Engine and Transmission Tech

At last I have a photo of the modular engine resting in the B's engine bay. The steering rack is not fitted but is resting on its mounts about 11/2 inches forward.


This photo shows the front view, it is not as bad as it looks, I have held the camera below wing level.


This photo shows the clearance at the rear of the engine.


Until I make some log style headers I do not know if there is sufficient clearance to lower the engine anymore. I think it will fit under an MGC bonnet with a couple of domes to clear the camshaft drives at the rear it will require a bigger bulge to clear the plenum and Throttle body. At the moment without any modifications it fits in and sits level with the crankshaft 11/4 inches lower than the standard 1800 engine. The MKVIII engine is 4 inches lower due to the intakes being lower than the heads and would be easier to install. The engine mounts will be on the front crossmember.



Edited 1 time(s). Last edit at 07/16/2013 04:39PM by waterbucket.

Thats awesome! Should be a monster!

The headers will not be a trivial task and I'll be interested in seeing how you handle that. On the Roadmaster we at first considered separate holes for each header tube through the fenderwell but there really isn't enough room around the shock absorbers for that approach, at least not if you want to be able to top up the shock oil. In the end we used the TA-Performance SE heads which have shorter exhaust ports and that let us stay inside the engine compartment. I don't think you have that sort of an option though.

Jim

Jim
I would be interested in some advice regarding the size of the tubing for the headers, The cross sectional area of the ports are 1065 sq mm and at the moment I have the choice of 1018 or 1280 sq mm. There are significant saving in space for the smaller tube but with tight bends will it restrict flow too much on the other hand will the larger tube slow down the gas flow too much to the detriment of torque. Any thoughts that you have would be appreciated.
Having looked at every posting for the Roadmaster I somehow missed the ones relating to its exhaust headers, any idea where they were?
Philip

OK for the benefit of the Americans, we're talking about a roughly 1.450" port, a 1.417" diameter tube and a 1.589" tube. Engine displacement is I presume, 4.6 liters or 281 cid.

On header design I like to go back for reference to the work done by Ed Henneman ("Headers by Ed"). It is true that his work does not apply all that well to unequal length systems but it does give me a good starting point for optimal tube sizes which can then be adjusted as desired. Since you stated that you intend to build a log type header we are clearly dealing with an untuned system, which means that we are dealing with mass flow only and cannot count on pulse timing or other factors to aid the design and in this regard the exhaust is basically identical to a cast iron manifold. So, making the assumption that ports are added as the log goes from front to back a typical approach would be to increase the tubing size as each port is added. Using that approach and the port in the head as an optimal size we would start with a 1065 sq mm tube (1.450") and progress to 2130 (2.047"), 3195 (2.511) and finally 4260 sq mm (2.900").

The progression tells us that the ports on this engine are rather large for a 281 cu. in. engine. which is in keeping with the modern trend. If we go back to the muscle car era we see that a high performance 300-350 cu in engine outputting over 300 hp uses a 2-1/4" header pipe on the stock dual exhaust system, Today we might consider this small, but for our purposes with these cars it makes a useful guideline for minimum sizes and a 2-1/4" exit from the log header for this engine should be quite adequate in terms of displacement, rpm, and power output. At the same time, the exhaust pulse is roughly 1/4 of the engine cycle so 3/4 of that cycle is not generating flow. This means that the normal flow additions do not hold absolutely and the step sizes can be reduced.

So considering all of that, what I would do is decide what I intend to use as an exhaust tube size and then using the 1065 sq mm tube size for the short independent port runners, step up the log as each runner joins in, in steps best calculated to result in the correct final size. And if the best sizes for those steps are not readily available in metric, use inch sizes.

The small step down at the port (a .016" step) and the short runner will have no effect on flow and the larger tube will not improve it.

HTH,
Jim

There is quite a gap between the back of the engine and the heater area. I would have thought you could move that engine back a bit further with some modification to the foot well boxes.

Moving it back would also eliminate having to move the rack forward and screrwing up the geometry.

That is one HUGE engine!

Probably good advice David. The steering rack should not be moved forward if it can be avoided as that is quite certain to create bump steer if moved very far at all.

As to the posts in the RM thread about the exhaust, there isn't that much. It was done by Dave VanWyck in his shop so most of the design work was over the phone. You could look from about page 34 forward.

I've looked at the tubular log headers on the 1UZ that DanB has here at my shop and it uses two tubing sizes in a similar manner to the log headers Dave designed for the RM, port size at the front port then stepped up at the second port and remaining at that size the rest of the way back. The first and second tubes look about like what I suggested above although I have not measured them.

Jim

I may have mislead you regarding the steering rack, I did not intend to mount it 30mm (11/4 inches) forward it was just to pre empt questions regarding its position. If the mounts are lowered by about an inch it will slide back underneath the sump and the uj will hook up as designed. The downside of moving the engine backwards is the gearlever position moving back past the centre of the hole also unless it is moved back about 8 inches there is no gain for the headers. Another reason to keep the engine in its current position is that the throttle body is the highest part of the engine and in the UK it will impair the drivers visability, If I can make the exhaust work and make this transplant viable I would like to fabricate a new plenum cover with the throttle body at the rear minimising the width of any hump. The gap at the rear of the engine would then be required for the air filter etc.
The car you see in the photos is an old bodyshell that will never go on the road again but is usefull for the preliminary work

Yes it is a huge engine and if possible I will weigh it, but all the (semi) accurate info suggests that the alloy block engine with a T5 gearbox and alloy radiator will weigh the same as the standard 1800 engine and OD gearbox.
Philip
,



Edited 1 time(s). Last edit at 07/18/2013 04:30PM by waterbucket.

