[SusieQ]

I spoke to Tom V. by phone. He knows his stuff. I'm taking his advice.

[Stripes]

Looks like no one likes the 80 pound pump except Butler, HO Racing, and of course the engineers at Pontiac. I bet those engineers at Pontiac had no idea how wrong they would be 40 years later! Everyone knows that 455SD was designed to spin 8000 rpms, thats why it needed that 80 pound pump.....with that high duration cam.... Could anyone tell us the story of how a 80 lb pump damaged their engine? And those Butler guys, how foolish they must feel recommending the 80 lb pump. Think how successful they could have been had they known what they were doing.

https://www.pontiacv8.com/articles/2018/3/26/oilpump

[Tom Vaught]

Stripes, Funny that you should mention the 455 SD engines.

In the early 70s (before 1973 and 1974), I was at a university located a few miles from my uncle's Pontiac Dealership. I was talking one day with a couple of college age guys and they said they worked for Pontiac Engineering in the summers as engine dyno operators.

They were Dyno Operators on the 455 SD Engine Program!
They mentioned a bunch of engine failures they saw on that engine.
Said they were blowing those engines up left and right.

Now in my research job we ran engines to failure too. Several times we had 2800 hours on the engines and no failures. Other times the engine's parts just failed from fatigue.

The people I was talking to told me about other failures.
Oiling failures, connecting rod failures, distributor drive failures (gears on the distributor and camshaft), to mention a few. Pontiac Engineering changed MANY things on the 455 base engine to give the 455 SD engine durability. See list below:

So Pontiac Engineering went to Teledyne - Continental (located on the western side of lower Michigan) and had them make the first 455 SD "A" Forged Connecting Rods.

Pontiac Engineering redesigned the Pontiac block to use the larger distributor gear and a camshaft to use the smaller distributor drive gear.

Pontiac had Melling Tool (Melling Oil Pumps) come up with a higher pressure oil pump.
Same gear set just a different contril pressure (80 psi) for the 455 SD engine.

I could list many other changes to the 455 SD engine to make it live.
Here is a quick summary: (info from a Hemmings Article)

The most expensive SD replacement item is the block itself. It's a unique casting, identifiable by the "132" (corresponding to its casting number of 490132) found on the driver's side of the block (1). Prices for the scarce few used and Service Replacement Super Duty short- and long-block assemblies that make it onto the market have exceeded the five-figure mark. Regular production 455s will have the displacement, instead of the casting suffix, marked on the driver's side (2).

Through the years, Pontiac included reliefs at the bore edges on those engine castings destined for use in high-performance applications with larger valves. The SD blocks are among those that received this treatment to unshroud the valves.

While not as much of an issue on stock-specification engines, those modified for performance with high-lift camshafts and high-rate valve springs running higher rpm often cracked around their unsupported lifter bores (4). The SD addressed that issue with added cross bracing between the lifter bores (5). The main bearing saddles were also thicker, as were the engine mount bosses on the torque side of the engine.

Four-bolt mains with nodular iron caps are another Super Duty trait. The SD engines did not come with windage trays, though this example's caps have been modified to accept one (6). A baffled oil pan came into use in 1973 to control slosh and prevent oil starvation during hard cornering. Standard 455s came with two-bolt main caps, usually equipped with a windage tray mounted on studs on the caps (7).

The 1973 SD engines were cast without an assembly-line transfer lug, also known as the "mountain" or "pyramid" (8). Super Dutys assembled for the 1974 production run had the transfer lugs used to move the blocks down the regular production lines (9).

A larger distributor gear was intended as a solution to issues with camshaft gear wear in high-performance applications. Getting the distributor with the large gear to fit into the block required an oversize distributor hole (10). This was also a feature found on the 303, 366 and Ram Air V 400s. The standard production block's distributor hole is shown for reference (11).

Rather than utilize a new distributor core casting to accommodate the oversize gear, the SD distributor was fitted with a sleeve. Accordingly, the corresponding cam shaft gear was undersized to match.

The rear of a regular production 455, or just about every other Pontiac block for that matter, is a rather nondescript affair. (Pontiac Engineering slipped in a hidden dry sump oil system designed into the 455 SD blocks.
To accommodate the dry sump system, an SD block's backside is a rather busy place. The spur-gear-style oil pump was designed to fit in the oversize opening around the cam bore. The pump was driven at half engine speed by a keyed protrusion on the back of the spur gear, which slotted into the back of the camshaft. The spur gear fed the oil into a unique oil galley, seen at the right upper part of the opening; this galley led to the oil filter mount pad and needed to be drilled out at that end to open it up. The large flat area around the opening was pre-machined relatively flat for the pump cover.

This rare-as-hen's-teeth spur gear system pumps the oil to the SD-unique galley, which leads to the oil filter mounting pad. An intermediate keyed stub rides in a bearing installed in the block. The bearing opening must be precisely machined in relation to the cam bore. The stub then interlocks with the back of the camshaft, with the gear system itself fitting into the large central opening.

