Mark - I've got a 4.7l in the garage and am looking to do the exact same thing in terms of performance n/a rebuild. Based on some power to weight ratios I've calculated, 340hp would suite me very well in my lightened 928. This is an exmissions except car also... I'm still in the research phase to see what options are out there for the 16v.

So it sounds like 340 n/a hp from a 4.7l 16v is entirely possible???

 

N/A 4.7 with Euro heads, TB and cams would get you less than a stock 4.7 Euro S at 300hp, due to lower compression. To get to 340 would be tough, even with headers an good exhaust. Go with a 5.0L block and headers and you're there.

It would be interesting to see what a Euro 4.5L would do with "S" heads, cam and TB/Intake. With no loss for compression, it should make around 287hp (just accounting for difference in displacement of .2 liters). With headers, X and free flowing mufflers, it could make 320+ ?? Bottom line guys with non S Euros, could be 13 HP shy of the S with very little work. Peak torque may actually go down a tad as the 4.5L had higher torque than the 4.7L "S" to begin with.

 

Thanks for the info... I just picked this 928 up after selling my M3 so I'm just getting into it. So the 5.0L block can be swapped in for the 4.7L short block? Or do I need the full 32V top end also?

 

You can put the 5.0L bottom under the Euro S top for about 320HP, 340+ with headers and good exhuast.
You have to modify the pistons for the larger valve cut outs, make sure your cam gears are round tooth to match the 5.0L bottom end. Other than that it's pretty much bolt together and start.

 

we did it in stages.
4.5 stock with headers and euro intake, 218rwhp
4.7 stock euro with euro intake 250rwhp
5 liter adder to above 290rwhp

I did on my 4.7
headers only 200rwhp
euro intake and cams 243rwhp
5 liter added 290rwhp

 

Mark, any idea what a 4.5L Euro block would do with all the "S" bits above (Heads, cams, intake, TB)and headers? Since compression would stay the same, seems you would only account for the .2 liter difference. Seems it would yield 287hp at the crank verse the 300hp for the 4.7L. Add headers and a nice exhaust and you'd have made up the difference and then some.

That would be good news for the 4.5L Euro folks, if they wanted an "in the car" project that didn;t require a new block or engine pull.

 

'78-79 4.5L ROW have same low 8.5:1 CR as US models. '80-82 4.5L ROW should have same 10:1 as 4.7L S. They make same 240hp as earlier engines but have 30Nm (380Nm/3600rpm) more than earlier 4.5L. This is only 5Nm less than 4.7L S has (385Nm/4500rpm). So torque is virtually same numbet but at much lower rpm.

 

scots made 218rwhp with all the euro bits, except the heads and cams. (82US)
my 4.7 made 243rwhp with the cams and the larger displacement, all other things being the same. these engines are pretty easy to change out, so the 4.7 is the way to go, especially if you can get the euro top end stuff
mk

 

Too bad my 4.7 is seized, we pulled the intake assembly and plugs to try and spin the crank without compression to rule out hydrolock… not a budge. Looking down the #8 plug hole we see what looks like water/coolant in the cylinder, I’m guessing sever oxidation. Car sat for 7 years after having a little ‘off road excursion’ rendered it no longer road worthy. Looking down the intake port, #8 is also the only intake valve that’s noticeably open, maybe it’s related. But that’s what you get with the $500 parts car. Bought it for the 5-speed, pedal assembly, sheet metal, bla bla bla… but was hoping to get some bits off the engine too. Was told it ran last October, that’s just laughable, this car hasn’t run since the last millennia. Maybe I’ll post some pics for everyone’s entertainment.

 

Since we are talking 16V rebuilding;
I know alot of people say 928 blocks are toast once the cylinder walls are scratched or scored; however, 2 machinists I have talked with say Alusil blocks can be re-sleeved with Alusil liners and then machined. One guy said he has done this on MB, BMW and other vehicles. Another said he used the semi-finshed Alusil cylinder liners on a 928 and it worked fine (said he resleeved all 8 holes). He further iterated he used Lokisil liners on a Boxter successfully.

So if the engine rebuilders out there could provide feedback, lets say I have a block with a scored cylinder (#3). Is it possible to repair a damaged block by resleeving that will be reliable in a normal operating environment?
By normal operating I mean, just rebuilding a stock engine, no stroking, superchargers, NOX etc.

BTW - I see Carl at 928 Motorsports has a block repair service called Nicom (Nikasil) - has anyone tried this? Results? Opinions?

Thanks in advance,

 

This is a great thread! I have two 4.5L 10:1 CR Euro engines, and access to a disassembled Euro S engine/heads ('84). I can also get an S4 short block for a reasonable amount of money.

And I wanna start building an engine. N/A and 350hp at the flywheel is my target.

But I havent chosen which path to go down yet. Stock Euro S parts over 5L displacement would do it, but with the S4 short block I will get CR and piston issues. So that's where I am now.... open for input in other words.

 

I had all 8 bores taken to 97.5mm from 97mm there are still oversized pistons available at 97.5mm and 98mm for the 4.7's and also 100.5 and 101mm for the S4's and above.

the boring procedure is at http://joe928.joe_icecool.fastmail.fm/alu_en.pdf it's about 1.3 mb.

the alusil liners you make get lucky with it depends what sizes, i was in touch with KS when i was rebuilding the engine and no availability ex factory but maybe stocks on suppliers shelves.

I plan to take an S block to from 97mm to 100mm and fit GTS pistons and GTS crankshaft, you need to find a good S block with no erosion around the tops on the water side and also nice straight castings, a few i've seen aren't centered well so bore thickness varies.

Joe

 

Should add the oversized pistons are weighted the same as the standard and are direct replacements, after boring so as long as the scratch is less than 0.5mm deep a 1mm oversized piston and refinish off the one bore will be ok.

Joe

 

AFAIK KS still sells raw liners which were basis for many different size they made earlier. If they are available its possible to make any type of liner their dimensions allow. Its not cheap to do and in many cases its much easier to find better block to build on.

 

we bored scots very scratched /siezed bored 4.7 euro to 100mm and we are using the 85 4 valve pistons. its racing fine !

MK