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Andy

Yet another XU9/10 engine build

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Andy

Neat idea to make a bung and tig, but I have neither a lathe nor a tig welder ( sob) so a £1.10 core plug was plan ‘b’  I would love to have both but just not enough space in my garage ( second sob)  Mind you, a collection of bikes might just be contributing to the space issue .

 

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DrSarty

Keep it up Andy.

 

I'm sure I told you about removing the ribs from the alloy block stiffener, aka the 'spacer'. It becomes a spacer (literally) on the iron block, purely to increase oil capacity; although in turn that's why one needs the deeper/ extended oil pump pickup.

 

I'm not sure, but I seem to recall the XU7 (alloy) block I'm using for the Xsara turbo had a windage tray already, but no spacer; but it maybe the other way round. QUESTION: Can anyone confirm please?

 

Either way, I want all 3 bits, even if that means rib modification: 'spacer', windage tray and extended pickup.

 

I either forgot to ask Pete when we met in Sydney about a month ago, or the beer has blurred my memory!

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Andy

Hi Rich,

 Hope your plans to move further south are progressing well. I am afraid I know nothing about the xu7 block so nothing helpful to contribute, although it does look like an ‘interesting ‘ engine . As far as I know, PeterT is the man for the extended oil pickup. He sent me mine  very quickly and at a very fair price . I then had it tig welded in place at a small engineering company in Derby . On my engine, all  sealed up now, so I will trial fit the inlet and bodies tomorrow morning so I can work out how the dipstick tube will route, then just about ready to drop it into the car and discover just how badly the manifold fouls on the tunnel and bulkhead ! 

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Andy

Beginning to look like an engine. Trial fit in the engine bay this weekend or early next week with any luck, unless the weather improves in which case bike riding will take priority 

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DrSarty

Lovely work Andy; I bet you're excited.

 

I hope some of the parts I provided are helping, such as the metal 'stat to radiator hose union from an 8v XU (?). I hope that's mine as I'd love to have contributed.

 

Please remember the 'heavy breathing ' aspect I mentioned, so good plumbing for that and your catch tank will help. Pete's (I think) 2.2 that Sandy mapped and video'd on this forum, was nicknamed ''Smokey Joe' IIRC made 260-270 bhp, so don't be surprised if yours is similar in terms of behaviour and performance. It'll be a chunky delivery I'm confident, i.e. scary!

 

Perhaps related: I'd consider more robust exhaust manifold fixings. I swear by some 'Rolls Royce' jobbies that (ironically) I got from 'Volksbolts'.

 

It's a steel stud with an Allen key end to wind in, with a locking steel nut. They're not essential, but give that extra assurance.

 

I also swear by Loctite 5920 (expanding copper?) sealant for the exhaust manifold as recommended by PeterT. The last thing you want is a blowing exhaust on such a canted engine! Get it right first time; for some reason the standard studs and copper nuts don't do it for me.

 

Call me if you like.

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wicked
15 hours ago, DrSarty said:

Perhaps related: I'd consider more robust exhaust manifold fixings. I swear by some 'Rolls Royce' jobbies that (ironically) I got from 'Volksbolts'.

 

It's a steel stud with an Allen key end to wind in, with a locking steel nut. They're not essential, but give that extra assurance.

Did google volkbolts and found stainless studs from them; will that work in an alloy head? My assumption was that you should never use stainless bolts in alloy?

 

 

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SRDT

Stainless bolt like to seize inside aluminium parts, even during assembly.

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Andy

I went to their website and found the studs that Richard referred to . Nicely made and a very good price, but they are not studs, but rather threaded SS rod either 50mm or 60mm long , so unless all the blind, tapped holes in the head are drilled to the same depth, these studs may protrude to differing amounts . 

Andy

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Tom Fenton

I'd stick with what you have Andy.

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Andy

And the next saga. Just about ready to drop into the bay, but I thought I would give everything a final check. The cambelt kept starring at me and muttering , and so it should . Andy the dipstick had installed it facing the wrong way . Now sorted of course, but what an error . Must have being having a ‘senior moment ‘ when I put it in first time .

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DrSarty

I'll defer to others' expertise re the studs. I've never had issues however. But the Loctite 5920 I think is a given.

 

Good luck; and be prepared for serious 'grunt'.

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B1ack_Mi16

Question about the crankshaft...  You didn't re-shape the circilar "counterweight" which drove the balancing assembly with the gear before balancing?

 

I was just wondering if that would have been beneficial, as I'm tinkering on my own DW12 crank build a little now and then, and I need to decide if I shall grind it to a "counterweight" shape or just leave it prior to balancing.

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Andy

After the ring gear was removed, the company who did my balancing for me reported a 17g out of balance before they begun their balancing work.  Clearly the crankshaft therefore had been designed to be balanced with that journal circular as although 17g is a significant out of balance weight, not in the league of grinding chunks of steel from that journal . 

Oh, good call using the DW12 crank. You will not run into the problems of main bearing journal diameter that I did using the petrol one . I have one of those too now, and will use one in preference to the petrol one when I build mynext 2.3litre  engine ( I have  a block bored to 87.00mm, some forged 87.00 mm pistons and some forged rods, so half way there .)

Andy

 

 

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B1ack_Mi16

Ok, thanks for your input.

 

I suppose the total balance might be good, but not so sure about the effective force created by the counterweights for that rod/piston assembly.

But it will only affect internal bending moment distribution in the crankshaft which might not be a real problem anyway.

 

Are you using the cometic 88mm headgasket for your 87mm builds?

 

I'm struggling now to acquire a 89mm gasket as my current block is 88mm bore and 94.5mm stroke.

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Andy

Hi. Cosmetic 87.00mm (which means that it is more like 88.5 mm in overall diameter ) If you contact a Cometic agent, they may be able to arrange a bespoke one . 

As for the crank, the counterweights are exclusively to counteract the big end journals, so that the crank runs as an independently balanced rotating component. The advantage of the 8 counterweight design that we have is that each big end journal is countered either side of its centre line, which reduces the twisting moment on the main bearings. Each rod/ piston assembly is countered by its partner , hence the need to rods and pistons to be balanced carefully. Ideally, each assembly also needs to have the same centre of mass so that at 

least  the secondary ( rocking) moment is equal across the axis of the crank . 

94.5 mm stroke. Offset grind on the big ends? Impressive . Next question. What have you done about rods and pistons. ? Because of the long stroke, I was concerned about rod angularity ( secondary moment ) so went for  the longest rod I could get and still have a sensible compression height on the pistons (29.00mm as it happens with 157.8mm rods ) 

Andy

 

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Andy

I mean cometic but this apple device keeps altering the spelling .

 Andy

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SRDT

You can also use a separate rings and have a standard paper head gasket cut with a laser or water jet.

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B1ack_Mi16

Spent some hours CAD'ing this weekend, might get a custom MLS gasket made for it in the end. :)

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welshpug

I'm using oem gasket on 87mm bore

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B1ack_Mi16

With pistons protruding the block deck?

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Andy

My cometic 87mm gasket would be quite happy with protruding pistons . I think the actual bore on the gasket was closer to 89mm, so you may well get away with an off the shelf Cometic .

 

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B1ack_Mi16

Indeed not, my 88mm cometic has exactly 88mm bore. I have in total 3 of those gaskets here and they are not oversize from their advertised bore sizes.

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welshpug

no protruding pistons, have enough compression without doing that!

 

have seen pistons with a chamfer on the crown which I guess would be to avoid contact with a gasket but that to me is far too close to the cylinder head

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petert

I have a DXF head gasket file that I use to get copper gaskets cut, if it’s any use.

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