Straight 8 Rebuild

[GOBO]

How many of you folks have had your straight eights rebuilt?I've got a 1950 Super that I set up with dual carbs.The engine is pretty tired.It's a 263 and the dual setup helped some.If you've had a straight rebuilt were you happy with it and did it perform much better? I don't think anything has been done to this engine other than my work.

[azimuth2000]

I too own a 1950 Buick Super Riviera 2 dr hardtop. It has a 263 engine in it and I also have a spare 263 enigine and transmission. I have considered having the spare rebuilt but hae not done so as of yet. One thing you need to do is a compression check on all cylinders. When I first bought my 50 Super, it had sat outside under a carport for 14 years and the engine was stuck. I poured Marvel Mystery Oil in all the cylinders and the engine freed up with a little rotating back and forth with a breaker bar on the crankshaft end bolt. Once free, the engine started and ran fairly smooth until the smoke of the MM oil was cleared out. I drove the car and after awhile I notice a loss of power. I did a compression check on all cylinders and found one to be out of range on the low side and all the rest were within and close to each normal. I then took a small box wrench and loosened the nut on the threaded end of the valve adjustment on the rocker arm for that cylinder ( determining first if it was an exhaust or intake valve leak and then using a flat tipped screw driver I turned the rocker adjustment stem until I heard the engine smooth out. I then retightend the nut and did another compression check and BINGO! the cylinder came back in range and the engine ran fine with the necessary power. Remember though this is a car that is equiped with a DynaFlow or I like to sometimes call it a Dynaslush transmission, it is not quick off the line like the other cars of 1950 such as Chevys, Merc's and Fords. It was not designed to be quick off the start but rather to be a smooth shockless transmission that you don't sense the shifting like other cars. Once the car gets moving though the Dynaflow is a powerful and smooth operator!!. Check for engine compression loss and besure to determine if it is the intake or exhaust valve so you can adjust the correct one to bring compression back. if not sure adjust each one as the engine is running at idle and besure to count the turns and direction of turn incase you need to put it back where it was. If it does not return to proper compression after adjustments of the valve pressure then the rings may be stuck or worn, but the engine would most likely smoke or burn oil..so check the compression first before deciding to rebuild what may be an engine with lots of life left in it. I made those adjustments right after I bought the car in 1983 and it still starts and runs like a top ever since then. In fact once my engine is started and it starts everytime with a few cranks, I can then set a glass of water on the valve cover and it will not shake the glass. The Buick Straight 8 is a geat engine, the dynaflow makes it slow and shockless at first. If unsure have the car taken to a mechanic and ask him to do the compression test and adjustments. It is really simple to do. It may end up saving you a lot of money in the end.

I hope this was of some help.
Best Regards
Jack

[1942limited]

Remember though this is a car that is equiped with a DynaFlow or I like to sometimes call it a Dynaslush transmission, it is not quick off the line like the other cars of 1950 such as Chevys, Merc's and Fords. It was not designed to be quick off the start but rather to be a smooth shockless transmission that you don't sense the shifting like other cars. Once the car gets moving though the Dynaflow is a powerful and smooth operator!!.

There seems to be a popular misconception, that the Dynaflow transmission shifts. It does not. Once you put it in drive, the torque converter does everything. It does have a low gear, but one must manually shift into Low, it will not do so automatically. Nor will it shift from Low to Drive, unless manually done so.

It isn't shockless; it is shiftless. You can't sense the shift, if it doesn't shift. If you do sense a shift in a DynaFlow, then there is a problem.

I rebuilt the DynaFlow in a '55 Super about 26 years ago, and was pleasantly surprised to find out that the torque converter is rebuildable.

[GOBO]

Thanks for the reply. I like to call it a "Dynaslow",that's a term the oldtimers used.I did a compression test a while back and did find a bit more variance than there should be.I just wondered if a rebuild would make a world of difference in reliabilty and performance.I just really dig the straight eights.

[alleycat]

There have been quite a number of posts about dynaflow trans all over this site, and I have made a number of them. The real misconception about the trans keeps popping up; that it has something to do with the preformance of the car. It does not. The dynaflow is a POWER transmission. The more power that is cramed through the trans, the better it works. All 3 str8's make not much power. And, when they get old, they make even less. Do not believe what you read in the buick service manuals as to the "advertised" power output. So, 50 odd years later, with a somewhat worn engine that is putting out perhaps 80-85 hp, the "performance" is very likely to be somewhat....off. Therefore, rebuilding the engine is a GREAT idea! Even if it runs! The removal of the crud that has built up in the engine over the years is reason alone. The other reason is the piston rings: they are junk. Nearly every str8 engine failure I have ever seen is caused by one thing: piston ring failure. There is another problem with the rings: they don't seal particulary good. There is a reason that the engines have all those crankcase vents. I don't know what the ring leakdown rate was on new str8's 'way back when' but I'll bet it was bad. Problem is, everybody that makes new pistons & rings for str8's is remaking nearly exactly what was made in 1940! It was the best that could be done in 1940, 70 years later, thats all that can be done? Huh? Egge makes a really good piston but they supply the same 'ol junk rings. The best leaknown I've been able to get on the old style rings is about 30%. I would like to get less than 10%. Won't happen with the old stuff. So, I'm going to scratch-build a set of pistons and try to come up with the most cutting edge piston/ring combo for the str8 possiable. I tryed to get Egge to step up to the plate; it's just too tough to program the cnc. Mmmm... sounds like the old computer excuse to me. So, rebuild the engine, with the best parts you can get. Port the head. Do the same with and run the dual carbs. Put on a MSD 6 ignition. The engine will make some power and that dyna WILL flow. And you will like your ride even more. alleycat

[GOBO]

Thanks for the reply. I'm glad to hear that rebuilding the engine would be worth doing. This engine has alot of appeal. Everytime I take it out to a cruise and open the hood I have to scrape the people off when I want to leave.I've even had a couple people (obviously not that bright ) tell me that they thought the engine was from an old airplane.

[alleycat]

Yes, it is absolutly worth rebuilding! And, I have even better news for you: the 263 is the best str8 buick built, and from the photo, it is diffinatly a 263 and since it is the 1950, it is the very best of the 263's. The thing is built like a brick outhouse, anything you do to it, it'll take it and make power. alleycat

[Buick Guy]

The Dynaflow is the original CVT transmission [continuously variable] and as such is now the predicessor to what power transmission will be in all GM cars [Government Mandated]. The biggest problem today is finding a person or shop willing to tackle a rebuild. Give the straight 8 a good rebuild and if you want some zip, put a turbo with modest boost on it and it will impress you and your Chevy friends.

[GOBO]

Buick Guy, have you put a turbo 350 or 400 in back of a straight eight? If so, what kind of rear end did you use to replace the original.I know the adapters are about $800 then you also have to replace the rear end and torque tube.

[Buick Guy]

My partner's 51 Roadmaster has a twin turbo 320 straight 8 w/a 700R4 behind it with a home made adapter. Required a lot of Budweiser engineering, but works great. The SaltCat race car has a 320 turbo w/a Tremec TKO 600 5 speed. Uses the same adapter. The rear end in both is Jaguar. This is a picture of the T-5 that the straight 8 overpowered and took 3 rd gear out of. The TKO 600 was nearly a direct replacement for it. It can be done given enough time. Doug