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3569 Posts Member #: 655 Post Whore Northern Ireland |
20th Jun, 2019 at 12:06:39am
What pistons ? DO they have oil holes or slots ?
9.85 @ 145mph
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240 Posts Member #: 11017 Senior Member Shropshire |
20th Jun, 2019 at 08:32:51am
Surely det starts on the crowns? That's what my mapper has been saying.
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 1030 Posts Member #: 1291 Post Whore Suffolk / Birmingham |
20th Jun, 2019 at 09:00:37am
How are you fueling this engine? You mention mapping? The outer cylinders are clearly running weaker. I suspect that's the cause of your issues.
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240 Posts Member #: 11017 Senior Member Shropshire |
20th Jun, 2019 at 09:16:50am
On 20th Jun, 2019 slater said:
How are you fueling this engine? You mention mapping? The outer cylinders are clearly running weaker. I suspect that's the cause of your issues. Also the valve seats can be 'blued' with a marker pen and you will soon see if theres and issue. If the valve is still straight then the seat/guide alignment might be out. Have you fitted new guides? I'm using the specialist component 5 port inlet system with a D400 ecu. It also doesn't explain cylinder 3 as that piston also had broken ringlands. Pistons 2 and 4 are fine. I'll give that a go today. I didn't build the head, but yes, new guides and valves were fitted. Edited by Steve220 on 20th Jun, 2019. |
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 1648 Posts Member #: 9038 Post Whore Carlisle, Cumbria |
20th Jun, 2019 at 09:28:21am
He's using the specialist components mpi 5 port injection kit |
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240 Posts Member #: 11017 Senior Member Shropshire |
20th Jun, 2019 at 10:39:43am
Sorted the cylinder head. 2 more goes with lapping paste and it holds fluid.
Edited by Steve220 on 20th Jun, 2019. |
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 6743 Posts Member #: 828 Post Whore uranus |
20th Jun, 2019 at 10:55:31am
what make of piston ? Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM |
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240 Posts Member #: 11017 Senior Member Shropshire |
20th Jun, 2019 at 11:05:57am
On 20th Jun, 2019 robert said:
what make of piston ? Nural 524107 pistons (21253 +20) |
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 12307 Posts Member #: 565 Carlos Fandango Burnham-on-Crouch, Essex |
20th Jun, 2019 at 01:18:49pm
i think they might just be wank pistons, i wouldnt use anything with a slot in, and also the finish dosent look great On 28th Aug, 2011 Kean said:
At the risk of being sigged... Joe, do you have a photo of your tool? http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1 https://joe1977.imgbb.com/ |
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240 Posts Member #: 11017 Senior Member Shropshire |
20th Jun, 2019 at 06:34:57pm
On 20th Jun, 2019 Joe C said:
i think they might just be wank pistons, i wouldnt use anything with a slot in, and also the finish dosent look great You're not the first person to mention their quality 
Anyway, engine is with Southam Mini & Metro Centre. Gone for +40 Omega cast with 10cc heads, MED centre strap and AFS bolts. |
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177 Posts Member #: 10990 Advanced Member Hornsea |
20th Jun, 2019 at 06:43:02pm
You won't be disappointed with southams, great bunch of lads and Rod put a cracking motor together for me with some great results.
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 4619 Posts Member #: 20 My sister is so fit I won't show anyone her picture Lake District |
20th Jun, 2019 at 06:59:19pm
The 21253 used to be a pretty decent piston, are they made differently/by another company now ?
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240 Posts Member #: 11017 Senior Member Shropshire |
20th Jun, 2019 at 07:53:21pm
On 20th Jun, 2019 Turbo Phil said:
The 21253 used to be a pretty decent piston, are they made differently/by another company now ? Phil. They used to be made by Nural, they're now made by AE. |
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 2091 Posts Member #: 9894 Post Whore Dorking |
20th Jun, 2019 at 09:05:19pm
Was gunna say those gaps don’t seem to bad.
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240 Posts Member #: 11017 Senior Member Shropshire |
21st Jun, 2019 at 10:05:15am
On 20th Jun, 2019 jonny f said:
Was gunna say those gaps don’t seem to bad. Think mine are 15 thou. As it’s used on track etc. Always go bigger with boost. Those were the gaps as they came out the packets, I didn't need to gap them hindsight says differently, I never realised until recently that the gaps may not be parallel either. You live and learn! I'm confident the engine builders will gap them wider for the boosted application. |
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12307 Posts Member #: 565 Carlos Fandango Burnham-on-Crouch, Essex |
21st Jun, 2019 at 10:18:25am
well, ive seen some pretty poor engine builds from "reputable" companys over the years,
On 28th Aug, 2011 Kean said:
At the risk of being sigged... Joe, do you have a photo of your tool? http://www.turbominis.co.uk/forums/index.p...9064&lastpost=1 https://joe1977.imgbb.com/ |
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240 Posts Member #: 11017 Senior Member Shropshire |
21st Jun, 2019 at 01:51:28pm
On 21st Jun, 2019 Joe C said:
well, ive seen some pretty poor engine builds from "reputable" companys over the years, I'd say your gaps are prbably a bit tight, but probably ok if you were running piston jets, but thats just a proberly. I always check anything done by a machine shop even good ones, also write down exactly what you want done, so stuff is less likely to get missed. As an example Ive had a block fitted with a 4 bolt main before, line bore and hone i told them... went to pick the block up and its just line bored so the finish is not great, basically they didnt want the faff of setting it up on theire hone machine so didnt bother, and of course once its at size its then a pain to re do as you need to take more material out etc etc, so i ended up stuck with it. I wasn't running oil jets :( I'm going to email Southam Mini & Metro Centre and see what they intend to use as gaps. |
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240 Posts Member #: 11017 Senior Member Shropshire |
21st Jun, 2019 at 03:44:39pm
Pics of the rings
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3569 Posts Member #: 655 Post Whore Northern Ireland |
21st Jun, 2019 at 08:29:45pm
On 20th Jun, 2019 Steve220 said:
Surely det starts on the crowns? That's what my mapper has been saying. will strip the piston down today and have a look. Find a new mapper. Of course it does not start on the crown...but it can start anywhere in the combustion chamber depending on the actual cause. Rings look fine, there are no signs of the ends butting together. And as already said, never use pistons with a slot behind the oil ring. No idea if yours have...Metro turbo pistons never did though. 9.85 @ 145mph
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