11 replies to this topic

[mvahora]

Hi all, 

 

Hope everyone is doing well.

 

So I have a '77 morris mini stock standard 998cc which used to be my daily drive to school. I got my hands on a 1340 engine (well supposedly 1340) courtesy of my uncles friend who had it in a mini sitting in a barn unused, only really started on the odd weekend for a joy ride out on the country back roads. He wanted it gone so I helped myself to the motor and g/box setup. The rusty old thing was pretty quick and so I thought i would swap it over with my 998. I started the swap and got pretty close to completion, but then just havent had time to finish it off and get back onto the road. 

 

So I am planning to complete this thing finally and would like some help along the way please. 

Firstly, I would like to know what i exactly got my hands on in terms of the motor & g/box setup.

From what I can see and old paperwork/receipts the specs are below:

 

- Higher rocker cover (yellow colored rockers when viewed from the top) not sure of lift, standard 1.3 or the higher 1.5 style

- Twin SUs with K&N filters HS2 1&1/4 (engine also came with a weber 45 dcoe & 6" manifold, not sure of comparison to Twin SU setup which was being used)

- Piper 285/2 cam

- Modified head to Stage 1 by Lynn Rogers (I googled this guy and he is a famous retired race engine builder here in New Zealand) 

- 2 extra studs on the head (rocker cover has been notched out in both places)

- Gearbox fully rebuilt incl late type layshaft, laygear & mainshaft, 4 gear cross pin diff

- double valve springs

- inner valve spring seats

- S/S race valves inlet 1.401 & ex

- double row timing gear kit

- comp rod bolts & nuts

- 1275 pistons +040

- main bearings -020

- conrod bearings -020

- camshaft bearings

- cam lifters

- Comp rockershaft

 

The receipt shows heaps of other little bolts and nuts, misc items and describes what looks like a full engine rebuild, totaling upto $6k 20 years ago.

 

The summary states
"to remove mtr/box, strp & hot tank clean, recond S/block, incl machining centre main cap for strongback, setup piper 285/2 cam, time in cam, drill & tap block & head for extra S type studs, resurface flywheel & backing plate balance, crank rods pistons + clutch assembly, rebuild gearbox incl late type layshaft, laygear & mainshaft, fit 4 gear crosspin diff. Supply & fit stage 1 modified head, reassemble mtr/box, refit & road test."   
 

Can someone explain the above mods for me; what exactly has been done to the engine and where does it sit in terms of modification, expected performance, bhp & torque?

 

Would you guys recommend any other things I do to the motor before I get it onto the road?

 

 

 

[nicklouse]

You have a well prepared engine.

 

some would say a very good engine based on a S block. Check for tippet chest covers. As the comment about drill into and taping for the extra studs contradicts this.

[Cooperman]

If that engine has push-rod chest covers on the back then you rally have 'lucked out' as it is a genuine 'S' block. The 11-stud head is evidence that this may be the case. Wow, a genuine 'S' engine is very valuable.

The spec looks great for a road engine. at +0.040" overbore it is actually 1310 cc capacity. You still have one firther bore to go, to +0.060" which gives 1330 cc. 

With those improvements I would guess around 90 bhp once all is set up correctly. The HS2 carbs might struggle a bit and a pair of HS4's would be better.

My advice would be to strip it down and re-assemble it carefully to ensure that all is well before starting it up. That way you can re-lubricate the bearings with assembly lube, prime the oil pump and know that the torque settings are correct. You can also measure the compression ratio whilst the head is off. Back when that engine was built people tended to run very high comp ratios and although there is no problem with that, it is nice to know what you actually are working with.

There is no mention of the distributor. With that specification you will need a different advance curve with probably a bit more available mechanical advance. The old 'S' engine ran without a vacuum advance/retard and the mechanical curve needs to be matched to the engine in respect of comp ratio and cam characteristics.

Good luck with this and remember we are all here to offer help & advice at any time.

[mvahora]

You have a well prepared engine.

 

some would say a very good engine based on a S block. Check for tippet chest covers. As the comment about drill into and taping for the extra studs contradicts this.

 

If that engine has push-rod chest covers on the back then you rally have 'lucked out' as it is a genuine 'S' block. The 11-stud head is evidence that this may be the case. Wow, a genuine 'S' engine is very valuable.

The spec looks great for a road engine. at +0.040" overbore it is actually 1310 cc capacity. You still have one firther bore to go, to +0.060" which gives 1330 cc. 

With those improvements I would guess around 90 bhp once all is set up correctly. The HS2 carbs might struggle a bit and a pair of HS4's would be better.

My advice would be to strip it down and re-assemble it carefully to ensure that all is well before starting it up. That way you can re-lubricate the bearings with assembly lube, prime the oil pump and know that the torque settings are correct. You can also measure the compression ratio whilst the head is off. Back when that engine was built people tended to run very high comp ratios and although there is no problem with that, it is nice to know what you actually are working with.

There is no mention of the distributor. With that specification you will need a different advance curve with probably a bit more available mechanical advance. The old 'S' engine ran without a vacuum advance/retard and the mechanical curve needs to be matched to the engine in respect of comp ratio and cam characteristics.

Good luck with this and remember we are all here to offer help & advice at any time.

 

Thanks guys for your response.

