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PostPosted: Fri Jun 06, 2014 5:17 pm 
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Yep, that is another option.

If I used 68mm flat top pistons with the 295 head I'd have about 9.8:1 C/R with a 998 crank
Or if I used +100 flat top pistons with the 295 head I'd have about 9.6:1 C/R with a 998 crank

Or I could get the 202 head modified with bigger valves and ported and go for 10.5:1

There is another 1098 engine unit available for me to get, so I might see what condition that one is in...

Many options! I'm still to commit to any to I'm open to different ideas :D

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PostPosted: Sat Jun 07, 2014 6:25 pm 
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Engine.in.a.box*
Attachment:
14362286442_fbec5804e5_o.jpg

*patent pending :P


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PostPosted: Sat Jun 07, 2014 6:33 pm 
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"Engine to go...>>>> " haha

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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PostPosted: Sat Jun 07, 2014 6:37 pm 
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Location: Under the bonnet son!
I built an engine like that. It currently resides in my '62 997 Cooper.

viewtopic.php?f=3&t=65421&p=778806&.#p778806

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PostPosted: Mon Jun 09, 2014 11:53 am 
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drmini in aust wrote:
"Engine to go...>>>> " haha

*some assembly required
Mick wrote:
I built an engine like that. It currently resides in my '62 997 Cooper.

viewtopic.php?f=3&t=65421&p=778806&.#p778806

Cheers, I'd never seen your build thread before. Were you happy with the RE83 cam? I thought that cam might be a good match for the 1098 as it peaks so low in the rev range.

At the moment the standard 998 with the HS2 doesn't like to rev much above 4000rpm. After a bit of fiddling with the timing it is a little better, but it stops revving at just over 5000rpm (valve bounce possibly?). Being limited on a 1098 crank to 6000rpm doesn't worry me too much!

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PostPosted: Mon Jun 09, 2014 2:25 pm 
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IMO 1098s seem to go better with an RE13 than an RE83. It gives them some top end sparkle that they lack with a stock cam.
A 1098 has great torque (compared to a 998) regardless of which cam you have in.

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PostPosted: Tue Jun 10, 2014 2:22 pm 
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drmini in aust wrote:
IMO 1098s seem to go better with an RE13 than an RE83. It gives them some top end sparkle that they lack with a stock cam.
A 1098 has great torque (compared to a 998) regardless of which cam you have in.

It would be handy if there was an idiot's guide to camshaft selection somewhere on here...

What is the approximate cost to get a cam reground?
If I wanted an RE13 regrind do I need to supply a certain type of cam, or can I use a 998 or 1098 one?
If I am using a reground cam, will I need more lift on the rockers?
What is the difference between 1275 and 998 cam bearings?

On a different note, what were so special about the 998 Cooper engines? They had:
295 head
Twin HS2 carbs
D-top pistons
8.3:1 C/R
And they had 55hp? I haven't been able to find much about the cams they used but they seem to be similar to the 1098

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PostPosted: Tue Jun 10, 2014 4:25 pm 
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timmy201 wrote:
drmini in aust wrote:
IMO 1098s seem to go better with an RE13 than an RE83. It gives them some top end sparkle that they lack with a stock cam.
A 1098 has great torque (compared to a 998) regardless of which cam you have in.

It would be handy if there was an idiot's guide to camshaft selection somewhere on here...

What is the approximate cost to get a cam reground? Was around $130 + postage if needed at GR's recently. Other places generally charge more.
If I wanted an RE13 regrind do I need to supply a certain type of cam, or can I use a 998 or 1098 one? Both will do fine if not reground previously.
If I am using a reground cam, will I need more lift on the rockers? You can use stock rockers, don't run S ones as they have least lift of all (I measured 1.16:1 ratio). The other BMC ones are all about 1.2:1. You can buy 1.3:1 rollers for a bit more lift. Keep 1.5 rockers for 1275s..
What is the difference between 1275 and 998 cam bearings?
1275 auto has the same ones as a 998. On 1275 manual the rear one is wider, you can use 998 ones if set flush with the inside of the block.

On a different note, what were so special about the 998 Cooper engines? They had:
295 head
Twin HS2 carbs
D-top pistons
8.3:1 C/R
And they had 55hp? I haven't been able to find much about the cams they used but they seem to be similar to the 1098
Cam on 998 Cooper was much the same as a 1098 one, the C/R was 9.0:1 and they ran a 3-1 exhaust header.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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PostPosted: Tue Jun 17, 2014 2:03 pm 
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Thanks!

