MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB GT V8 Factory Originals Technical - 317 cubic inches

I was reading through the archives today and came across the threads about putting the chevy 305 pistons and liners in the 215 block to create 317 cubic inches (with a buick 300 crank.) Did anyone ever do this? The problem seemed to be in the liners shifting in the old buick blocks, but what about in the new rover 4.0L blocks that have press fit liners in them? Could we now safely stroke out these motors to approx 5.275 Liters?

Justin
Justin

If you want a motor that big, why not just put in a 302 Ford and be done with it? That's what I'd do. I mean, just being realistic, the 302 is so much more developed it's insane. That being said, I have a Rover V8 and have finally got everything in order, but whenever they send me a Summit Racing catalog that has ready-to-go 302 crate motors I just wonder why the heck that's not a better solution. I mean Larry did it and he didn't even have to bulge the hood. I realize you give up 50-70 pounds but I don't think that'd make all that much of a difference ... plus you can just put an alloy bonnet on there and that alone'll save about a quarter of the added weight.

The next car, if I stick with MGBV8s, is going to have either a 302 Ford or an LT1 Chevy if it'll fit.
Ted

Ted this isn't necessarily about what one "should" do, it's about what one "can" do. I just thought it'd be a little more wood for the fire when talking about these bigger v8 conversions. The question was never successfully answered the first time it came around, so I thought another stab might be interesting. The 348 c.i. motor from the V8 newsletter seemed awfully damn cool too.

Justin
Justin

Justin
Check with Dan at D+D, he has some good info on it.

Bill
bill jacobson

Justin,I don't think you could get enough airflow through the heads(even Buick 300) to suport the added cubic inches.Ted Lanocha in Maryland builds very high perf Rover engines for TR8s,and he ends up using extremely ported Buick 340 heads(cast iron)painted silver.Besides,the costs will be very high,price out the machine work to bore out the old sleeves and install new,and anytime custom is mentioned in a machine shop,time and money spent gets out of hand quickly.
Dave

JUSTIN ,there's now a 6 litre rover block with 4 bolt mains, & 1.9 inlet &1.6 exhaust valve heads starting with around 400bhp stock available in U.K,performance costs money;by keeping to Rover block you doing like the factory building a sportscar, if you put a junker 302 in you building a hot rod, up to you ,STEVE
Stephen Foldhazy

Lets not be so condescending! If you saw Steve Carricks car with the 302 you would think it was factory. It is C L E A N!!!! Originality went out the window the first second we thought about putting a different motor in the car. Ford, rover, chevy, whatever, it's all the same in my eyes when it comes to UNoriginality. ;)

That's half the fun though isn't it?
Justin

p.s. I'm not saying I want 317 cubic inches, I just thought the topic was interesting when it was around. Sources whom I trust impeccably recommend the 4.2L rover v8 as the best bang for the buck....
Justin

the 4.2L is very expensinve, a buick or 3.5 rover would be best $$ wise. Last I heard even the 3.9L motors were $2k and that is without the computer, harness and some accy's..

Larry Embrey

Stephen Foldhazy wrote:

"by keeping to Rover block you doing like the factory building a sportscar, if you put a junker 302 in you building a hot rod...:

Say what? I'm believe this comment requires a bit of explantation. Otherwise, I'm afraid it's just a bit of nonsense.
D Masters

I must agree with Dan M,
A 302 is not a "junker" by any means. Seing as the factory ONLY produced 2600(roughly) GT V8's nothing we do to our roadsters is anything factory. Hot Rods are not junk either, I am a bit confused on what you are trying to say? Why is my 302 powered, 2400lbs MGB a hotrod and not a sportscar? Is it becuase I can crank off a 13sec 1/4mile and a rover car can't without a blower or NOS, while I can still corner with all the other MGB's?

I have seen rover conversions that are hack jobs and do not look half as nice as Steve C's 302 conversion, so does that mean they are better simply because of the choice of motor?

I would be a tad leary of driving a 6L Rover block based off the old buick alum. Your talking Racing equipment to get that much displacement out of that block, wild crank, rods and pistons etc. Those motors are designed to go a couple hundred miles at best before a complete tear down and rebuild prior to the next race. Plus the power curve would be somewhat less than streetable. Don't get me wrong I love power like the next guy, but if it is not everyday drivable to/from work why bother.. our little MG's are meant to be driven daily, not once a month..

I'll get off my box now..

Larry
Larry Embrey

A point often or most times usually overlooked in these discussions is simply MG used the Rover V8 because it was all they had!

Engineering purity had nothing to do with it.

It was a simple case of "use any PRODUCTION engine you want" and that was it.
No doubt politics played a part in making sure the Triumph V8 Stag angine was used only in the Stag st the Rover 3.5 was Hobson's choice (ie a choice of one and one only)

By the way Issoginnis faced the same restraints when the Mini was planned and he ended up using the A series unit because that was all the management of Morris / Austin would let him have.

The car business is exactly that; a business.
Sorry but one of the sad facts of the world we love in.

Larry's comments about the factory NOT making roadster V8's and what ever owners do is not factory anyway is totally accurate.

Cheers, Pete.
Peter Thomas


http://www.espritv8.net/id331.htm

Greg

This thread was discussed between 22/09/2002 and 29/09/2002

MG MGB GT V8 Factory Originals Technical index

This thread is from the archives. Join the live MG MGB GT V8 Factory Originals Technical BBS now