[MarkS57]

Originally Posted by mgarblik

Yes, that Magnavox ignition system was like rocket science at the time. I was at the Delco Remy plant in Anderson, IN at the time it was introduced. At Delco, they were frantically trying to get the Delco system in production for the anticipated wide spread use of of coil packs in most of GM's cars. The Oil pump likewise was a huge step forward from the external little gear pump Buick engines had. Those pumps often lost their prime during oil changes and had a hard time maintaining 5 PSI on hot summer days with the AC on idling in traffic. Oil light would often flicker. the Buick GN pump was crank driven and a wet sump. Seeing the entire SD-455 system installed would be very interesting.

Tell me about the 3.8's oiling, I had an 81 GP with one of those, did exactly that and spun a bearing. The GN / 89 Turbro T/A's still used the original oil pump set up though. The "distributor" was just a cam sensor for the EFI & ignition.

[mgarblik]

Originally Posted by MarkS57

Tell me about the 3.8's oiling, I had an 81 GP with one of those, did exactly that and spun a bearing. The GN / 89 Turbro T/A's still used the original oil pump set up though. The "distributor" was just a cam sensor for the EFI & ignition.

I looked around and could not easily find a oil circuit diagram for a 3800. But the oil pump was housed in the timing cover with a flat inner and outer gear much like the possible SD-455 gears pictured. The steel gears would over time tear up the aluminum housing when dirty oil was run through them from extremely high mileage or neglect. 3800 engines didn't have too many issues with this. The older Buick engines had an external oil pump, camshaft driven. Hanging outside the engine, it had a long pick-up and the pump was down low. When changing oil, if you drained the oil and let it drain for an hour, there was a good chance it would not re-prime after the oil change. We were told at the dealer to drain them no longer than 5 minutes and re-fill immediately and start the engine. Still had a few that the pump had to be taken apart and packed with Vasoline to help it re-prime. A pretty weak oil pump overall.

[mgarblik]

Originally Posted by PAUL K

Any chance you could Sonic scan of the cylinders?

Unfortunately the SD blocks I've checked the thickness isn't very impressive. I've only scanned about a half dozen or so and all have been 1974's or SR blocks. I'm curious if the earlier cast blocks may have been different .

This is the interesting stuff I was hoping for in this thread. I will weigh the block in a few days. Not a certified scale, but a electronic shipping scale. I wasn't planning to sonic test the block, but I will at your request. Are there say two cylinders that would do the trick? Or is the entire block necessary? If a couple will do, name the ones you want me to scan.

[PAUL K]

Originally Posted by mgarblik

This is the interesting stuff I was hoping for in this thread. I will weigh the block in a few days. Not a certified scale, but a electronic shipping scale. I wasn't planning to sonic test the block, but I will at your request. Are there say two cylinders that would do the trick? Or is the entire block necessary? If a couple will do, name the ones you want me to scan.

Thanks Mike, they were always the inner cylinders. I recall one being around .070 thick ninety degrees from the thrust on a 4.191 bore. The outer cylinders were always average.

I wasn't there, but believe this may have been an issue for the 1968 FAST Firebird that ran nines. They started out using an SD455 block and had an issue with it shortly after they started racing the new mill.

It also, most likely explains the deal with the H-O Super Stock car slowing down with a .030 over rebuild. They gained it all back and then some by sleeving all eight cylinders.... But again, I wasn't there.

[Dragncar]

The horrible oiling of the Buick V6 was their demise at the Indy 500 when they used to qualify #1 but could not finish the race back in the 80s.

[mgarblik]

Question for the SD guys: I was getting some gaskets and seals together and cleaning some parts. This engine has a 5 tab oil pan with welded-in baffling in the pan. So obviously, it is a replacement oil pan. Previous owner confirms the pan was replaced as part of the overhaul in 1980-81. Anything specific different about the factory SD pan? I assume it was a 3 tab at the rear. Anyone happen to have a pic of the interior? Just curious if the baffling was the same as the one I have. Thanks

[johnta1]

The stock pan had a baffle in it. No windage tray on caps.
Just make sure the corners of the pan at rear have the metal pieces under the bolts that help seal the pan gasket.

[mgarblik]

Yes, I need to order those corner reinforcements. I really like the look of the little trap door H.O racing added to the stock pan baffling. You would never see it and it would add a layer of security cornering and braking. I plan to drive the car when it's up and running. It's never going to see a trailer while I own it. I don't want to have to worry about those giant bearings starving for oil. A few things to think about.

[Skip Fix]

Mike I have an original HO pan on one motor and I bought a trap door form Canton and copied one for another motor in the 81 TA. I did find when using the HO pan autocrossing with road race tires a "stop box" at the end where you had to stop hard would drop the pressure some, but corners no problems.

I never had any luck sealing 3 tab pans. Seal was half round so it would slip easily and it seemed 1/8" too long so it was starting to move just laying it on the pan. I use a dremel to convert them to a 5 tab and use the flat 5 tab seal. Most aftermarket pans are 3 tabs.

