from a domestic V8 engine, surprised how light and thin they are compared to the 4 and 6 cylinder Japanese vehicle I have experience with.

The progress I have made was this weekend. I friend of mine is an ex-Ford tech and has loaned me the 1993/94 car repair manual discs. I set up an old computer I retired last year in the garage and now have an electronic repair manual in the work station. Super sweet!

After getting the software installed and figuring out how to navigate the program I began going through the Granny's wiring instructions. There a lot of differences between his wiring and what is required for my application. Some of the work/connections have been simplified. As I located all the wires on the 5.0 harness I resistance checked them to make sure I grabbed the correct wire, labeled them and created a simple spread sheet to track my notes.

I have never done an engine swap or wiring customization but I do have lots of experience with wiring diagrams, circuit operation and wire repair. So I found most of this to seem pretty easy. I will defiantly re-check and triple check to make sure I got it all right. Do want a visit from the fire department once I crank the engine over.

I am still thinking about how I want to do my fuel system. If I can find an FB fuel tank I may pick it up and cut out my spare tire well. This would make things a lot easier I feel because I can mount the fuel pump in the tank and not worry about where to externally mount and the pump making tons of noise.

Very nice.

Following your build, because I am about to start something similar.

Nice im having trouble getting EFI parts for my car. Mostly the witing harness. Everyone on CL has no idea what they are talking about which makes it a pain!

You can also look at the tanks Inc pa4 module. Self contained tray and pump module. Using it in my duster. May be cheaper and easier than finding another tank.

I have started looking into looking how I can modify my tank to accept an in tank fuel pump. Tanks PA-4 looks like a great option but I am not sure I can cut a wide enough hole to accept it. The hole has to be either 4 or 4.5" ( I haven't found a copy of instructions to clarify the diameter of the whole). At best I have a 4.75" spot to work with. Not sure the mounting flanges will have the space to fit. I am going to try and call Summit or Tanks to confirm the diameter of the mounting flange and hole. If it fits I will go with this.

I also found Aeromotive makes a similar kit. It is twice the cash but seems to be a lot nicer. It only requires a 3.5" hole. Pretty sure I can make it work but it's $500.

Researching both of these products started making me think about making my own set up. Realalisticly all I need it a mounting plate that uses screws and has the two lines coming off it and I can make my own set up from there. I was hoping to see if the donor mustang bolted on, but I am not so lucky. It has one of those locking rings that twists in place. Finding the right flange/mounting plate maybe a. Challenge.