thinking rebuild..new block or keep old?

fongo · 01-08-2001, 01:41 PM

Hey everyone!
Need some feedback and recommendations here. I have about 134K on my 93GT, an the car runs great (daily driver, never gone past 4000 RPM's, well-maintained etc.) but I'm thinking of a rebuild when it hits somewhere around the 150K or so, and keep it as my "weekend" car. I was thinking of just re-doing the stock block with the Summit rebuid kit. Or is it worth getting a new block with new bearings, pistons etc.?? I can't spend more than $1500 (married, got a kid..well you get the pic) I don't plan to visit the track in the near future (probably not at all), just plain old street driving with a little kick and punch every Sunday or so. I do plan to get new heads, new cam, and probably a new GT 40 intake. Let me know.
Thanks
fongo

------------------
1993 GT, K&N filter, Accel dist.,Splitfire plugs, BBK: 1 5/8 unequal length shorties, hi flow H-pipe w/ cats; Flowmasters 2 chamber American Thunder catback system, Motorsports 3-core radiator, 180º thermostat...the rest is bone stock!

NO SLO PK · 01-08-2001, 01:47 PM

Hey Fongo,

I have an alternate suggestion - Central Coast Mustang (and others) were blowing out the remaining 5.0L short blocks for dirt cheap, like under a grand. It's a heckuva deal for a new short block. I don't know if they have any left, but if they do I'd jump all over it.

Good luck!

------------------
'91 LX
Procharger, 3 row intercooler, extrude honed Cobra intake, Mac full Length Headers, 30# inj., 73mm C&L, 75mm tb, E303 cam, 289 rods, ported E7 heads, MSD, T-Rex w/255 lph Walbro, 5 lug conversion, Cobra R wheels, 3.27 gears and Moser Axles.

pro88 · 01-08-2001, 11:39 PM

Why spend a whole bunch or dough? Freshen up your motor's bottom end, throw the cam in, don't forget timing chain,get a valve job on your heads, and put the intake on. It doesn't sound like you're going to thrash and bash like I do. Just by doing the basic freshening up you should feel a big difference without dumping a bunch of money on a bunch of trick parts.

89LXNB · 01-09-2001, 11:02 PM

Fongo,
May I suggest you do a few things before you tear your motor apart?

Do a compression test. Find out just where you stand beforehand.

Do a leakdown test to see just how much power you are losing from blowby.

If you do not have one, buy a $40 dollar code scanner and run a full diagnostic routine and then a cylindar balance test.

I think you should at least consider performing these tasks on your vehicle before you tear your engine apart. I would hate to see anyone throw a lot of $$ before they did the above. The 302 is legendary in durability and I can tell you first hand that with regular oil changes(this is key) and maintainence you could EASILY see 200,000. I know, I had 242,000 on my Mustang before I decided to overhaul the motor. The only reason I did so is because I had to go in anyway to change out the timing chain.

Good Luck,
Dan

silver_pilate · 01-10-2001, 12:52 PM

The original block should work fine as long as it's in decent shape. If you're not using very much oil, it's likely that the cylinders are still in good shape. In that case, you reuse the stock pistons with just a good hone job to re-thatch the cylindar walls.

Some people argue that the used blocks are slightly stronger anyway because of the repeated heat/cold cycle effect on the iron.

--nathan

------------------
--silver_pilate

'91 GT, Built 306, Wolverine 1087 cam, ported Windsor Jr. Irons, and all the goodies...click the link to the left to see a full list of my mods...

Tried and True 302 Being Built to Outrun You! heh heh heh...
--Texas Panhandle--
Check out my site

MiracleMax · 01-11-2001, 05:12 PM

Fongo, I'd reuse the old block. I dunno about thermal cycling increasing strength?(makes sense though), but thermal cycling does work all the wrinkles, so to speak, the block is dimensionally more stable than a new casting and is pretty much settled into whatever shape its going to be in. For the most part this is academic unless you are going to blueprint the engine and need a foundation which won't change after you've got the engine together and running.

If I were going to do a rebuild, I'd do the following (keeping the old block, rods, and crank)

1. Clean the old block up (tank it, bore and stress plate hone, deck it)
2. Clean the crank up (resize if nessecary and polish)
3. Clean the rods up (polish and balance along with new rod bolts and resizing if needed.)
4. If your not going to use a poweradder then get a set of hypereutectic pistons and some gapless rings (zero blowby and a tight piston to wall clearence for little or no blowby down the road)
5. Get a set of GT40p heads and set'em up like you want or just get a set of complete heads and match the springs to your cam.
6. get a set of 1-1/2 headers, maybe a cobra intake and a 65mm t-body. 24# injectors. and a bullet mass air meter.

