Saloon 6 cylinder engine differences

[WhiteV]

Hi -- This has come up over a pint or two?
1. What if any is the difference between mk1 2.5pi and mk2 2.5pi engines?
2. Vitesse and GT6 changed to mk2 engine in 1968, but saloon mk 1 bodyshell
   didnt change to 1970 - so did 68 to 70 mk1 saloons run with mk1 engine or mk 2  
   2000 engine?
3. Later Mk3 Gt6 changed to dome pistons, so did Mk 2 saloon change then as well
   from flatop pistons?
4. What made the difference with 99 bhp 2500tc and 106 bhp 2500s - was it the head
    and manifold etc -- but I understand they were the same 106  bhp on later cars?

Sorry if this has done the rounds already-- but it might help as several people I know
swap for better items? instead of rebuilding the original engine? If anybody has engine numbers as well it might help.  It all seems so simple to follow, but from my own experience for instance 2 litre Vitesse ran small bearing mk1, large bearing mk1 and then mk2 engine (easier to identify I admit if the head is still attached) but they all have HC as a prefix. Even the late Vitesse 1600 looks like a 2 litre at a glance especially if fitted with strombergs.

Happy new year to you all --- regards WhiteV

[thescrapman]

Off the top of ,y head quickly

1. Crank definately

2. Mk1 2000's stopped in '69 when the Mk2 2000 started. Vitesse and GT6 engines changed from Mk1 to Mk2 engines in '68 as well.

3. yes.

I'll let others fill in gaps.

Cheers

Colin

[CRAJ]

1. On the MK1 the crank is cross drilled, and there are no ribs on the nearside of the block, it also has stanpart stamped on it. Cam is MK2 GT6 and vitesse item.

4. HS6 (1 3/4'') instead of HS4 (1 1/2'') carbs and different inlet manifold I believe.

Colin.

[Glenn]

4.  The cam was also different.  The 99bhp 2500 had the same cam as the 125bhp PI, so I think bolting on HS6 carbs will give a more powerful engine than the mild cam'd 2500S.  Especially if you skim the head by 75 thou to increase compression ratio - could be talking about 120bhp.   8)

So the '74 TC cam could be a decent second best alternative to the early PI cam.  But I've heard that it's rather prone to wear.   :'(

[WhiteV]

Hi --Many thanks for the replies.  Question 3 is the one which we are not clear on. Did late
Mk 1 2000 saloons 68-69? run Mk 1 engines or Mk 2 engines ala Vitesse GT6 which changed in 68. I suppose we have to look under the bonnet of a G or later plate 2000 Mk I. -- regards

[Richard B]

MkI's had MkI engines.

Well the H Reg MkI Estate I owned for a week did anyway.   :'(

[thescrapman]

All Mk1's have Mk1 Engines (exposed pushrod tubes) except PI's.

All Mk2's have Mk2 Engines (enclosed pushrod area)

The changeover day seems to be at Model revision time.

There are 3 types of Mk1 2000 engine.

Vanguard type, bored out 1600 vitesse type (sam;ll bearing), big bearing mk1 vitesse 2L type.

Cheers

Colin

[Alex]

So Colin how do I know what I have fitted?

Cheers,
Alex

[Richard B]

Has it got a crankcase breather by the oil filter bowl? If so early Type 1 or 2.

[andy thompson]

Mk1 2000 saloon engines also had the long backed crankshaft like the Mk1 PI although I'm not sure when they change to the bigger Mk1 PI/ Mk2 crank bolts ie 3/8" to 7/16". I know the early 2000 engines with the 2" mains only had 3/8" flywheel bolts.

Ie Mk1 2000's effectively have the Mk1 Pi / TR5 light flywheel

What crank did Mk1 and Mk2/3 GT6's use? short or longback? I know the flywheel is different

[DJB_Harvey]

Mk1 GT6/Vitesse engines used shortback cranks ...so to use them in a MK1 saloon you need to use a spacer between crank and saloon flywheel...ala autos...

[Richard B]

According to the Rimmers GT6 & Vitesse crank and bearings changed @

GT6 Mk1 (early, to engine no KC/KD5000E)
Vitesse Mkl (2 Litre) engines from HC4501E

Both have flywheel Part No. 148042 for the later cars not sure what was fitted tot the earlier cars.

So one of the first 5000 MkI GT6 with with an OE engine is a little revver!  :)

[thescrapman]

Richard_B wrote:

According to the Rimmers GT6 & Vitesse crank and bearings changed @

GT6 Mk1 (early, to engine no KC/KD5000E)
Vitesse Mkl (2 Litre) engines from HC4501E

Both have flywheel Part No. 148042 for the later cars not sure what was fitted tot the earlier cars.

So one of the first 5000 MkI GT6 with with an OE engine is a little revver!  :)

Or one of the first 4500 Mk1 Vitesse's.

To answer Alex's question partially.

The Vanguard engines do not have the castings on the sides of teh blocks for the Vitesse engine mounts. I foiund one in a "C" plate 2000.

There must be an engine number where the Mk1 2000's went from small to big bearing, and it must be comparable to the Vitesse / GT6 change point.

And yes, the small crank 2L engines do seem livlier.

Cheers

Colin