Engine rebuild - tips for upgrades?

Compulsive · 07-16-2008, 08:00 PM

I am taking my engine apart to find out why there is a knocking noise. While the parts are scattered around on the floor it would be a great time to install some upgrades parts inside if the budget allows. Can you walking 930 encyclopedias give me some advice? This powerplant need to support a K27HFS making over 400hp.

I know that it is getting ARP rod and head bolts and 964 cams. Other than the normal wear and tear parts that will get replaced with OEM Stuff what should I upgrade?

Are the original valve springs and retainers ok if I keep the RPMs under 6500?

If I do need pistons and cylinders what should I get? OEM? C2 turbo full finned? Aftermarket? What pacakge will last for 60k miles? I don't want some piston slappy race stuff!

Is the 930 oil pump good?

I need to keep the parts budget as low as possible but if the pistons and cylinder are toast it will add up fast

DSPTurtle · 07-16-2008, 08:29 PM

Here's my tip... make a budget, double it, double it one more time and then get started.

You don't necessarily need the ARP head studs... the OEM steel or the latest fully threaded OEM studs are sufficient. Two things I wish I would have done are the rod bolts and the cams... you have those on your list so that should work. You might also want to get the intake ports opened up a little bit when you get the head work done. That is another place that I wish I had gone but didn't. Oh well, there is always next year.

NathanUK · NathanUK's Garage

I wouldn't use the stock head studs if you get that far into the engine.

The fully finned cylinders are the way to go. 3.4 P's & C's are nice, they also can give a bump up in CR which helps off boost performance. Of course you should also then lower your boost pressure though.

A bigger bore benefits from twin plug ignition, the list goes on and on

DSPTurtle · 07-17-2008, 03:22 PM

Nathan is Mr. Negativity today

Stock, steel headstuds work. But then again, so does ARP and Supertec. On my next pull I think I will go Supertec but till then I have a Frankenstein... all dilivar on #1-3 and stock coated steel on #4-6. Sweet!

Compulsive · 07-17-2008, 07:08 PM

Well guys this has been a rocky start to my quest for information

Required or not I am doing the ARP bits.

Who makes the best piston and cylinder sets for a road car? The original Mahle stuff is the most pricy. What do you think of Nickies and the other aftermarket stuff out there? I can't see there being much diff going from 3.3 to 3.4 but a bit more compression would be great.

Valve springs

Are the original ones fine for 964 cams?

DSPTurtle · 07-17-2008, 08:12 PM

According to the literature, the stock valve springs are fine as long as you are not increasing the size of the head of the valve too much or planning on building a motor that will make power past 7000 rpm. Have you gotten Wayne's book?

NathanUK · NathanUK's Garage

There are some people that haven't used top quality headstuds & have had their heads lift

The titanium retainers are nice as they save some weight. Hopefully someone will comment on the valve springs. I would make sure they can cope with any extra lift the cam might have.

Compulsive · 07-18-2008, 05:34 PM

Good info guys.

The big lingering question is which piston and cylinder set?

Have any of the non-Mahle sets proven to be reliable over the long run?

Sure race guys use the forged & CNC'd stuff but I refuse to do rebuilds every 20k!

930gt-40r · 930gt-40r's Garage

I would certainly drill for twin plug even if you are not going to use it immediatly. A pair of 964 cams will be cool. I would try to see if you could get a set of Pauter rods, the stock 930 get weak in the face of big power. If you do not plan on going over 400- leave the rods and just stick the arp fasteners in. Nathan has a point about the 98mm pistons/fully finned cyls. I would use the Mahle stuff for road use, they are good. Other things to do: Shuffle pin the case, valve springs/retainers, and I am sure there are others that i will remember later.

930gt-40r · 930gt-40r's Garage

freshen up the heads... light port and polish...

Compulsive · 07-18-2008, 06:56 PM

Quote:

Originally Posted by 930gt-40r

I would certainly drill for twin plug even if you are not going to use it immediatly. A pair of 964 cams will be cool. I would try to see if you could get a set of Pauter rods, the stock 930 get weak in the face of big power. If you do not plan on going over 400- leave the rods and just stick the arp fasteners in. Nathan has a point about the 98mm pistons/fully finned cyls. I would use the Mahle stuff for road use, they are good. Other things to do: Shuffle pin the case, valve springs/retainers, and I am sure there are others that i will remember later.

I will stay with the stock rods. 964 cams are going in. 6500rpm will be my limit.

