1275cc upgrade to 1971 Minor van

[Spikesdriver]

I have recently bought a 1275cc Marina A+ block with a MG Metro "big valve" head and a SU Hif 6 carb. I have the Minor front and rear plates and the appropriate flywheel.
Assuming these to be compatable, I am about to bolt them together but have some questions.

1. Will the standard distributor from a 1098 work with the Marina block?
2. The Metro head does not have a bypass pipe outlet beneath the thermostat housing. I bought a "Sandwich" plate that goes under the thermostat that has an outlet but it is much bigger than the pipe outlet on the top of the water pump. Any ideas how I can neatly connect the two? (Out of interest, which way does the water flow through the bypass hose and what is its purpose? I say this in case it can be discarded.)
3. What spark plugs would be best?
4. The Marina block has a single timing chain with a tensioner, would there be any advantage in fitting a duplex chain?
5. Any suggestions as to the carb needle and spring required for this setup?
6. Tappet settings?

many thanks
Tom

[philthehill]

To answer your questions in the order that you asked them.

1. The 1098cc 'A' series distributer will not fit the 'A' Plus block as the way the distributer is secured is different.
2. It is not necessary to have the bypass hose. The sandwich plate (not necessary) allows coolant to flow via the heater valve on warm up to alleviate localised heating in the head. To overcome any deficiency of the coolant to circulate on warm up - keep the Minor heater valve open.
3. N9Y or similar is ok.
4. The duplex can be fitted to the Marina 'A' Plus instead of the simplex and the tensioner can be used or discarded. I use the duplex with tensioner on my 'A' Plus engine. Do not forget to countersink (82 degree countersink required) front plate for countersunk screws if duplex fitted.
You will need to drill a couple of extra holes in the Minor front plate to accommodate the simplex tensioner. Picture of modified Minor front engine plate with the extra holes attached
5. I would start with the standard needle and move on from there if needed.
6. Set rocker clearance to 15 thou for both inlet and exhaust.
Phil[frame][/frame]

[bmcecosse]

Has the backplate been modified to take the larger 1275 flywheel hub? The dizzy is probably not suitable - the Marina dizzy has a one hole fixing with a Y clamp. Don't worry about the bypass hose - either keep the heater valve open all the time (which you should anyway to circulate water to the back of the head) - or drill a couple of holes in the thermostat rim. The usual N9Y plugs will be fine. Starter needle is BDL for the big valve head/big carb. Use 15 thou valve gaps. And unless changing the cam - just stick with the single chain for now.
Edit - Sorry Phil - much as you have said - I went off for my dinner after typing and before posting..........

[Spikesdriver]

All good advice, many thanks.
The Minor backplate and a flywheel was already fitted when I bought the engine, the seller said they are OK to attach to my standard gearbox.
Tom

[bmcecosse]

Does the fly have 6 bolts - or 4 holding it to the crank?

[Spikesdriver]

Thanks for your help, the flywheel has 6 bolts.
My block doesn't have the one hole plus Y clamp dizzy connection. It looks the same as my 1098 Minor so I think the Minor 25D or 45D dizzy will fit.
Tom

[bmcecosse]

Well i'm surprised - give it a try.

[philthehill]

Does your 'A' Plus block have the additional ribbing as per the attached photo.[frame][/frame]

[bmcecosse]

I missed the point about the water pump - you need a 1275 pump without bypass connection - or block the one on your pump. Forget the sandwich plate. Let's see some pictures of your 'A+' block - and in particular the dizzy mount. Is the dizzy driveshaft still in the block ok?

[Spikesdriver]

Gents
thanks for your help, I am beginning to think that I was mis-sold the block as an A+ when it is actually an A.
See attached shots. What are the differences?
Thanks
Tom[frame][/frame]

[Spikesdriver]

another view of my block.
Tom[frame][/frame]

[philthehill]

Unfortunately you have been sold a pre 'A' Plus 1275cc engine in other words a 1275cc Marina engine.
Still good for normal use but for ultimate power the 'A' Plus has the stronger block.
If you so desire - you can replace the internals with the 1275cc MG Midget crankshaft / rods & pistons.
Phil

[Spikesdriver]

Thanks Phil,
I have asked the seller to call me. I don't know yet if I have been stitched up. The seller even misidentified the carb as an Hif 44 instead of an Hif 6. I am now wondering if the "MG Metro" big valve head with it is really that after all.
Cheers
Tom

[bmcecosse]

Only way to check is by lifting the head. Don't worry about the carb - as long as the float bowl is vertical the HS6 will be fine.

[IslipMinor]

The HIF6 and HIF44 are essentially the same carburettor - 6 x 1/8" = 1.75" and 44mm ~ 1.75".

The SU overhaul kit from Burlen is common to both.

The most common 12G 940 'Big Valve' head has 1.4" (35.56mm) inlet valves and 1 5/32" (29.37mm) exhaust valves - this is the standard for the MG Metro.

There was a version used by the early 'S' Minis that had a larger exhaust valve 1 7/32" (30.96mm), but had a history of cracking between the inlet and exhaust seats, so was changed in the later 'S' to the smaller 1 5/32" exhaust valve.

[philthehill]

Tom
Can you please post a picture of the front top area of the head around the thermostat housing.
Phil

[Spikesdriver]

Here is a picture of the MG Metro big valve head.
I cant see how to add more than a single picture with each message so another shot will be posted separately.
Tom

[Spikesdriver]

The website is not letting me post images. Will try later.
Tom

[amgrave]

Reduce your picture sizes to 640 x 480, they should load up OK then.

[Spikesdriver]

Much smaller scans attached.
Tom
Tom[frame][/frame][frame][/frame][frame][/frame]