1.9 16V To 2.0 16V Bottom End Swap Worthwhile?

[Jim 1]

Hello,

 

I've got a very healthy 1.9 Mi16 in my 205 but I'm considering an S16 2.0 bottom end.

Engine mods are:

Shenpar ported head with 3 angle seats,

Autosprint 276 degree reprofiled inlet cam with #4 pulley,

DCOE 45s (40mm chokes)

4-2-1 manifold with 2 1/2" Pugracing exhaust,

Sump mods (no oil surge)

 

The car is quite torqey & pulls hard. Peak power feels to be around the 6850 to 7000 RPM mark.

 

The car is a second car for fun only with maybe an odd trackday.

 

I have searched and read through loads of old posts on here but still can't make up my mind.

 

Can anyone say, from experience, if the gains of changing to a 2.0 iron block are worthwhile?

 

Thanks

 

Jim

Edited March 24, 2016 by Jim

[Tom Fenton 1,541]

I don't really understand what you are hoping to achieve? Are you hoping the extra 100cc will make a big difference? (it won't).

Plus the fact you stand to add a lump of weight to the front of the car right where it needs it least, I can't quote figures but I'm sure its in the region of 15kg at least.

If your alloy Mi is a good one then I'd leave it well alone.

You don't mention any other car spec in your post but if its a serious trackday car then the money could probably be spent better elsewhere, rose jointed wishbones, limited slip diff, bigger rear torsion bars, etc etc etc.....

Finally, I see you are local-ish, the South Yorkshire PSCUK group meets are 1st Monday of the month at the Winter Green pub just off the Sheffield Parkway, why not come along and meet some likeminded folk!

[welshpug 1,657]

I agree with tom, it'll be minimal for the outlay, especially with how worn Iron block engines are these days, you will more than likely need a full rebuild at the very least, if not an overbore and fresh set of pistons.

 

you'd gain more by going for a decent throttle body setup with a nice inlet manifold, and putting more cam in.

[Stu 18]

I think the only benefit to going over to the iron block is if you run an 88mm crank and get it to just shy of 2.1; even then i dont think i'd do it as from experience, when going from an Mi to a J4RS the extra nose weight was very noticeable, so for this reason alone i probably wouldn't do it. I realise we're not exactly comparing like for like, but we're talking similar numbers.

 

Given the choice, i'd take a healthy Mi over a S16 or J4RS any day of the week.

[Jim 1]

Thanks for your replies.

 

Tom, I was wondering about the gains for the extra cc plus the unshrouding of the inlet valves. It sounds like it's not worth the hassle/expense if I would only get minimal gains. Also I don't like the sound of the effect of the extra weight.

The car is only for fun only, nothing serious.. I was just hoping to do a trackday or two this year.

Other mods are: Quaife Diff. 309 front arms with competition spec driveshafts. New Bilstein B4 shocks all round, & New Eibach springs (which I plan to replace with reset OEM springs). Solid rear beam mounts, 306 gti front brakes, Mi16 Master cylinder, Mintex 1155 pads all round.

All bodywork is standard & has full interior.

P.S. Thanks for the invite. I will try & make it to one of those meetings.

 

Welshpug, Ideally, I would like to swap to TBs but I've deceided to stick with the carbs (I like tinkering). I was thinking of trying a catcams 527 inlet only. Any input welcome?

 

Stu, I will be sticking with the alloy block.

 

Thanks again,

 

Jim

[Alan_M 66 1 Cars]

Have a read of PeterTs website....an insight into XU9j4 tuning.

 

http://www.taylor-eng.com/

[Jim 1]

Alan, Thanks for the link. I read Peter's site last year and did the sump/oil pump mods, I also changed the inlet pulley from a #2 to a #4 to increase the dynamic compression.

[petert 586]

I'd do it. The extra torque and hp on the track is very noticeable. None of my racing buddies here in Aus run 1.9 blocks any more. Once you start to go beyond the standard tune the hp unlocks more easily. It's easier to get more compression and the larger bore unshrouds the valves, yielding better port flow.

[petert 586]

I should add however, that while ever your 1.9L is alive, I'd leave it spend the money elsewhere. eg torsion bars. When it eventually dies, then do it properly with new pistons etc.

[Jim 1]

Thanks for the advice, Peter.

Part of my reason to change to an iron block was to up the compression using a thinner MLS gasket, or by using the 88mm crank. I'm concerned about the MLS gasket sealing properly on the 1.9. Should I be?

Edited March 26, 2016 by Jim

[petert 586]

Getting a good surface finish on top of the liners will be your biggest issue with an MLS gasket. I'd use a copper gasket on a track 1.9L before anything else. The liners (with correct protrusion) do a great job of sealing against the copper, without the need for an o-ring.

 

A cheap and chearful performance S16 can be built by skimming 1mm off the block, if retaining the 86mm crank. You'll get the compression ratio to low 11's with a standard head gasket, or higher with an MLS. You need to o-ring if using a copper gasket.

 

Keep in mind you'll need to check valve to piston clearance if you start fitting bigger cams with thin head gaskets.

 

If you have an S16 with a good crank, I'd save up for a new set of 87mm flat top pistons. Skim 1mm off the deck and put your existing complete head on that (with a bit more inlet cam as an option) with an MLS gasket.