A suitable crank... 1300/1200

[Richard_M]

Hi all

First thread here - hoping for informed Triumph tuning opinion... be gentle!!

I'm wondering whether cranks from Herald 1200 engines could be re-used in short stroke 1300s.

I realise one essential difference - the 1200 has an oil scroll on the rear for oil retention whereas the mk3 1300 uses a seal. But, can the 1200 crank be used in a 1300 block with scroll and seal working together?

Your thoughts please. I'm hoping this works as low-use, low-stress STD 1200 cranks are much easier to come by than similar 1300 mk3 Spit.

[Nick Jones]

Later 1200 cranks are exactly the same as small crank 1300 (FD, & GE).  The earlier ones have the rear seal scroll issue.  Don't know when the change point was.

Nick

[Richard_M]

Thanks Nick.

That's a shame, 2 of the 3 1200s I'm breaking have the scroll so far - and the 3rd has a similar GA engine number. Ah well!

What do you think of the possibility of running a scrolled crank in a seal block - crazy?

R

[heraldcoupe]

As long as you match the crank to the appropriate alloy seal block, there should be no problem. Every engine which yields a good crank should yield the sealing block to go with it, so there should be no shortage of them.

If you want to mix and match the scroll crank with the later lip-seal block, I fear you're on a hiding to nothing.

Cheers,
Bill.

[Nick Jones]

As Bill says..... though I'd go to some trouble to avoid the scroll seal.....

Surprised you have found so many scroll sealed ones - my early '65 Herald (surely a 64 build) had a lip seal and that was definitely the original engine.

Nick

[heraldcoupe]

I've had plenty of Heralds with scroll seals, and never found them prone to leakage, provided I never parked pointing up a steep hill....

Cheers,
Bill.

[drofgum]

Richard M,
You might want to check a product called Speedi Sleeve from SKF. They are meant to be used to save a shaft that has a groove worn into the seal surface, but they may work to convert from a scroll seal to a lip seal.
                                                                               Cheers,
                                                                               Paul

[Steve Cureton]

Nick_Jones wrote:

As Bill says..... though I'd go to some trouble to avoid the scroll seal.....

Surprised you have found so many scroll sealed ones - my early '65 Herald (surely a 64 build) had a lip seal and that was definitely the original engine.

Nick

My '65 1200 left the factoty 28th October 1964 and still has the original engine with a scroll seal.

[Richard_M]

Thanks for all your wisdom.

My motivation for Spit mk3 crank collection is as spares backup for race engines - I'm entering a car in the CSCC Swinging 60s series next year - so I suspect the interim 'it'll work' measures are not going to work.

Ah well (again), at least one of my 1200 purchases yielded an alloy bellhousing (GA 1200 from a Courier I believe...).

Cheers

Richard

[Casper]

Quote:

Don't know when the change point was.

According to my notes GA206771E in Jan 1966.

Quote:

my early '65 Herald (surely a 64 build) had a lip seal and that was definitely the original engine.

engine, perhaps, but it may have been changed.

Quote:

My '65 1200 left the factoty 28th October 1964 and still has the original engine with a scroll seal.

Just before the 'Hot Cam' engine at GA178101E in Nov 1964
C.

[Richard_M]

Bugger. My other 1200, yet to be stripped, is GA199310.

Still at least it has the 'hot' cam! Wonder what 'hot' means in 1200 terms.... :)

Richard

[Deleted User]

1819 wrote:

Thanks for all your wisdom.

My motivation for Spit mk3 crank collection is as spares backup for race engines -
Richard

I seem to recall reading somewhere the MkIII cranks were made of better steel than the other cranks.

[Nick Jones]

380 wrote:

I seem to recall reading somewhere the MkIII cranks were made of better steel than the other cranks.

I think that is a myth.  I broke my mk 3 one (snapped through web between no 1 BE and front main) and replaced it with a 1200 one.

Nick

[Richard_M]

Maybe the seeds of a new, exclusive, club here - I broke my mk3 crank in exactly the same place.

Still ran ok - bit noisy - and the end float was a little 'out of spec'....

[Casper]

Quote:

Still at least it has the 'hot' cam! Wonder what 'hot' means in 1200 terms....

GA1200HE (Type A)           8:1 CR, 12-52-52-12 lift 0.281”
39 bhp               

GA1200HE (Type B)          8:1 CR, 18-58-58-18 lift 0.312”
??               

Hot Cam GA1200HE (Type C)  8.5:1 CR, 18-58-58-18 lift 0.336"
48 bhp                    GA178101E (Nov 1964) on

GD12/50HE (Type D)          As Hot Cam, but prefixed GD, fitted
48/51 bhp                             to GA cars from Comm. No. GA235,000 (late 1968 ).
                                       and to 12/50s (51 bhp with 12/50 exh. manifold)

No-one seems to know what the type B engine put out, but 48 bhp is a 23% improvement over the early 1200s.
The 'Hot Cam' was used right through the 13/60 and into some of the small saloons.
C.

[Deleted User]

Nick_Jones wrote:

I think that is a myth.  I broke my mk 3 one (snapped through web between no 1 BE and front main) and replaced it with a 1200 one.

Nick

I believe the better grade of steel used allowed the crank to be hardened to good effect.

[heraldcoupe]

The interim engine's been quoted at 43bhp.

Treat the engine number change points quoted in the workshop manual with some scepticism. I can't recall the exact details, but there are some anomalies in the changges recorded,

Cheers,
Bill.

[heraldcoupe]

380 wrote:

I seem to recall reading somewhere the MkIII cranks were made of better steel than the other cranks.

Do you mean the type of crank fitted to Mk3s being different to the other visibly identical types?
Or do you mean that shape of crank, common to 1200s in the Herald and Spitfire, all being made of a supposedly better steel?

Cheers,
Bill.

[mikeyb]

my mk3 crank in the rally car snapped between rear main and end 4 :-(

[Nick Jones]

1819 wrote:

Maybe the seeds of a new, exclusive, club here - I broke my mk3 crank in exactly the same place.

Still ran ok - bit noisy - and the end float was a little 'out of spec'....

That sounds familiar, mine also ran but sounded like a big-end had well and truly gone. Wasn't until I'd dropped the sump and all the big end caps and found them perfect that the penny dropped.

I have also seen a couple snapped at the other end as Mikey describes but I didn't break those.....

I had mine looked at by a metallurgist working for a foundry that produced cranks (big truck ones) as well as the parts they were making for my company, and he reckoned it was a fatigue failure due to an incorrectly ground fillet radius, so I'm sure my regularly revving it off the end of the tacho had nothing to do with it  :P

Nick

[Deleted User]

Nick_Jones wrote:

and he reckoned it was a fatigue failure due to an incorrectly ground fillet radius , so I'm sure my regularly revving it off the end of the tacho had nothing to do with it  :P

Nick

Very probably, machining was often very hit and miss and some of the horrors that passed for 'quality' engineering at BL & Co would make one weep if you were a concientious QC engineer. I have a 2.5pi crank in the garage, very nice one too, but if you look at the front main bearing, you can see where the machining has uncovered an inclusion in the casting and left a pit in the ground face, it should have been scrapped, but I suppose the fact it lasted without protest all those miles and years says something.