1988.5 GT can I lower compression | Ford Escort Owners Association (FEOA)
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1988.5 GT can I lower compression

Discussion in '1st Gen 1981-1990 CVH' started by stangowner8687, Jul 31, 2020 at 4:59 PM.

  1. stangowner8687

    stangowner8687 FEOA Member

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    So A 2 owner 1988.5 escort GT landed on my lap. Being the hoarder that I am, I’ve got a turbo manifold,an exp turbo head, an XR ecu, and vam. I have 2 routes. 1st route is to use my entire SVT parts car for an engine swap. The 2nd idea is to go turbo. Either way I’m only looking for about 170-200whp. Now I know 7-8psi is a safe boost I also know the 1.9HOs’ compression is to high to get crazy with boost. I know I’ve read somewhere around about thicker head gasket. But aside from a changing pistons is there anything else I can do for compression? Or is 7psi safe is anyone else running a low boost on stock bottom end GT?
  2. stangowner8687

    stangowner8687 FEOA Member

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    This guy ran ethanol and 12psi he says there were no issues before upping the boost To 12psi hopefully this is the only issue. I’ve spent countless hours researching over this plan. I’m really hoping someone has some good news. Also is there anything else I’d need to do as far as electronics goes? I’m not good at dealing with things like mega squirt. I failed miserably when going F/I with a 4.9 I6 bronco megasquirt
  3. 1982 EXPert

    1982 EXPert FEOA Member

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    Only hope is to change the pistons, 1987-1990 1.9 CFI pistons are flat with valve reliefs and with your Hemi head will get you from (about) 9.2:1 down to about 8:1 - I'd have more accurate numbers but I don't have access to all my CVH data.....

    Changing the headgasket thickness will help some but not enough to make a difference, I believe Cometic is the only one making thicker & thinner CVH headgaskets and their thickest isn't much thicker than the factory Ford headgaskets.

    The stock bottom end is pretty strong, Ford claimed the rods were forged - as good as they are, they're not that good haha But old posts here claim them being good for 200hp, at that point I'd switch to more reputable rods.
    Jack Roush however made great stride on factory internals in 1981, check out this article I wrote. https://en.wikipedia.org/wiki/Ford_EXP#PPG_CART_Indy_Car_Series_Pace_Car
    Everything in there is straight from a very rare article talking in-depth about the Pace Car Roush and SVO developed before they made the 1.6T in the EXP & Escort Turbocoupes.

    Which SVT do you own? Stay away from the Contours lol
  4. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    Use the 2.0 SPI head.
  5. stangowner8687

    stangowner8687 FEOA Member

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    I have an 04 svt focus parts car. I also have a 90 LX complete engine, would it be better if I just used the short block off that? Or are the rods inferior? Also I didn’t know the 2.0 spi head works on the 1.9cvh. I’ll have to check that article out about roush.
  6. 1982 EXPert

    1982 EXPert FEOA Member

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    The CVH heads are all interchangeable BUT when changing them they need to match your pistons (hemi pistons won't work in the lean-burn or swirl heads for instance) and they need to match your intake manifold because there are 3 different intake patterns:
    All 1981-1990 carbureted & EFI 1.6/1.9 intake pattern is the same
    All CFI & 1991-1996 SEFI 1.9 intake pattern is the same
    The 2.0 SPIs are the odd ducks having a unique intake pattern using secondary valves

    The CVHs all have the same rods (though varying in length)
    The CVH pistons are all cast except for the 1.6 Turbo's forged pistons

    Either of your CVHs would serve you well, best combo for high boost would be the CFI pistons with EFI HO head to get closer to 8:1 compression. Should you go that route I'd take your EFI HO pistons if they're decent :) I'd even take the whole 1.9 block and bottom end too if you're close enough!
  7. stangowner8687

    stangowner8687 FEOA Member

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    I appreciate the info and help with this potential build but as far as the 1.9HO stuff goes, I’m a hoarder by nature. I am a firm believer of “have it and not need it vs. need it and not have it.” But getting back on track with that 2.0spi here’s a pic of what a nearby junkyard has as far as escorts go, I assume I’ll find the 2.0 in the 97 and newer? So I’ll need heads and pistons?

    Attached Files:

  8. 1982 EXPert

    1982 EXPert FEOA Member

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    Yes and yes

    You also need the intake manifold of the 2.0 SPI if you pickup one of those heads and keep in mind they use secondary throttle butterflies so you'll need a controller for those or just delete them.
  9. stangowner8687

    stangowner8687 FEOA Member

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    Ok this is probably a dumb question, I’m gonna guess it has something to do with motor mount locations or bell housing, but if I’m using the head/intake and pistons from the 2.0, why not just take the whole 2.0 and be done with?. Also I’m looking up new pistons for the 2.0 and prices vary but it looks like it’d be around $400 for a whole set of new pistons and rings etc...vs. a junkyard grab. being I don’t know how the cylinder walls are on this 1.9HO.... I’m getting ahead of myself, this sucks. I won’t be able to tear this motor apart for an actual machine shop overhaul because I’ve got 3 other projects on my plate. I was really hoping this would have been a slap on and drive deal... man this kills me. However the least I can do is upload some pics tomorrow so you guys can see what I’m working with
  10. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    Using the entire 2.0 SPI engine will not give you a low compression engine.
    I forgot about the oddball intake port pattern on the SPI. There are actually two patterns, with matching intake manifolds. One is for the Escort, the other for the Focus.