What does it mean to shuffle pin the case? Why?

So you vote for Mahle above others? Do you mean the 7.5:1 CR 3.4L set? Damn they are expensive

Are Jerry Woods bearings the best or does it really matter?

RarlyL8 · RarlyL8's Garage

ARP heads studs and rod bolts as well as beefy valve springs are excellent insurance for your expensive engine. It's not the power that kills, it is the accidental overrevs and overboost.
An HFS will make power past 6500rpm, no need to be scared of taking it there after spending the money on a rebuild.
Cams and open up the heads. Really not much else you need to spend money on in the engine to get your 400WHP. Stock P&Cs are fine at that level.

BReyes · BReyes's Garage

First of all I would recommend to use a Porsche machine shop. Lots of good machine shops but best bet is with an expert. You can get a lot of expert advice on the forum, and will need a real one too. I have my well trusted wrenches. I can trust what they recommmend will be the best. Getting your budget in order before hand is essential. Shuffle pining the case is a machine shop procedure to pin the case halfs to keep it tighter and crank aligned. It is mostly for high hp, which you are leaning towards. The machinist may want to do some very expensive boring, decking, flame ring, et al procedures. That is what i mean by choosing an expert who you can trust and let them do their stuff before you build. BTW if your crank will need work on one journal they will all probably send it out to the same guy to do his magic.

Let's see I have had CIS before (SC not 930) and have been reading more and may venture to say you will need to do a lil something something to your system if you expect to get > 400.

So yes it sounds like she is going to be real mean.

Regards,

PNCs, well, that is a tough one. Has your machinist told you yours are out of spec?

Bearing are different depending on mfr. Getting the good ones is important. Jerry Woods bearings huh. Probably a nice piece.

930gt-40r · 930gt-40r's Garage

Shuffle pinning is the process where the machine shop drills the mating flange of the case halfs and they put a set of dowel pins for the sake of keeping them from shifting- very good idea- my machine shop charged me $330. Ive never used the JW bearings, I assume they are good, but I would stick with stock. If you do not plan on going nuts, the stock P/cs are ok, but the added displacement of the 98s help. But you would be better suited to port the heads lightly with the 964 cams. If not aftermarked rods, most def. use arp bolts. Heads, cams, and K-27 HFS+ supporting fuel mods will make one hell of a machine.

NathanUK · NathanUK's Garage

Shuffle pins installed in one side of case. There will be holes in the other side for them to fit in to. Not my pic!

DSPTurtle · 07-19-2008, 05:01 AM

I thought that either Wayne or Bruce Andersen said to stay away from shuffle pinning the later cases unless you are going to make really big horsepower. I forget the logic, but I know I read that in ink somewhere.

RarlyL8 · RarlyL8's Garage

You can overbuild anything. 400WHP is no big deal for these engine and nothing fancy is needed. Studs, rodbolts and springs are good insurance for overrevs, which can happen to anyone. If I were building a stock engine I would add those parts.

Craig 930 RS · 07-19-2008, 02:01 PM

Sell the 930 heads, buy SC heads

K27 HFS turbo

Fuel management - search for 'Leask'

Hardware, as mentioned

Stock rods are 100% fine

Shuffle pin on a 930 engine = waste of money

3.4 P&Cs since you most likely will be replacing them anyway - get 7.5 compression - MAHLE

A few more things I'm sure, but I gotta go -

Compulsive · 07-19-2008, 04:12 PM

Nice tips Craig

Quote:

Sell the 930 heads, buy SC heads

How much power will they add to a 400hp 930? Going price? Got any for sale

Quote:

3.4 P&Cs since you most likely will be replacing them anyway - get 7.5 compression - MAHLE

I hope I don't need them since they will set me back $4500! Are none of the aftermarket options as good? It would be so nice to buy good P&Cs for $3000!

polizei · 07-19-2008, 07:18 PM

Quote:

Originally Posted by Compulsive

I hope I don't need them since they will set me back $4500! Are none of the aftermarket options as good? It would be so nice to buy good P&Cs for $3000!

I've seen used 3.4 Mahle's go for around $2k on ebay - very rare though. A lot of guys run JE Pistons without any troubles. A pretty cost-effective solution would be a set of 3.2 fully finned cylinders bored out to 3.4 then nikasil coated. Tack on a set of new JE pistons with the compression ratio of your choice, and you'd be there within your budget.