This engine was an ebay special - £40 with little or no info. The seller left it out in the rain with no plugs(!) but on removing the head all is well. Very well in fact. Except...
I kept finding loosened bolts everywhere so when the engine performed well but sounded noisy under load I dropped the sump to convince myself he hadn't loosened the rod bolts. He hadn't but I was intrigued by the fact the crank looks like it's been attacked with an angle grinder!!!
At least it's symmetrical
The shells were stamped 010 U/S which would make me think 10 thou oversize.
What do people think?
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PS - it's a sight better than the 948 that came out (that had 4:1 compression - see how lonely the piston looks in the pic!)<br><br>
Nothing special there - yes 010 means 10 thou oversize shells - to suit 10 thou undersize crank. The bores look quite worn in that huge picture! Why does the title say 4:1 compression ??
Well - if you mean 4 Bar compression test reading = 60 psi - that's desperately low. I'm surprised the engine would even start ! Good reading would be 160 psi ( ~ 10 or 11 Bar). As I said above - the bores look very worn.
The bore WAS desperately worn - the picture's just there for entertainment value. I couldn't believe how worn it was.
Needless to say it was very noisy and lacked power! I daren't thrash it and never went over 40mph. This car clocked <100 miles for several years so I didn't worry!
As for the large pic, it was taken on a different camera (to the 1st). Maybe it didn't like the exif or something.
Any thoughts on the crank though? I wonder if it's a bodge job or whether somebody fitted a balanced and ground replacement. I've only stripped 3 A series engines before but not seen post-casting machining, though I know it's done. Not the pattern Vizard recommends if I recall though
I can't imagine any crank balancer doing that- the stress risers caused by an operation like that don't bear thinking about!
I've seen my local man going at it with the angle grinder, but on the periphery, and using a flapwheel after to smooth the edges.
Maybe someone had angle ground off a rounded bigend bolt, going into the crank rather than th big end cap?? Can't think of any other reason for it!
The balancing slots look factory-machined using a convex milling cutter. The parts of the crankshaft they have milled into are counterweights. They won't be subject to much stress compared to the big ends.
Alex Holden - http://www.alexholden.net/
If it doesn't work, you're not hitting it with a big enough hammer.
Why "Not a chance"?
The area that has been machined is consistent with crank balancing even if the method looks rather crude.
Has anyone else seen a crank that looks the same?
I've seen a few and I'd have been horrified to see one like that.
Isn't the bit that has been removed from the edge of the lobe at the bottom of the picture the factory balancing?
That I've seen before.
MarkyB wrote:Why "Not a chance"?
The area that has been machined is consistent with crank balancing even if the method looks rather crude.
Has anyone else seen a crank that looks the same?
I've seen a few and I'd have been horrified to see one like that.
Isn't the bit that has been removed from the edge of the lobe at the bottom of the picture the factory balancing?
That I've seen before.
I agree with you Mark that the lobe work looks to be factory balancing, the other machining looks a rather unusual especially as its done at a diagonal angle, you often see factory balancing of the flywheel where a hole or holes are drilled in the rim to improve balance.
Cheers
Kevin
Lovejoy 1968 Smoke Grey Traveller (gone to a new home after13 years)
The 'lobe' mark is just a tidying up mark on the bare casting. If anyone was going to balance the crank - they would have taken greater care than that (these rough cut marks may cause stress raisers! ) - and would also have 'bladed' the crank at the same time. I've had balanced cranks before - they don't look like that!
bmcecosse wrote:The 'lobe' mark is just a tidying up mark on the bare casting. If anyone was going to balance the crank - they would have taken greater care than that (these rough cut marks may cause stress raisers! ) - and would also have 'bladed' the crank at the same time. I've had balanced cranks before - they don't look like that!
I hardly think maching that amount of a lobe is to clean up casting deffects it would have been very poor to have that amount machined out.
I hate to disagree but 'bladed` as you call it (I know it as having the crank wedged) is not part of initial balancing and normally only done if lightning of the crank is being done as well.
Cheers
Kevin
Lovejoy 1968 Smoke Grey Traveller (gone to a new home after13 years)
Blading and wedging not the same thing! But I think normally one wouldn't bother balancing the crank unless either blading and/or wedging is being done. If the whole crank assembly is being balanced - the largest whirling forces are by far in the flywheel - and that's normally where most of the 'balancing' is done.
