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Discussion Starter · #1 · (Edited)
For this who might be interested I figured I’d start a thread on my 89 PGT...

I originally bought this car back in 1999, it had a warped head due to being overheated. I repaired the car and got it back on the road. A few months later I sold the car to a friend for a down payment on a new home.…

Fast forward to a month ago (23 years later), my old friend messages me via FB and asks if I want to buy the car back- Of course I said yes because I had always regretted selling it.

History: Shortly after he bought the car (in 2000) he pulled the engine and had it rebuilt with Ross pistons, ported the head, had everything balanced, etc..He also bought a bunch of other parts (clutch, etc). Has the receipts from 2001
for everything.

He never put the car back together and it has sat in a heated garage for 22 years. I will be heading to MN (from WI) in a couple weeks to pick it up.

I plan on getting everything put back together and perform some minor modifications and post the progress here..

Here are a couple pictures of the car from yesterday- first time seeing sunlight in 22 years!

Tire Automotive parking light Wheel Automotive side marker light Car

Car Wheel Vehicle Tire Hood

Handwriting Font Rectangle Parallel Pattern
 

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Are you planing on running the factory turbo or upgrading?
You mentioned you warped the head, did you have it shaved or replace it?
The receipt mentions "Square Deck Block".
You mention Ross/Wiseco pistons, do you know their compression ratio?

All three of these things will raise engine compression ratios.
You need to run a compression test on that engine and because it never ran after the rebuild that is a pain in the ass.
When you do start it I recommend letting it idle for 10minutes and dumping the oil and the filter and run 20W50 oil. This is the standard procedure with rebuild engines.
Also make sure the head gasket is a felpro or factory mazda, all the other brands melt and fail within 500miles.
The engine going in my 626GT was in a Probe and a Protege guy I know bought it from an importer complete with transmission (he imported a motor and transmission from europe that was built in the US), he gave up on his project and sold me the motor. The euro owner had reassembled the motor with new gaskets and seals, they even rebuilt the transmission, can tell by the gasket maker (don't know what they did inside the trans but it's still opened diff), they cleaned the head and did the valve stem seals... When I pulled the head the head gasket was melted and shot, I had to shave the head and port the combustion chambers... I guarantee that engine didn't run for 500km before their head gasket melted and that's why they scrapped the car.
I had the same thing happen to my .050 " over block in 2001, during a no boost break in at 400km the topline head gasket melted, coolant pissed out everywhere and warped the port and polished head. The engine shop who chose the gaskets and assembled the engine took no responsibility, they shaved another 0.010" off the head (total of 0.016" shave). I used felpro head gasket to reassemble it, no more head gasket issues but the engine kept spinning rod bearings, after them rebuilding it 3 times I tore it apart myself and the number 1 rod channel was machined off center, they said they sub out the cranks and it's not their responsibility. I never did business with them again, used stock blocks and had no issues until I reached 19psi on a larger turbo and the over shaved head stated lifting and popping rad caps. Top line head gasket cost me a really good P&P head and the machine shop cost me a fortune.


The 1989 F2T is rated to run 87octane but if the compression ratios are higher you should run 91 octane.

Ask your friend what head gasket he used and what torque pattern he used to install it.
At the very least you should redo all the head bolts, back them off a couple turns and retorque them in the proper order
10 6 2 3 7
. 9 5 1 4 8

Personally I would pull the head and cc the combustion chambers, you need plastic wrap and a syringe that holds 60CC / ML (milliliters) of liquid with 1ml/cc measurements lines on the syringe. Remove the rocker assembly's, Wrap the head face tightly with many layers of plastic cling wrap. Mix food coloring with water, put 60ml/cc in the syringe and inject it in the combustion chamber through the plastic and subtract whats left in the syringe from 60 to know combustion chamber CC's. 50CC is factory. Factory piston dish is 20CC (not including the valve reliefs in the pistons).
You know the block deck height has been shortened (decked) this decreases the clearance between the piston TDC and combustion chamber and increases compression ratio. If the CC of the head and pistons are any lower than 70CC your compression will be even higher. You can sand and port the combustion chamber while watching TV, every CC you sand out that gets you closer to 70cc combined piston and head ratio which with the decked block will still put you above 7.8:1 factory compression.

Lower compression = more boost potential = more power potential.
Higher compression can yield better fuel economy and more power per PSI but wont make the turbo spool faster and could actually make it spool slower. If the factory block has about 85 cc of clearance (head gasket thickness, piston to deck clearance, piston dish, combustion chamber) and a performance block with shaved head, zero deck block, and flat top pistons has 50CC clearance the factory block will take 35cc more air in at 0 vacuum and although it's burn is less efficient and it's velocity leaving the head is slower it's volume is higher and the unburnt air and fuel in the exhaust burn in the manifold and turbo and make it spool.

For me 75cc of clearance with a slightly worn cylinder wall (more ring gap = lower compression) is the magic number, it allows for up to and possibly above 30psi boost without cracking the the ring lands or causing head lift.

Do the research first and spend the $ /do the work once or Do the work, then do the research, spend more money $ and do the work again .

Take 2 F2T's both with the same quality pistons, head gasket, mods and tuning, if one runs 8.5:1 CR and the other 7.4:1 CR the lower compression engine will allow for more boost on the same fuel without cracking the pistons, lifting the head or igniting the air fuel charge due to combustion pressure. If head lift, piston stress and pre ignition where not an issue and both cars where running racing fuel and the timing and boost could be tuned to the limits of the fuel not the engine you could make more power with the 8.5:1 comp ratio.
 
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Discussion Starter · #3 ·
Thanks for the response- lots of great info.

Since deciding to buy the car I have been reading/research as much as I can on the F2T engine- I’ve got a lot to learn but have found some great resources (such as this site and many of your posts I’ve been reading and a couple YouTube channel).

