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MG MGB Technical - Building a fast engine?

I'm getting ready to purchase an early 5-main engine for a fast road mod, and the more I read the more I realize how little I know. The idea is to build the best, most powerful engine possible, retaining driveability and reliability. Cost is not an issue since it will be a long-term project. Am I nuts trying to tackle such a project when I've never comlpeted a full stock rebuild from start to finish? I can't afford to shell out the money for a pre-built engine of that caliber. Maybe I should buy the head ready to go? Or does anyone know where I can go to talk with someone about planning an engine when I intend to do most of the work myself?
Steve Simmons

Have you thought about a V8?
Bruce

Yes, for about 8.6 seconds. :) I want the originality of the period engine.
Steve Simmons

Steve. Engines are not fast. Cars are fast. But, I know where you are coming from, having been there myself. First thing to do is to purchase a copy of Peter Burgess' book on the MGB engine. (How to Power Tune the 4-Cylinder MGB Engine.) That will give you some ideas and serve as the basis for further discussion. You can contact Peter through his website which is available off of this website. Peter is a GENTLEMAN, and will be considerate enough to answer all of your questions. (I have dealt with him for a number of years and am getting ready to send him a cylinder head for my daughter's car next week.) I would suggest you examine his "basic big bore" engine specification which is .060" over HC pistons, one of his Fast Road cylinder heads and K&N filters. You might discuss the cam with him. He has suggested the Piper 270 or 285 for what I want to do. I still have to meet emissions standards with my cars here in Arizona. Hence, I will opt for the Piper 270 myself. If you do not have this problem, the 285 may be better. Make sure that all the parts are balanced by your machine shop. MGs were never the fastest cars on the track. They were, however, very reliable and easy to repair. They also handled and stopped very well. Properly set up, an MG is as quick, point to point, as almost anything ever made. If you go for a "faster engine" do not forget a "faster" suspension and brakes. Brit-Tek has non-racin V-8 brake pads, a worth while upgrade. Les
Les Bengtson

I do own that book, and have found it the best I've read on the subject. I'll contact him as you said since it sounds like he's so helpful. Isn't he located in the UK? Long way to send your parts!

The suspension and brakes will certainly be redone, the brakes slightly better than original and suspension much moreso. Also steering should be done long before the engine. THanks for the input!
Steve Simmons

Steve:

Brit-Tek also has engine major engine re-building kits. The kits are very complete. These seem reasonably priced and would be the way to go. I recomend buying the ARP rod and head bolt kits right away. No need to wait until you break a bolt on re-assemby, let alone at speed!

Budget on a new distributor. Much of your potential power will be missing if this end is not in top shape. Same for the SU carburators, re-build and re-bush or buy new.

Unless I really wanted to do it more than once, I would buy the prebuilt engine. There is a lot less to tossing a set amount of money into a savings account every month than there is to learning by trial and error (and expense) how to build an engine.

Your expenses will include: A torque wrench. A dial indicator with magnetic stand. A degree wheel. An engine stand. A few micrometers. These will add up to about the interest on your credit card if you used it to purchase a pre-built engine! Plus you get to stick the lump in and drive it right away.

Me? I would build it myself again. ;)

Pete
Pete

Steve-
No, you're not nuts. There's no mystery about what makes the BMC B Series engine tick. We're not talking about a Ferrari racing engine. It's the perfect Beginner Mechanic engine.

First, the most important thing is to do a lot of careful research so you won't end up wasting money on components that work at cross-purposes, such as combining a Piper 255 camshaft with 2" Big Bore exhaust, for example. Next, you have to know your limitations. Machinework and sculpting ports is something for a professional to do. Third, use this BBS to ask questions. We've got enough people here whose combined experienced is enough to answer almost any question if you'll just ask.

Prebuilt engines come in two forms:
1) Production-built to a budget using quanitiy purchase discounts on their components to maximize profitiblity. Some of these are reasonably decent engines built by reputable people. On the other hand, some of them have so many used, worn old parts scavanged from a variety of old engines that have passed through the shop that you get a 30 day warranty. Unless you know just exactly what the builder has replaced with new parts, don't be shocked when a valve spring breaks and the engine sucks a valve after eight months.
2) Custom-built to the customer's specifications. No quantity discounts on components, more expensive, but exactly what you want. Because of the lack of discounting, it would be cheaper for you to source the components yourself because you don't have to pay the builder to do the paperwork.
Steve S.

Check out the www.aptfast.com website. (No
personal financial interest, just an occasional
satisfied customer.) They try to sell
consistent quality bearings, pistons. A bit
expensive, but if you want a more powerful
than stock engine maybe the way to go.
They also sell custom cylinder heads, again not
cheap, but this is where you can get a lot of power.

