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3 litre 8v dilemma


ORIGINAL: nick_968


ORIGINAL: 333pg333

While I agree with Nick in principle (and practice), I think it's still do-able on a less than 'Kabillionaire' budget. Both Mike's and Markus' builds went very well until both motors suffered due to increase boost. Markus had actually sold his motor by then so it wasn't actually he who had the accident. Mike couldn't resist turning up the wick. Now it's possible that both of these motors may have been weakened over time with forced induction but I can't be sure. Markus reached somewhere near 500bhp on his so lets assume this is possible! You could also buy some custom Wossner pistons for approx. 700GBP. Rods are not too expensive either from the same maker if my memory serves me correctly....it does beg the question....
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Questions for you Pat.....

1. On average how much more in % do you spend on a project than you originally budgeted?
2. How easy is it NOT to turn up the boost?
3. Add the rods, the pistons and your into the same territory as any other 3.0 build and you know where that ends right?

[8D]
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1. Too hard to say, but it's always a fair bit more. The only thing I'd say is that there is a lot of info out there to make more of an accurate speculation on overall budget, that the % increase over initial numbers may not be so much more....it's just that the original budget may start a bit higher than you desire.

2. I guess this is user determined. Some guys are pretty self disciplined, and perhaps more on this forum than others, but I agree that temptation is great to just squeeze a little bit more out of it. Having said that, you can set in place alarms and failsafes too.

3. Not necessarily...but again, yes, this can happen. My mechanic is going to try a reasonably cheap version of a 16v turbo project with an S2 motor. He's ordered the pistons & rods (Wossner), SFR intake, and will use his Vitesse Maf & piggyback to control it. May even use my old Stage V turbo. Obviously being a mechanic he doesn't charge himself a labour rate and we already had the S2 motor from a Japanese LHD import so while it's not going to cost him a lot, it would cost Joe Public quite a bit more.
 
I am following with interest progress on 16v turbos as one day I hope to use the head from my engine, or my whole engine to build a 16v turbo once I see a build I like the look of and can replicate. Do these Wosner pistons work ok in the Alusil block and with the same Carillo rods I have in my engine at the moment?
 
Nick, don't you think the 16V head would already work with (y)our Mahle pistons?
 
As far as I know it does not work, unless you know different? I have never been able to get a definite answer as I dont know of anyone who has made it work. People who do 16v always seem to use different pistons as the Mahle were made specifically for 8v.
 
The Wossners have an Alusil compatible coating but I guess the jury is out until we have someone running around for many thousands of miles before we can definitively put the thumbs up. My friend will have his done for next season so I imagine he'll finish it off sometime later this year. So long as the Carillos are the right dimension then I'm sure they'd be fine Nick.
 
Well all the studs are out of the 968 block, but most of the studs are in the 2.7 block for good it would seem, any body know how much new studs are? I can't find any online prices apart from racers edge in the States and the are a bit steep/far away for a temp fix.
Have tried OPC but the parts dept closed at 1pm oops.
I dont want to put any more work in if they are loads but I do need the car running fairly soon so may have to bite the bullet anyway.
 
I haven't done a back to back comparison but I have to assume that the studs for the 16v head will vary in at least location, if not size and number, against the 8v head? So to clarify James, are you planning on using the 8v head temporarily until the 16v one is refurbished?
 
The stud location is the same but the 8v ones are shorter due to the reduced height. Yes I am planning to use the 8v head on the 16v block, (edited to add) until I make my mind up as to what to do with the car.
 
Good news OPC quoted approx £31 for studs, there's none in the UK but they reckon 4 days. So with luck the car should be running by the weekend.

Now where's that turbo....
 
Not much progress due to heat/work/beer.
After ordering an 8 valve cambelt as the 16 valve belt is too long (should have been a clue really) it turns out on assembly that the 8 valve cam sprocket has 4 teeth less than the 16 valve. Time to tear it down again and fit the crank pulley from the 8 valve engine.
Bugger.
 
James, make sure you order the washer that goes with the t-belt pulley on the crank.
The 8V timing belt is narrower than the 16V timing belt (less valve springs = less strain = narrower timing belt) so the pulley on the crankshaft is narrower as well, also the pulley on the tensioner.
Compare the sketches in PET or directly on your original 2.7 engine to see all the parts you need.
 
Cheers for that, will transfer the whole part from the 2.7.

Pretty sure the valves will clear the pistons, will find out tonight hopefully it should be running.
 
You might want to change the timing-belt tensioner as well, and the stud layout holding the tensioner on the block is a bit different too.
 
Yep had to change the whole tensioner assembly. Called it a day for now, all that is left is the vac pipes, throttle cable and I have to try to find the king lead. Oh and the valves do clear the pistons.
It certainly isn't that quick a swap but I have all the parts and need to have the car running.
 
It lives!
Started first time and idled fine on the 16v map.
Couldn't run it for long as the neighbours may have something to say about me not finding the exhaust bolts but wanting to start it anyway!
 
I love this mix and match approach to building engines. Good work James. Looking forward to hearing how you develop things as you go foreword.
 
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