hacker-pschorr

Scott M, and Marc@Devek - you have a PM.

Stan.Shaw@Excell.Net

I have one '86.5 motor available now. I pulled it from a car, after driving the car, so know it to be good. I also have the computers available (and wiring harness).

hacker-pschorr

Stan - you have a PM.

Speaking of "cheap" engines to rebuild. How about parts availability?
Per 928international's web site:
4.5 rings - $67.00 x 8 = $536.00
4.7 rings - $25.00 x 8 = $200.00

4.5 shortblock = $500.00
4.7 shortblock = $750.00

Bearings will be the same for both, gaskets look the same - your better off getting a 4.7 vs a 4.5.

Mark or Jim - any reason why the 4.5 rings are so expensive vs the 4.7 and 5.0?

Jim bailey - 928 International

Hacker , The 4.5 rings are Porsche dealer only as I recall and almost no one ever rebuilds a 4.5 (4474 actual) without over boring honing to 4.7 or (4664 actual) so there is little demand . The 85-86 5 liter (4957) short block makes a nice 16 valve "hybrid" engine. And bigger is better in this case.

hacker-pschorr

I know with Euro heads an 85-86 block will require new valve relief's to be cut in. Will a US head require the same mods to work with an 85-86 block?

Will an 85-86 5.0 block setup for Euro 16v heads work with US 16V heads without any further mods?

I'm not looking for the "best" combo, just thinking outloud about different combo's. I have a lot of options in front of me for my car. Any combo will be better than the 160rwhp I currently have.

Jim bailey - 928 International

Correct you must machine valve reliefs in the appropriate location for the 2 valve head the larger cuts for the bigger Euro valve is more than adequate for the USA BUT both become interference engines which can bend valves.

hacker-pschorr

Thanks Jim, reason why I ask is because if I go with a 5.0 motor, I'll probably find a way to cut Euro S valve relief's into the motor and run US heads for a short time. I'm not sure how soon I can spring for Euro heads. I'd rather cut the pistons once, add heads later. I realize this is not the most ideal for overall performance, but anything is better than what I have.

I'm assuming the Euro heads listed on 928intl's site is just the head, no valve's, cams etc.... right? What do you get for a pair of complete euro heads with cams?

Jim bailey - 928 International

The heads have valves ,cams are separate $1,000 for a pair of Euro Cams ...or you get a complete Euro 4.7 good engine for about $3,500.....

docmirror

The USA/Euro head CASTING is the same? or Diff? If the same, the valves, cams, and springs can all be modified for Euro spec. I wonder how well heat treated the Porsche cams are, and if they will take a regrind and heat treatment?

I know it's old school, but if a guy has a strong bottom end, the HP is in the heads. That's where I'd spend my HP money. Euro cam profile, Manley valves and springs. New seats, some quality time with the pot grinder/polisher. Hey, I sound like a hot-rodder!

hacker-pschorr

At $1,000 for a set of factory porsche cams, the cost and possible quality loss of a regrind is not worth is.

Rich9928p

The USA/Euro head CASTING is the same? or Diff? If the same, the valves, cams, and springs can all be modified for Euro spec. I wonder how well heat treated the Porsche cams are, and if they will take a regrind and heat treatment?


The Euro S heads are different (larger valves, same size as 944s), Euro S cams are different, and Euro S pistons are different. Euros used different engine control, or perhaps to qualify the same engine control from '77 - '83 CIS K-Jet was used and then from '84 - 86 LH/EZF were used. It wasn't until '85 that the US models got LH/EZF. US 80 - 84 used L-Jetronic.

Changing a US-Spec car to Euro isn't trivial. The pollution control equipment also is quite different. So for a street car, by far the easiest way to get more HP in an '84 or earlier US spec 928 is to add a supercharger.

rob rossitto

Elgin Cams http://www.elgincams.com/ has been doing 928 regrinds for quite a while...you can get a "hotter" cam by reducing the base circle a bit...changing valve ht a bit is no big deal if you are doing new valves/porting anyway...

advantage is that indexing is spot on, less than a new billet job...they re-nitrite them for excellent hardness/wear and also have some custom indexing jigs for really custom jobs on the 928(ie changing lobe timing)...w/the hydraulic lifters on a 32 V, IIRC you have about .070" to play with (not sure on 16V), so a mild regrind (.020" or so) can even use stock valve hts (ie no lash caps), while increasing lift and duration a bit...only performance gains this way, and you get to re-use your OEM hardware w/out any of the headaches from a more rad profile(ie, increased spring pressures/wear, coil bind, float,etc)...

nice guys too...they take about 3wks for turnaround and can do coatings if you are into them...nice to have options...I'm using them for my stroker GT regrinds, were recommended by a few 928 builders...guess we'll see, but I'm pretty confident (hope/hope/hope) they'll be fine...

be careful on porting, larger valves - too big only helps top end, as maintaining intake velocity is important at low rpms(IIRC, not so good for a street car)...
IMO/from what I've seen/been told, unless you are changing the displacement or tuning for higher revs, Dr P's gang didn't seem to leave a lot on the table to mess with, without sacrificing something...

from what I've experienced w/just upgrading my 32V heads from 85 to 89, engine swaps/partial swaps don't seem trivial (ie poor $$/HP), can be a maintenance nightmare (hmmm what year part/spec should we use here?), and don't leave much for a return to OEM should the need arise - so FI might just be the best HP/$$ around for older sharks(pre-86)...no mess, no fuss, just pure bolt on bwaaaa....just my opinon, of course - but hope this helps...

regards!

docmirror

Well, all that, and I still don't know if the head CASTING is different.

I respectfully diasagree about the cam regrinding too. I've had $1000 cams from a F car reground and treated to P6(Euro) specs at less than $200. AFAIK, they're still running well. So, the question still is: Can one take a non-Euro head, install bigger cams, valves, springs, and rechip the LH for Euro-like performance, on somewhat of a budget, using already owned castings.

Almost forgot the relief grinding too.