Its a little more involved than just a simple rebuild but wouldn't be that much more expensive, plus things would be good for another 100,000 miles along with some extra power. You might want to go with a new cam but don't go much over .500 lift (or .550) since more valve lift increases wear. Also it would be a good idea if you get a new cam with more lift to go with a set of roller rockers. Not so much for a reduction in friction or even the more accurate ratio's but the reduced side loading on the valve. 1.7's are an option (works out to .472 lift with the stock cam).

the best way to go about this would be to purchase the extra parts beforehand and let'em sit in the closet until you do the rebuild.

Less'see (dug out a Summmit catalog for prices)

1. Cobra Intake 399.95
2. 65mm T-body/EGR plate 230.90
3. Windsor jr. Cyl Heads 624.95
5. 1.6 FRPP Roller Rockers 239.69
6. E303 Cam 159.95
7. ARP rod bolts 39.95
8. Complete Gasket set (EFI) 156.95
9. KB Sil-O-Lite pistons 186.99
10. Total Seal Gapless rings 128.69
-----------------------------------
Parts Cost 2168.29

Machine work would be in the neighborhood of 300-500 dollars (maybe 700? but I if I remeber correctly on past projects the total machine work was not that much) So I'll go with 700.00

2900.00 bucks minus injectors and mass air meter which would bring it to about 3500.00

This is for new equipment so a fair bit of money could be saved by hunting down used stuff in good condition (however I've always subscribed to buyer beware in this instance since you don't know what people have knowingly or unknowingly done to them) Also I substituted 1 or 2 items because I couldn't get a price out of the catalog on them, but I figure there a good reference in any case.

Skyman · 01-11-2001, 06:24 PM

Wait?

You never go past 4000rpm, and don't plan to? Why rebuild it at all?

It runs fine now.

Skyler

------------------
-1989 Saleen Mustang #406-
TFS Heads, Edelbrock intake, E-303, 3.73's, 1 5/8 shorty headers, Offroad-Hpipe, 2chamber flows, 36psi FPR, playing with timing still, 70mm tb, 73mm maf, 24lb injectors, K/N, March Crank pulley, MSD6a, 9mm wires and FMS Aluminum driveshaft.
Best ET 13.2@106mph Needs tuning...

01-08-2001, 01:41 PM	#1
fongo Registered Member Join Date: Jan 1999 Location: Farmingdale, NY Posts: 139	thinking rebuild..new block or keep old? Hey everyone! Need some feedback and recommendations here. I have about 134K on my 93GT, an the car runs great (daily driver, never gone past 4000 RPM's, well-maintained etc.) but I'm thinking of a rebuild when it hits somewhere around the 150K or so, and keep it as my "weekend" car. I was thinking of just re-doing the stock block with the Summit rebuid kit. Or is it worth getting a new block with new bearings, pistons etc.?? I can't spend more than $1500 (married, got a kid..well you get the pic) I don't plan to visit the track in the near future (probably not at all), just plain old street driving with a little kick and punch every Sunday or so. I do plan to get new heads, new cam, and probably a new GT 40 intake. Let me know. Thanks fongo ------------------ 1993 GT, K&N filter, Accel dist.,Splitfire plugs, BBK: 1 5/8 unequal length shorties, hi flow H-pipe w/ cats; Flowmasters 2 chamber American Thunder catback system, Motorsports 3-core radiator, 180º thermostat...the rest is bone stock!

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01-08-2001, 01:47 PM	#2
NO SLO PK Registered Member Join Date: Mar 1999 Location: Arcadia, CA, USA Posts: 731	Hey Fongo, I have an alternate suggestion - Central Coast Mustang (and others) were blowing out the remaining 5.0L short blocks for dirt cheap, like under a grand. It's a heckuva deal for a new short block. I don't know if they have any left, but if they do I'd jump all over it. Good luck! ------------------ '91 LX Procharger, 3 row intercooler, extrude honed Cobra intake, Mac full Length Headers, 30# inj., 73mm C&L, 75mm tb, E303 cam, 289 rods, ported E7 heads, MSD, T-Rex w/255 lph Walbro, 5 lug conversion, Cobra R wheels, 3.27 gears and Moser Axles.

01-08-2001, 11:39 PM	#3
pro88 Registered Member Join Date: Dec 2000 Location: roseburg, oregon Posts: 87	Why spend a whole bunch or dough? Freshen up your motor's bottom end, throw the cam in, don't forget timing chain,get a valve job on your heads, and put the intake on. It doesn't sound like you're going to thrash and bash like I do. Just by doing the basic freshening up you should feel a big difference without dumping a bunch of money on a bunch of trick parts.

