300 Stroker questions?

[MGBV8]

The late Rover heads are also a bit heavier than the 300 heads.

I was curious about this, not that a pound or two is gonna sway a decision.  So, I went out to the garage & weighed three heads. Scale used was my Soehnle German digital bath scale.

Buick 300  18.8 lbs
Early Rover 3.9  20.1 lbs
Late Rover  20.8 lbs

All heads weighed with valves & springs, but no rocker shaft assemblies.

[BriansMGBV8]

Jim... "I don't agree with several things they did on that engine but most particularly the use of the long gears in the oil pump. They have been shown to cause wear in the drive gears and if the rest of the engine is built properly are completely unnecessary".

Jim, concur. Believe this article may be a bit dated but I like the pics of the different oiling mod drill portions. If there's something else you're not agreeing with please share.

My intent if I use the 300 is a mild build of the block with all new components. I don't need a stroker engine as anything north of 250hp is more than enough and I believe I can get there with an updated cam and flowed 300 heads with the larger intake/ exhaust valves.  

I have most of the parts needed (minus internals) to move forward with the 300 build, once I know the status of the intake manifold build (Willpower) and how much massaging the transmission tunnel will be needed (67 GT) I'll make a decision. I also have a nice Rover 4.6 if the 300 becomes too much of an issue.

[BlownMGB-V8]

Thanks for doing that Carl. The Rover block is also a bit heavier than the 215. I think the 300 heads are the same weight as 215 heads but not certain.

Brian, I did not read the article thoroughly so I'm hesitant to criticize and as you say it is dated. Much of what is in there is useful but not necessary, such as enlarging the delivery side of the oiling system. If it isn't gushing out at the bearings it doesn't take so much volume. I also think there is something to be gained by increasing the suction galley past 1/2" as evidenced by Buick going to a 5/8" pickup but a piloted drill is needed to do that safely, I use 9/16" and it seems to work quite well. You can go bigger but you risk a breakout. If that does happen it is repairable with hardware store brass tubing. but best avoided. I find radiusing the corners in the suction side and porting the pump and stabilizer plate to be helpful but the main thing is to keep those clearances tight.

For a max build some of those other things could help. I've been known to drill from the mains to the cam 3 o'clock position for example but I'm not at all sure that made any difference. Another thing that you used to see was an external line to the rear of the oil pressure galley. But again, that was back when they were trying to run SBC clearances. Sometimes you might see an oiler for the cam/distributor gears and once in a great while you might run across  piston squirters. But a 250 hp build is very nearly stock and you can quite possibly get there with the right combination of carb and exhaust on a stock engine. You are already at 210. If you do no more than increase the valve spring pressure so that you can get up to the 5500-6000 range you should be there. We are limited on the headers of course so that can't help very much. A small bump in the cam will do it though. 100-120lbs of seated pressure should get you there. Porting is generally either expensive, or risky and labor intensive and primarily suited to when you have to have that little extra boost to get past that one guy on Saturday nights. Bigger valves don't hurt if you are replacing them anyway but lots of times you don't have to. I'd use the cam and not get overly enthusiastic with it. The bone stock 300 is admirably well suited to the MGB so the performance is quite pleasing without it, and as Chuck is discovering with his stock SBC, has the advantages of low speed torque which makes driving it a rare pleasure. That's that 310 ft/lbs of torque working for you. So my suggestions would be either shim or replace the valve springs, give a small bump to the cam, and see how you like it.

Jim

[BriansMGBV8]

Jim, great info/feedback as usual. thanks for taking the time.

Current thought for setup is the 64 300 block and heads with larger valves and stiffer springs. Undecided on the rocker & lifters setup whether to retain stock (new steel inserts for heads) or go with something off the shelf. Cam is a Crower 230 or 232. I've got the original intake and a Willpower being cast for the 300 setup. The Willpower will more than likely rob some low end torgue but thinking there's enough to spare and and with the FitTech TB setup I may recoup some torgue. I'm thinking to dyno with both intakes just for comparisons sake. I have a stock 300 flywheel that I'm gonna see if I can get machined down to 24lbs. The rear gears are GM 7.5 3.42 gears with torsten posi and disks. The tranning is a new GM T5 V8 with the .73 5th gear.

Jim N is local to me and a wealth of info so I just keep picking his brain. Eventually I'll get up his way to visit.

[BlownMGB-V8]

The main difficulty with the stock flywheel is the balance cavity which is on the back. If the flywheel is lathe turned to reduce the weight it means that some means must be used to restore the proper balance if the mass is cut from the back as the size of the cavity will be reduced. I have lightened one to about that weight by turning the face, but then had to use countersunk capscrews to have room for the clutch hub, an approach I'm not sure I would recommend. It is possible to bolt on a weight opposite the cavity on the back side to restore the balance. If the engine is to be balanced during rebuild this is a bit less of an issue.

