Mulling over the swap

HOWNDOG · Dec 30, 2006

....been awhile, Life and all.

It appears that my 91 stang may have blown a gasket. 70-90lbs compression in 3+4 and aweful knocking from where the motor goes (Car is in beautiful shape though).

It so happens I have an 87tc next to the shed with some body damage and rust on inner fender-firewall (kids and I picked up at auction for fun a year or so ago). Few other issues from previous dip**** owner but mechanically seems fine.

Anyways, I pulled the cover off the stang and notice roller rockers/followers which got me wondering which parts to keep if I was to swap the 87tc motor into the 91dis. Intake, head, cam, computor, etc. etc.

Also, the TC motor seems to be a bit low on compression (to what I'm used to) so I was planning a rebuild. What readings should be expected on a lower compression turbo motor?

I'm kinda stuck as to which way to go as the car was our daily driver and my wife's freedom. Fix it or Swap it now?

Appreciate the help.
HD

ps. Merry Christmas and such to you all.

mg man · Dec 30, 2006

Do the swap in my opion. Then you'll have best of both works 4 cylinder economy and v-8 power. You have all the parts except a exhaust and misc like new hoses belts etc. Compression will be lower how much I don't know. I don't remember what mine was when I did it. Welcome back Good luck let us know how it goes

realtripp · Dec 31, 2006

these engines are only supposed to have about 8:1 compression in stock form.

My engine builder cc'd everything, including the head gasket and figured that it was only about 7.5:1 compression.

HOWNDOG · Dec 31, 2006

realtripp said:
these engines are only supposed to have about 8:1 compression in stock form.

My engine builder cc'd everything, including the head gasket and figured that it was only about 7.5:1 compression.

Unfortunatly my guage doesn't read in ratios and I'm not sure where to start in doing the calculation myself.

HD

HOWNDOG · Jan 3, 2007

Couple more Qs

Seems the timing belt is quite difficult to get off the crank pully. I don't have to remove the pulley do I?

A few of the head bolts on the exhust side seem pretty gummed up and a new set is $70. I don't really want to waste the money on the NA engine unless its something I can reuse on the Turbo later. Any suggestions?

Which head, cam, and intake should I be using for the turbo?

thx
HD

mg man · Jan 3, 2007

Use the Turbomotor complete. Use turbo block,pistons,heads, injectors etc. Since you'll have it out good idea to put in new headgasket from my experiece and read engines hard on headgaskets. You can save na intake to use later it you decide to get into modifing them. Can't use na injectors. Pulley has to come off I think I got mine off with deadblow hammer. Came off easy this may not be normal don't know. If 91 stang is roller cam you can use it in the turbo head. Don't when roller cam was started to be used in stang. Stinger's site has info on wiring. Is 91 a DIS engine? His site will tell what to do about distributor. My stang was 89 so no problems. Good luck

Dr_EluSivE · Jan 3, 2007

Do it!

go ahead and do the swap, if the engine in the tc runs, i would clean it up, put a new VC gasket and pan gasket and drop it in. i wouldnt mess with the head unless it really needs it. Swap in the mustangs cam, and i would put in a new set of lifters (i didnt, but wish i did) and maybe valve seals. Other than that i wouldnt mess with the turbo engine much. Use the instructions on stingers site and go to town. Be prepared for nickle and dime stuff like belts, hoses etc. i did my wiring, dropped in the motor, and it fired up and ran good on the first crank. So i know the instructions are good IF you follow them closely. Car will be MUCH more fun after the swap

Dr.

HOWNDOG · Jan 4, 2007

Thx.

Ya the 91 is a DIS and has a roller cam.

So in short use the:
Everything from the 87 TC.
Use the cam and rockers from the 91 and possibly the intake.

I've been printing off the stuff at Stingers site (and drooling over the headers etc.). The computor and wiring has me a bit leary and pulling the motor might be a bit of a logistics problem with the room I have in the driveway etc.

