A Few Techie Questions About Crank, Cr, Cams And Bodies

[Richie-Van-GTi 70 2 Cars]

Im sure all of these have been answered individually at some point but none of the answers are going to be specific to my needs so please give me advice.

I have managed to get hold of an XU10J4R lump and an XUD9 crank courtesy of Psychosimon (thanks mate). Im planning a whole new build and selling off the stuff I dont need in my sig to fund it. I now have lots of questions to aid my quest for power

 

1) how much will current engine be worth excuding both manifolds, carbs, oil pressure sender and alternator? The head has just had new stem seals and valves reseated / shimmed, new cam seal, new dizzy cap and rotor and new beru leads. ?

 

2) If fitting the XUD9 crank I know I gain stroke and CR, what shells do I buy xud9 or xu10 for fitting and do I use current rods and pistons, does anything else need to be taken into account?

 

3) With that crank am I right in expecting around 11.1 CR and should I use stage 1 or 2 cams from petert ?

 

4) Im going to use bodies, probably bike bodies to save on cost, can I use the bike injectors?

 

5) Whats the cheapest way to control this lot? IE megasquirt etc and what exactly will I require. Im pretty handy with wiring and soldering etc (electrical engineering student )

 

6) Whats the best exhaust system to use with the gti6 manifold, can I use current one with a modified downpipe?

 

PS, I have aa 215mm clutch flywheel with the extra ring gear on if it helps with managment issues

 

 

before anyone asks I already have a buyer for carbs and inlet mani etc. Exhaust mani will be going up for sale though

[smckeown 1]

on petert's website he does state what CR is applicable to which of his cams, if that helps

[Richie-Van-GTi 70 2 Cars]

cool, if Im right in thinking the xud crank will give me 11.1 then I can run stage 2 which is nice

[petert 554]

You'll definitely end up with 11:1 with that combination, thus the Stage II would be suitable. However, another consideration is valve to piston clearance. You need a minimum of 0.080" on the inlet, which will occur 6 deg. ATDC. So you'll need 0.090" at TDC. The Stage II grind has 0.105" lift at TDC (106 deg. centreline). So that's a total of 0.195".

 

I would advise you to verfiy that the inlet valve has 0.195" of travel before making your cam choice, and/or be prepared to machine the valve pockets.

 

You may wish to retard the inlet cam fractionally to 0.092" at TDC (109 deg. centre line), but that would be the minimum.

 

 

The 205 downpipe bolts straight on to the GTi6 manifold, but you'll have to shorten and re-angle the pipe.

 

I've got no experience with Megasquirt, but you'll definitely need to control the advance curve to get the most out of it. My choice for your setup would be Haltech E6X.

 

Any XU10 mains bearing should fit. You can use XU9 or XU10 rod bearings. (keep in mind I've never used a diesel crank!)

[Richie-Van-GTi 70 2 Cars]

excellent, Ive been trawling threads anyway and from what Ive read it seems the general opinion is to just bang the derv crank in with derv shells and use normal pisotns and rods. Only flaw possibly is the lip at the top of the bore may need to be honed or possibly rehone the full thing and fit new rings.

Looks like a few people have now done this crank swap and Ive not come across anyone having valve clearence issues but then again nobody has mentioned which cams they used or what kind of advance they are running etc.

I dont know how to measure up for this valve travel accuratley as Ive not done it before, any pointers and equipment reccomendations would be welcomed at this point , I love to learn these things

 

whatever happens, my cam is going for a plane ride soon, just waiting on a friend to pay for his parts of me

Edited April 27, 2007 by Richie-Van-GTi

[petert 554]

Measuring Valve to Piston Clearance

 

Assemble block, crank (2 bearings will do), one rod, one piston (no rings). Establish TDC accurately. I find it's easy to use the flywheel as protractor. One Motronic tooth = 6 degrees. Mark TDC on the flywheel. There's a very convenient M6/M7 hole near the top starter motor hole to use for a pointer mounting location point. Do search on the net on how to find TDC accurately.

 

Assemble head with just one inlet valve, no spring, collet or retainer.

 

Torque down head with gasket to Stage II only, using old bolts. You don't want to stretch your new bolts or break old ones. The head gasket will compress correctly.

 

With the piston still at TDC, drop the inlet valve onto the piston. Measure how far it drops with a dial indicator. That will give you the total distance the valve can possibly travel. If that measurement is less than 0.195" you can't use the Stage II grind unless you make the valve pockets deeper.

 

Do the same with the exhaust if you like, but if you're using a standard exhaust cam you'll have plenty of clearance. There should be minimum of 0.100" at 6 deg. BTDC, which equates to 0.110" at TDC. You should aim to advance the std. exhaust cam so it runs at 0.060" lift at TDC. So the exhaust valve will need a total of 0.170" in this case. If things are still a bit tight, keep in mind that the standard exhaust cam runs at 0.032" lift at TDC. So anywhere from 0.032' to 0.060" will be fine.

[Richie-Van-GTi 70 2 Cars]

excellent thanks peter, I'll get it all measured before I post the cam out to you so I know which profile to have

[petert 554]

Don't consider machining the pistons to be a major hurdle. If you don't have the skills/machinery, measure what you have then box them up and mail the pistons to someone like QEP who does that work regularly. They'll have a jig to hold the piston correctly, at the right angle, making setup time minimal. A machine shop which doesn't have the right jig for your size piston, will take longer and charge you more, probably for making a jig which they'll use again anyway! There's only two hours work maximum to do such a job if setup correctly.

[Richie-Van-GTi 70 2 Cars]

ok, theres a machine shop near me that does a lot of peugeot engine work who I trust anyway and they are reasonable. Shame they dont do flow work anymore. I think it will be stage 2 anyway, no point in going milder and regretting it later.

 

Ordered a set of very low mileage r1 bodies complete now as well.

 

just need answers on the injectors and management now