The engine is stripped down – so what do we actually have?
Welcome back for more ‘The View From the Garage‘ – Much like waiting forever for a bus and suddenly two come along in short order!
So what do we actually have? The engine number on the block is ‘FH51818HE’. A quick Google tells us that the ‘FH’ confirms the lump is from a Mk4. The ‘HE’ suffix confirms that it’s a high compression unit as opposed to the low compression variant ‘LE’ or the emissions controlled USA spec unit with the suffix ‘UE’. The ‘E’ part was tagged onto the end to indicate ‘Engine’ and stop any confusion with commission numbers which also started ‘FH’.
Some more detective work told us that every ‘FH’ engine after 25,000 (1972) had a less sporty 18°-58°-18°-58° camshaft fitted to reduce emissions and improve fuel economy. The Mk3 and early Mk4’s had the more ‘tuned’ 25°-65°-25°-65° variant which is why the stock Mk3 is preferred among those in the know.
This, combined with heavier end bearings (to allow Triumph to use parts from the Toledo) and a new, lower final drive ratio of 3.89 (to lower fuel consumption) left the Mk4 drivetrain down on power from the 75bhp of the Mk3 unit to a reported 63bhp….
Being a later iteration of the engine, it does benefit from larger valves but I’ll have to think about how to add a few extra bhp to it.
One thing that always annoyed me about the car when it was running was the wrong rev counter in the dash – It had the later electrical Smiths model instead of the much prettier cable driven Jaeger unit. That should be an easy distributer swap (fingers crossed) as the unit that was in the car doesn’t have a cable drive on the shaft.
Another plus is that the later engines sported a graduated timing plate – every cloud….
It looks like the drivetrain all hails from circa mid to late 1973 which I’ll need to bear in mind when ordering parts. I want it to visually remain as a Mk3 as I much prefer the look of the roundtails and the Mk3 in particular, but even the bodywork has a touch of the ‘bitsa’ about it. I’ll investigate it fully when we get to that part but I’ve long been convinced that the bonnet is from a Mk2 and was modified by the previous owner.
As mentioned last time, we’ve started with the block and it does seem to be in decent order! The initial plan to have it acid dipped to remove the old paint and surface rust might be changed as some elbow grease and a little time invested so far seems to be reaping rewards. We might just save the money for the head!
The Crankshaft & Camshaft await a good clean and inspection before we decide if they need any work before refitting – They may need eyes and expertise beyond my level too.
If we have any trained or experienced eyes that spot anything of interest in the picture of the crankshaft & camshaft above, or if you have any comments or observations at all, feel free to leave a comment below the post – It would be great to have your feedback !
We’ll ensure the water jacket is free from any debris and check the measurements of the bores before re-honing them and giving the block a protective coat of fresh paint and then starting the rebuilding process. We’ll refurbish as many parts as we can along the way and enjoy the learning experience!
Till next time – Stay Safe!
Tony (and Adam!)