Boring Mi16 Liners

[Cactus 1]

Well after being away for a while i have got round to re-building my ally block mi16.

 

I want bore the liners from 83 to 83.5mm but i am struggling to find anyone who is willing to do it was wondering what experiences others may have had with this sort of thing. so far about 6 local firms have highlighted concerns over distortion.

 

I am told that to machine the liners they need to be clamped in the block by placing a thick steel plate over the top. If you try to machine them with the liners out of the block distortion occurs.

 

anyone faced this problem before?

[petert 588]

I've had quite a few sets done but only in 83.5 and 84.0mm. They speak the truth. They distort badly. They need to be held in a jig/fixture that simulates how they are loaded in a block. Keep trying. Boring liners is a specialised field but plenty of other cars have liners.

 

Why 85mm? This also makes it more difficult and they'll be bugger all left down the bottom. Either rev it higher or go to an iron block if you want big cubes.

[engine killer 6]

i am running big bore liners and piston too. tried to bore the stock liner before but failed badly as petert described, distorted badly. the liner itself is already too thin, so by clamping the liner already distorted it.

 

my mechanic bought after market one for me but the price.....

[S@m 156]

I have spoken to a few engine places about boring wet liners, usually you hear alot of teeth sucking. Very few places take in on, and the ones that will charge silly money but then they do have the reputation/equipment to back up that silly price usually.

 

Sam

[Cactus 1]

Hi Peter, i think you mis read, i am only going up half a mil to 83.5 and thats just because i have some forged pistons laying around that are begging to be used

 

I am beginning to think sourcing an iron block may be a better idea?

 

I spoke to Darren at spoox a few minutes ago and he seems confident that they can be done but in light of what i have heard from others i am reluctant to shell out hard earned cash for what may end up being scrap liners.

[Cactus 1]

Peter, when you bored out to 83.5 were these clamped in the block as i described?

 

Being a resourceful chap it may be an option for me to fab an appropriate plate to clamp them in place and let my local guy have a go.

[welshpug 1,661]

I believe Sandy or Miles may know people that can offer this.

[tony perks 1]

I have just had mine done by Maynard engineering PM for phone number, and a great job he did too, he has fabricated a fixture which holds the liner in the bottom the same as a block would, and is clamped circumfrentialy, on the top the same as the head would, and they are then honed to your piston size befor removal from the jig.

Edited August 2, 2011 by tony perks

[Cactus 1]

Tony - you been pm'd

[tony perks 1]

Tony - you been pm'd

You cant PM me aparently I have had a message from you.

[welshpug 1,661]

http://www.maynardltd.co.uk/

[petert 588]

Sorry, I did misread the bore size (iphone without my glasses!). I have two places that do a fantastic job. Both charge AUS$50 per liner as guide. It's certainly easier and cheaper to rebuild an iron block and you get better results. ie more favourable rod ratio. If you do persist with the alloy block how will you address locating the conrod? None of the forged pistons I've seen are machined internally.. If you wish to retain this feature it means modifying the piston as per the pic and making thrust washers. Alternatively, get some 8V rods bushed. Otherwise the 16V will flog about, crashing into things it shouldn't.

[Cactus 1]

Well that’s another problem I didn’t know about I am going to have to go and have a think about all of this, it’s obviously a little more involved than I first thought. I guess the decision to be made is alloy or iron block? (Oh no not that old debate again!) I hadn't even considered that there would be a piston/rod problem. It seems that somewhat naively I thought I would just bore the liners chuck the pistons on the mi16 rods and off I would go happily rebuilding my engine. Once again I am enlightened by the wealth of knowledge on this forum - thanks guys

 

questions questions...

 

If I go down the Iron block route do I eliminate the piston problem? This has the benefit of being able to get the block bored locally too

 

Will all the ally block internals be interchangeable (not the liners before someone suggests where they might fit ?

 

Are there any iron blocks to avoid? I think I read somewhere that there were some differences

 

Am I right in thinking that bores are all 83mm and it’s the stroke that changes - hang on is the XU10 not a bigger bore too - can’t remember.

 

Right, obviously I need to go do some research but if anyone has any thoughts as to the best way forward or has any info to hand let me know.

 

 

Tony, I don’t know what you are running, I am using omegas; did you face any piston problems? I checked Maynard’s website btw, I will give them a call when things are a bit clearer.

[Cactus 1]

Forgot to mention, I have an unused recon head (if thats not a contradiction) off a xu10 I believe ( has the extra exhaust manifold stud) that i intended using -will this affect which block I source if I go down the iron block route?

[petert 588]

If I go down the Iron block route do I eliminate the piston problem?

 

Yes, XU10 rods are located by the crank.

 

Will all the ally block internals be interchangeable ?

 

Mostly. You'll need XU10J4 rods, harmonic balancer, tensioners etc. You can use your 88mm crank for extra stroke.

 

Are there any iron blocks to avoid? I think I read somewhere that there were some differences

 

Best is XU10J4 in my opinion, as you get full floating rods and they are the longest. The rest are press fit. This block also has oil squirters, but so does the XU10J4RS.

 

Am I right in thinking that bores are all 83mm and it’s the stroke that changes - hang on is the XU10 not a bigger bore too - can’t remember.

 

 

Iron blocks are 86.00mm bore x 86.00mm stroke. So you can easily make 86.50mm x 88.00mm.

 

The head type doesn't make any difference, other than which head bolts to use.

Edited August 3, 2011 by petert

[Cactus 1]

I dont know if i am missing something with this piston/ rod problem but i have compared the standard piston/rod to an omega piston/rod and there seems to be a similar amount of lateral play i aint had a dial guage on it yet but at a guess i would say about 0.3,0.4 mm. They feel very similar. The omegas are machined on the inside by the look of it - will post some pics shortly.

[Cactus 1]

Just tried to add pics and realised i can't - sorry I will try to sort something out

[Cactus 1]

Finally here are a couple of pics

[petert 588]

That's excellent. I'll buy some of those next time.