Jim

[Wilitrun]

Is there someone I can contact at the V8Buick site about getting my account approved as a full member? I did send Jim at Trishield an email, but that was almost a month ago.
I'm not as anxious about posting as being unable to view the photos, I can only see thumbnails which means I'm missing out on some good visual aids posted over the years.

[BlownMGB-V8]

Usually that is automatic once you've made the minimum number of posts. Something like 5 or 10 I think?

Jim

[Wilitrun]

Hi Jim, thanks and sorry for the late reply. I did join but at the moment I neither have posting privileges nor access to image macros. Jim Wiese posted in the News section that as of last August 15th all new registrants have to be manually approved by him. Cheers.

[BlownMGB-V8]

Can you send him an IM?

[Wilitrun]

Jim, unfortunately that isn't an option either until I'm approved but if you know of another member who has his ear I'd happily send an email to them. It doesn't look like joining the site adds any functionality at all until the manual approval is done and I have reached out to him via email.

[mgb260]

David, What is your user name for the V8Buick site? I'll try to PM Jim.

[BriansMGBV8]

Same boat here.....joined over a week ago and have had no response other than I need to wait for approval.  Unusually slow for an online forum.

[mgb260]

Brian, I'll mention you too. What is your user name?

[Wilitrun]

My username is the same as it is here Jim. Thanks for looking into this.
In the announcement thread where Jim states this new policy moderator Brett Slater asks Jim to check his conversations, and that was on Jan. 1st, so I wonder if Jim is OK.

[BlownMGB-V8]

Probably just busy. He is a respected engine builder.

Jim

[mgb260]

Jim Weise says David and Brian are good to go on V8Buick.

[Airwreckc]

Hello everyone,

I'm new here and planning my engine build (for a MGB-GT Sebring project).  I have a Buick 300-4 (aluminum heads and 4 BBL intake).  Was planning a non-stroker with the original crankshaft and the following:
-   Intake manifold ported and converted using Doc's dual plane approach
-   Holley 650 4 bbl carb
-   Original cast iron exhaust manifolds ported, polished and ceramic coated (inside and out)
-   502032 Crower "performance" cam
-   .030 cylinder overbore
-   Nascar 6.320 connecting rods with Ford Turbo 2.3 flat top pistons—estimated 10.3 compression ratio

Before I commit to this approach, I wonder if anyone has any idea the approximate power difference between my plan and a stroker build using the Buick 350 crankshaft?  I realize I'd need to change the pistons (currently looking at some Chrysler V6 flat top pistons with a lower compression height, which I'll have to hone slightly for the Ford wrist pins)—the goal is a similar 10.3 compression or so.

Also, IF I were to acquire a 350 crank, I see most of them are reground—will that cause any issues with rod bearings for my Nascar rods (which are supposedly 2.0" with bearings)?  Any other issues with a stroker build that makes it a lot harder than keeping the original crank and lower CID?
Thanks everyone.

[mgb260]

Eric, Maybe 50HP and 50TQ depending on cam. I'd go up one on the cam. The stock exhaust manifolds won't fit. There are some Rover ones that may but you will have to use a different ujoint on the steering, You can get undersize bearings the same as the rod journals on the crank. What piston are you thinking about trying?

[mgb260]

Rover exhaust manifolds:

[Airwreckc]

Thanks Jim!  Your insight is really appreciated.  50 is definitely a number that makes this worth considering. I guessed I should have also asked what the total HP/TQ numbers might also be, as I want to make sure I'm not going to destroy my transmission (a Tremec 3650--supposedly a lot stronger than a WC T5, but still has its limits).  Good to know on the exhaust manifolds, too.  The pistons I'm looking at are Chrysler/Dodge minivan 3.8 V6 flat top (3.78 bore and 1.283 compression height).  I haven't spent too much time looking at whether the pistons or block deck might need a bit of milling, but it seems to be close (and I'm sure the choice of head gasket will affect the quench number, too). The piston pin hole is a bit smaller than the Ford size (.901 vs .912), but I was thinking that I could use Ford pins and have the piston holes honed to fit.

[Airwreckc]

Jim, in your opinion, which of those two Rover manifolds would flow better?  And are the shiny ones aluminum?  That might be nice, too.

[mgb260]

Sounds like a plan. I try to build one HP per cubic inch for a strong street motor . 350HP and about 400 TQ if done right. Your transmission will be fine, What length are your rods again? Shiny ones are probably Jet Hot coated. They are also Tri Y design. Two pipes go down from them to a Y on each side. The top one is more conventional,

[mgb260]

TS import big bore RV8 headers:

[mgb260]

I ran those pistons on the calculator and they are .020 below deck and 10.8 . If you remove the lug in the chamber you would be 10.5. Looks good.

[Airwreckc]

Jim, thanks for running those numbers.  I am not an expert on engine design, obviously.  I have done some reading and I read that ideal "quench" clearance seems to be .040"  With the pistons .020" below the deck and a composite head gasket, will that give me this optimal quench?  Of course, also removing the lug you mentioned.