Swapping an 86 5.0 into an 87 GT?

[cjrpony]

Need more info on what is worn out with the existing engine.

If the engine is worn, yes, you can simply swap the long block assembly, and reconnect the 87 electronics and it should work. That would include using the mass air setup if the 87 has it.

Otherwise you would need to swap the 86 computer and engine harness into the 87, which is sort of an unnecessary step backwards.

Probably best to troubleshoot the 87 before pulling anything apart.

+100% Spend a little time and troubleshoot this before you swap. 500 bucks is a lot of dough when this could really be a simple issue. I would say that if you can turn the motor over by hand, and the guy was being truthful about it running before, then this is probably a starting issue. And since it has been sitting awhile, prime the oil pump if/before you try to start it again.

 

[cjrpony]

Personally, I think you're going about the whole thing the wrong way.

If that car has just been sitting, then it's unlikely (although no timpossible) that the motor itself is at fault. What's more likely is that old ass gass or a HOST of other things are wrong. Things that will STILL be wrong even if you swapped in a brand new crate motor!

I would urge you to find a mechanic buddy (or hire one if necessary) and take him with you to go look at this car. Explain the situation as best you can and let him take it from there.

The fact that it's "not cranking" alone, is definitely no reason to start swapping motors around.

+100% on this response too!

 

[psycho78]

Hmmm, thats true. I did plan on replacing the fuel pump as well but is there anything else that would cause the engine NOT to crank thats not engine related? (Its not the battery either lol)

 

[RatStang]

Cranking by itself:

Starter, Starter Solenoid, Bad wiring, bad ignition switch (all assuming a good battery. lol).

Starting and idling for a car that's been sitting:

I'd be pulling/flushing the entire fuel system. From the tank, all the way up to the fuel injectors. I'd also be looking at every accessible Vacuum hose and replacing those that are questionable.

 

[Vinnietbird]

The '86 cam was slightly more aggressive than the '87 up 5.0 H.O,and you can swap an '86 engine into the car with no worries.Even a Mass Air car.I've done it.

 

[cjrpony]

Cranking by itself:

Starter, Starter Solenoid, Bad wiring, bad ignition switch (all assuming a good battery. lol).

Starting and idling for a car that's been sitting:

I'd be pulling/flushing the entire fuel system. From the tank, all the way up to the fuel injectors. I'd also be looking at every accessible Vacuum hose and replacing those that are questionable.

There should be a neutral safety switch or interlock on the transmission that prevents it from starting in anything but Park or Neutral. That could be bad also. Make sure its plugged in. And make sure the ground cable from the battery is connected to the engine.

Try this: Make sure the car is in Park and take the starter cable from the solenoid and carefully (it may throw a few sparks) touch it to the positive terminal on the battery. It should crank if the starter and starter cable are good (you said it had a new starter). If it cranks, I would check the solenoid wiring, ignition switch and neutral safety switch. If it doesn't crank, check starter, starter cable, ground cable and make sure engine isn't seized. Again, after changing the fluids in the motor and priming the oil system! This assumes that you have the old style starter.

If you have a multimeter, see if you are getting a voltage at the solenoid on the ignition wire (I think it is the small red or pink and white) when the key is turned to start.

Hope all this helps

 

[jdl95stang]

I agree 100% on what these guys are saying. There should, and i do mean "should" be no reason for the engine itself to be the issue. Find out, first off, if the car just won't run or if it won't crank over. Let us know what you come up with. No reason we can't figgure this out. good luck

 

[psycho78]

Thanks guys, I appreciate the help. The main issue being that aside from simple engine work, Im not very skilled with the stuff. I could probably figure most of it with an easy walk thru, but Ill be honest, this car has really had me nervous all day today. Im afraid of dumping a bunch of cash into the car and not getting it to run. Now, I bought the car today for a mere $700. Body is solid, no rust except a few small bubbles on the trunk lid which i can easily replace, the conv. top is great with only the window needing replacement, and then just a few cosmetic parts need to be done. I think I can easily come out ahead with all of this and I was just trying to avoid buying a few things for the engine then realizing it needs to be changed but it seems like the stuff u guys are asking me about wouldnt be difficult. i suppose I could hire someone to come take a look at the engine (I dont suppose anyone here lives near Tampa? lmao!). I do know this for a fact, the guy told me this morning that it def' needs a new fuel pump and solenoid. The tranny should be good, it had just been put in before it set and has only 500 miles on it...

