"Sometimes you don't know what you don't know" or "A schoolboys error!"

[Malcolm Venn]

During the process of restoring my MkIV Spitfire, I happened to notice on eBay a reconditioned engine being sold by a professional engine rebuilding shop in the Newark area (since gone bust!). Thinking that all 1296 Triumph engines were the same (there's the schoolboy error or at least one of them!), I hopped along and bought it. Many years down the line when I had become more aware of the nuances of Triumph engines, I noticed that the engine I had bought was in fact from a Toledo 1300 (engine prefix DG - over-bored to 60 thou I think). By that point, I had fitted an re-skimmed unleaded cylinder head, Accuspark electronic ignition in a reconditioned Delco distributor (very good) and was in the process of trying to tune the carbs which I had fully rebuilt. That proved tricky so, I engaged the services of a professional (George Reid in the Lancashire area - highly recommended) and eventually after fitting richer needles (AAH) my Spit performs reasonably well cruising comfortably on the motorway in the 70mph region at 3500rpm. Oh, by the way, I bought a reconditioned diff from Mike Papworth (also highly recommended) who said it was a version better suited for cruising than acceleration (sorry - can't remember the ratio at this moment) and I have a J type Overdrive fitted.

So, what is the problem? Well, apart from my general ignorance as demonstrated above, I would like to know if there is anything I can do to pep up the performance a little bit especially at the low end. I keep thinking the Toledo camshaft might be significantly different to that for a MkIV. Is that so and would it make a difference? Could it be slid out and a better one slid in without removing and dismantling the engine? (the oil pressure and compression are good). I believe there may be issues to do with camshaft bearings that may need to be considered. Or, should I just look out for an FH engine and start again?

Once the laughing has stopped (this is my first post by the way!), your charitable thoughts would be most appreciated.

[Colin Lindsay]

20 minutes ago, Malcolm Venn said:

Once the laughing has stopped (this is my first post by the way!), your charitable thoughts would be most appreciated.

I don't think many of us have the right to laugh; sympathise certainly, but not laugh. We've all done more or less the same in our time....

I know the Toledo camshaft was detuned to meet planned emission controls, so a good start would be the equivalent Spitfire version. Spitfire Mk3, or is that too early for that block?

[Pete Lewis]

yes but to fit/replace the camshaft its head off ( or find some way to lift the followers, dizzy drive out 

and because of length   remove the radiator then retime the camshaft with the 4 possible bolt  hole incremental design 

ie there 4 holes and two sides gives 1/4 tooth increments of adjustment 

the base block crank is pretty much common across the  model range 

the cyl heads vary with valve diameters and CR   depending on age /model year 

Pete

[DanMi]

You would also have to look and find out what is actually in the engine, has it been rebuilt to Toledo spec or has the cam, cylinder head etc been replaced. Most parts can be interchanged between the basic blocks so after 50 years and probably a few rebuilds things may well not match the engine no.

[KevinR]

Be wary of  Spitfire MKIII camshafts - also fitted to pre FH25000 MKIV spitfire engines, as they need the block to have camshaft bearings fitted.

From Spitfire MKIV engine number FH25000 onwards, a detuned camshaft was fitted - probably similar to the Toledo spec one - and it didn't need to have camshaft bearings in the block.

It IS possible to buy a Spitfire MKIII profile camshafts which have the bigger journals so you don't have to fit bearings in the block.

[Mathew]

59 minutes ago, Pete Lewis said:

yes but to fit/replace the camshaft its head off ( or find some way to lift the followers, dizzy drive out 

and because of length   remove the radiator then retime the camshaft with the 4 possible bolt  hole incremental design 

ie there 4 holes and two sides gives 1/4 tooth increments of adjustment 

the base block crank is pretty much common across the  model range 

the cyl heads vary with valve diameters and CR   depending on age /model year 

Pete

I have managed to pull out the cam follers with the head on, saves the head coming off but by the time the radiator and other items are off to gain access? But if after having the performance increased the head off and some port to gasket matching with some smoothing of ridges would help.

[Malcolm Venn]

Thanks guys, great response in only a couple of hours - guess no one is watching the snooker! I think I'm going to keep my eyes out for a standard MkIV camshaft preferably reconditioned and go from there. I guess I could invest (is that the right word?) in a Kent camshaft (road car version) as they seem to have a good reputation. However, with my 'mongrel' of an engine, I think trying something less exotic to start with might be the sensible option. Good to know the camshaft might slide out if I can remove the followers which would save a lot of work.

[thescrapman]

As Kevin said, just get a Mk3 profile cam if it doesn't already have one.

also do a quick check on compression ratio, should be able to do that fro measuring the head thickness.

[Iain T]

Malcolm,

Welcome to the forum, if you follow it you'll see we tend to perhaps sometimes deviate from the subject but all in the best possible taste!

Try Newman camshafts, ask for Ken Newman as he is a font of knowledge. He made me a hybrid for my Vitesse which works extremely well.

Iain

[Anglefire]

2 hours ago, Malcolm Venn said:

Thanks guys, great response in only a couple of hours - guess no one is watching the snooker! I think I'm going to keep my eyes out for a standard MkIV camshaft preferably reconditioned and go from there. I guess I could invest (is that the right word?) in a Kent camshaft (road car version) as they seem to have a good reputation. However, with my 'mongrel' of an engine, I think trying something less exotic to start with might be the sensible option. Good to know the camshaft might slide out if I can remove the followers which would save a lot of work.

I bought a Newmans cam - PH1 - for mine and works very nicely. TRIUMPH-CAMSHAFT-MANUFACTURING-PRICELIST-2021.pdf (newman-cams.com)