Here's the cover plate for the pump gear. To complete the installation, you have to drill and tap the cover's mounting holes. At the filter mount, an adapter/bypass block is required to route the oil to and from the sump tank.

At the front of the SD block, there isn't much different from the regular production 455 with the exception of the oil plug holes. These were tapped and fitted with threaded plugs to avoid leaks and potential blowouts. The SD's 80 p.s.i.-rated oil pump (compared to the stock 60 p.s.i.-rated pump in the standard 455) did cause some issues during cold starts early on: Some folks blew out their oil filters during the first start of the day.

The full casting/part number is also found at the top right rear of the block.

There are four possible engine codes for Super Duty engines: XD and ZJ denoted automatic and manual transmission-equipped cars in 1973; Y8 and W8 are the corresponding codes for 1974.

(Ken Crocie was involved in putting the article together for Hemmings writers)

I will not post the Pictures from the article but here is the link:

https://www.hemmings.com/stories/art...side-the-glory

So knowing Tom Nell on a personal basis, (RIP Tom), and talking to Herb Adams for hours at different car shows you get the real story on the 1972 455 engine vs the 1973 & 74 455 SD engines.

So to answer your question, if you did not use the Pontiac Engineered 455 Oil pump drive system you could have excessive wear on the camshaft and distributor drive gear.
Drag Racers or car show people would never see the difference in wear.

Tom V.

ps Stripes, you ask a lot of good questions and voiced your opinion on the subject.
I posted facts. Pontiac Engineers changed stuff on the 455 SD engine vs the normal 455 engine for REASONS.

[Bill Hanlon]

I'm trying to understand something that doesn't make sense to me Tom. I think distributors must turn at the same speed as the camshaft. How can this be if "Pontiac Engineering redesigned the Pontiac block to use the larger distributor gear and a camshaft to use the smaller distributor drive gear"?

[Steve C.]

Fast forward to today's technology one might wonder if a distributor gear made from Carbon Ultra-Poly would of solved the 455 SD issue.

Similar to the BOP Composite Distributor Gear used by many now in a Pontiac application. I know for a fact many of us have used it in conjunction with 80 lb pumps with no signs of wear issues at higher RPMs.

.

[Formulajones]

Originally Posted by Steve C.

Fast forward to today's technology one might wonder if a distributor gear made from Carbon Ultra-Poly would of solved the 455 SD issue.

Similar to the BOP Composite Distributor Gear used by many now in a Pontiac application. I know for a fact many of us have used it in conjunction with 80 lb pumps with no signs of wear issues at higher RPMs.

.

I've used those in a few builds with 80 psi pumps and no issues to date. Actually I've been using 80 psi pumps in Pontiacs for decades, with rollers and flat tappets and never had any distributor gear wear issues or any other issues related to it. My bird has had an 80 psi pump in it for 25 years, I daily drive it, race it all the time.
My opinion, doing the check ball modifications, blueprinting the pump, and making sure the pickup tube is secured properly is more important than worrying about 20 psi.

[Tom Vaught]

Originally Posted by Bill Hanlon

I'm trying to understand something that doesn't make sense to me Tom. I think distributors must turn at the same speed as the camshaft. How can this be if "Pontiac Engineering redesigned the Pontiac block to use the larger distributor gear and a camshaft to use the smaller distributor drive gear"?

1) sorry for the confusion, Bill. Would you agree that the 455 SD Block has a larger distributor hole machined into the block and you need a distributor housing "sleeve" to run a conventional Distributor Gear and Conventional Camshaft? Not a Pontiac SD Expert by any means like Tom S, but assumed that the 455 SD camshaft and the 455 SD Distributor Gear were a matched set. And I assumed that when I wrote the post that Pontiac Engineers put a different configuration (sized) gear on both the distributor and the camshaft to handle the higher pressure 455 SD Pump.

What am I missing here? Why recast a new Pontiac block with a different distributor installation hole size for no reason?

Tom V.

[Tom Vaught]

Originally Posted by Formulajones

I've used those in a few builds with 80 psi pumps and no issues to date. Actually I've been using 80 psi pumps in Pontiacs for decades, with rollers and flat tappets and never had any distributor gear wear issues or any other issues related to it. My bird has had an 80 psi pump in it for 25 years, I daily drive it, race it all the time.
My opinion, doing the check ball modifications, blueprinting the pump, and making sure the pickup tube is secured properly is more important than worrying about 20 psi.

So with your roller camshaft (steel) I assume you also used a different material distributor gear? Apples and oranges comparison, but that is what you posted.

Tom V.

[Steve C.]

We went out on a limb and made composite gears for use with the RAV and 455SD camshafts with the smaller cam gear. These are made from the same material as our other composite gears and will work well with the 80lb pumps. We also have many customers using our standard size composite gears with the 80 lb pumps and cast iron cams. They are not in the catalog or website yet so please call if you need one.

Wade Congdon
BOP Engineering
Hi-Performance Specialty Parts for Buick, Olds, and Pontiac
www.bopengineering.com

.

