i have been given a short engine. There is no knowledge of its origins other than it is a 1.6 mk1. is there any way of telling if it’s a 90hp without dismantling?
engine number maybe?
ta
If it is a short engine there is no head or fuel injection on that does not help.
I know of no way from the engine number to tell if it is a 90 bhp car.
If you research the piston top shape that may help but you will have to do that yourself.
It may well be a eunos engine and that is more powerfull but again how do you tell.
The cutoff between 4-slot/8-slot is B6-127441. I think the numbers applied were used on all B6s, eg used in Familias etc. So expect the 90hps to have highish numbers. The ones used for 90hp MX5s seem to be in the B6-900000 range. There were about 300,000 115/105 hp MX5s built, so the maths is straightforward.
I think the 8 slot/4 slot divide denotes short or long nose crank, not power. It might just go in the scrap.
thanks
Yes, but that indicates the engine numbers used around 1990, when the switch occurred. What is the engine number? There is a reasonable relationship between age of engine and engine number.
If it still had a cam cover, its easy to tell the difference; low power engines had the plain steel cam cover bolts.
That’s interesting, I see where you are going with this. I will check it for a number. Thanks. If the low power engines had plain steel cam cover bolts what did the high power ones have. I have 3 mk1 s that all have chrome bolts. Is this what are referring to.?
What do you mean by a short engine? Just a block, crank & pistons? I don think that the block and crank changed at all for the B6 engine.
Hi Robbie, yes I just have the block, crank and Pistons. I,m told that the 90 hip have different Pistons to the 115. It is possible to buy 90hp Pistons and 115 Pistons so it seems this is correct. I was interested to see which mine is as it came with no history, and I just wondered if there was a quick and simple was of telling.
Sorry, yes, you’re right, it was the cylinder head that stayed the same. You can tell the difference between the pistons by the location of the small dot that has been cast into the crown. If you post a good photo of the top of a piston I’ll tell you which type it is.
Brilliant. will do.
ok. This is a picture of 2 and 3 cylinders with the bottom of the picture being the front of the engine. I see dots facing the front. Does this have significance? Thanks Robbie.
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This import has had a 90hp engine fitted at some point
Earlier cars had domed chromed bolts.
Thats useful rule of thumb knowledge. I,m not sure I’ve ever seen those type of bolts. Obviously I would imagine they are an easy swap for somebody wishing to bling up the engine bay which could confuse matters, but thanks for your Input.
That’s an early engine, the later ones have the dots on the flat part of the piston crown rather than on the dished bit.
Excellent info. Thanks