so uhh turns out our knocking 100 dollar engine I procured was very built. .125 overbore, short stroke crank, olds 324 rods and a reground cam with 110 pound springs (feels like it at least.) with comp cam timing gear and lifters and a larger than stock tbi I only tore this iron duke down to save the head and block for anyone who needed it but now I'm probably gonna rebuild it since it just needs lifters and bearings done plus checking for a cracked block or head since oil isn't supposed to be diarrhea green. also if my flexplate reusable? im iffy aboutit but my spare is just gone
Looks like you stumbled onto something good but I believe that a .125 overbore is beyond what is recommended on the Duke engine. If the engine had a knock then it would be good to mic all the crankshaft journals. About 15 years back Dawn and Neil Kline built a similar performance Duke and they said it ran well. IIRC, they used a cam and small block pistons and rods. If you want to be on the path to 125HP check out Ira Crummy's web pages here: Performance Duke Pages
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
[This message has been edited by Dennis LaGrua (edited 09-06-2024).]
it was making more than 125. it snapped every bolt in the flywheel with little effort. and based on how far apart i have the 50k mile automatic with the ecu I pulled from the csr it was in(finally found the mileage on the reg from 93 when it was parked due to a blown engine since I had to buy a cheap cluster off ebay for it) it was well on its way to exploding that as well. it was definitely as quick as a 2.8 v6 with how fast it was getting to 60. (8 seconds which is scary fast for an all original 84) the head has been ported quite far and the exhaust path was chamfered for more flow into the valve. I will be likely sending the crank off to be checked for roundness (or throw it in my buddies lathe with a micrometer on it) and definitely gonna get the rods checked throughly. nothing was spun or even that scratched up so I think it had just enough lube to save it
Looks like you stumbled onto something good but I believe that a .125 overbore is beyond what is recommended on the Duke engine. If the engine had a knock then it would be good to mic all the crankshaft journals. About 15 years back Dawn and Neil Kline built a similar performance Duke and they said it ran well. IIRC, they used a cam and small block pistons and rods. If you want to be on the path to 125HP check out Ira Crummy's web pages here: Performance Duke Pages
also that's exactly what these pistons are. they are overbored small block chevy pistons someone made fit. I might have to bore out further and sleeve the block with a fire ring for a bit more strength. also just kind of concerned the block has cracked under a cylinder bore but I haven't cleaned it up yet
Honestly, it doesn't even look like there's a ridge there. I'd get the crank checked out to make sure it's in spec (unless you can properly measure it with a caliper), and if everything checks out... I'd just throw in some new bearings and put it all back together. The flywheel looks fine, but you'll want to get some ARP studs. Those flywheel bolts should not have sheered like that. My guess is that they didn't torque them down properly and / or they didn't use thread locker on them either.
so uhh turns out our knocking 100 dollar engine I procured was very built. .125 overbore, short stroke crank, so you are saying they went for LESS cubic inches?
Honestly, it doesn't even look like there's a ridge there. I'd get the crank checked out to make sure it's in spec (unless you can properly measure it with a caliper), and if everything checks out... I'd just throw in some new bearings and put it all back together. The flywheel looks fine, but you'll want to get some ARP studs. Those flywheel bolts should not have sheered like that. My guess is that they didn't torque them down properly and / or they didn't use thread locker on them either.
That's pretty bad-ass though.
it's looking like we got this just out of cam break in. also I torqued those bolts to spec amd it definitely broke them since there was little bits in the crank. otherwise everything is still checking out
so uhh turns out our knocking 100 dollar engine I procured was very built. .125 overbore, short stroke crank, so you are saying they went for LESS cubic inches?
