Rebuilding the engine, what should I do while I'm there?

MadMikeyL

SCCoA Member
The motor in my 89 XR7 spun a rod bearing about 6 months ago, and I'm finally getting around to fixing it. I have another engine that I pulled out of a 90 XR7, so I figure I'll rebuild this one and then just swap them out. Once done, this car is going to be a daily driver, so I don't want to go too crazy with it, but I would like to get some more power. Hopefully the cylinder walls will clean up with just honing, then I won't have to get new pistons and I can spend the money somewhere else. Everything else looked good in this motor, so I'll clean it all up and put new bearings and rings in it, and it should be good to go. But while I'm in here, where would my time and money be best spent to get some more power and reliability?
 
stock ported heads and a mild cam, then if you ever wanted to put down some real power you wouldn't have to go into the motor again.
 
Yeah I would say do a cam even if you don't port the heads cause it's alot easier to change the cam while the motor is out of the car.And heads aren't to bad to change in the car later on if you want to upgrade them.I don't think you have to worry about reliability too much our motors are pretty solid.




Jay
 
Speaking of reliability I'm replacing the crank sensor just on general principles while doing my other engine work. I don't know the history of this engine and "crank sensor" comes up waaaaay too often in my archive browsing :)

Cheers
Doug Dwyer
 
Where should I get the cam from? Also, what is considered mild? I've only ever built V8s before, so I don't know if different specs would behave differently on a V6. I do know when I pulled the stock cam out, it looked pretty pathetic. Anyway, how big should I go? Its a 5-speed car, and I wouldn't mind a little lope, but like I said, the car will be a daily driver, so I don't want it to be ridiculous. What does everyone reccomend? Also are the stock lifters and valve springs OK for the larger cam? Also what about roller rockers, would 5.0 ones work, or do they make ones specifically for the 3.8?
 
You need to think about what your goal is. Horsepower level, how much money you want to invest, dependability etc. Heads and cam is always
a good start for any later upgrade. Maybe new pistons and rods. Wanna keep it mild or make wild. I like wild. Good luck

Mike:D
 
Where should I get the cam from? Also, what is considered mild? I've only ever built V8s before, so I don't know if different specs would behave differently on a V6. I do know when I pulled the stock cam out, it looked pretty pathetic. Anyway, how big should I go? Its a 5-speed car, and I wouldn't mind a little lope, but like I said, the car will be a daily driver, so I don't want it to be ridiculous. What does everyone reccomend? Also are the stock lifters and valve springs OK for the larger cam? Also what about roller rockers, would 5.0 ones work, or do they make ones specifically for the 3.8?

My car has the Comp Cams Stage I cam in it from SCP, www.supercoupeperformance.com. I like it, but I think I should have went with the stage II. My car was also built as a daily driver.
 
Don't Forget ARP Studs!

The motor in my 89 XR7 spun a rod bearing about 6 months ago, and I'm finally getting around to fixing it. I have another engine that I pulled out of a 90 XR7, so I figure I'll rebuild this one and then just swap them out. Once done, this car is going to be a daily driver, so I don't want to go too crazy with it, but I would like to get some more power. Hopefully the cylinder walls will clean up with just honing, then I won't have to get new pistons and I can spend the money somewhere else. Everything else looked good in this motor, so I'll clean it all up and put new bearings and rings in it, and it should be good to go. But while I'm in here, where would my time and money be best spent to get some more power and reliability?

Well, all of the power guys have spoken so I'll address the reliabilty issue. I had to replace a rod bearing in my motor a couple of years ago. Finding a reman crank kit was hard but I found one in NC. I did no power upgrades since it is my DD but I did install ARP Main bearing, rod bearing and head studs in the motor.

Ed
 
The motor will definitely be getting ARP head studs, but I'll leave the stock fasteners for the bottom end. As far as my goal, I want a reliable daily driver with as much power as I can get for as little money as possible. I know cheap power and SCs don't exactly go together, which is why I'm asking where is the money best spent when starting with a stock rebuild.
 
The stock springs are good for about .500 lift, depending on age, which also happens to be about the limit of stock unported heads. You can get 300 rwhp with stock heads but that probably requires a blower upgrade.

