Advice Please. I have 2 triumph engines 1 is a 2l and the other 25l question is can i put the 2l head on the 25l blockwould i ha

I have 2 Triumph engines 1 is a 2l and the other 2.5l question is can I put the 2l head on the 2.5l block!
Would I have to change anything internally ie push rods!
Thanks

this may be a stupid question, but why would you want to do that! To keep the engine as a 2.5l won't you need to use the 2.5l head! Surely they would have kept the blocks the same and just changed the head to get the extra capacity!

Well the main reason I ask is I want to keep the twin stromberg's not the SU's, And as they have a purge line from the rocker cover that I don't want or can I just change the the intake manifold and use a closed circuit breather!

No. Engine capacity is swept volume. Nothing to do with the head.

The heads could be identical. You could compare bore, stroke, conrod length and compression ratio to determine if that's the case. I expect the cylinder pitch is the same.

Measure the valve sizes, some otherwise similar heads run smaller valves on the lower capacity engines. Offer a head gasket up to it and compare it side by side with your old head.

Surely use the stromberg manifold and the appropriate rocker cover.Should be no need to change the head itself.

as far as i know they are theoretically identical BUT the 2 liter head may be thinner or thicker than the 2.5 and i know the push rods are different as per engine model number, I know that the 2500tc and PI and S Engines have forged push rods, and would assume they are longer, its better to get a complete engine and not mess around with guess work imo , otherwise everything else on the head is all backward compatible " http://www.rimmerbros.co.uk/Item--i-GRID008643 " , link to Rimmerbros were shows differant parts

According to hte info below they are the same bore but different stroke & it also looks like the heads are the same as there is no mention of a 2000 head as opposed to a 2500 head.

Type: 6 cylinder in line, OHV
Capacity:
2000: 1998 cm³
2500: 2498 cm³
Stroke:
2000: 76.0 mm
2500: 95.0 mm
Bore: 74.7 mm
Firing order: 1,5,3,6,2,4
Compression ratio:
2000 Mk1: 8.5:1 or 9.1:1
2000 Mk2 (69-73): 9.25:1
2000/2000TC Mk2 (73-77): 8.8:1
2·5PI Mk1/Mk2: 9.5:1
2500TC/S: 8.5:1
Power:
2000 Mk1: 90bhp(net) @5000rpm
2000 Mk2: 84bhp(DIN) @5000rpm
2000TC Mk2 (75-77): 91bhp(DIN) @4750rpm
2·5PI Mk1: 132bhp(net) @5500rpm
2500TC Mk2 (74-75): 99bhp(DIN) @4700rpm
2500TC/S Mk2 (75-77): 106bhp(DIN) @4700rpm
2·5PI Mk2: 124bhp(DIN) @5500rpm
Maximum torque:
2000 Mk1: 117lb.ft @2900rpm
2·5PI Mk1/Mk2: 153lb.ft @2000rpm
2000 Mk2: 100lb.ft @2900rpm
2000TC Mk2: 110lb.ft @3300rpm
2500TC Mk2 (74-75): 133lb.ft @3000rpm
2500TC/S Mk2 (75-77): 139lb.ft @3000rpm
Oil pressure: 40 to 60 psi @2000rpm
Oil capacity: 5.1 litres
Coolant capacity: 7.7 litres

Valve train
Inlet: Clearance: 0.254 mm (cold)
Material: En53
Head dia (MkI): 33.10 mm
Throat dia (MkI): 30.18 mm
Stem dia: 7.90 mm
Outlet: Clearance: 0.254 mm (cold)
Material: 21-4-NS
Head dia (MkI): 29.92 mm
Throat dia (MkI): 27.00 mm
Stem dia: 7.87 mm
Seats: Angle: 45 deg
Material: Cast iron BS 1452/14
Rocker: Ratio (MkI): 1.50:1
Spring: Material (MkI): En 49 D
Crash speed: 6600rpm
Rate/inner: 28.5 lb/in
Rate/outer: 150 lb/in
Free length/inner: 1.56???
Free length/outer: 1.61???
Inst. length/inner: 1.140???
Inst. length/outer: 1.386???
Coil dia./inner: 0.654
Coil dia./outer: 0.923???
Wire gauge/inner: 0.076???
Wire gauge/outer: 0.128???
Act. coils/inner: 6.0
Act. coils/outer: 3.25
Camshaft: Lift at valve (MkI): 0.312
Opens/inlet (MkI): 18 deg BTDC
Closes/inlet (MkI): 58 deg ABDC
Opens/exhaust (MkI): 58 deg BBDC
Closes/exhaust (MkI): 18 deg ATDC
Max tappet acceleration at flank: 210 m/s² @1000rpm (engine)
Max neg. tappet acceleration at nose: 73 m/s² @1000rpm (engine)
Guide: Material: Cast iron BS 1452/14
Length: 2.72???
Outside dia., inlet: 0.502???
Inside dia., inlet: 0.313???
Clearance, inlet: 0.0023/0.0008???
Outside dia., exhaust: 0.501???
Inside dia., exhaust: 0.312???
Inside dia., inlet: 0.313???
Clearance, exhaust: 0.0030/0.0015???

Fuelling
Carburettor type (2 off):
2000 Mk1 (-MB 60718): Stromberg 150 CD ??

Nuf said!

yeah swapping a head just to keep your preference of carb is going over the top just switch the inlet manifold.Arent SU carbs generally regarded as being better than strombergs!

exhaust valves on the 2000 and the 2500 are differantthe 2000 is 1.19 inch the 2500 is 2.25 inch, but then again, it also depends on the engine model and year of the engine

Cheers guys I'll look into it further when its that time!
Heads are different thicknesses.
Noticed the SU inlet manifold where the water flows through has all corroded.
Engine for the 2.5l is MM3256HE not much of a high revving engine like my 2l.
Does the compression ratio play a part in that! I pretty sure the 2.5l has 8.5:1 and the 2l 9.1:1