with the overbore and longer rods this is now a 0 deck block. (pistons are actually like .005 below deck but close enough) so it's an attempt with the longer rods to get more rpm by making it more of a square motor and that worked very well considering it would rev to 6k. I'm not honestly sure why they spent so much time and money on this engine considering each bit is worth over 500 on its own. but definitely something went wrong with its oiling system
it was making more than 125. it snapped every bolt in the flywheel with little effort. and based on how far apart i have the 50k mile automatic with the ecu I pulled from the csr it was in(finally found the mileage on the reg from 93 when it was parked due to a blown engine since I had to buy a cheap cluster off ebay for it) it was well on its way to exploding that as well. it was definitely as quick as a 2.8 v6 with how fast it was getting to 60. (8 seconds which is scary fast for an all original 84) the head has been ported quite far and the exhaust path was chamfered for more flow into the valve. I will be likely sending the crank off to be checked for roundness (or throw it in my buddies lathe with a micrometer on it) and definitely gonna get the rods checked throughly. nothing was spun or even that scratched up so I think it had just enough lube to save it
We have read claims of guys building Duke engines to 200HP . While I cannot dispute this it may be pushing the limits of the Duke crank and block. Regardless you have an very interesting project there and hope that it goes well. BTW, high ZDDP Zinc oil does help. It coats everything with a protective coating that bonds to the parts. Just be sure that no CAT is used. If you run an automatic I recommend a shift kit,
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I would check the parts #s on the parts and mic out the crank. I doubt you have a short stroke crank, the longer rods are likely due to a change in wrist pin height of the pistons. There would be no reason for a shorter stroke. You are not trying to reduce low rpm torque for traction and the 2.5L can't live in the 5000+ rpm where you start the see the gains from the short stroke.
FWIW, there is an obscure brand of high-zinc oil (Brad Penn) that is dyed green. Small chance that could be what you found in it.
haha. I wish. no I put this oil in and it's using primarily 10-30 conventional with a bit of 5-30 since it's what I had at the time. its full if coolant somehow but I haven't found the crack yet.
I would check the parts #s on the parts and mic out the crank. I doubt you have a short stroke crank, the longer rods are likely due to a change in wrist pin height of the pistons. There would be no reason for a shorter stroke. You are not trying to reduce low rpm torque for traction and the 2.5L can't live in the 5000+ rpm where you start the see the gains from the short stroke.
I triple checked these psrt numbers in pure astonishment. I'm planning on porting the head even further and converting the block to roller lifters since it's pretty easy and doesn't require any mods but if I'm honest this engine is not going back in the 84. I have a very different project in mind and it's quite crazy and is gonna take about a year to get in motion but when it's done it'll be one of if not the first of its kind.
I would check the parts #s on the parts and mic out the crank. I doubt you have a short stroke crank, the longer rods are likely due to a change in wrist pin height of the pistons. There would be no reason for a shorter stroke. You are not trying to reduce low rpm torque for traction and the 2.5L can't live in the 5000+ rpm where you start the see the gains from the short stroke.
did they offset ground the crank for more cubic inches?
Originally posted by 82-T/A [At Work]: PICTURES!!!!
haha yeah I'll get some. it's a painted duke just like gm would have done so it's garbage and the oil pan is white currently since it's the only undented one I had.
did they offset ground the crank for more cubic inches?
honestly not sure. the part number returns as a performance crank from China so yeah. same with the camshaft, the lifters and everything else was from a good manufacturer
Originally posted by 82-T/A [At Work]: PICTURES!!!!
every picture is on the same night. took 2 hours start to finish and actually only took 20 minutes to drop the engine in from the top and get the mounts and trans bolts in. guess doing it 4 times helps.
every picture is on the same night. took 2 hours start to finish and actually only took 20 minutes to drop the engine in from the top and get the mounts and trans bolts in. guess doing it 4 times helps.
What year car was this again? It's so interesting to me... because my daughter's 1985 looks totally different from yours. The A/C lines, the fuel lines, they're all totally different.
This is a 1986, and the engine compartment looks like mine. Note, they put "Tech-4" on the air cleaner, but it's not a Tech-4 motor...
I just came across an 84, and it looks more like yours. I guess yours is an 84?