When I bought the car back in 1999 the original owner had warped the head (if I recall correctly) and if memory serves me it was likely shaved.

My plan is to carefully review and inspect all the parts and thoroughly clean the engine bay. I will go through the brakes and all the suspension components. Get everything road worthy..

The engine is currently sitting wrapped in plastic as a long block and so it will be easy to get data and confirm the parts (pistons), gaskets, redo head torque, combustion cc. The friend I am buying at back from has many years of experience building race engines and so I am comfortable with what I am starting with…

I will initially go with the stock turbo to get the car up and running and ensure all is ok. Plans down the road would be a bigger turbo, but nothing has been decided.

Little more history: When I was a freshman in high school my best friends dad bought a new 89 PGT. We used to sneak out at night and push the car down the driveway and then hop in and race around at night (We lived in the country). First car I went well over 100 mph in…His dad autocrossed the car for many years. Lots of good memories!

Anyways, will start posting more details when I get the car back home and in the garage..
 

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Whenever you want to make big power and start modding the engine do yourself a favor and gap those rings for more boost to. Ring gap is critical. If it's the only mod you end up doing to the engine youll make some serious power out of it before you hurt it. Ringlands break from excessive temp causing expansion in the rings. (Knocking will also break the pistons similarly but the damage looks different.) If you don't have enough ring gap they'll end up touching after X horsepower (how much heat the pistons and rings can take) whatever that is on the stock rings. I wouldn't know. Once they touch, the only way to go is up or down. Bye bye ringlands. This is the main reason the Ej2.5 always blows up. Damn kids shooting for 4-500 in their subaru haven't opened the engine up once. Dealt with that a lot hqnging out with my subaru friends. My wiseco pistons are gapped for a lot of boost. Since they're forged aluminum they also stay cooler and expand less than cast or hypereutectic pistons. More ring gap means more crankcase pressure though so a proper venting system is necessary. If you don't plan on making big power out of it in the future I'd leave the ring gap stock as that'd provide the best oil life and your stock venting system will work up to X hp. My wiseco pistons are 8.5:1. I have an aftermarket cam which lowered my static compression by about 35-40 psi on each cylinder. You can also do that to a stock cam by retarding the timing a degree. (And by no means am i telling you how to build your engine!)Based on internet calculators for dynamic compression and a rough static compression estimate with the mods I've done it shows my dynamic compression to be somewhat low around 6:1. You can also calculate your dynamic compression ratio based on the boost you are running. I found that at 15 psi on my build my dynamic compression is around 14:1. Next time I have it open I want to measure my head chambers using the method mentioned above and port/ polish the head. Most people don't understand how dynamic compression works and how it effects the turbo build. If you have a big cam your intake and exhaust valves are typically open at the same time for a short duration allowing for scavenging effect to be optimized. It also lowers your static compression. This will also cause uneven intake velocities at idle that can be hard to tune around. This also significantly reduces compression in the lower rpm range. Hence why cammed cars especially NA have a slight lag when you accelerate. If you have a turbo system where during that lack of compression stage in your power band you still have enough exhaust pressure to spool up the turbo you'll be dominating. Choosing the right turbo is key here. You don't want the turbine to cause excess exhaust pressure because that will rob hp. Too little exhaust pressure and you'll have lag forever and need a shot of nitrous to get it going off a launch.
Thats all based on the bang your setup, how the exhaust manifold is set up, whether equal lenght or not, charge pipe size and length. These engines are great air pumps!! I noticed mine was able to rev higher with the aftermarket cam and 2 feet of exhaust runner for each port before the turbo inlet. Itll pull all the way up to 7500 rpms wastegate wide open 18 psi at 90% duty cycle on my 750cc injectors with a 57mm t3/t4 on a 96 octane mix . I didn't spend much time up that high in the revs as I want to do that specifically on a dyno. I know it holds together up there and still.pulls hard so i should be looking to get onto a dyno mid summer after i build my black car. Ditch the factory fuel pressure regulator and cap the port. Run a fitting off the end of the rail. That'll prevent some fueling issues others have had. The GT has an oil cooler I think. Correct me if I'm wrong. I'd reccomend adding an oil cooling system of some sorts whether it's stock gt parts and sandwich plate or its aftermarket with a sandwich plate for like American v8s and you just tap the adapter to the thread pitch in our Mazda. That's what I did so I had nice new shiny sandwich plate with ports for turbo feed and oil Temp sensor. Get yourself a coolant pressure sensor too whether its a standalone unit or in my case just another input for my Megasquirt 3X youll want to know as soon as your head gasket starts to go so you can limp it home. Youll immediately see a spike in coolant pressure soon as the first small leak shows up or a quick lift of the head. Itll show up in the datalogs. Also have a safety set up in my ms3 to prevent me from grenading the enging under X parameters, i.e oil pressure low and high setpoints, iat trim table, AFR trim table, coolant pressure setpoints etc. Also youre going to want arp head studs and hardware with their lube. Good luck with the build! Lots of good info on this site.
 

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Here are the stock cam specs fyi. You cant see how the stock cam also effects the dynamic compression tho. I haven't calculated it on stock cams I'll get on that later.

Int: 177° @ .050 / .210 Lobe Lift / .374 Valve Lift
EX: 186° @ .050 / .230 Lobe Lift / .409 Valve Lift

The cam I use INT: 186° @ .050 / 260° Adv Dur. / .230 Lobe Lift / .409 Valve Lift

EX: 187° @ .050 / 262° Adv Dur. / .237 Lobe Lift / .422 Valve Lift

I couldn't find the duration on the stock cam but that'd be the other piece of info I need for that calculation.
 
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