01-09-2001, 11:02 PM	#4
89LXNB Registered Member Join Date: Jul 2000 Location: San Jose CA Posts: 149	Fongo, May I suggest you do a few things before you tear your motor apart? Do a compression test. Find out just where you stand beforehand. Do a leakdown test to see just how much power you are losing from blowby. If you do not have one, buy a $40 dollar code scanner and run a full diagnostic routine and then a cylindar balance test. I think you should at least consider performing these tasks on your vehicle before you tear your engine apart. I would hate to see anyone throw a lot of $$ before they did the above. The 302 is legendary in durability and I can tell you first hand that with regular oil changes(this is key) and maintainence you could EASILY see 200,000. I know, I had 242,000 on my Mustang before I decided to overhaul the motor. The only reason I did so is because I had to go in anyway to change out the timing chain. Good Luck, Dan

01-10-2001, 12:52 PM	#5
silver_pilate DURKA DURKA!! Join Date: Sep 1997 Location: Lubbock, TX...(TX panhandle) Posts: 1,418	The original block should work fine as long as it's in decent shape. If you're not using very much oil, it's likely that the cylinders are still in good shape. In that case, you reuse the stock pistons with just a good hone job to re-thatch the cylindar walls. Some people argue that the used blocks are slightly stronger anyway because of the repeated heat/cold cycle effect on the iron. --nathan ------------------ --silver_pilate '91 GT, Built 306, Wolverine 1087 cam, ported Windsor Jr. Irons, and all the goodies...click the link to the left to see a full list of my mods... Tried and True 302 Being Built to Outrun You! heh heh heh... --Texas Panhandle-- Check out my site

01-11-2001, 05:12 PM	#6
MiracleMax Registered Member Join Date: Apr 1999 Location: Hayes, Va, USA Posts: 798	Fongo, I'd reuse the old block. I dunno about thermal cycling increasing strength?(makes sense though), but thermal cycling does work all the wrinkles, so to speak, the block is dimensionally more stable than a new casting and is pretty much settled into whatever shape its going to be in. For the most part this is academic unless you are going to blueprint the engine and need a foundation which won't change after you've got the engine together and running. If I were going to do a rebuild, I'd do the following (keeping the old block, rods, and crank) 1. Clean the old block up (tank it, bore and stress plate hone, deck it) 2. Clean the crank up (resize if nessecary and polish) 3. Clean the rods up (polish and balance along with new rod bolts and resizing if needed.) 4. If your not going to use a poweradder then get a set of hypereutectic pistons and some gapless rings (zero blowby and a tight piston to wall clearence for little or no blowby down the road) 5. Get a set of GT40p heads and set'em up like you want or just get a set of complete heads and match the springs to your cam. 6. get a set of 1-1/2 headers, maybe a cobra intake and a 65mm t-body. 24# injectors. and a bullet mass air meter. Its a little more involved than just a simple rebuild but wouldn't be that much more expensive, plus things would be good for another 100,000 miles along with some extra power. You might want to go with a new cam but don't go much over .500 lift (or .550) since more valve lift increases wear. Also it would be a good idea if you get a new cam with more lift to go with a set of roller rockers. Not so much for a reduction in friction or even the more accurate ratio's but the reduced side loading on the valve. 1.7's are an option (works out to .472 lift with the stock cam). the best way to go about this would be to purchase the extra parts beforehand and let'em sit in the closet until you do the rebuild. Less'see (dug out a Summmit catalog for prices) 1. Cobra Intake 399.95 2. 65mm T-body/EGR plate 230.90 3. Windsor jr. Cyl Heads 624.95 5. 1.6 FRPP Roller Rockers 239.69 6. E303 Cam 159.95 7. ARP rod bolts 39.95 8. Complete Gasket set (EFI) 156.95 9. KB Sil-O-Lite pistons 186.99 10. Total Seal Gapless rings 128.69 ----------------------------------- Parts Cost 2168.29 Machine work would be in the neighborhood of 300-500 dollars (maybe 700? but I if I remeber correctly on past projects the total machine work was not that much) So I'll go with 700.00 2900.00 bucks minus injectors and mass air meter which would bring it to about 3500.00 This is for new equipment so a fair bit of money could be saved by hunting down used stuff in good condition (however I've always subscribed to buyer beware in this instance since you don't know what people have knowingly or unknowingly done to them) Also I substituted 1 or 2 items because I couldn't get a price out of the catalog on them, but I figure there a good reference in any case.

01-11-2001, 06:24 PM	#7
Skyman I need 110mph Trap Speed! Join Date: Feb 1999 Location: So, CA Posts: 4,315	Wait? You never go past 4000rpm, and don't plan to? Why rebuild it at all? It runs fine now. Skyler ------------------ -1989 Saleen Mustang #406- TFS Heads, Edelbrock intake, E-303, 3.73's, 1 5/8 shorty headers, Offroad-Hpipe, 2chamber flows, 36psi FPR, playing with timing still, 70mm tb, 73mm maf, 24lb injectors, K/N, March Crank pulley, MSD6a, 9mm wires and FMS Aluminum driveshaft. Best ET 13.2@106mph Needs tuning...