Xu7j4 Perfect Basis For A 1600 16v

[Batfink 201]

As i want a high revving race engine, i think it would not be wise to have a weak point in the rod. This also means I can run a smaller piston and longer rod. I believe the XU7 piston is smaller in depth than the mi16 so will be lighter so I need to confirm that as I think that would be a better option than an mi16 one (though I dont think you can get high compression pistons for that engine so its custom again).

I'm using an mi16 block and a possibly a gti-6 head (or xu7 depending on what I can get hold of)

Reason I am doing it over the TU engine is really due to my gearbox and dry sump setup and I love to do something a little different.

Its more work as there are no off the shelf parts but the costs will be roughly the same.

[Saveit 0]

The XU7 rods are the same as the XU5, 22mm pins though, not the 20mm I said in that quote!

 

It's all fine except the pistons. You'll need a crown height (distance from pin centre to block deck) of 37.5mm, which coincidentally is the Mi16 height. The intruder needs to be at least 5cc net. The rods need to be narrowed slightly at the small end and bushed ideally, but that does leave them very thin over the pin, so proper rods would be preferable really.

 

For a 1600, you have to consider using the TU 16v, because it will be a much simpler build.

 

Why would i need to bush the rods? The pin is appearently the same size so (except from narrowing the rod or widening the piston) it would be a direct fit, so i cant see the reason for bushing them? How did you do the intruderish mi16 piston - with an angle grinder or on some fancy machine? Could you possibly do a set of pistons for me?

 

As i want a high revving race engine, i think it would not be wise to have a weak point in the rod. This also means I can run a smaller piston and longer rod. I believe the XU7 piston is smaller in depth than the mi16 so will be lighter so I need to confirm that as I think that would be a better option than an mi16 one (though I dont think you can get high compression pistons for that engine so its custom again).

I'm using an mi16 block and a possibly a gti-6 head (or xu7 depending on what I can get hold of)

Reason I am doing it over the TU engine is really due to my gearbox and dry sump setup and I love to do something a little different.

Its more work as there are no off the shelf parts but the costs will be roughly the same.

 

Agreed about the TU engine. Ill do this conversion for the same reasons as you.

[Batfink 201]

in sandys original post he said 20mm which was a mistype. he meant 22mm. Are the mi16 not bigger still?

[Saveit 0]

Off the top of my head the pin is also 22mm in an mi16 piston. So the rods would be a direct fit other than being to wide. But i could be wrong.

[petert 588]

Crown/compression height of the Mi16 piston is actually 37.1mm. So you're still behind the eight ball anyway. And as Sandy said, you still need 5cc of dome on the piston. As for rods, you're going to have to spin it to 8500+ to make decent hp, so you'd have to think a set of Carrillos are mandatory.

[DrSarty 90 1 Cars]

RE: Carillo rods. Pronta (my friend & VW forum moderator) built a 2litre 16v dub engine using Carillo rods, and he got friend pricing of £800 for the set.

 

I can see that whilst this thread has a simple notion, i.e. a 16v 1600cc XU based engine, there are so many options and suggestions flowing around one (Saveit) could easily get confused, particularly when there seems to be an unrealistic restriction on budget.

 

I agree with Baz, that if you're going to do this you need to {a} go full tilt at it, i.e. don't do great work on the internals then cut corners on fuelling & ignition and {b} realise that it's a simple concept but with lots of hurdles, that can only be overcome with some serious expertise & some serious dosh (money).

 

You're doing well consulting the forum experts (I don't include myself in this) and there's certainly a load of fascinating info in here from which I'm sure you'll get a decent result, however I think you need to increase your budget and prepare yourself for a tough job.

[Saveit 0]

I think ill go with standard balanced rods for start. I have PM'd Sandy to hear if he can do me a set of those mi16 domed pistons.

 

What about mi16 high comp wossner pistons - would those be too high?

[Saveit 0]

RE: Carillo rods. Pronta (my friend & VW forum moderator) built a 2litre 16v dub engine using Carillo rods, and he got friend pricing of £800 for the set.

 

I can see that whilst this thread has a simple notion, i.e. a 16v 1600cc XU based engine, there are so many options and suggestions flowing around one (Saveit) could easily get confused, particularly when there seems to be an unrealistic restriction on budget.

 

I agree with Baz, that if you're going to do this you need to {a} go full tilt at it, i.e. don't do great work on the internals then cut corners on fuelling & ignition and {b} realise that it's a simple concept but with lots of hurdles, that can only be overcome with some serious expertise & some serious dosh (money).

 

You're doing well consulting the forum experts (I don't include myself in this) and there's certainly a load of fascinating info in here from which I'm sure you'll get a decent result, however I think you need to increase your budget and prepare yourself for a tough job.

 

I agree with you Sarty. I believe am up for the job mechanically wise. But yes the budget seem a bit too tight if this is to be done correctly.

[DrSarty 90 1 Cars]

I suspect custom (forged) pistons are a must. That's £600+ to start with.

