I've torn down a bunch of 3800SCs, but never a Na 3800. Read about" top swaps", but HOW does the NA get it's 9.5 compression Ratio (pistons or combustion chambers). if the" pistons" are the "same dish"as a SC piston, putting a "top swap" still yields 8.5 to one. but from what I've read, the pistons Are Different, so putting the SC Heads on a NA shortblock would still have 9.5-1. How can you run a supercharger on a 9.5-1 shortblock with out detonation ? Thing is: I have a Ported series2 SC, ported series2 manifold and Ported series2 HEADS, but am having a problem finding a decent SC shortblock ! thus the reason for my Question. any help appreciated.
Except for the injector ports, the heads, crank and block are the same for SC and N/A. Series II The pistons, connecting rods and wrist pins are different. On the Series III the powdered metal connecting rods are the same. But the pistons are different. By what I have read, GM had Alcoa make the earlier SC pistons. All "Buick" V engines that I have ever taken apart have dished pistons. With smaller head roof chambers compared to "Chevy" engines. The compression is determined by the depth of the depression/dish. Some older ones (225v6, 300v8) had raised dimples in the center. I'm sure there were others. Top ends swaps will bolt on. However it may not be worth the hassle. You will have to "detune" due to the raised compression ratio and the piston/connecting rods not being designed for boost. The timing maps are going to be very mild. Early turbo 3.8s that were in Rivieras 1980/80 1/2 had an Ecm only for timing controls. I had seen a few that the ESC(electronic spark control) failed and punched nice round holes in the top of the pistons. A few things that make it expensive to rebuild Buick engines. First all the yield to torque bolts that have to be replaced. Series II connecting rod, main cap, side cap, and head bolts. The connecting rods have to be machined for concentricity. Found that out the hard way on a Series 1. And finally pistons. Most of the time when a Series II goes out it is due to a connecting rod bearing. Then if the crank can't be machined, it goes too.
in this case, someone left the engine outside, uncovered with" injectors missing" for who knows how long. #3 was full of water, actually "ate off" part of the intake Valve, and Pitted the cylinder wall so bad it is unusable !. What a waste, pure stupidity. so a na block and sc block are exactly the same. cranks interchange, rods as a set interchange, and pistons as a set interchange, correct ? wish I could find another shortblock.
in this case, someone left the engine outside, uncovered with" injectors missing" for who knows how long. #3 was full of water, actually "ate off" part of the intake Valve, and Pitted the cylinder wall so bad it is unusable !. What a waste, pure stupidity. so a na block and sc block are exactly the same. cranks interchange, rods as a set interchange, and pistons as a set interchange, correct ? wish I could find another shortblock.
There have been a number of "top swapped" 3800SC that have been created so the top bolt on stuff is the main difference. The 9:1 compression might factor into the boost and tuning though. There were over 1.5 Million 3800 series II and III engines made by GM. Look on www.Car-Part.com and you'll find many of them close to you
------------------ " 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 "
It has been 3 years since I replaced my Series II SC with a much fresher Series II n/a. The n/a had a confirmed less than 14,000 miles on it. For the most part I don't really miss the SC. There are some times, however, I miss the vacuum cleaner. The SC engine had a lot of miles on it. Showing it's age. Before replacing it, I had a long time known machine shop quote me pricing to have it gone through. I've known these guys for over 20 years and they would have gave the best pricing they could. They are semi retired now. Even with that it would have still cost me $1500.00. And that was 3 years ago. I kept the SC core for over a year. Hoping someone would take to rebuild. No takers. A lot of lookers, but no takers. The shop I work at finally stated it had to go. The scrapper that did take it from me tore it down. He was having the idea of having it gone through for a Reatta he had. Even with his connections, he found it too expensive to have it done. He is in his late 60s and has known a lot of people who would have helped him along. But to no avail. It did stae that I must have taken good care of it, due to it being one of the cleanest old engines he had tore down. "sigh" Back to the n/a subject. The Series II SC was rated at 240 hp. The n/a engine rated at 205. The Series III rated at 260 gen 5 blower. The n/a engine was rated for W, G and H bodies with all the accessories on it. However the n/a flywheel is drilled for the big car torque converters and the smaller torque converters found on N bodies. I am using a converter from a N body 3.4 and is at least 15lbs lighter than the bigger converters. Also being that you lessen the amount of belt accessories, that has to be at least a 5hp gain from removed weight. That is without any mods on the engine itself. With mild exhaust, porting and rocker mods, people have got around 235hp from n/a engines. They will run all day like that on lower octane fuel. I have gotten upwards of 32 mpg in mine on the highway. It moves the car enough to still be fun. With the SC I could run up against 90% of the cars a came across. With the n/a about 75%. I'll settle for that. This is my daily driver now. I'm not out to run against anyone. Can run crap gas. And is dependable. Low mileage K engines should still be plenty. The one I have is kind of a mutant. It came out of a 2005 LeSabre. Last year for the K. By talking to machine shops. It supposed to have the Series III heads, but with the Series II crank, rods, pistons and intake.
they sell "entire engines" and they think they are made of gold, then shipping !
With car-part.com, you can do a search of all the yards in your area and in your state. I've received some excellent buys through that site and have picked up all. . One was a 4.9L w 4T60e and a 3800SC w 4T65eHD . Both were low mileage (53K and 61K) for $600 each powertrain. IMO, those were very good buys.
------------------ " 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 06-20-2019).]
