Hello all,
I am just finishing off all of the mods for the bottom end of my engine and now looking at the cylinder block - crankcase joint. I am thinking of adding extra holding down studs to give the engine greater integrity.
I know people have used the cam bearing stud hole to bolt the front of the block down and would appreciate any photos people have how they have done this mod.
I know of the classic 9 stud mod for 3 bearing engines by using two offside centre main bearing studs and drilling an additional hole through the block base into the valve chest. I was wondering if anyone has thought or done this mod with a 2 bearing crankcase. I think there is enough meat to put a thread in next to the centre cam bearing.

Also I would be interested whether anyone has any views on whether any of this is really necessary or am I just making modifications for modifications sake.

Thanks

Tom

Location: Guildford

Tom
No experience with studs, so can't help, but......

Well worth lapping the bottom of the block and the top of the crankcase. I did this and then assembled with Loctite 515 and no gasket along with nylocs.
It never leaked and during the recent strip down I had to suspend the engine upside down on the stand and belt the block with a mallet to get it apart!

Steve

My favoured approach is to ensure that you "through bolt" the block. This simply involves drilling through the stud holes where you can, countersinking the underside and replacing the studs with countersunk machine screws. I've upgraded to 3/8 where I've done this and can tighten up with a very satisfying amount of torque. And seal the joint with Loctite 515 for extra security.

Charles

I was thinking about through bolting as I want to build a supercharged enging eventually. I presume you drill the thread out on the top face and then continue down through the water jacket and then drill the thread out on crank case so the stud goes through from the inside of the case through to the where the head studs normally attach. How do you seal the water jacket around the stud? Do you have any photos of what you did or any further details?
I remember reading about Loctite 515 on the VSCC website. I may need to get a contact in USA to get hold of some for me!

Thanks

Location: Guildford

Charles,
The through studs on the valve chest side of the crankcase is the mod I have just completed.
I had been thinking about through studding the block as well as an experiment at some point. I would need to seal the water jacket somehow. This is probably a mod that I will really start thinking about in more detail for the supercharged engine.

Tom

Location: Guildford

Tom, best person to ask I think is John Sutton

Loctite.........

My Loctitie 515 is empty, so a new tube is required.
Last time I used ebay, but it is still quite expensive so any suggestions would be useful. I will try Amazon as suggested.

I too am or was thinking of bolting down the block in the valve chest area, but given my low state of tune and the fact that it was well and truly stuck I think in my case it is not required. I thought that this was also designed to help in cases were a fancy cam was fitted?

re the through studs , this was also done on a friends Ford Pinto (apologies for swearing) which was turbocharged to around 2 bar and was a very good mod, but it was quite tricky to do. It may be worth looking on Google for Ford YB Cosworth engine tuning info and other such things as this mod was and is done to them and you may glean usefull information on sealing and other problems.

Steve

I think the most important points re holding the block on to the crankcase are,How vicious the cam is,How hard the valve springs are,and is the crankcase bolted solid to the chassis.
I have some tubes of 515 loctite left,came from OZ as used in the gas industry £11 tube.

Steve,
A quite a few performance cams are more vicious than they really need to be. My Dads engine blew when the block came adrift on the way back from Kop Hill 2009. My understanding is that the valve chest side is the weakest and the block tends to rock on the crankcase this can cause the studs to break or work loose. The nice thing about modifing the inside of the engine is that it makes it stronger but is completely invisible.

I did hear of a guy in Oz who was running as a seemingly impossible boost pressure and would be interested to see what he did to his engine but I think it was an extreme modification.

Dave D were you offering to supply some 515 if so can I reserve a tube and I will e-mail you!

Location: Guildford

An option which may suit those who don't need to mod to "race" standard is to spot face the underside of the top of the crankcase where the block/crankcase studs are held. Unbrako screws are then screwed in and held with Loctite Studlock.
A similar mod could be used to replace a stripped thread with a suitable Unbrako bolt but I think I would prefer a Helicoil insert.
Ron

Location: Thornbury, S Glos

Resurrecting a 7 year old thread here....

We're in the process of building another single seater special using a '30 SWB chassis and a '30 crankcase with a '37 head, Phoenix crank, Honda pistons and a MAG blower driven off the nose. Every part used thus far with the exception of the Phoenix crank and new pistons came out of Dad's 40+ years of collecting and playing with Austin 7's. We have a '26 Chummy, '28 Top Hat and '33 Type "65' as well.