If you do a search, you'll find many using .520 or .540 lift cams (usually regrinds until recently) with 5 speeds and several options of suppliers. Some suppliers are hesitant to play the numbers game because numbers don't tell the whole story. Does it have to pass emissons tests?

Minimum support for 300 rwhp would be 42# injectors, fuel pump, MAF, IC fan and a SCT chip or EEC tuner might be needed. Don't forget the balancer, crank pulley, and mounts. Also, a 180 t-stat and colder plugs are suggested.
 
I've got the tools for porting, so I'll probably do a little bit of work on them. Where could I get new valve springs for the higher lift cam? Also is lift what these motors really respond to, or do they respond better to duration? I haven't checked the specs on it yet, but when looking at the stock cam, the duration just looks pathetic compared to the V8 cams I'm used to seeing. As far as having to pass emissions goes, it does, but it doesn't if you know what I mean. The car will have cats and be tuned right, so even with a huge cam in there it should pass, but if for some reason it doesn't, I have my connections.

I'll definitely get 42lb injectors, 255lph fuel pump, MAF, and a tune. I also have a spare intercooler sitting here, so I was thinking of trying to make a double intercooler myself, and also get rid of the stock intercooler tubes for some aftermarket ones that will flow better. I also know I'll need a raised blower top. As far as the blower itself, I was originally thinking of just finding a 94/95 blower, but I don't know if that would be enough, so I'm still debating whether to spring for a magnum powers setup or not.

The balancer/crank pulley I have is still good, and with the price of the BHJ, I think I'll stick with what I've got for now. The motor mounts were just replaced about a month before the motor blew, so I'm good there.
 
You can get a cam from Dave Dalke he'll spec one for just what you're looking to do and for a regrind it's only like 150 or 175 don't remember.You can get upgraded valve springs from him also cheap.As for roller rockers no the 5.0 ones won't work you have to either get some that are made for a 351 cleavland or some spec'd just for a 3.8.The 3.8 onmes are quite expensive and probably won't gain you very much with a mild combo.



Jay
 
I've got the tools for porting, so I'll probably do a little bit of work on them. Where could I get new valve springs for the higher lift cam? Also is lift what these motors really respond to, or do they respond better to duration? I haven't checked the specs on it yet, but when looking at the stock cam, the duration just looks pathetic compared to the V8 cams I'm used to seeing. As far as having to pass emissions goes, it does, but it doesn't if you know what I mean. The car will have cats and be tuned right, so even with a huge cam in there it should pass, but if for some reason it doesn't, I have my connections.

I'll definitely get 42lb injectors, 255lph fuel pump, MAF, and a tune. I also have a spare intercooler sitting here, so I was thinking of trying to make a double intercooler myself, and also get rid of the stock intercooler tubes for some aftermarket ones that will flow better. I also know I'll need a raised blower top. As far as the blower itself, I was originally thinking of just finding a 94/95 blower, but I don't know if that would be enough, so I'm still debating whether to spring for a magnum powers setup or not.

The balancer/crank pulley I have is still good, and with the price of the BHJ, I think I'll stick with what I've got for now. The motor mounts were just replaced about a month before the motor blew, so I'm good there.

A little porting on a 94/95 blower will go a long way. I mean why not just stick with one since it's going to be a DD. It'll be ALOT cheaper. As far as sticking with the stock balancer, I wouldn't recommend it. If you look around, many people have problems with trying to reuse them. They will most likely fail before too long and will cause alot more problems down the road. The money you save on the blower upgrade will most definitely pay for a BHJ, getting it machined, etc etc.

Also, why not check into one of those chin spoilers on SCP.com
Since it's going to be a DD, why not run cool at the same time.
 
Cleveland rockers will work? I wasn't aware the cleveland ever came with pedestal-mounted rockers, I thought they were all stud mount.

I guess I'm on the lookout for a 94/95 blower casing and inlet then. If I get bored with it, its easy enough to upgrade that later. As far as the balancer goes, we will see. Mostly its just sticker shock seeing the price of that thing. The brand new balancer for my 393 cost me $60, and shortly after buying that I looked at the BHJs for this motor, and the cheap-@$$ in me refused to shell out that much money when there's nothing wrong with the stock one.

As far as the chin spoiler goes, if I get one of those it would be after the car is up and running properly. I'm much more concerned with the car being able to drive than running a few degrees cooler.
 
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