 

One additional piece of advice is to spend with the right person to get EVERYTHING matched and balanced.

 

Kyepan (Justin) on here posted something very, very interesting on K-series engines being uber-balanced. Naturally it can be done with all engines, but I think some people only get a few items matched & balanced, and with a high revving engine, you'll achieve a significantly better result by spending well in this area.

 

I'm sorry I can't be more technically accurate in my description (perhaps Justin will repost the link to the K-series article if he reads this) but thinking about it plain and simply, the engine spinning is generating forces in all kinds of directions. Some of these are purely 'up & down', the others are rotational; but inbetween these are a mixture of undesirables caused by vibration, friction and inbalance, and this includes generating heat and sound for that matter which all reduces the final power output.

 

Investing in a complete engine component balance, which means careful choice & treatment of each item, then collective treatment by rebalancing as you add each component to the engine to the Nth degree will be worth the effort and expense - higher power, greater durability, smoother revving & higher confidence in the engine.

 

My estimates at costing would be: (my prices include additional machining etc)

 

Block & sump set up £120

Pistons £700

ECU £400

Bike ITBs & manifold £400

Head £500 (cams included)

Mapping £400

Ancilliaries £400 (water pump / hosing / filters / alternator etc etc)

Full balancing £400 (guess price)

 

Total estimate: £3,320

 

Now I've just done this (perhaps pointless) exercise, I realise that after my 2.2L 16v project, a guideline price for a bloody good, custom 4cyl engine build of almost any capacity IMO is ~£4,000.

 

This pretty much covers all areas, although a lot more funds are then required to bring the rest of the car up to the standard of the engine (brakes, suspension etc), which means in my opinion a decent, enjoyable but competitive car, starting with nothing and to include the full safety, custom engine, brake and suspension set-up must require a budget of £7,500 - £10,000.

 

The point of my rambling is that you perhaps need to clarify exactly what you have to spend in total, as this may limit how far you go with this.

Edited May 12, 2009 by DrSarty

[Saveit 0]

Block & sump set up £120

Pistons £700

ECU £400

Bike ITBs & manifold £400

Head £500 (cams included)

Mapping £400

Ancilliaries £400 (water pump / hosing / filters / alternator etc etc)

Full balancing £400 (guess price)

 

Total estimate: £3,320

 

You have some good points Sarty. But i do not agree with the prices you mention here. I used my calculator and checked some prices and this is what i came up with (remember i live in Denmark where prices seem a bit cheaper?):

 

1.6 GTI engine (already have) £0

Pistons (wossner - bought in dollars) £450 with pins, rings and everything else included

ECU (megajolt for ignition only) £270

Bike carbs (already have some R1s) & manifold £50

Mapping £250

Head (will do some minor porting myself) with new cams and GTI-6 springs £300

Ancilliries £300 (have some spare alternators)

Balancing and piston/conrod assembly (will balance rods and crank - already have a lightened balanced flywheel) £250

 

Total estimate: £1,870 and actually i dont think i have set the prices too low.

Edited May 12, 2009 by Saveit

[DrSarty 90 1 Cars]

Total estimate: £1,870 and actually i dont think i have set the prices too low.

 

I hope you're right.

 

Remember what I mean about TOTAL balancing. Yes you have a lightened and balanced flywheel, but I mean balancing that with the crank, then with the rods & pistons fitted, then with the head fitted. This means lots of assembling, checking, possible work then reassembling.

 

Remember you may need an extended oil pump pickup, custom exhaust manifold and other bits that will come and bite you in the arse.

 

Trying to do this on a (tight) budget is the challenge, not the work itself.

 

Should be an interesting adventure for you/us.

[James_R 3]

You'll need to stick about £500 in for bearing, belts, fluids, decking the block, honing the liners and other misc items you've not included in that costing.

[Grim.Badger 15]

I've toyed with this idea, as with many others , and always come back to the realisation that TU is the better way to go. It's a more modern engine design, the parts are available off the shelf, the engine is already in a higher state of tune, and they are freely available. Sure it's an iron block but a few kilos can be made up somewhere else on the car, or you can fiddle around with the alloy TU blocks but I think you then end up in the same position as the XU7 engine

 

If you're determined, I would get the engine totally sorted and run it on cheap management whilst you save up for a decent ECU and ITB's

[James_R 3]

TU's seem the better option now that BE4 boxes are available to let you run a non chocolate gearbox

[petert 588]

The rods don't have to be Carrillo, but I certainly wouldn't use original. For example, a local manufacturer, www.ridgecrest.com.au makes custom rods for AUS$1200 for the set. You need to see them as an investment rather than an expense. At least tell the misses that. Don't forget that also includes ARP rod bolts.

Edited May 12, 2009 by petert

[Saveit 0]

Okay, you've convinced me regarding the budget. So if you guys were to recommend the right setup for this engine (it will be used in a danish endurance racing series) within a sensible budget, what would it be?