Originally posted by 82-T/A [At Work]: What year car was this again? It's so interesting to me... because my daughter's 1985 looks totally different from yours. The A/C lines, the fuel lines, they're all totally different.
This is a 1986, and the engine compartment looks like mine. Note, they put "Tech-4" on the air cleaner, but it's not a Tech-4 motor...
I just came across an 84, and it looks more like yours. I guess yours is an 84?
this is the white 84 we put an engine in. hence the title of the thread since it needed another
Originally posted by 82-T/A [At Work]: What year car was this again? It's so interesting to me... because my daughter's 1985 looks totally different from yours. The A/C lines, the fuel lines, they're all totally different.
This is a 1986, and the engine compartment looks like mine. Note, they put "Tech-4" on the air cleaner, but it's not a Tech-4 motor...
I just came across an 84, and it looks more like yours. I guess yours is an 84?
That's a good size throttle body I see there. Should give excellent throttle response. With al that work I hope that it rewards you with strong performance. Look forward to hearing the results of a road test.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
the reman block I got (stock replacement since the performance one needs to go be checked for cracks professionally and it wasn't worth the effort of putting back together yet) has a broken start bolt. gonna heat the casting and drill the bolt out and then hammer in an extractor but I'm pretty annoyed since I got this block for 300 from the guy I bought the white 84 from. guess I'm not buying stuff from him ever again.
The flywheel looks fine, but you'll want to get some ARP studs. Those flywheel bolts should not have sheered like that. My guess is that they didn't torque them down properly and / or they didn't use thread locker on them either.
I was going to comment on the fly wheel as well. They did NOT sheer due to too much power. Something else was wrong. I have stock bolts in m y SD4 engine, It probably makes around 170hp and no problems with my flywheel and/or bolts.
this is the white 84 we put an engine in. hence the title of the thread since it needed another
LOL... I got so distracted with the content I forgot the title.
quote
Originally posted by Dennis LaGrua:
That's a good size throttle body I see there. Should give excellent throttle response. With al that work I hope that it rewards you with strong performance. Look forward to hearing the results of a road test.
What are you looking at specifically? It looks like a stock 84-86 TBI unit. Is there something modified that I'm not seeing?
I was going to comment on the fly wheel as well. They did NOT sheer due to too much power. Something else was wrong. I have stock bolts in m y SD4 engine, It probably makes around 170hp and no problems with my flywheel and/or bolts.
in our case it was the engines power. we put another duke in (just 120) and it was significantly slower. seems like the old stuff was built up for a 300 hp turbo build that didn't happen.
What are you looking at specifically? It looks like a stock 84-86 TBI unit. Is there something modified that I'm not seeing?
that is a stock one that's got a larger plate in it at least on ours. also 3rd engine was the ticket but unfortunately isn't making enough power to rival our formulas 0-60 time anymore. soooo maybe a turbo is in the future for this car
that is a stock one that's got a larger plate in it at least on ours. also 3rd engine was the ticket but unfortunately isn't making enough power to rival our formulas 0-60 time anymore. soooo maybe a turbo is in the future for this car
Nice! Was that something you did, or you bought it that way?
Originally posted by 82-T/A [At Work]: Nice! Was that something you did, or you bought it that way?
Is it bored straight through the intake as well?
bought it that way and intake Ports are matched and it looks like someone ran the casting reaaal thin in a few areas while porting. I'll likely end up making a custom intake for the built engine as well as equal length headers
bought it that way and intake Ports are matched and it looks like someone ran the casting reaaal thin in a few areas while porting. I'll likely end up making a custom intake for the built engine as well as equal length headers
If you happen to get it apart again, I'd love to see a picture.
My daughter has a Holley TBI unit, which of course has a larger throttle plate... and it essentially does NOTHING when used with a stock Fiero intake because the opening for the TBI is no bigger than the stock TBI's throttle plate. I've thought about possibly buying a second one and boring it out to the size of the Holley TBI unit.
It used to be the Offenhauser and Holley intakes were pretty common, but I haven't seen one pop up on eBay for years now...
