7 R case work complete I hope?
 

Hi guys,

some snaps of my 7 R cases with machine work completed . Unless you tell me I may need more. ?

They will form the basis of a 2.7 twin plug 10:5 / 1 engine with TB's and S cams .

Work illustrated is oil pump by pass, shuffle pinning, case savers and some windage work.

http://forums.pelicanparts.com/uploa...1227272577.jpg
http://forums.pelicanparts.com/uploa...1227272621.jpg
http://forums.pelicanparts.com/uploa...1227272659.jpg

That case should be quite robust. Why not go all out and build a 2.8? Is this a track or street motor? What cams?

It will have S cams or similiar. I need new or refurbed cylinders. Whats involved with a capacity increase to 2.8 ? i cannot afford new crank or rods and as you see the case is done?

70.4mm stroke crankshaft and 92mm Nickasil cylinders = 2.8

Or, with unlimited $$$$$$, you can get a rare 1974 Turbo Aluminum case and use bigger cylinders with the Supertech Supercrank with a 66mm stroke and build a high rpm screamer.

Line bore?

7r cases
 

I didn't line bore since we set it up on an industrial inspection table and measured the bores at the mains and the diameter of the mains. They are concentric , parrellel and consistent in diameter to within three thou ( worst total arror). at stable temperature of 22 deg c.

I reckon that it'll be ok at that ?

My crank is the standard from a euro 2.7 S is that the correct throw for 2.8. Can my existing mahle cylinders be used to get to this capacity ?

If your line-bore is good then that's great...just not common... some have issues with the crank binding upon assembly...mostly due to the fact that the bores are not parallel anymore

That crank is correct for a 2.8RSR type motor. You can use your cylinders but they need to be bored, and replated, at 92mm. then you'll need the pistons to match.

The case looks good!

7R cases
 

Brilliant, I just spoke with the machine shop and they think the case may have been bored previously , guess I'll never know except that it measures true which I suppose is the most important.

Since I have the correct crank and already need to get the cylinders replated I may as well go to 2.8. The only additional cost will be the cylinder boring.

I intend using JE pistons will they be able to provide the correct size if I just say 2.8 capacity on a 2.7 crank . Then I can get the cylinders bored and plated to suit ?

andy

Andy

You can quickly check the case bores by installing the crank and bearings with some assembly lube, torquing down the through bolts and ensuring the crank turns with without binding.

JE pistons are made from a different alloy than Mahles. The JE pistons will have excess clearance when cold in Mahle cylinders. For less noise and wear, use LN Engineering "Nickies" cyliders which are matched in expansion rate and clearances to the JE pistons. The "Nickies" are Aluminum alloy milled to superior specs than the Mahle cast cylinders. They both have the same Nickel-Silicon-Carbide coating in the bores.

It's very easy to spend other people's money, isn't it.

Sure that is a superior solution, it should be when they cost 3x as much as replating and boring the old ones.

I'm building a 3.2 using mahles and 9.8:1 JE's. I think you'll be happy hassad with this combo in ur 'budget' 2.8 screamer. Keep us posted on the build!

Apparently JE offers pistons in different alloys now to accomodate cylinder choice. I still went the Nickie route...even Mahle's cylinders don't compare.

Looks good. What kind of oil pump are you planning on? Some choices require additional grinding...

I have the later oil pump with the bigger volumes as recommended by Wayne. It fits my cases so I think thats ok.

The alloy drive gear from the crank is slightly worn having a small burr raised on the edge of each tooth . Is there a backlash tolerance or is this normal too

Thanks for the advice about cylinders. My finances only stretch to the re-use option with my cylinders . But I will make sure I get compatible materials for the pistons . I am tempted to use superseal rings , friends have good experience of them in Imp engines any opinion here?

The heads are being twin plugged at present.

I haven't heard this before. Is it generally accepted the JE/LN Eng. combo is "better" than the Mahle P/C set?

Sherwood

Yes. Just look at the beautiful CNC machining of the Nickies on LN Engineering's website. http://lnengineering.com/

Hello, Andy.

TBH . 3 though misalignment is significant is it not?

Yes the crank will flex and the oil will compress a bit so iot doeas not bind up totally..but I'm sure we commonly see the effects of this on strip-down..with one or more bearings being marked to one side..

what we don't see is the power losses this incurs..

I agree with the advice to check the crank spins freely..

Kind regards
david

Yes, very impressive. Any other objective reviews you can share?

Thanks,
Sherwood

Ok folks. I put the crank in with the old bearings and nipped it up to torque. The crank is free as a bird so all good advice noted. Reckon the cases are ok.

Still worried about the oil pump drive gear backlash, I measured about 12 thou' (0.3 mm) any views?

andy.

PS I'm convinced about 2.8