Engine and Transmission Tech

I used the cylinder hone today just to see what improvement i could get. I did maybe 40 passes stopping and oiling every10 or so. The improvement was noticeable but nowhere near perfect which I expected. So, The machine shop can give it a try at 040 over and thats the most it will get. If that gets them smooth then we’ll see if they can drill it out to 1/2” and what’re ever is needed to get the copper insert in. The breakouts are about 6 inches in so that much would need to be a little larger to accommodate the insert I guess.

Scott, people have bored that out to 5/8, though 9/16 is more common. When the machine shop sets it up they will use a slightly smaller than 7/16, like the original hole and center, before they drill it larger. If you look down with a light you will see the point where the factory drilled the short hole and in the long hole. After the tube is pressed in, they just need to patch where you broke out. They will charge more for the brass tubing than the Ebay ad. You may want to ask them if you can supply the tube and they can install it.

I'm sure they will be able to go to .040. If they can you will want to order the pistons we did. Silvolite 1463c +1.0 oversize direct from Silvolite and we bought Hastings plasma moly rings from Summit. You won't know bearing sizes until the crank is done, but we used King bearings, I think from Summit too.

Thanks Jim, I will order the same parts when the block is ready, (Fingers crossed). 9/16 would probably accommodate the brass or copper insert. Appreciate the help!

Scott, No problem. Summit has those pistons too but in a six pack and you can get 2 singles. Same with the rings.



Edited 1 time(s). Last edit at 05/24/2025 02:18AM by mgb260.

Is the spacer on the pump the D+D booster plate? I’m looking at the pictures of the oil port mod. The hole is oval which Ive read here somewhere. Once I know what I’m doing, I’ll open it up per the instructions.

I’m assuming the gears are supposed to slide off. They’re not exactly sliding off, so I’ll figure that out with a pair of pliers. The wear marks are bit concerning. I guess I’ll be reading more about the pump before I go screwing it up.

As a machinist I feel obligated to tell you that your shop guy isn't going to like that hole. It's crooked and it'll push the drill to the side. The only way to straighten it would be with an end mill that has a flat end so it doesn't follow the hole but an end mill long enough to reach past the breakout is just about going to have to be carbide to be stiff enough, otherwise it will also follow the hole. Even a carbide end mill will try to follow the hole a little, and the end mill itself is going to cost upwards of $100-200 and will most likely have to be bought specifically for this job. Once he gets past the breakout the standard long drill will work, assuming this is done on a milling machine.

You will have a void on the outside of the tube and it will have to be inserted with sealant. The potential for a leak will exist. Don't attempt to tig the breakout afterwards, you will probably melt the tube and burn the sealant. Better to fill the cavity with sealant. It should only have to resist a vacuum.

When I had a breakout (on an iron block) I made up a piloted drill with the flutes ground away so it could track the original hole to get back on center. This resulted in a snake like path meaning insertion of the tube was a bit challenging but the breakout was to the inside so there was no issue with leaking oil. A little air seepage could be tolerated if necessary but that engine developed fine oil pressure. I don't know if tube insertion is commonly done but hardware stores do carry thin wall brass tube assortments that can be used if the hole is the right size. But I wouldn't just assume that the machinist is prepared for this job. Anyway best of luck with it.

Jim

Jim B raises valid points. the machinist will have to decide how to proceed. On the oil pump, it looks like the High Volume with spacer that lets the longer gears stick through and is hard on the cam and distributor gear and front cam bearing. The booster plate is thinner and is a solid plate and the stock gears don't stick out that much. Jon had the High Volume pump too, and we replaced with these parts.

[www.rockauto.com]

[www.rockauto.com]



Edited 2 time(s). Last edit at 05/24/2025 03:52PM by mgb260.

I looked up the melting point of brass and it is around 1700F! the brazing rod is only around 750F, so you would be fine there. You could have the machine shop do that too.

Well that is worrisome. I haven’t reached out to the machine shop yet, but when I do I’ll find out what they think. They may not want to touch it. I’m still not sure the gouges will come out with the .020 bore. I guess I’m going to find out. As far as the pump, if it’s the high output one, I’ll replace it. I watched a video of a guy replacing one and it was pretty interesting but not very simple. They used a shim from TA to get the right tolerances and checked using plastic-gauge. .
Thanks for the input guys!

