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Aug 18, 2011 12:09:11 GMT
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I'm too cheap to get my new engine rebuilt before I put it in the car so just want to do some rudimentary checks on it before spending too much time on it and before putting it into the car.
The thing I wanted help with was working out if the pistons and bores were ok or not.
It had very good even compression before I took the head off. It was running perfectly before it was taken out of the donor.
Looking at the tops of this pistons there are some clean areas which concern me slightly. The clean bits are around the inlet and exhaust valves but particularly the inlet. I think this is fairly normal but I suppose I should check if the pistons have changed shape at all.
What about the bores. How do I know if they are ok?
In an ideal world I would get the crank refurbished with new shells and I would get the bores honed and new pistons fitted. In this same ideal world I would also have loads of money to waste on project cars. Shame it's not an ideal world. I already have a set of new pistons but they are first oversize so no real hope of installing those myself. Might save them for later.
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Aug 18, 2011 14:06:59 GMT
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If it ran perfectly in the donor and I wasn't planning a big rebuild I wouldn't even have taken the head of tbh. Put it back on!
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To get a standard A40 this low, you'd have to dig a hole to put it in |
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Aug 18, 2011 14:56:23 GMT
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Going for an uprated head. I also accidently snapped an exhaust stud on the previous head and then accidently drilled through the water-jacket on the head when I was trying to drill the stud out. Can you imagine what that day was like! Fortunately I have about 5 of these engines.
The engine as it is nearly went into the car a couple of years ago. But when I caused all the problems with cylinder head I decided not to use it and left it sitting in the garage for a bit.
I've cleaned the piston tops and they say 1995 on them. I'm guessing that is a date. The car was a 1989 so assuming time travel wasn't involved the engine is actually a rebuild or replacement anyway. I've taken off the bearing caps on mains and rods to check for spun or damaged bearings and all look great. The car had about 170k on the clock so I would have expected to have seen a lot of the copper showing through at that milage. Only one bearing out of all of them was showing only the faintest orange hint.
I'm pretty confident this engine is sound enough to use for a little while until I can afford a mega rebuild. I'll put it all back together with new gaskets and seals, clean and paint it.
Fingers crossed!
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Aug 18, 2011 23:32:48 GMT
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Good chance the numbers are just part numbers tbh. On standard pistons, the numbers rarely mean anything. If you've got plenty of them - slap this in, get it roadworthy. Build up a second engine with go-faster bits  |
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You're like a crazy backyard genius! |
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The numbers aren't on other pistons. That's why I think they are dated. Possibly something to do with a warranty claim. I'm also familiar with their part number system and they never look like dates.
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Oh... and I think this will be engine number 4 to go in during my ownership. I'm getting pretty close feeling as though I should spend some money and get a proper rebuild done.
The first engine was alright but the previous owner said he'd scraped the bearings because he didn't care if the engine lasted well or not. He wanted the crank to be looser so the engine would spin faster. The next two engines both burnt oil. The second one burnt oil straight away. The 3rd engine has lasted a long time but has started to burn oil as well now. I overcooked it once which warped the cylinderhead. I fixed that by only changing the head and gasket and left the block as it was. Possibly permanently damaged after that but it seemed to be mostly working so wasn't too bothered.
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Last Edit: Aug 19, 2011 8:01:56 GMT by ejenner
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Aug 19, 2011 10:02:49 GMT
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TBH, on an old cast-iron block, it's usually only the head that suffers damage anyway.
But this made me laugh:
Sometimes, I seriously have to wonder at how people survive on a day-to-day basis, without stabbing themselves in the face, from being just pure idiots.....
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You're like a crazy backyard genius!
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Aug 19, 2011 10:31:58 GMT
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Aug 19, 2011 11:11:38 GMT
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TBH, on an old cast-iron block, it's usually only the head that suffers damage anyway. You can still damage the relationship between the bores and the rings. Particularly if you have been running the engine with the wrong compression on the cylinder with the poor seal for an extended period as I have. The head warped in Germany and I continued to drive home to the UK after that. I had 1/2 compression on one of the cylinders so even though the head had warped it was difficult to tell that there was any major problem. I was driving it normally round the streets for a while after getting back from the European tour as well. Was only at one point when I noticed the idle including a little 'putt' from the exhaust once every cycle that I decided to carry out a compression test. |
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Aug 19, 2011 12:50:58 GMT
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tbh, scraping existing standard bearings, seriously isn't worth the efft. Yes in theory it makes the journals last a bit longer I suppose, but not if you end up making them smaller than the journals in the process.... Might as well be running without bearings at all if that happens
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You're like a crazy backyard genius!
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