The intention is to use the new single seater for the Simola Hillclimb and the odd local event. We already have a period single seater special, built circa '49, also based on a '30 motor and chassis - you can see Dad & I about 4.40 into this video - https://www.youtube.com/watch?v=JuWD9g6oqks&t=324s

I need another Hillclimb car as my lovely wife has taken an interest and commandeered the Green Job. As the new motor will be blown at engine speed and reading what yea learned folk say about the crankcase-to-block joint, I'm keen to add additional hold down studs to the block & crank case - I've read about the Oz special with the extra stud inboard on the valve chest and also about the Pigsty mod to add extra studs at either end of the block. One picture on the 'net shows an extra tab welded to the back of the head to take an extra stud on the outside of the block above the flywheel.

We're starting with a blank canvas on this car, so all and any mod will be considered, especially if they help keep the oily bits together. The Competition Handbook has been invaluable, but there are no details on extra hold down studs...

What I can't find are any clear details of how these extra stud mods were done, close up pictures would help... Any additional advice would be gratefully received.

Cheers
Greig

Location: Port Elizabeth, Sunny South Africa

Hi Greig,I thought as no one has answered your questions on here I would.
The simplest way is blocks bolted into the tappet chest and down into the crankcase camshaft bush areas.My opinion is 8 5/16" studs isn't sufficient to hold the block and head on,and so must have Austin considering the engine failures in 1930 when racing them hard as they added 2 more studs.
The extra stud as 3 brg crankcase as only good when using a machined out 3 brg case as there is little metal in a 2 brg.
As previous threads have mentioned it is possible to extend the 2 tappet chest studs to bolt into a plate where the sump gauze fits but you have to grind radial grooves in the camshaft to clear them and they don't clear a counterbalanced crank.
It is also possible to extend the 2 studs next to the 1/4" bsf jet cleaning holes through the water jacket in the block and through the head,I only did this as the block had been linered and this leaves the base of the block weak.It isn't easy to do and difficult to seal.

Location: Channel Islands

The cars driven by Bishop and Hernandez all had small aluminium blocks bolted to the cylinder block ends with three extra bolts going down into the crankcase. When i asked why, they told me that a block had once lifted off on the brake due to the stronger valve springs they had fitted.

Ian Bennet's Pigsty supercharged engine has extra block studs somehow. He often contributes on here.
Dave.

Location: Sheffield

May I add my own ideas to this thread?

In the pursuit of strengthening the block to crankcase fitting I modify the crankcase to take 5/16 BSF cap screws fitted from the underside. The idea being that the stress is taken more on the cap screw shoulder rather than the limited thread in the crankcase face.

This is possible in five positions. I have a special counter-bore tool as shown in the picture. This works by screwing the brass guide into the stud hole and the fitting the cutter from the underside. Then an electric drill is attached to the outer part of the shaft and using a slow, reverse speed the cutter is pulled outwards until a clear shoulder is produced.

The crude part of the operation is that the 5/16 BSW tapped hole has to be re-tapped as 5/16 BSF to take the cap screw. It may prove necessary to chamfer the cap of the screw to allow clearance of the cam lobes etc (as shown in the picture). In extremis I have used a 3/8 BSF or BSW cap screw and turned down the outer part to be 5/16 BSF. This required a larger counter bore cutter and guide.

If I remember correctly the original idea came from 750 MC Special Builders Guide or Companion.

If anyone would like more details of the tool or even borrow it please let me know.

Location: Beautiful North Hampshire

Martin, as far as I can see both BSF and BSW cap screws are available, at least according to Google. If true, might avoid some angst next time?

Regards,
Stuart

Stuart

Depends if you want to use a BSW thread for the pull down nuts.

Another plus I forgot to mention is that cap screws are made of a much higher spec steel than normal studs.

Location: Beautiful North Hampshire

Hello Gents

Thank you for all of your valuable inputs, the various suggestions are all greatly appreciated.

We're currently busy with modifying the crankcase and block to take 5 cap screws from underneath. We're also making a pair of little blocks to bolt down either end of the block

The Phoenix crank is in and we've now got to align the double oil jet mod with the crank pockets and pump paraffin through them to double-check the squirt. Credit must go to Mike Forrest for this way back in the '60's I believe.

The oil pump has been bored out and hopefully we have decent pressure, I've got around 6 to 8psi hot with the Green Job and that's only running the conventional 2 jets.

I've got a bit more welding to do on the tube frame, then it's off to get clad in ally and then a lick of paint. I'm almost done with the supercharger mounting plate, it incorporates the front shock mounts - the plan is to lock one and use the alloy shock link on the other two eliminate axle movement sideways while still allowing axle movement.

We're really having fun building this little single seater, I'll try post some pictures for you.

Makes a change from rebuilding the 750/101 Giulietta's

Cheers
Greig

Location: Sunny South Africa