 

[ratio411]

Check the fuel pump relay before you go replacing a fuel pump!

 

[psycho78]

Hey thanks again guys - well I thought about it and was going to simply try and figure out the engine, however, I have a mechanic who has volunteered to swap the engines for me for free, provided he can keep the 302 5.0 thats currently in it (he wants to rebuild it for a truck he has). So rather than trouble shoot it, I honestly think its easier to simply have him throw the engine in for the $150 that the complete 86 engine (with headers) is costing me (not to mention that he says he has quite a few spare parts if needed like starters and alternators). Again, thanks for the help guys, I really appreciate it.

 

[cjrpony]

Well good luck to you, let us know how it goes and if you find out what was wrong with the motor.

 

[RatStang]

Hey thanks again guys - well I thought about it and was going to simply try and figure out the engine, however, I have a mechanic who has volunteered to swap the engines for me for free, provided he can keep the 302 5.0 thats currently in it (he wants to rebuild it for a truck he has). So rather than trouble shoot it, I honestly think its easier to simply have him throw the engine in for the $150 that the complete 86 engine (with headers) is costing me (not to mention that he says he has quite a few spare parts if needed like starters and alternators). Again, thanks for the help guys, I really appreciate it.

Copy all but be warned... I think you might be a crucial point that folks are trying to make and that is:

You could swap a BRAND NEW motor into that car and end up EXACTLY where you are now.

Until you have pin pointed the reason that this car is not running, you're just spinning your wheels. At this point, what you're attempting to do is just like performing a heart transplant on a corpse in an effort to bring him back to life.

You need to determine the cause of the no crank condition. Swapping a perfectly good motor into a car with a fuel injection problem, or ignition problem, or a wiring problem, etc. will get you nowhere. You'll just be removing a perfectly good motor and replacing it with another perfectly good motor and whola... bupkis. hehe

 

[RatStang]

double post

 

[RatStang]

triple post

 

[psycho78]

Oh yeah, I totally understand that - but heres my thought process:

Having a good running engine thrown in for $150 will eliminate a large amount of potential problem points. I'll know for sure, if it doesnt run, what it isn't and that should narrow it down quite a bit. To have a mechanic play around with the motor and try and figure out would probably cost me more then $150 anyway, and if thats not the problem, I'd be in the same situation anyway so Im not really losing anything, as far as Im concerned. Plus, to be honest, some of these smaller shops can be untrustworthy and Im afraid of them tacking on a bunch of extra things they said I needed that i didnt really need. The guy whos swapping the engines isnt making anything off me except the motor, so I cant see him wanting to add a bunch of things to it since he isnt making any labor costs. Does that all make sense? lol

 

[Mikey1968]

Swapping one old engine for another makes no sense....for example, you do the swap and the fuel pump is bad....you will not have done anything but pour time and money down the toilet...you will still need to change the fuel pump.

This whole thread makes no sense except you are dead set on changing the engine regardless of what all us old timers tell you......

Swapping an engine can induce many more problems and is not an easy thing for a novice...you may be left off worse than when you started....not just the same.....and with empty pockets, too!

Simply fix the engine or buy a new car with a warranty.

'nough said....

 

[dls322]

I do know the 86' is speed density and the 87' is MAF.

WHAT??????

 

[dls322]

Foolish move in my opinion...but i think everyone else already threw in their .02. Doing an engien swap for a car that won't crank. Could be a ton of $5 parts that could be causing it. Fuel Pump.....no. Will still crank with a bad fuel pump. Since you bought it ask some mechanics what they will charge to "go over the car" and they can probalby find the problem easily.
DEFINATLY will reduce resale on the car for some people.....i personally would not buy a 87 with a 86 engine in it, i would with a 87-93 engine in it but not an 86.

Good luck with your project.

 

[psycho78]

Hey guys, I apologize if it came off as if I were dead set on changing it - I should really clarify whats going on. I have a mechanic and a 2nd engine - however, I am having the mechanic go through the engine first to find out if he can see what the problem is. Currently he thinks it could be the computer. Hes having it checked in the morning. I basically have the 2nd engine as an alternative if he cannot figure this out. He seems to know his stuff. If he gets the 87 running, hes keeping the 86 in payment, if he swaps 'em, hes keeping the 87. I did stress to him to try and keep the 87 in after hearing everyone's opinions.

 

[dls322]

Cool, let us know how it turns out!