Melting point really isn't the issue here, it's the thinness of the brass tube. Sort of like trying to tig something on top of a sheet of aluminum foil. Yeah you can tig it but at some point the arc is likely to jump to the tube and poke a hole in it or at the very least boil off some of the surface. That is going to contaminate the weld and make it porous. It'd be easier to just weld up the block and then redrill it. That thin section is going to melt out though so it'll be a long scar. It can be repaired, but compared to the cost of another block is it worth doing? That 300 block is looking a little more attractive. Or at least a late Rover. Even just another 215 block. But then maybe your stroker crank won't work with the Rover and it's cool to say you have a stroker, even if it's a 215/266. I just hate putting money into questionable hardware. It took me decades to learn my lesson though so I really have no excuse to talk, I stayed married to the 215 for much, much too long before jumping ship for the iron blocks. You'll never have a better excuse to do the same, unless somebody just gives you an engine and how often does that happen? Still, most folks are at least a little resistant to change and I understand that. But I've never seen anybody replace a 300 with a BOPR. Why would they when the engine just doesn't go bad?

Jim

So, what did we figure is the weight difference? Is it comparable to the iron 4 banger they came with? I’m not against using a 300 if the 215 is not worth fixing. Maybe I can part it out at that point. Unfortunately I have the crank getting serviced and the cam is getting reqround, So, I’m already in a hole. Once I get the crank and cam back , I’ll be reaching out to the machine shop. If they think it’s a waste of time and money, I certainly wont move forward with this block.

Scott, I think the 300 with the 64 only aluminum heads and intake is only about 60 lbs heavier but I think you would have to change to the T5 transmission as there is no GM bellhousing for the Rover LT77 transmission. You can reuse your motor mounts and headers and it uses the same design front timing cover, distributor and oil pump.

With the alloy heads and intake the 300 is 50lbs heavier than the B series 4 banger. With iron heads and intake it is 100lbs heavier. That represents the biggest bargain as you can pick up an iron head 300 very cheap and they had 9:1 compression. TR6 spring spacers can be used to set ride height and swaybar size used to get neutral steering. All this info and much more is in the 300 sticky thread: (The iron heads also breath a little better btw.)

[www.mgexp.com]

Your reground cam will work fine in the 300 as they are essentially the same engine. Come to think of it, so would the crank should you need it. You can also fit a 350 (Buick) crank though that is more involved. But with a base line of 210hp and 310ft/lb that should be on down the road somewhere maybe.

Jim

The mains on Scott's crank were turned down 200 thou to fit the 215 block. If he had a late Rover block the mains would not have needed turning.

Forgot to mention the cam would work.

Thanks guys! So, If I got an iron 300 block; can I get alloy heads or is that a problem or really expensive? Will my cam add anything to the stock 300 output?
Clearly I’m over my head here.

Scott, That cam dynoed 300HP at the wheels in Mike Moor's car. I think he had the stock 64 only aluminum heads and intake with the Elelbrock carb you have. The iron heads have larger ports and valves and would make even more power.

[www.britishv8.org]



Edited 1 time(s). Last edit at 05/27/2025 01:35PM by mgb260.

Last time I looked for a set of alloy 300 heads they were going for something over $300 a set on ebay when they showed up, undoubtedly more now. That's a bolt-on swap for the iron heads. If the pistons/rods get replaced as in a rebuild or stroker, the late Rover or TA heads can be used with some tig work in a couple of corners to fill small voids that don't quite get sealed off. The late Rover heads are heavier than the 300 heads and the TA heads are heavier than the late Rover heads. An iron head is 17lbs heavier than the stock 300 head so the weight savings with an alloy intake is only 34lbs. Meaning the iron head engine with the alloy intake is 84lbs heavier than stock. We are well into the range where the weight is unimportant unless you are racing. It's more than made up for by the power output. Buick enthusiasts realized this almost immediately and along with the larger port and valve size there was little incentive to swap for the earlier heads.

The task is to find that donor 300 in the first place. It usually takes a dedicated and intelligent search. It isn't to be found in a scrap yard that empties the bins every 5 years. But with a half-million made, they are out there. The ideal scenario is finding a 20- or 30-something who is building a Tribute GS using Granny's Regal. Those aren't uncommon. Also Buick forums help. Then there's the old car magazines, (Can't recall that one name that is so big online and at meets), Heck I've even called TA to get the phone numbers of regional junkyards that hoard old Buick parts. That last one might cost a bit more but is a pretty reliable source.

With that done the next thing depends on what you got. Can be as little as a clean-up in some cases or as much as a full rebuild in others. I'd try at least to lean towards the first. Any Buick 300 under 50k miles is going to be almost new inside and those do exist. With proper care, modern oils and fuels these old engines can give 1/4M miles of service due to the high nickel content of the block and heads.

Jim