Bottom end rebuild?

JasonMiller94SC

Registered User
Well after having the top end of the motor apart twice this year I finaly got the car tuned and had a chance to take it to the track. My previous best was a 13.69@98mph with a 55 shot of nitrous. The first pass this weekend was right off the highway on the street tires, no nitrous, and I was pleased with the run. 13.26@ 105.34 mph. I swapped on the drag radials and only managed to gain a little with a 13.21@104.73 mph. The next pass went up to a 13.4 @ 102mph. I decied to let the car cool and change the blower pully from the stock one to a 10%. The result was a 13.26@104. I was running out of time so I decided to put the 55 shot on and break into the 12's. On the way back to the stanging lanes I heard a noise comming from the engine. I was told by a fellow racer that it sounded like a rod bearing. What I want to know is there any way to find out for sure what the it is without taking the motor out? If I do have to rebuild the bottom end who should I talk to? If I'm going to rebuild the motor I want it to last. I'm looking for some recomedations for parts and someone to do the work. I've never been in the bottom end of a motor before so I don't know if I want to do the rebuild myself or not. I don't have a garage so I don't have anywhere to do the work. Looks like I'll be driving the stock 94 SC until I get the other motor fixed.
 
you can check the bearings in the lower engine by droping the oil pan, and taking off the oil pump, the bearings should be right there then, I however am in the process of dealing with the same problem. I just bought a 95 sc and the thing was knocking a little bit, and it just got worse, I was going to change the bearings but I was told by numerous people that if you replace the bearings, it will probally wear them out again shortly after you replace them because most likely there is some kind of grove on the crank, which would wear the new bearings down again, on mine, I am just getting a remanufactured one from ford and putting that in since I have been told that the cost to rebuild one would be close to the same price, and it would take alot longer to send it off and have everything done to it, than to just buy one, hopefully you dont have to deal with all that , but thats the problems I had and sounds like yours are kind of like mine.

Good luck with whatever you do
 
Jason, well it is good to hear that the heads and cam part worked out well for you. Sorry the rest of it wasn't up to the task though. :(

I will say a couple of things about the motor.

1) Don't run it at all any more. If you are lucky the crank might be salvageable. Determining that is the first thing you have to do. If the crank is not salvageable then you will be looking for another motor.

2) I do not recommend a reman motor for your application. I would highly recommend rebuilding that one. The 94 has better rods and a windage tray that are both worth keeping.

For a high performance application you really need blueprinted clearances and tolerances on the block and crank/rods. I think that a reman is pretty much a guess as to what you are going to get. A reman is a good option for a stock or mild motor but I don't think yours falls into that catagory.

The other thing you should be looking at is forged pistons. I am working with Wiseco to provide an OE replacement forged piston that does not require rebalancing of the motor and does not require aftermarket rods. I think this would be a very wise choice for you.

Too bad I'm so far away and booked up so heavily right now. I'd love to build a shortblock for you but I'm afraid it would be fall before I had anything ready for you.

David
 
Yea Dave, your cam done good. Wish I had put the drag radials on for that first pass. Bet it would have been real close to a 12 second pass. I'm not driving the car. Had it trailered from the track to a friends house. I'll go pick it up this weekend. I'd like to get the car running before June so any tips on what a good rod/piston combo would be is greatly appreciated.
 
bottom end

i was wondering if you could pull the pan without taking the engine out, and still have the room to pull the bearings, rods and crank? i am having a rough time with my 94 and i am about to just redo everything! what kind of bearing are recommended for main and rod? also is it a good thing to replace the rods and pistons while i am doing this?
 
For bearings I prefer Sealed Power. If you want OE type pistons then Sealed Power is the choice also. If you want forged then Wiseco offers the best price (check the group buy forum for pricing). Stock connecting rods are fine, but you can also run 351W rods if you want to upgrade.

To check bearings without pulling the motor you'll need to drop the K-member.

If you don't want to have to balance the motor you are best running stock rods and a replacement piston either cast or forged. If you go with any rod other than stock you will need to rebalance. Balancing is nice regardless but it is not always necessary and it will add significant time and cost to your rebuild.