[mgarblik]

I was able to spend a few hours looking over and taking more detailed measurements on this SD-455 engine. I have decided to make some small changes in my plans. First thing I did was measure every piston very carefully. These are TRW +.030 factory replacement SD pistons. To my surprise, they were very poorly finished for size. The skirt measurements at the tip varied by .004" through the set!! That's pretty bad, IMO and although pistons are definitely more accurate today, I don't remember them being that bad in general 30 years ago. Under the oil ring measurements vary by .002" through the set. Skirt taper varies from one piston with a negative taper of .0005", to an average taper of .002" on the other 7 which is OK. Overall, pretty disappointed in the quality of the pistons, although they look fine visually. That's why you have to measure everything. So my new plan is to re-hone the block and select fit each piston to a cylinder and set the correct .006" piston to wall clearance. Fortunately, they are all too tight now around .002", so it's just a matter of finish honing. The line hone is similar. Too tight. The housing bores are .0005'-.0007' tighter than I like them. I put them right on spec. and these are slightly tighter than tolerance. My understanding is this was typical 30 years ago as shops were concerned about spinning bearings in large main size performance engines. But since I have to hone the cylinders anyway, I might as well fix the line hone as well. Finally, after some careful thought, I have decided to change out the rod bolts. ARP makes rod bolts specifically for SD-455 rods. The head design is a little different. I hope the weight is similar. Will have to weigh them and see. I am concerned with stretching the original bolts 3 more times. once to measure the rod housings, again to dial bore gauge the oil clearance, and a third time for final assembly. Just too many cycles as these bolts may be original and I don't know how many cycles they already have on them. So a little work ahead to make sure everything is as good as I can get it.

[mgarblik]

Originally Posted by Skip Fix

Mike I have an original HO pan on one motor and I bought a trap door form Canton and copied one for another motor in the 81 TA. I did find when using the HO pan autocrossing with road race tires a "stop box" at the end where you had to stop hard would drop the pressure some, but corners no problems.

I never had any luck sealing 3 tab pans. Seal was half round so it would slip easily and it seemed 1/8" too long so it was starting to move just laying it on the pan. I use a dremel to convert them to a 5 tab and use the flat 5 tab seal. Most aftermarket pans are 3 tabs.

Agree, the 3-tab seal is a lousy design. Over the last 15 years or so, I have had best luck eliminating the seal entirely. I think I will weld up the 5 tab slots and just use a 1/4" bead of RTV. That has been working well for me .

[74SDformula]

This is the oil pan off of my '73 SD TA. As has already been stated, it is just like any other oil pan for that year. I do not use the 3 or 5 tab rubber seals any longer. Have had too many issues with them over the years. I use the long thin cork seal exclusively.

[77 TRASHCAN]

I'm surprised that the pistons were NOT fitted to each cylinder.

Did you figure out if a torque plate was used by previous builder?

I've read a lot here about using the cork rear pan gasket piece, all good!!!

[77 TRASHCAN]

I'm surprised that the pistons were NOT fitted to each cylinder.

Did you figure out if a torque plate was used by previous builder?

I've read a lot here about using the cork rear pan gasket piece, all good!!!

[johnta1]

I also use the cork gasket on rear of pan. (with sealer of course)

[steve25]

I have a notion that Herb Adams with the hand that he had in this and his eye for wanting to use it in his 64 road racer is the only reason why that rear bulkhead dry sump pump was added to the Design.

The big question I have is how he got this costly change passed the eyes of his upper supervisor’s during preproduction.

I think I have seen signs of this oil system in photos of one of the experimental overhead cam motors, so it may have been around for a while, but to include it in even a limited production motor still had to be a big cost.

I guess like we have heard in stories over the years that even though upper management was against this motor Pontiac sales already had so many orders for F body’s with this motor, and since parts where already made they had to reluctantly go with since the cost would then be covered.

To me all the positive advertising and word of mouth that came from the making of this last true super car was worth any monetary loss the division would have to swallow, in fact to me this is what set the stage for the later huge sales numbers of the TA models post 1974.

[steve25]

While the heads are apart could the OP provide the measurement of the intake throat diameter and the height of the port from the apex of the short turn to the roof.

Thanks in advance!

[mgarblik]

Originally Posted by 74SDformula

This is the oil pan off of my '73 SD TA. As has already been stated, it is just like any other oil pan for that year. I do not use the 3 or 5 tab rubber seals any longer. Have had too many issues with them over the years. I use the long thin cork seal exclusively.

Thank you for the picture of your SD-455 pan. The pan on my engine looks exactly the same with the exception of the 5 tab lip for the later seal. PO said that was the PMD replacement pan in the late 70's when he bought it. So they had already purged the 3 tab pans from the parts inventory I guess. Steve25: When I take the heads apart, we can talk some more and I will take pics and get measurements you are interested in. My plan is to just clean them and put them back together and check the springs. The original invoice from A-Hines says guide liners were installed. No other real details. Very hard to read. Hand written and 40 years of faded ink. Heads are assembled and bagged. Probably be a month to 6 weeks before I can get to them. I want to get the short block back together first.

[74SDformula]

Use caution when removing the rod bolts. The way the rod bolt is made creates a window that may contain shot-peening material. Years ago, I was removing the bolts from a set of SD rods and had trouble getting a couple of bolts out. I initially thought they just had a tighter press fit. However, after getting the rod bolts out, I realized what was going on. Apparently, there were a few small pieces of steel shot from the shot peening process that had gotten into this "window" on the connecting rod.

[steve25]

Was this Malay only in the A series stamped first production rods, or others?