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Post by only1wilber on Mar 1, 2016 22:05:43 GMT
So following on from my MOT thread and the bottom end going not three miles after passing its MOT I now need to decide what Im going to do with regards to engine replacement/repair/
Quick vid on how the engine now sounds:
Last year the exhaust cam welded itself to the head of the engine currently in the car. I thought the problem was a blocked oil way that lubricated the cam as on further inspection it was rammed solid with bits of the metal filings.
I purchased a replacement engine as I couldn't find a head on its own. I did think about just dropping the new engine in but as I didn't know the history of the engine and it looked like it was starting to suffer from the keyway on the crank been worn I went for the easy option of just replacing the head. Obviously that was the wrong decision as not 5 miles driven since and the engine seized and now I have the knock in the vid.
So the option I have now is I have access to the bottom end of the engine I took the head from last year sat on me garage floor. I would like to use this for ease really, I wouldn't mind taking it to bits a replacing the seals/piston rings etc and maybe the oil pump as this would be relatively cheap option and I get a refreshed bottom end. I'm just worried about the keyway. I know there is the locktight option but with the car been supercharged I don't know how long that would last. I do have a mig welder, I could put a blob of weld on the end and shape it, has anyone done that before or even weld the woodruff key in place?
Pic of the keyway:
I also have an auto eunos sat in me mother in laws garage, has about 115000 miles on. I Have been doing a bit of reading the past couple of nights on the auto engine and I have read quite a few posts of people using the auto engine to good results in a FI application because of the lower compression of the engine been 9.0:1 opposed to the 9.4:1 in normal manuals.
The auto engine has a less aggressive profile cam that produce about 100bhp but more torque low down than that the 115bhp manual.
If I go down this route and use the bottom end from the auto, I would like to use the head off of the engine with the knocking bottom end (head/cams from 115bhp eunos) as I have just replaced all the valve stem seals and lapped the valves in and gave it a good clean.
What I couldn't find out is is the head different from a Automatic Eunos compared to the Manual version. If I put the head from the manual on the bottom end of the auto is it still a lower compression?
Another option is to just buy another 1.6 engine I suppose but I would really like to use what I have access to as I don't have an abundance of coin.
Going to put a lightweight flywheel on too whilst I have access.
Any opinions welcome.
Lee |
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Post by Horney on Mar 1, 2016 23:04:43 GMT
I believe Auto Vs Manual the block and pistons are the same. The difference is all in the head and cams.
What a bummer on the engine failure. It's a tough choice where to go next really. I think I might well be in your boat by the end of the year as well.
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Post by only1wilber on Mar 2, 2016 8:28:10 GMT
Its quite hard to find definitive info on the auto block. I have read that the piston rings on the auto are 3mm in width compared to the 4mm of the manual, wouldnt that mean that the pistons are different? Ok, just read on here that the auto uses lower comp pistons: www.solomiata.com/Mx5Engine.htmlSo the head could possibly be the same between the auto and manual and its just lower comp pistons and less duration of the cams that make it 9.0:1. If I do go the auto route im killing that car too, decisions decisions. How do you find the lightened flywheel on your car Horney? read conflicting info on inertia and all that jaz about how that can help a turbo application but the heavy flywheel benefits the supercharger? |
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Post by skuzzle on Mar 2, 2016 9:38:38 GMT
Correct the auto has a 3mm oil control ring so they are different but I'm not sure about compression. If anything it could only have been higher, but that seems unlikely
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Post by Horney on Mar 2, 2016 9:47:59 GMT
How do you find the lightened flywheel on your car Horney? read conflicting info on inertia and all that jaz about how that can help a turbo application but the heavy flywheel benefits the supercharger? It's ace but it depends what you want/expect. You get much faster pick up of the engine and therefore it accelerates quicker but engine braking is far more violent as there's less inertia, combined with the SC drag on the crank lifting off is quite brutal. |
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Post by only1wilber on Mar 2, 2016 11:23:12 GMT
Correct the auto has a 3mm oil control ring so they are different but I'm not sure about compression. If anything it could only have been higher, but that seems unlikely So it could be the head of the auto has a slightly different shape combustion chamber to the manual that gives it the lower compression rather than lower compression pistons? So by adding the head off a manual with the manual cams would improve the bhp of the auto block? Skuzzle as you see these engine all the time, would you be worried about the keyway on the bottom end I already have or would you treat that one as a none starter and just go the auto route? |
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Post by only1wilber on Mar 2, 2016 11:34:28 GMT
How do you find the lightened flywheel on your car Horney? read conflicting info on inertia and all that jaz about how that can help a turbo application but the heavy flywheel benefits the supercharger? It's ace but it depends what you want/expect. You get much faster pick up of the engine and therefore it accelerates quicker but engine braking is far more violent as there's less inertia, combined with the SC drag on the crank lifting off is quite brutal. The car is going to be purely for fun/track days really. Do you happen to know the weight of yours? TTV do a really nice looking steel version at 3kg for 300 notes or on the other end of the scale there is a XTD chrome-moly one on ebay for 170 at 4kg but have read indifferent things about the XTD. |
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Post by Horney on Mar 2, 2016 11:41:40 GMT
I don't actually know off the top of my head. It's the Competition Clutch "Ultralight" Flywheel.
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Post by Horney on Mar 2, 2016 11:44:26 GMT
Googled it and it's 5KG which actually seems not that light. Ha ha.
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Post by only1wilber on Mar 2, 2016 12:00:16 GMT
So if a 5kg is brutal a 3kg is probably going to be off the chart! so the cheaper option maybe the better way forward, hmm.
Im sure betabuilder had the XTD one in his supercharged car, I'll do some more reading on them.
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Post by skuzzle on Mar 3, 2016 20:15:31 GMT
If the keyway is anything other than perfect just write it off for a goodun
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Post by lazza on Mar 5, 2016 20:35:03 GMT
Auto has lower compression pistons and different cams to give it more mid-range torque which suits an auto better. They are an excellent choice for FI!
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Post by dale1uk on Mar 6, 2016 8:26:18 GMT
So if a 5kg is brutal a 3kg is probably going to be off the chart! so the cheaper option maybe the better way forward, hmm. Im sure betabuilder had the XTD one in his supercharged car, I'll do some more reading on them. I had AK Automotive fit an XTD flywheel to my mk2 rs when I was getting a new clutch fitted last year. It's been a nice upgrade, I've got nothing negative to say about it. |
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le sigh