All that surgery and you're worried about moving the hole for the shifter?? I also think you will find the engine/trans will squash the stock MGB front springs flat - aluminum block or not.

I'm with Mr. Stabe on that you be. Modifying the tunnel for that is easy
compared to the other tasks you face. I have my rv8 back/down as far
as it'll go without modifying the body behind it. I'd say always mount the engine
as far back as you can. Getting the mass behind your front center line
will do wonders for handling.

Keep us updated on weight / cross weights for the car. Maybe this
will pave the way for some 5.0 coyote swaps!

I have now weighed the engine and the weight is 440lbs the photo shows 200kg this is for a complete engine minus the starter, flywheel and exhaust manifolds. This is very close to the 445lbs that I have seen in most articles.


I did not really make it clear why I was going try and install the engine in the position shown in the previous photos, it certainly was not to get the gear lever in the centre of the transmission tunnel opening. To get this installation to work a piece of the cylinder head has to be cut away, this is shown in this photo.


This is for the steering shaft to pass through between the cylinder head and the bellhousing, fortunately it serves no use full purpose other than to mount ancillaries or brackets. If the engine is moved backwards by two inches a number of problems arise, the first is that the steering universal joint will be trying to rotate in this gap. Secondly the rear of the engine will will have to rise with the steering shaft, if the engine goes back two inches it will rise about 11/4 inches. Thirdly the piece of bulkhead marked in black will have to be removed. This includes part of the pedal box. Lowering the steering column at the bulkhead is not an option because it has to go through the gap between the head and bellhousing.


Although many others have removed the whole heater platform to fit Chevrolet engines the width of the modular engine means that a good chunk of the cone for the steering universal joint has to be removed as well. Due to the small gap for the shaft to pass through I think it is impossible to get it to work.
The bulkhead on the other side is no problem. The following photo shows what would need to be removed.


The more I look at this I realise that Dan Masters is correct, it is impossible to fit, how ever that makes it a more interesting challenge that I will try to overcome. In my opinion moving the engine backwards is not an option due to clearance issues with the the steering uj. I still believe it can be made to fit in this one position only, but if it fits the only body mods are clearance bending for the exhaust manifold and for clearance of the bellhousing. I accept it is heavier than a 302 but what a joy to look at this massive piece of work. I can claw some of the weight back, a lightweight flywheel gains 12 lbs an aluminium radiator 10 lbs and a light weight starter 5lbs. I think that the all up weight engine, gearbox and radiator will be 560lbs against about 530 for the MGB 1800 engine,od gearbox and standard radiator.

If you are thinking of trying this with a LHD car there is another problem to overcome, The cylinder head on the right hand side has a similar piece of casting that would need to be removed. Unfortunately it appears to be part of the oil gallery. I will post a photo next time I update on my progress, probably when I have made some prototype headers.
Philip



Edited 2 time(s). Last edit at 07/24/2013 04:10PM by waterbucket.

Thinking from another direction, numerous cars have steering arms mounted a "top" of the spindles. This, up and over aproach, sometimes helps. Good Luck, roverman.

Phillip and company,

I made a trip to Moss the other day for parts. Was speaking with
a gentleman at the front counter who mentioned Mike Alexander
is in the process of fitting the coyote 5.0 V8 in his MGB. Perhaps
he may have something to add to the conversation.

Cheers

"The steering rack should not be moved forward if it can be avoided as that is quite certain to create bump steer if moved very far at all. "

Actually Jim, moving the rack forward or aft will have little effect on bump steer. What it will change Ackerman. If height is changed even a little it will change bump steer.

Basically True. If centering is correct to start with, which it never is over the entire range of motion. Otherwise it can have some effect at any point where the centering is off a bit, but the effect of the ackerman change will be greater. In any case it should be avoided if possible. Changes in height can be compensated to a large degree by changes to the steering arms.

Jim



Edited 1 time(s). Last edit at 07/26/2013 04:49PM by BlownMGB-V8.

Anybody ever measure bump steer on a stock MGB? It has a ton as it comes from the factory.
and moving the rack down makes it a lot worse.

I am doing work on a Pantera (the perpetual project). I spent a lot of time getting rid of the bump steer. The problem is it comes with a rack where the length between the tie rod pivot point is too wide. I moved to a MGOC power steering rack used for the MG conversion (Which was shorter then the Pantera rack and even different from an MG rack.

I spent a lot of time working the geometry to get the Pantera right:
[www.rc-tech.net]

In the end I ended up with zero bump steer.

You don't need Suspension prog to figure out bump steer. You can work it by how it moves the wheel in or out as it goes up or down. You can tell if it is too high, low, wide or narrow by the curve.