 

I would say:

Healthy XU7 engine to start with

XU5 crank (have)

Custom pistons £500

Custom rods (including arp bolts) £500

Full balancing £300

Bike carbs (have) and manifold £50

New cams, springs and so on for the head £400

Others (bearings, metal headgasket and so on) £500

(TB's and ECU £1200)

 

I have a feeling i forgot something? Anyway this wil be about £2250 without the TB's and ECU. Is this realistic then?

Edited May 12, 2009 by Saveit

[Batfink 201]

I think gti-6 camshafts are a lot more than £400

[TVH 0]

Okay, you've convinced me regarding the budget. So if you guys were to recommend the right setup for this engine (it will be used in a danish endurance racing series) within a sensible budget, what would it be?

 

I would say:

Healthy XU7 engine to start with

XU5 crank (have)

Custom pistons £500

Custom rods (including arp bolts) £500

Full balancing £300

Bike carbs (have) and manifold £50

New cams, springs and so on for the head £400

Others (bearings, metal headgasket and so on) £500

(TB's and ECU £1200)

 

I have a feeling i forgot something? Anyway this wil be about £2250 without the TB's and ECU. Is this realistic then?

 

What about healthy XU5 fully balanced bottom end, ported and skimmed XU10 big valve head, Catcams of your choice (not too much duration but lots of lift because of valve shrouding), bike carbs and manifold, 4-1 exhaust header. 170bhp/7500rpm should be realistic with careful cam choice and intake/exhaust tuning (tube diameters/length, gas velocity is the key not big CFM numbers...)

 

Also pay attention to the gearbox, you will need a very short gearbox with a high-reving engine.

Edited May 12, 2009 by TVH

[DrSarty 90 1 Cars]

Anyway this wil be about £2250 without the TB's and ECU. Is this realistic then?

 

Good suggestion above Finnish post ^^ .

 

Ref the revised budget I'd say yes. Your £2250 plus good ITBs, an ECU AND most importantly a good mapping session would see you roughly at my figure anyway.

 

So with your bits and all this knowledge I reckon you can go to it. Be prepared though for the cost to creep up to nearer my figure as the project progesses. Been there; done that!

[Saveit 0]

Be prepared though for the cost to creep up to nearer my figure as the project progesses. Been there; done that!

 

Haha yeah ill have to be careful

 

 

Now the only thing i am missing now is a positive answer on which pistons i can use? I would like to use those high comp wossner mi16 pistons which i linked to in my first post, but i need to know if these will fit?

 

EDIT: Did some calculations to determine if there is enough clearence when using xu5 crank and conrods and wossner high comp mi16 pistons. To do this i first determined how long the stroke + conrod is in a mi16. Stroke 88/2 = 44mm which is the height that the crank will throw from its center. 44mm + 143mm (conrod C/C length) = 187mm from center of crank to center of small end conrod. Doing the same calculations for the setup i am planning on: Stroke 73/2 = 36.5mm. 36.5mm + 150.5mm (conrod) gives a total of 187mm. This shows that if there is room in an mi16 engine for a high comp piston then there will also be room for the mi16 high comp piston when using my setup since the height from center of crank to center of small end on conrod is exactly the same. Then the only hurdle to overcome now is getting the high comp mi16 piston to fit the conrods.

Edited May 12, 2009 by Saveit

[welshpug 1,661]

As has already been mentioned, the only real hurdles are the rods and pistons, and of course making it run properly.

 

Here's what I've picked up so far to have a go at building one, albeit a mild spec...

 

XU7JP4 engine £50

XU10J4R head £50

Standard XU9J4 pistons £20.

Newman PH2 cams, £200.

XU5 crank, free.

XU10J4RS head, FREE as it has 10 bent valves, DOH! Not going to use that this time...

 

so far then £320

 

No labour for bolting it all together of course, but there will be some for checking the crank and any grinding/polishing required and modifying the rods.

 

Bearings £100?

 

Add management and induction, who knows what I can pick up over time

[DrSarty 90 1 Cars]

^^^ Dream on my Welsh (sheep shaggin') friend. It simply will not turn out like that.....and deep inside, you know that.

[EdCherry 34 1 Cars]

Why use old technology (carbs) on an engine such as this? If your going to do it, like I said before do it right. ECU and TB's are the way forward.

[welshpug 1,661]

of course I do know that it will add up, but so far it's not cost me a great deal

[Saveit 0]

As has already been mentioned, the only real hurdles are the rods and pistons, and of course making it run properly.

 

Here's what I've picked up so far to have a go at building one, albeit a mild spec...

 

XU7JP4 engine £50

XU10J4R head £50

Standard XU9J4 pistons £20.

Newman PH2 cams, £200.

XU5 crank, free.

XU10J4RS head, FREE as it has 10 bent valves, DOH! Not going to use that this time...

 

so far then £320

 

As far as i can tell from reading this thread you will have too low CR because of the standard mi16 pistons, and both XU10 heads will be too "big" for the cylinder capacity according to JamesR. Right?