    I believe the mounts and bellhousing patterns are the same for all CVH engines, but hey, I've been wrong before.
  11. 1982 EXPert

    1982 EXPert FEOA Member

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    Stangowner you don't HAVE to mess with it, enjoy what you got until it's gone then decide what to do from there. Turbocharging everything isn't realistic in the real world despite what youtube sensations advertise, for an engine to last (especially with the CVHs becoming ridiculously rare today) there's a lot of work, time, and money involved.

    If you're truly interested in turbocharging your current EFI HO you'll be quite pleased with just 6-8psi of boost in the safe range. Your car has 110hp right now (assuming it's a well-kept motor), little mods and some time will get you to 125hp, safe levels of boost will get you around 150hp. And this is in a 2200lb car, honestly you won't demand anything more unless you're trying to prove something or only do 1/4mile runs.
  12. austin86

    austin86 That nut who spends way to much on a escort.

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    I asked about putting an HO head on a block with cfi pistons in the past and was told It would dump the CR down to around 6:1. Witch is way to low in my book.

    I would leave the CR alone. Run a good/big intercoller, run no higher then 8psi and use a 180 degree T-stat or drill the stock one. From there a roller cam and rockers, some exhaust work and general tuning will go along way.
    1982 EXPert likes this.
  13. marclar

    marclar Moderator Staff Member

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    will the large spi intake valves clear the pistons...? the spi pistons have massive reliefs cut into them.
  14. stangowner8687

    stangowner8687 FEOA Member

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    Ok so to knock out a few posts here goes...
    I have a 1970 mustang with a 351 clevor, a 2014 explorer sport (TTV6) an SVT focus with mild work. So do I “need” a turbo escort GT? No, I’ve got way faster toys. But if some of you remember back about 10 years ago, I’m the guy who had the silver EXP turbo (pixie) that got totaled in the middle of the night parked on the side street the car was hit by a drunk driver. There were many here who helped me piece that car together because I got it in pieces a lot of you sent pictures and videos to me showing me where vac lines went. And so forth. Since losing that car I’ve wanted another little turbo CVH. If not that then a snappy little 1st gen escort gt. And I know to the world it sounds stupid because I’ve owned fox body mustangs and turned down turbo Zx3 focus’ and even walked away from a RS focus even trade for my 70. Ive done engine swaps from 6 to 8. And as much as my wife hates it... I just love a 1st gen GT, to date I’ve owned an 87,88.5, and a 90. My grand father had an 84 wagon and my uncle, an 88 GT. I would be absolutely fine with my GT putting down 150-170whp I’m not out to be the fastest car on the road, just want a little more umph from my odd obsession of a ford. If 8 psi is a safe run for my 1.9cvh stock block, (I’m sure I have a exp turbo head laying around) then I’ll send the head out for some port work and freshen up the piston rings and bearings and get this build underway.

    Attached Files:

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  15. austin86

    austin86 That nut who spends way to much on a escort.

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    The GT is a lighter car so you may end up liking it more then the EXP.
    If you run 8 psi make sure you have a good intercooler. If not run no higher then 6psi.
    If you want more then 8psi I would get better rods and forged pistons with the right CR for boost.

    Also the ARP head studs rod bolts and main studs for a 1.6l CVH will fit a 1.9l HO. Rod bolts and main studs are not needed at 150-170hp. If you're shooting for more then 200hp rod bolts are highly recommended, main studs are only worth it if you are going high RPM. Head studs on the other hand I highly recommend with boost. But you can get by without them.
    The PN for the studs is 151-4203.
    1982 EXPert likes this.
  16. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    Also if you are fooling around with turbos and such you will no doubt have the head off a few times for testing, etc. so the reusable studs start to pay for themselves.

    The 2.0 crankshaft has the same stroke I believe, and has improved balancing from what I hear so might be a consideration as an upgrade, depending on how much work it is to swap in.
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  17. austin86

    austin86 That nut who spends way to much on a escort.

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    Anther good reason to have them.

    That is worth looking into. I read that the early 1.9l crank is different too with how its balanced too.
  18. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    I don't know the details, but it may be that the cranks, although having different internal balancing, do have the same net balance, i.e. are functionally interchangeable.

    I guess you could check into it by weighing 1.9 and 2.0 pistons and rods. If they are all the same, then the balancing must be the same. Of course crankshaft balancing is somewhat of a black art anyway.
  19. 1982 EXPert

    1982 EXPert FEOA Member

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    All the CVHs before 1991 have 4 balance-weights, the 91-96 1.9 was supposed to have 8 balance weights for smoother operation but the 2.0 definitely does. But if I remember right the journal sizes of the 8-weight cranks are a different size.....
  20. Joey_Twowagons

    Joey_Twowagons FEOA Member

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    According to Rockauto the main bearings fit from '85 to 2002, and the reconditioned con rods fit similarly.
    The crank is the same from '87 to '96.

    Another reason for me to like and support Rockauto.

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