Guest Recian Posted September 28, 2011 Share Posted September 28, 2011 Well the engine I had fell through and im having trouble hunting a good used engine within a few hours. I dropped off my block at the machine shop today to have it checked just to see if it's safe to rebuild. I sat down and started bs'ing with the guy and we discussed my broken piston and the scars on the cylinder walls. He was telling me the most effective way to remove the scars is to bore it. When removing the grooves it'll effectively make the bore larger anyway and will need bigger pistons/rings to compensate. Just like machining a rotor the only way to remove the grooves is to cut the rotor thinner than the grooves. My question is since it's gota be bored .10 at least while im in there ive considered boring it .30 over and making it into a 4400 (4.4L) I have no doubts the block will handle it if i do padgett's upgrade to 185 degree operating temp but what effect will it have on the computer controls? Will it be able to compensate or will the car need a bigger fuel pump and injectors mixed with an upgraded spark plug gap? ive bored carbureted engines but they'll naturally compensate and can be adjusted but the ECM is a little different. Any ideas? Link to comment Share on other sites More sharing options...
Ronnie Posted September 29, 2011 Share Posted September 29, 2011 ive considered boring it .30 over and making it into a 4400 (4.4L)4400? You might need to check your calculations. I think it will be considerably less. Link to comment Share on other sites More sharing options...
Guest NEMO Posted September 29, 2011 Share Posted September 29, 2011 Your going to dump a large amount of cash. A junk yard motor would be much easier on your wallet. And the extra motor will be complete. Link to comment Share on other sites More sharing options...
handmedownreatta Posted September 29, 2011 Share Posted September 29, 2011 4400? You might need to check your calculations. I think it will be considerably less. maybe with a longer stoke crank. Link to comment Share on other sites More sharing options...
Ronnie Posted September 29, 2011 Share Posted September 29, 2011 Maybe with one more cylinder. Link to comment Share on other sites More sharing options...
padgett Posted September 29, 2011 Share Posted September 29, 2011 I make .030" over to be an increase of 4 ci or 60 ccs. Agree - look for a ded stock running engine with accessories. Might even find one with a tranny and a shed. Link to comment Share on other sites More sharing options...
Guest Recian Posted September 29, 2011 Share Posted September 29, 2011 like i said i've tried that and im not satisfied with engines with 200k miles. That's all I can come across. I scan craigslist daily and i go to junkyards every weekend hunting parts for people as a side business and still cant find any engines with low mies there either. Uness there's another way to calculate it, bore x bore (.30 over = 4.1") x stroke (3.4") x .7854 x 6 cylinders = 269ci as opposed to the 231ci in the stock 3800. The 269 equates to about 4.4L. The 4ci gain from .30 over would be per cylinder Link to comment Share on other sites More sharing options...
Ronnie Posted September 29, 2011 Share Posted September 29, 2011 Uness there's another way to calculate it, bore x bore (.30 over = 4.1") x stroke (3.4") x .7854 x 6 cylinders = 269ci as opposed to the 231ci in the stock 3800. The 269 equates to about 4.4L. The 4ci gain from .30 over would be per cylinderI assumed you meant .030 (thirty thousandths), which is a standard oversize bore, in your calculations. That would increase the engine displacement to 235.027 cubic inches or 3851.41cc.If you have found some .30 (three hundred thousandths) oversize pistons for the 3800 your calculations are correct. If that is the case please share with the forum where you found the pistons. I'm sure they were extremely hard to find. Link to comment Share on other sites More sharing options...
Guest Recian Posted September 29, 2011 Share Posted September 29, 2011 my engine builder should be calling me today on what he found for oversize pistons so ill keep you updated. ill see how much hes gona bore it too. or how much he can bore it. Link to comment Share on other sites More sharing options...
2seater Posted September 29, 2011 Share Posted September 29, 2011 When I had mine done several years ago, it was bored . 020" oversize for 233 cu.in. total. I "believe" the limit is .040" oversize, or 3.840". There are supposed to be stroker kits available or the crank can be offset ground to increase the stroke but would require different rods. I'm not sure how much work would be involved since there are six discrete rod bearing surfaces due to the split pin design. If you do go the rebuild route, watch the compression height and dish volume of the new pistons. Many replacements are "destroked", assuming the block will be decked and the dish may be larger, both of which will lower the compression ratio, even with a larger bore. Now that isn't all bad, it works very well if you add boost. I used Silvolite hypereutectic pistons for a vin "L" which are a little taller than stock (9.1:1 compression ratio) and I did not investigate OEM replacement pistons which may be the best direct replacement depending on cost. Link to comment Share on other sites More sharing options...
Guest Recian Posted September 29, 2011 Share Posted September 29, 2011 that makes sense now. if i bore it i kinda wana go all out and ive thought about turbo eventually so thats why im considering boring it. but what effect did just .020 have on performance in urs? before turboing it. Link to comment Share on other sites More sharing options...
Guest NEMO Posted September 29, 2011 Share Posted September 29, 2011 Too much time and money, to rebuild a motor. I would wait for a replacement motor to turn up. Put the car in storage untill you find one. Link to comment Share on other sites More sharing options...
Rawja Posted September 29, 2011 Share Posted September 29, 2011 I've got an '88 59K drivetrain if you're interested. Link to comment Share on other sites More sharing options...
Guest Recian Posted September 29, 2011 Share Posted September 29, 2011 yea its not so easy to store a car when u live on rental property that requires ur cars run with valid tags. you dont have another car to drive and dont have the drivetrain still in the car Link to comment Share on other sites More sharing options...
