A10 anti wet sumping ball valve modification to A65 setup photos and dimensions

[chaterlea25]

Hi All,
Starting a new topic on this so hopefully these modification photos can be found in future

The spring and ball are as supplied by SRM, the spring is 1in. long (25.4mm) and ball is 1/4in. diameter
The oil gallery hole is enlarged to 5/16in, (7.9mm) diameter
The gallery depth to the face of the grub screw is 13/16in. (20.5mm)This dimension is for a roller bearing converted engine. The measurement for a bush engine is 1in. +- The new longer blanking screw should come as far as the rear edge of the drilling to the bush
There is no countersink or recess in the rear face of the SRM pump,
The ball seats against the pump face, even a very light "tap" on the ball will widen the sealing face noticeably
There is enough space around the ball for the oil to flow around it to the crankshaft bearings

Addendum,
I dismantled the cases today and measured the length of the plug that is fitted when modding to the A65 setup
The plug measures + - 17.5mm. 12.7mm for a bush engine

John

[Daithi]

Lovely work John 👍 Are you doing that bearing conversion yourself?
Dave

[chaterlea25]

Hi Daithi,

Are you doing that bearing conversion yourself?

No, that was SRM's work
I have rebuilt quite a few A engines with bush and needle roller conversions
Calculating the time involved and jigs that would need making it makes sense to me to hand the work to
people who do this every day
Having visited their workshop and seeing the tooling and machines they use, I feel I would be very hard pressed to equal their results

John

[Daithi]

Hi John, sorry, just read your posts in the "wet sump/mag cut out" thread. The ball and spring mod is one I would attempt myself.
BTW, I wonder if you can recommend a good machinist to do a timing bush and big ends? I have never used a reamer on a timing side bush but am thinking about it... a lot. 
Thanks, Dave

[kiwipom]

hi guys, dont know where i got this from but shows removal of existing ball and spring from pump side, also information from SRM when i purchased a new pump,  may or may not be helpful info, cheers

[muskrat]

G'day kiwipom.
I would not try (in situ) to open up the hole to remove the ball and spring as one can not be 110% sure any swarf doesn't get into the oilway to the bearing/bush and prv. 3/8" is too large, 5/16" is the correct size.

Thanks John 
Cheers

[RDfella]

Kiwipom - I think musky misunderstood you post. As I read it you are suggesting a way to service the existing spring and valve, and the collar is to bring the hole back to normal size. Sounds worth investigating. but I'd really like to see a dimensioned section of that oil gallery before doing that. If someone were to section an old scrap casing, then we could produce drawings / dimemsions for these modifications.

[RDfella]

Thanks for that info, Chaterlea. Very helpful and informative. Just what we need to better understand the issues involved.

[Swarfcut]

   On behalf of fellow sufferers, I raise a toast to the enlightenment furnished by Chaterlea John.
 Swarfy.

[chaterlea25]

Hi All,

 

On behalf of fellow sufferers, I raise a toast to the enlightenment furnished by Chaterlea John.
 Swarfy.

 
Embarrassed to say that the RGS engine is still in kit form having had the bottom end converted to needle roller, crank ground, dynamic balance, MAP rods, Wiseco pistons etc, etc  back in 2011/12

Some of the strip down disasters here,
https://www.a7a10.net/forum/index.php?topic=4556.msg30787#msg30787

Hoping to get stuck into my own projects over the next 12 months
John

[RDfella]

Following on from Kiwipom's suggestion, does anyone know the dimensions of the bore for the original grubscrew / spring / ball?
The idea of accessing this by opening the oil hole from the pump side and then refitting the oriiginal spring & ball by using a sleeve for the ball to seat against is certainly appealing.

[duTch]

 

Following on from Kiwipom's suggestion, does anyone know the dimensions of the bore for the original grubscrew / spring / ball?....

 I would expect that to be only enough to allow the 1/4" ball to be 'free to move'   

[muskrat]

G'day RD.
See reply #5 ^^^^^
Cheers

[chaterlea25]

Hi All
I need to address some of the measurements I gave for the conversion in my earlier posts
Those measurements were for a roller bearing converted engine

I have modified my original post now

On the converted engines the oil feed tube is nearer to the timing side than on the original bush setup
If the 17.5mm blanking screw was fitted to a bush engine it would block the feed to the crank 
At the time I did not know or "twig" this vitally important point

It was only the other day when I went to change a Huntmaster engine to the modified setup that the penny dropped,
The "new" figure for the depth to the back of the oil feed hole to the bush is +- 1in. (25mm)
The new blanking grubscrew measures 0.5in (12.7mm)
Hopefully the Huntmaster casing is the same as A7/10 ? The important thing is to NOT interfere with the oil feed to the bush when fitting the longer blanking plug

OK, I realise the spring is now going to have less compression than on the roller bearing engine but figure 1/4in should work ??

John

[RDfella]

I know this has been discussed before, but maybe this is the place to clarify the spring issue. I believe the A10 and A65 springs are different, although some vendors apparently sell the same spring for both. So which one is recommended, and, to identify, what is its size - ie OD, LOA, no of coils and, importantly, wire thickness.