A lot of people run 6.2" rods and forged pistons for a bullitproof combination. Keep in mind though that $3000 goes real quick if you head in this direction....
 
I replaced my oil pan this weekend and did as Dave said. Dropped the K-member. Basically I had the entire front suspention and subframe out of the car (I think the only thing left connected was some power stearing lines).

It was a one day job, but a big one.
 
XR7 Dave said:
The other thing you should be looking at is forged pistons. I am working with Wiseco to provide an OE replacement forged piston that does not require rebalancing of the motor and does not require aftermarket rods.

I have a 94 SC short block that I plan on rebuilding. It will be a backup to the 1995 Mustang NA block that I am currently using. I really like the idea of Forged OE style replacement pistons. I figure the OE forged pistons, 94 rods and SC crank would work well in my daily driver and occasional strip use.
 
So it is possible to replace everything without taking the motor out? If I can replace my parts with forged pistons and stock rods I think I may do that. Anyone have part numbers for some new rods and pistons?
 
I wouldn't do it with just pulling parts and swapping it. Pull the block and do it right.

Factory tollerances just aren't all that great so taking the opportunity to deck the block and align hone the mains can have real benefit. Plus get those cylinders bored true to the crank and you'll be set to rock and roll.
 
Just thinking about doing all of that work with the engine in the car makes my back and arms sore. While it would save having to pull the engine, I'd much rather assemble the crank, rods and pistons and check clearances on an engine stand. I'm also not sure if you can pull the pistons out through the bottom of the bore. Previous experience with other engines says no.
 
JasonMiller94SC said:
So it is possible to replace everything without taking the motor out? If I can replace my parts with forged pistons and stock rods I think I may do that. Anyone have part numbers for some new rods and pistons?

Do you really think you'll need new rods? You can email me about the replacement forged pistons, they are a semi-exclusive design that I have worked with Wiseco to make for us.
 
I'll be in touch. I still gotta get the car back from my friends house. Gotta find a trailer. I wonder if it's possible somethign let loose in the valve train that would make a knocking sound. Car sounds fine at idle but starts clattering at about 2500-3000 and gets worse when you let off the gas.
 
Jason, I agree with the rest. You have to get that engine out to do it right. You've torn down the engine to do the hg's (more than once i think?)...taking the whole thing out is a hop, skip and a step away. That will give you a chance to do alot more things to the engine, clean it up, add other parts, etc, plus the priceless assurance that things are done the right way.

In terms of checking things out first (which is a good idea) i'd get one of those mechanic stethoscopes and check things out. I've read of roller rockers coming loose.
 
I think if a rocker came loose then it would make noise all the time, not just at 3000. I do have a mechanics ear that I might try once I get the car to the house. The bad part is the my garage is full. I'll have to do all the work out in the driveway. With the 20 degree slope of the driveway it makes things tough when you got to get under the car. If I could get the motor out I don't have anywhere to put it to work on it. Doing the HG's in the driveway was bad enough but I don't know if I can do a motor pull there.
 
100% it's rods. Don't run the motor any more or you'll be replacing the crank. If it only knocks at higher rpms then it might be salvageable with a .010".
 
JasonMiller94SC said:
If I could get the motor out I don't have anywhere to put it to work on it.

By this do you mean space or an engine stand? If its the later, i have one you can use anytime you want.
 
DamonSlowpokeBaumann said:
Dave ya should always balance a motor when changing pistons..COMMONE!

If I change rings, should I balance the motor?

If I replace pistons with stock replacement pistons should I balance the motor? What is the difference?

If I replace OE cast pistons with forged pistons of equal weight must I balance the motor? If so why?

Of course an SC motor could benefit from balancing but does every rebuild require balancing? Of course not. Balancing is an extra cost upgrade that can be done just like any other extra cost upgrade. Whether or not the pistons are changed is not what should determine whether you spend the money on balancing.

I have worked with Wiseco to develop a forged piston in exactly the same weight as the stock pistons so that people can upgrade to forged pistons with no other changes. This is an option that people have asked for a long time now.

Please explain to me why this will not work? :confused:
 
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