Ouch!...Now that's what I call a dropped valve
Commiserations to Rusty 
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| 1098 Engine Project - Take 2 - Big Bore/Short Stroke https://www.ausmini.com/forums/viewtopic.php?f=5&t=99579 |
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| Author: | drmini in aust [ Fri Jan 31, 2020 10:29 am ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
I've used 526 springs for years on road cars, no problems with GR's cams. But years ago I took 4 lobes off a Camtech VP 3 cam in 30,000 miles using Penrite HPR30 oil.... Same springs. I would only use 527s on a race motor. |
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| Author: | 68Rusty [ Fri Jan 31, 2020 8:11 pm ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
Attachment: IMG_0643.JPG Attachment: IMG_0651.JPG Attachment: IMG_0573.JPG
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| Author: | drmini in aust [ Sat Feb 01, 2020 3:54 am ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
Rusty, Were those valves small bore length, or from a 1275? What springs? 526 or 527 are too long for small bore valves.. |
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| Author: | 9YaTaH [ Sat Feb 01, 2020 6:48 am ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
Ouch!...Now that's what I call a dropped valve Commiserations to Rusty
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| Author: | timmy201 [ Sat Feb 01, 2020 10:40 am ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
Hmm, I better double check which double springs I put in my 1098, and what length valves they are! |
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| Author: | drmini in aust [ Sun Feb 02, 2020 5:19 am ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
timmy201 wrote: Hmm, I better double check which double springs I put in my 1098, and what length valves they are! We used VSP580P double springs from Karcraft on Joe's 68mm bore (998 crank) motor. Valves are 998 Cooper inlet, 27mm exhaust. RE266SS camshaft. |
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| Author: | 68Rusty [ Sun Feb 02, 2020 6:24 am ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
drmini in aust wrote: Rusty, They were valve springs recommend to me at the time, I cannot remember exactly which model springs they were, maybe I have an invoice still which will list the part number, I will check.Were those valves small bore length, or from a 1275? What springs? 526 or 527 are too long for small bore valves.. Perhaps they were too long, could well explain it. Sent from my moto g(6) using Tapatalk |
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| Author: | timmy201 [ Sun Feb 02, 2020 7:33 am ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
drmini in aust wrote: timmy201 wrote: Hmm, I better double check which double springs I put in my 1098, and what length valves they are! We used VSP580P double springs from Karcraft on Joe's 68mm bore (998 crank) motor. Valves are 998 Cooper inlet, 27mm exhaust. RE266SS camshaft. I did buy some VSP... springs from Karcraft but I’ll have to check which ones. The valves are 31.8/27.2 from GR, I assume they were small bore length but I’ll have to check that too To be honest I didn’t even think about it when I ordered the springs |
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| Author: | drmini in aust [ Sun Feb 02, 2020 10:10 am ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
Tim, if they were double springs for a smallbore from KC, they are VSP580P. Good for 7,000. Their other VSP springs are singles for 803, 850, 998 and 1098. |
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| Author: | timmy201 [ Sun Feb 02, 2020 10:33 am ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
Oops. I’ve checked and I ordered VSP3964P# (7000rpm) - 1275 double valve springs. Will these be an issue with the 998/1098 valves? They are the GR Paul Ivy race valves, so they are a really nice valve, but will the fitted length of the 1275 springs be a problem? Quote: Small Bore valves – Race quality Paul Ivy Valves Nitrided Stylite tipped, Polished, Excellent quality. http://russellengineering.com.au/mini-products/ If the valve stems are the 998 length I’ll have to order some new 998 specific springs and swap them over? Hopefully there has been no damage in the last 1000km. I have the RPM limit set at 5750rpm, so I don't need super high rpm capable springs |
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| Author: | timmy201 [ Thu Feb 06, 2020 4:54 pm ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
I got the crank back from the shop today. The crack check showed no problems and it was good to go at 10/10 which was great news. The stroke measured up as 70.0mm Here is a comparison of the short stroke 1100 and standard small bore 1100 cranks. Attachment: 9CCF846D-66E0-43F0-AFF2-8FE6972536FE.jpeg One of the appealing features of this crank is the overlap between the main journals (red lines) and the big ends (green lines). In combination with the large 1275 size journals, it makes a really strong crank  Attachment: 6CCCE7C3-8414-492B-BC7E-644F8EFD1BA2.jpeg
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| Author: | TK [ Thu Feb 06, 2020 7:20 pm ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
"I would only use 527s on a race motor" I would not. |
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| Author: | GR [ Thu Feb 06, 2020 8:38 pm ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
HI Tim Those valves are longer than the small bore valves they will take the 1275 springs. The spring height will be around 1.380 to 1.4 in those small bore heads. Graham Russell |
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| Author: | timmy201 [ Thu Feb 06, 2020 8:47 pm ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
Thanks Graham, I was going to give you a call sometime. I had a vague memory you said to use the 1275 springs - these include the bottom collar for the double springs so I’ll see if I can measure them |
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| Author: | simon k [ Wed Apr 01, 2020 1:36 pm ] |
| Post subject: | Re: 1098 Engine Project - Take 2 - Big Bore/Short Stroke |
where did you get the crank? I'd love to build one of these motors |
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