[tom s]

I think this thread in the street section was started about if a 80 lb pump is "needed"?I have been doing this stuff,street driving and for a period of my life racing stock and super stock pontiacs with max rpms of about 6500 and I have never found the "need" for the 80 so I have just stayed with the 60.FWIW,Tom

[Steve C.]

Tom, your right. I don't know how that project turned out. I should have mentioned it was for information only.

I've been using only solid roller cams with billet cores for over 20 years now, first with bronze gears with no big issues other than the expected wear. The bronze gears are sacrificial so they will wear-out. And now the BOP gears with thousands of miles.




.


.

[Formulajones]

Originally Posted by Tom Vaught

So with your roller camshaft (steel) I assume you also used a different material distributor gear? Apples and oranges comparison, but that is what you posted.

Tom V.

I'm saying I've used them both ways. I've had composite, brass, on rollers, and just plain ole 50 year old distributor gears on flat tappet cams. I've had every scenario, and they all have or had 80 psi pumps on them. I've never had any kind of gear problem with any of it.

I don't really care if people want to use a 60 psi pump, I don't have a problem with it and I'm sure it works fine. Kind of funny it's even a debate, lol. I'm simply providing my experiences with it.

I'm more surprised people aren't more concerned with the crappy quality of the Melling pumps. The bodies aren't machined flat and haven't been for many years, and they need quite a bit of work to make them right. Melling is aware of the situation. Their answer as I got straight from Paul is that their molds are 60+ years old, and they have no interest in investing the time or money to fix that.

[Steve C.]

Articles from MSD will point out the effort that goes into a ring-and-pinion installation. Yet many don't think twice about the distributor gear/cam gear relationship unless performance starts to suffer.


.

[Formulajones]

Originally Posted by Steve C.

Articles from MSD will point out the effort that goes into a ring-and-pinion installation. Yet many don't think twice about the distributor gear/cam gear relationship unless performance starts to suffer.


.

Yep,

It's important to dress the gear on the cam before installation to remove the sharp edges and burrs. That's been talked about on this forum quite a bit over the years yet very few people seem to practice it.

With that done, and the soft bronze gear on a steel roller cam, I actually haven't had issues with the bronze prematurely wearing, even with an 80 psi pump. These days I just go for the composite gears because I feel it's a better solution, but I still dress the cam gear regardless. Depth is another thing that needs to be checked as well. How many actually check the pattern??

[Tom Vaught]

Well Susie Q, stopped by my house a few minute ago, we swapped "pump pressure" parts and she is happy and I am happy I could save her some money vs buying a different Melling Pump.

The rest of this thread is basically comments about what worked for other PY Members.

I am like Tom S, I have never needed a 80 psi oil pump when I could help someone
like Mark at Luhn Performance make 862 HP at 5300 rpm.
(Vortech Boosted Engine at 13 psi of boost pressure)
The only issue we had with that engine was the main cap fretting on the two bolt main block.

Tom V.

[Steve C.]

Mark's custom oil pump has a taller gear set and larger diameter pickup that results in 87 percent more flow per revolution than a regular Melling oil pump.

Here to add fuel to the fire.....regarding oil weight

When I was dealing with Mark regarding his oil pumps he told me that he had conversations with both Mahle and Dura-Bond engineers and he mentioned they tend to shy away from 20W-50 oil in street cars. They would prefer 10W30 or 10W40. For the most part I've always used 10W30 oil.



.

[grivera]

Seems most agree an 80 psi pump isn’t “needed.” To Stripes point though, why did Pontiac deem it necessary in the SD block if as mentioned here 60 psi pumps are used in higher horsepower engines? Apologies in advance if I missed the reason in an earlier post.

[Formulajones]

Originally Posted by Steve C.

Mark's custom oil pump has a taller gear set and larger diameter pickup that results in 87 percent more flow per revolution than a regular Melling oil pump.

Here to add fuel to the fire.....regarding oil weight

When I was dealing with Mark regarding his oil pumps he told me that he had conversations with both Mahle and Dura-Bond engineers and he mentioned they tend to shy away from 20W-50 oil in street cars. They would prefer 10W30 or 10W40. For the most part I've always used 10W30 oil.



.

And then you get into cold pour ratings to add more fuel to the fire as all 20-50's are not created equal, and that all plays a roll as well.
We could just go on and on about this or that. LOL

[Singleton]

Originally Posted by Bill Hanlon

I'm trying to understand something that doesn't make sense to me Tom. I think distributors must turn at the same speed as the camshaft. How can this be if "Pontiac Engineering redesigned the Pontiac block to use the larger distributor gear and a camshaft to use the smaller distributor drive gear"?

I believe that the driven gear and the drive gear tooth count of the SD remained the same as standard pontiac engines at 14 for each gear, just at a slightly different diameters

["QUICK-SILVER"]

The silver car has a 400 in it now. Changing from 60 psi to 80 psi oil pump pressure relief DID NOT change how long it takes me to mow the yard.

Go Figure?
Clay