I've had a quick look at the heads and valves this morning. Worst case scenario would be bottoming out the valve springs with the valve guides contacting with the spring top cap (unless the springs have bound by then?)
Image
In that situation the exhaust value sits down approximately 5mm below the bottom of the 295 head, and the intake is down about 3.5mm. I'm not sure if this is enough to hit the block or need a notch cut in it?
Image

And for the 202 head:
Image
The valves on the 202 head barely come down past the bottom of the head.
Image

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PostPosted: Tue Jun 17, 2014 2:55 pm 
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No need to notch the block if the valves clear when that low.

It's usually only when fitting a 1275 head to a smallbore that the block needs notching. But people get away without, if the cam and rockers are stock, and the exhaust valves have sunk into the seats a bit.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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PostPosted: Fri Jun 27, 2014 10:47 pm 
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drmini in aust wrote:
No need to notch the block if the valves clear when that low.

It's usually only when fitting a 1275 head to a smallbore that the block needs notching. But people get away without, if the cam and rockers are stock, and the exhaust valves have sunk into the seats a bit.

Excellent. I was hoping that it would be ok with these valves.

In regards to fuelling, I've got an HS4 which looks like it has been rebuilt. I don't know if this will be big enough to give the power I'm after? I'm aiming for 50hp at the wheels, which would be about 65hp at the engine...
Attachment:
last-import-24_14519223185_o.jpg

Twin HS2's would be an option too. Is there anything special about the carbs on twin carb cars? Could I just get left and right fuel bowl carbs and a linkage kit and manifold and rebuild them to the same specs, or is there something else I should be looking for?


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PostPosted: Fri Jun 27, 2014 11:12 pm 
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I think Vizard reckoned a single HS4 was OK for up to 70HP at the crank.
If the motor is 1098 or bigger, with the usual engine mods, an HS6 could be better.
Twin HS2s as on a Cooper or S work fine, as long as you have the 30 deg bowl angle on both, it's all good.
I'd be tempted to try an aftermarket twin HS2 manifold instead of the Cooper one, it could flow better.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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PostPosted: Sat Jun 28, 2014 8:27 am 
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drmini in aust wrote:
I think Vizard reckoned a single HS4 was OK for up to 70HP at the crank.
If the motor is 1098 or bigger, with the usual engine mods, an HS6 could be better.
Twin HS2s as on a Cooper or S work fine, as long as you have the 30 deg bowl angle on both, it's all good.
I'd be tempted to try an aftermarket twin HS2 manifold instead of the Cooper one, it could flow better.

I always forget to check that book... Looking at the carburation chapter, figure 7.3 has a 1430cc engine with an HS4 and HS6 comparison. The difference is only about 6hp, with the HS4 at 108hp and HS6 at 114hp at the flywheel. From that it makes me think there would not be much difference between them at the range I'm looking at.
Some modifications to the HS4 as per the book could close the gap further I guess. There is plenty of scope on this one to improve around the throttle plate area...

Attachment:
last-import-26_14521392942_o.jpg


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Last edited by timmy201 on Tue Jan 16, 2024 7:56 pm, edited 1 time in total.

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PostPosted: Fri Jul 18, 2014 11:57 am 
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Good news! I got out the one last piston that's been stuck! It might not be much use anymore however...
Attachment:
14493632898_5c6dfb15cf_o.jpg

I've also cleaned up the 1098 crank and got rid of the rust
Attachment:
14677081741_d9374a5e5f_o.jpg

There is only one bearing face that shows any damage and it has some bad pitting on the surface. It is already oversize at -020 according to the bearings.
Attachment:
14657273876_57a33dac7b_o.jpg

What is the safe limit for going undersize on main bearings? I've seen 030, 040, 060... I'm not sure if that will be enough for this one though?


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Last edited by timmy201 on Tue Jan 16, 2024 7:57 pm, edited 1 time in total.

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PostPosted: Fri Jul 18, 2014 4:02 pm 
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Geez that journal looks bad.
[edit] Even if it's saveable, I'd get it crack tested before you spend any $$ on it.

I'd grind to -.030" or -.040" absolute max on a 1098, any more just bin the crank and find another 12G82.
I have one here if you're stuck, I think it's std or -.010" sizes now.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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