 

Have checked and no unfortunately no rear chest covers. Im assuming yes the extra studs have been added in and so is not an S block. Not sure then what the recond S/block refers to 

 

Im pretty sure they are HS2s (watched mini manias identifying SU carbs vid) how can I confirm they are definitely HS2s or if they HS4s? There is no marking tags that I can see.  

How would the weber go compared to the HS2/HS4 on this motor? Since ive got the weber on hand would it be easier to go with this? When we did pop the motor in a few years back i had advice to use the weber so with the engine out, we cutout and welded in a weber box to suit. Still being new to the mini scene and mechanics in general though, I didnt really no anything about it. Reading mini forums now tends to reveal a heated discussion SU vs Weber with no definitive answer, so not to sure of which carb best suits.

 

Re the distributor, it is the old type 25D with vac takeoff going to the SU carb body. GT40 Bosch coil.

I was planning on using the old mobelec electronic ignition setup from the 998 and replacing the points? I assume this is not recommended 

How do I go about matching the mechanical curve to the engine in respect of compression ratio and cam characteristics? I dont really want to disassemble & strip. Can I measure the CR without disassembling or would we be able to take an educated guess based on the specs?

 

I will also be using my old exhaust manifold and exhaust setup by the way. It is an LCB with welded connection into the original single box exhaust. Is this going to be another issue?

 

Excuse the beginner Qs 

[KTS]

as well as the motor, you want to be making sure brakes and suspension are also up the job.  what brakes do you currently have ? 

 

if the donor mini the engine came out of is still available might be worth seeing what was fitted as it may also be worth swapping over to yours

[nicklouse]

Carbs. You will see very little difference in performance between either except that most people use more fuel when using the Weber as they tend to be harder on the accelerator.

 

personally for a road build I would use a single HIF44. out of your selection I would need to know what you exactly have. 

 

for su info

http://burlen.co.uk/...hop-manual.html

and the Weber should say on it.
 

[mvahora]

as well as the motor, you want to be making sure brakes and suspension are also up the job.  what brakes do you currently have ? 

 

if the donor mini the engine came out of is still available might be worth seeing what was fitted as it may also be worth swapping over to yours

 

Sorry forgot to mention, we did pull the disc setup from the donor & install so I assume it should be okay? They are 7.5".

Rear I am using my existing drums which have the built in 1" spacer. I have 13x7 Mini lites so upgraded from the standard drums a while ago. Will these be sufficient?

 

Suspension is standard.

[KTS]

yep - 7.5" discs should be adequate  

 

typically the 7.5" disc setup is used where people want to run on 10" rims, but as you're using 13x7's you could, if you wanted, switch to the 8.4" disc setup

[mvahora]

Carbs. You will see very little difference in performance between either except that most people use more fuel when using the Weber as they tend to be harder on the accelerator.

 

personally for a road build I would use a single HIF44. out of your selection I would need to know what you exactly have. 

 

for su info

http://burlen.co.uk/...hop-manual.html

and the Weber should say on it.
 

 

The weber is a 45 dcoe on a 6" long manifold.

SUs are Twin HS2 on BSK2 12G2464 manifold.

Edited by mvahora, 20 April 2020 - 12:17 AM.

[nicklouse]

 

Carbs. You will see very little difference in performance between either except that most people use more fuel when using the Weber as they tend to be harder on the accelerator.

 

personally for a road build I would use a single HIF44. out of your selection I would need to know what you exactly have. 

 

for su info

http://burlen.co.uk/...hop-manual.html

and the Weber should say on it.
 

 

The weber is a 45 dcoe on a 6" long manifold.

SUs are Twin HS2 on BSK2 12G2464 manifold.

 

If that is the options then the 45 on that manifold. The HS2s will be too small.

[mvahora]

 

 

Carbs. You will see very little difference in performance between either except that most people use more fuel when using the Weber as they tend to be harder on the accelerator.

 

personally for a road build I would use a single HIF44. out of your selection I would need to know what you exactly have. 

 

for su info

http://burlen.co.uk/...hop-manual.html

and the Weber should say on it.
 

 

The weber is a 45 dcoe on a 6" long manifold.

SUs are Twin HS2 on BSK2 12G2464 manifold.

 

If that is the options then the 45 on that manifold. The HS2s will be too small.

 

 

How hard are the webers to setup? I am reading online various different views with the SUs vs the weber. Most view the weber as a race only carb, say its too noisy (I dont think id mind the roar to be honest), too thirsty, and poor at lower/mid rev range compromising driveability. Also comments on a complicated path to get the webers setup right, but then the same goes for the twin SU setups ive heard! 

 

I havent experienced a Weber in real so I cant comment on drivability or sound, but thought these twin SUs went and sounded pretty nice on the short exp I had with them.

 

A mate of mine has got a set of twin HS4s off a triumph, but I assume however that they will need a rebuild, new jets etc, costly and/or a tricky job DIY?

Would you think this would be better suited to my engine? 

 

This is a road car, but not used on a daily basis, but more so for weekend use, or for short run arounds, so would prefer lower/mid end over top end.  

[nicklouse]

Ideally I would fit a single HIF44 carb on a good cast manifold.

 

I would not bother with twins or a Weber but like I said if your options were as you stated then as I said.