Now the engine had been replaced and the invoice says it's a DF engine, but it clearly wasn't wholly a DF, hence my signature.
I had learnt that the key differences between DF and DG were the inlet manifold, cylinder heads (smaller ports and valves) and a different camshaft. I had noticed that the peak torque value for the two engines was very similar, so the power difference would be noticeable only at higher revs.
With some ongoing help and advice from Itchyfeet I have discovered that my DF engine does in fact have DG heads. The first port of call was to look at the casting numbers, as referred to in this thread http://forum.club8090.co.uk/viewtopic.php?f=37&t=147483
Here's what mine looked like, after a little cleaning with a brass brush
The casting number has been ground away (why
), but there's no casting suffix visible, which according to the thread above suggests they are early DG heads, but this was only an assumption.Next task was therefore to take off the inlet manifold and have a look at the ports. Nice easy job, remove the air cleaner and 4 bolts.
This is what I saw, looks as though there are two gaskets
Not knowing the size of the ports on either head I took a measurement pressing paper against the port and the inlet manifold to be able to measure with a rule. They measured approx 28mm x 40mm. They looked a bit on the small side, so I was starting to think DF heads, and then Itchyfeet sent me a picture from another thread at http://forum.club8090.co.uk/viewtopic.php?f=37&t=148521, 4th post.
This clinched it. A DF engine has almost square ports, the DG are rectangular. I have DG heads. The only question remaining I think is do I have a DF camshaft..... and I'll need to measure the valve lift and have the original specs too to check against to get that answer, without stripping her down, which I don't need to do.
I decided to make this post initially to share what I found out, in reality it's just pulling together knowledge already in the forum, but maybe someone will find it useful.
Thanks again to itchyfeet for his help, I would be interested if anyone has any idea of where in the range of 60-78hp my engine will likely be.