Funny that the shop manual nor none of the other "how to's" I've read mentioned that the pulley needed to come off to replace the belt.

HD

mg man · Jan 4, 2007

Like Dr said use turbo motor complete Just save intake "future use" Start out running driving enjoy learning like me. Modifications come later.Everyone 87 has intercooler above turbo correct? If so what is everyone suggestion for him to handle that. Try projecthp.ford23.com/tech/tech Has article on belt replacement with pictures. I read it he doesn't mention removing pulley. Like Dr said read carefully doublecheck your wiring twice or more, sounds bad but now just use care.

HOWNDOG · Jan 5, 2007

...maybe it's an issue unique to the DIS engine due to the crank sensor

I got the old belt off anyway by stuffing it between that guard and then turning the crank. Not sure if I wanna do that with a new belt though.

I'll probably swap the cam as per Dr (and it seems almost everybody uses the roller one if they have one) but I'm gonna go out and start the TC and make sure it runs good tomorrow, before I decide to swap.

65ShelbyClone · Jan 5, 2007

HOWNDOG said:
Unfortunatly my guage doesn't read in ratios and I'm not sure where to start in doing the calculation myself.

I think he meant that the 2.3T engines don't have high compression when they're new, let alone when they have some wear. 145-165psi would be decent for a used turbo engine.

HOWNDOG · Jan 5, 2007

65ShelbyClone said:
I think he meant that the 2.3T engines don't have high compression when they're new, let alone when they have some wear. 145-165psi would be decent for a used turbo engine.

Thx. I was expecting lower readings from the TC, just wasn't sure what was acceptable.

If I remember (can't find the paper I wrote it on) it was around 130lbs or so when I tested.

My NA engine was around 165lbs (in the cylinders where the head gasket was still ok)

Both engines have around 200,000kms on them.

HD

65ShelbyClone · Jan 5, 2007

Well, 130psi is a hair on the low side. If all the cylinders are within 10% of each other, the engine is probably still worth running provided it doesn't use much oil. If it does, that increases the danger of detonation. I'm not sure if my SVO has 80 or 180k miles(130 or 290k km), but my simple compression test came to roughly 160/160/145/160psi.

A leakdown test would tell you what is worn out, be it valves or rings.

HOWNDOG · Jan 5, 2007

All cylinders are within about 10% of each other and it doesn't seem to burn much oil.

I stuck the batt in today and it fired and ran smooth. This is after not running for 3-4 months so I'm pretty happy about it. If the previous dip**** owner hadn't treated the car so poorly (used to be a nice car), I'd drive it. Can't complain for $900 as mechanically it doesn't seem too bad. I'll redo the test (wet and dry) when it stops raining.

I have a vacuum guage that I can probably use to get a better idea of the valves. Other than that my tools are somewhat basic.

Thx, much appreciate the help.
HD

One more thing, The 91 DIS looked like it was full of creosote (like a stove pipe) when I pulled the head. Never seen a car so full of flaky, chunks of carbon.

HOWNDOG · Jan 7, 2007

Found this in Stinger's tech pages.

"7. Ideal results would give you 120-150psi in each cylinder for a turbo motor and 140-170 for a N/A engine. If your lowest psi is more than 20psi from the highest psi (140 and 120 for example) then you have a problem."

HD

HOWNDOG · Feb 18, 2007

Update.

I redid the head gasket on the NA until I have the time to do the turbo swap properly.

As for the timing belt, I was able to get it off the crank pulley and put the new one on by jamming it between the pulley and guard and turning the crank. With the new one, you'll want to be carefull so you don't twist, cut, or damage it in any way.

Timing was a bit tricky as when ever I released the tensioner I was a tooth, or so, off. Take your time here and check and recheck to make sure it's right (bit of a bitch with the marks being on the cover.....).

HD

ps. Still gutless but runs great.

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