Also check out www.mgbmga.com for more rebuilding
possibilities.

I notice you're in California, hope you're not planning
to do this with a 74 or later car, as passing
smog will be a real problem with a fast road
camshaft. (Passing will be impossible if you
change carbs, manifold, and ditch the cat
converter due to the visual inspection.)
However, check out the thread "stealth smog motor"
in the archives, and Barry Kindig's mods for some
more ideas. Good luck, and please let us know
how things turn out.
Ronald

It's a '65 so no worries about the smog issues. Thanks for the link, I'll check it out right away!
Steve Simmons

Steve,
I recently had a clutch failure, and may be doing a similar engine rebuild to my 69. I would love if you would keep me posted on your progress, and where you end up buying your parts etc... I'm in Nor Cal, so if you have any ideas for good machine shops up here, lemme know.
Bill
Bill Mertz

Steve,
If you are worried about shipping to UK, try ARP they are in your backyard. They supplied my rods and crank for my race MG. Sean Brown just north of you, preformed his magic on an 18L head for the car. I just got my second win in three starts this season over a very determined Rabbit driver. We had qualified within 0.2s of a second at Portland International Raceway. With the chicane it is about 2 miles.

Question for the engine builders here; with the high flow pumps or even stock pumps, what do you do with the oil cooler fitting at the rear of the block? This fitting necks the flow down to .360" and since oil is not compressable, this limits our oil flow. The normal work around is to boost the oil pressure to force more oil through and then we go to bronze pump gears because the increased load takes out the steel gear and the cam. Comments?
Leland Bradley

Leland-
Yes, the bronze gear is the way to go when you're running higher loads on the pump. Since the idea behind an oil cooler is obvious, run braided oil lines and a larger-capacity cooler to tend to the needs of you race engine.
Steve S.

Leland I always figured they choked it there to either drop pressure through the cooler so it wouldn't split the seams or to limit flow rate to provide 'dwell time' through the cooler in order to have an adequate delta T. Lacking good flow rate/volume/temperature data, I figured it was a non-issue. I did put on an oil thermostat, I don't see the sense in running without one. Do you use a pressurized reservoir?
Art Dodge

Art,
The oil cooler is going to see full system pressure any way as the pressure gauge is after the cooler. My concern is we are elevating pressure between the pump and that restriction and putting a higher than necessary load on the oil pump. I am not using an Accu-Sump (removed) or a oil thermostat but I am considering a thermostat as oil temp in the pan does not get above 170 in a 30 minute race. I am running 5-50 Castrol Syntec.
Leland Bradley

Steve,

Les has laid out the basic components of a fairly quick, eminently streetable B engine; .060 over, Burgess head, decent cam. The B engine is very simple. You have the right book; read and re-read the sections on engine assembly, especially in regards to balancing pistons, rods, etc. There is nothing there that can't be done by an average guy with good mechanical skills.

Even with shipping costs, Peter B's heads are reasonable. I've compared prices of a few people here in the States with his. To quote the man himself, "A copy of a Picasso is a nice picture, but not quite the same as the original, is it?". Which reminds me, I need to get a head in the mail to him.
Hooks

Leyland

Why did you remove the Accusump?

Nigel
Nigel Steward

Nigel,
I was going through engines faster than I could assemble them. The Accusump is a good idea for a number of problems ie oil pump drive failure. But if the oil pressure is marginal and drops as the rpm drop than the Accusump supplies oil to the engine. Very good that but as the rpm comes back up and the engine needs more oil flow then part of the oil flow goes to the Accusump to recharge it. Is this a real problem or was I grasping at straws? Removing the Accusump didn't change anything, I was still averaging 5 miles to the engine.

Over the winter, I built up a fresh block. The oil pump gasket has a 1/2" hole for the oil discharge so I drilled out all the oil passages from the pump to the oil outlet at the rear of the block to 1/2". This removes the threads for the cap, above the pressure relief, so that is replaced with 1/4" pipe plug as are all the gallery plugs. The stock oil outlet has been replaced with 1/2" pipe to -10 AN fitting with a 2" piece of 1/2" tubing bridging the oil gallery. I have -10 Airquip hose to a remote oil filter to the oil cooler and then to a early style oil filter adaptor. I also drilled out the oil feed to the center main as it supplies oil to two rod bearings. I know the normal answer is a cross-drilled crank so number 2 and 3 rods get oil from mains 2 and 4. But I didn't want to buy a cross-drilled crank. I may reinstall the Accusump but the car is still over weight for the class. Last race car and driver weighted 2220 and class allows 1950.
Leland Bradley

This thread was discussed between 02/06/2002 and 05/06/2002

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