Guest NEMO Posted September 29, 2011 Share Posted September 29, 2011 It will take longer to rebuild the motor then to swap it. Link to comment Share on other sites More sharing options...
Barney Eaton Posted September 29, 2011 Share Posted September 29, 2011 There was a 4.1 V6 cousin to this engine but only used on rear wheel drive Buicks. I think this came up before and 2seater said the block was not designed for front wheel drive. Link to comment Share on other sites More sharing options...
Guest Recian Posted September 29, 2011 Share Posted September 29, 2011 i talked to my builder today and he hasnt looked at the block yet. if he says its not cracked or damaged itll be about a grand for a completely overhauled re sealed and bored .040 over engine as opposed to a 1500 rebuilt from the store. not a bad price im at for a fresh guaranteed engine. my builder has a guarantee on his work and parts so she shouldnt burn oil or have any issues. we use him for work at the dealership thats why i trust him. if its not any good ill probably be getting up with u rawja Link to comment Share on other sites More sharing options...
2seater Posted September 29, 2011 Share Posted September 29, 2011 The effect of slightly larger capacity has very little effect on any operating system. The .020" overbore (.5mm) increases capacity <1% and the system has far wider operating latitude to adjust, so it is a non-issue. Increasing the compression ratio has a small benefit, but better to leave it as is, or lower, if adding boost. Unless the one I have is a fluke, the '88 cam I have is a bit more aggressive than the later vin C cams so the offer an '88 engine might be a good consideration.The image is crude but is a graphic representation of the cam measured in the same engine at various lift points. The larger lobes are the '88, the smaller is from an '89. Link to comment Share on other sites More sharing options...
Guest Recian Posted September 29, 2011 Share Posted September 29, 2011 fascinating. When you bored yours did you have to run the 185 thermostat and ECM upgrade to compensate? I assume with less metal it'd be mandatory to run it at the 185 instead of 220 or risk chance of damaging the engine Link to comment Share on other sites More sharing options...
2seater Posted September 29, 2011 Share Posted September 29, 2011 I was already running a 160* thermostat with a premium fuel chip with additional timing and other mods. I don't think any change from the standard thermostat is needed with the minor change to the engine. The high temperature stock t'stat aids fuel mileage, the low temp. aids full throttle power production but the 180* seems to be a good all around compromise. This was all done 12-15 years ago and many changes followed, not all a rousing success Link to comment Share on other sites More sharing options...
Guest Recian Posted September 30, 2011 Share Posted September 30, 2011 Did you run the 180 without making changes to the ECM to turn on the fans before 220? I know it has no issue now but it gets hot here in the summertime Link to comment Share on other sites More sharing options...
padgett Posted September 30, 2011 Share Posted September 30, 2011 I change the fan settings to go along with the 180 thermostat - 185/183 low 189/186 hi on/off. I also push the turnoff up to 50 mph.Total duration is something of a wash, 88 has more lift but slightly less duration. All are designed to have a flat torque curve from about 1800 to 4400 rpm Link to comment Share on other sites More sharing options...
Buicks4Life Posted September 30, 2011 Share Posted September 30, 2011 If someone were doing a build and/or going turbo I recently learned that the 3.8 GN heads are a bolt on for the series 1 3800. Verified with knowledgeable Buick mechanic GN top end and a turbo in a reatta I love the idea Link to comment Share on other sites More sharing options...
padgett Posted September 30, 2011 Share Posted September 30, 2011 Didn't the GN have a special (forged ?) crank ? Link to comment Share on other sites More sharing options...
NCReatta Posted September 30, 2011 Share Posted September 30, 2011 Good luck finding yourself a GN engine though... Link to comment Share on other sites More sharing options...
2seater Posted September 30, 2011 Share Posted September 30, 2011 I have not actually tried the GN heads on a vin C but the layout of the intake ports is different, so I do not see how that is possible. The GN has paired intake ports on each bank, similar to a smallblock Chebbie and the later engines, AKA 3800's, do not. I think there are other differences as well but the biggest one is: the 3800 heads flow better than the earlier design. See Stan Weiss website for flow data on many different heads. A variation of the later model heads was used on the turbo Firebirds in 1989, with a GN lower end, so I imagine there may be a basic physical matchup, but I imagine a hybrid cam of some sort would need to be fitted? The GN cam won't work in the 3800, as it was a flat tappet design and still had the drive for a distributor at the front. The total 3800 engine is a superior package, IMHO, although the ultimate strength of the GN block (high nickel content), is probably better. I remember one of the GN guys from many years ago tested the early 3800 blocks to see if they would be a viable replacement for the more rare GN variant. He found the stock bottom end was good to 500 hp. before it showed it was at the limit. There is very little difference between the S/C and N/A early 3800 shortblocks, so a moderate amount of boost can be added to the base engine relatively safely. There is some evidence that the connecting rods are different but I have not seen verification they are actually stronger. They would carry a different part number due to the full floating piston pins. It won't be a race engine without extensive work, but if used with reasonable care and restraint, the stock parts are capable of moderate increases in performance. Link to comment Share on other sites More sharing options...
Guest spiering.lucas Posted October 2, 2011 Share Posted October 2, 2011 I found my complete supercharged motor with 90k on it for 200$. The motor I am taking out has 100k on it and I found it also for 200$Wouldn't you be better off just throwing in a Super Charged 3800 and getting 245hp and 300 torque bare bones stock! Link to comment Share on other sites More sharing options...
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