3.0 Rebuild

[zevenbergena]

So I'm looking to rebuild my 1980 3.0 next year, and starting planning and plotting for the build. I want a motor that will have a bit more pep than stock, and looking to get another long life, reliable motor out of it.

Here is the stuff I want so far:

964 Cams
Steel replacement Headstuds
Carrera Oil-fed Tensioners
High Performance Valve Springs
Titanium Spring Retainers
Enlarged intake valve to 78-79 spec
Headers

A couple questions:

What is the benefit of RaceWare headstuds vs. the OE Steel replacement head studs? My goal for the car is to be a very fun street car that I can DE confidently. At best I will be running 2-3 DEs per year, the rest will be street driving as a DD. Does it justify tripling the cost for performance/reliablility?

High Performance Valve Springs and Retainers: I want to be confident driving hard in the higher RPM range and this seems like a no brainer. Is this correct way to do that, or are there other things/parts to consider as well?

What are we looking at for cost of head work to enlarge the intake ports? Ive read between $1,000-1,500 for cleaning and machining to orginial specs, havent found cost for enlarging ports. Also, I would need new larger intake valves, correct?

The cost of regrinding my original cams vs. buying 964/similar profile aftermarket cams. I forgot the name of the company but I think the name of the grind profile was 20/21 or something.


This is preliminary 'dream sheet' work so when the time comes, I already know what I want and ready to go. Am I missing out on anything major? Its my goal to keep this rebuild below $5K in parts, I'm open to all ideas, but please, no "sell it, go 3.2 with efi" recommendations. I don't want to drop $3-5K and then look at a rebuild another couple years down the road for 2 motors instead of one.

[yelcab1]

With that much work, I don't think 5K is going to do it.

[emac]

I just spent over four grand for a tranny rebuild---

No way on 3 to 5

[Scott R]

I did all that and a few more things, was more like 15~17 k.

[OldTee]

This might help you.
http://dorkiphus.net/porsche/showthread.php?t=17192

[zevenbergena]

Originally Posted by Scott R

I did all that and a few more things, was more like 15~17 k.

What all else did you have done?

I searched Pelican and came up with the approximate costs of each of these:

Complete Steel Head Stud Kit: $400 PEL-REBKT-02N
Ti Valve Spring Retainers: $300 930-105-911-TI-M336
High Performance Valve Springs: $500 901-105-901-50-HP-M336
Bursch Headers: $500 PEL-BURH-911-02
MSD Box: $200 MS-6200
Engine Gasket Kit: $320 H-100-907-03KTN
Carrera Tensioners ~$635 10-0445-105-M260


The currently unknown costs being headwork and a cam regrind/replacement.
All the above costs about 3K, I guess I didnt include things like new piston rings, valve guides, etc. which Im sure add up quite quickly on their own.

[Scott R]

Originally Posted by zevenbergena

What all else did you have done?

I searched Pelican and came up with the approximate costs of each of these:

Complete Steel Head Stud Kit: $400 PEL-REBKT-02N
Ti Valve Spring Retainers: $300 930-105-911-TI-M336
High Performance Valve Springs: $500 901-105-901-50-HP-M336
Bursch Headers: $500 PEL-BURH-911-02
MSD Box: $200 MS-6200
Engine Gasket Kit: $320 H-100-907-03KTN
Carrera Tensioners ~$635 10-0445-105-M260


The currently unknown costs being headwork and a cam regrind/replacement.
All the above costs about 3K, I guess I didnt include things like new piston rings, valve guides, etc. which Im sure add up quite quickly on their own.

Cam regrind I sent to camgrinder on this board, then you need to address all of the rockers as well, he does those as well. In all honestly you have a million "while your in theres." Things like cam sprockets, and the probable cracking of the case once you get down that far.

Just get waynes book, the prices are bit out of date, but you will see.

[euro911sc]

Depending on how patient you are you can reduce costs considerably. I took 3 years start to finish and I think i have about 4k into it. $1200 of that was heads to OEM spec. The other big chunk was the Headers/muffler/new oil lines and Powder coating of lots of tin. I kept my old cams and rockers as they were in fine condition and I already had Carrera tensioners.

If you are patient you can pick up a lot of good parts used here and on fleebay. that is how I was able to keep my costs down to some extent. You just have to be fast and watch the classifieds all the time for that part or upgrade you are looking for. Posting a WTB works as well, but it could take weeks for you to get a hit on it.

Best regards,

Michael

P.S. $15-17k??? I think you can get a crate engine from Porsche for less than that... There is no way in hell I could justify spending 2x the whole cost of my car on an engine rebuild... I would just buy a whole new used car at that point... woo hoo 1000th post

[mca]

You can TOTALLY do it within $5-7K depending on if you can reuse your cylinders. I already have headers and carrera tensioners so that was not part of the cost. Nor did I enlarge the intake. My head studs were already steal.

I am at $6100 right now in the middle of my rebuild. All I have left are some CIS hoses to buy.

964 cam grind, new JE pistons, head refurbished (all new valves, guides, springs, etc), rods refurbished, engine oil cooler cleaned and tested, crank polished, engine tin and valve covers powder coated, etc etc.

If you want more details PM me. I have receipts for everything and a list of all work done by EBS.

PS ... this work was done on an 80 3.0L.

[emcon5]

Stock springs will work fine where 964 cams make power. Quoting Henry Schmidt from another thread "the closer you get to .500 lift and 8000 rpm the more you need a high performance spring. " You really don't need Ti retainers either, as your operating RPM range should be about the same as stock.

When I did my engine, I used ARP rod bolts and 993 head studs, on the advice of Steve Weiner. Not sure if there is something better now.

If it was me, I would probably leave the ports alone as well. Here is why:

A few years ago I graphed torque curves for a few different engine configurations, and two that really stood out were the dyno sheets from Dane's (rdane) and Jim's (Superman). Here are the torque curves:



Jim's engine is an 83, Dane's (at the time anyway) a 79. Both engines had early-style exhausts with Web 20/21 cams (slightly hotter than 964), and CIS, and these were done on the same dyno, on the same day. Dane had lower compression, but larger ports. It looks like the smaller ports and compression gave Jim a boost in torque down low, but as the RPMs climb, the Torque drops off earlier (5000 rpm vs 5600) and faster than Dane's. Jim drops 20% between 5K and 6.4K, Dane only drops 13% and most of that is >5.6K.
Dane's torque holding up longer in the RPM range equates to a slightly higher peak horsepower, 182hp vs 173hp, even though Jim's engine made 7 lbs more peak torque. Dane had more HP on tap up top, but Jim had a slight edge up to about 5K rpm. Depending on the track, either car could have an advantage (but to be honest, I would probably prefer Jim's).

High res versions of the 2 runs are available here.

I would put the money you don't spend on engine parts and machine work toward improving the suspension.

Tom

[Scott R]

Originally Posted by euro911sc

Depending on how patient you are you can reduce costs considerably. I took 3 years start to finish and I think i have about 4k into it. $1200 of that was heads to OEM spec. The other big chunk was the Headers/muffler/new oil lines and Powder coating of lots of tin. I kept my old cams and rockers as they were in fine condition and I already had Carrera tensioners.

If you are patient you can pick up a lot of good parts used here and on fleebay. that is how I was able to keep my costs down to some extent. You just have to be fast and watch the classifieds all the time for that part or upgrade you are looking for. Posting a WTB works as well, but it could take weeks for you to get a hit on it.

Best regards,

Michael

P.S. $15-17k??? I think you can get a crate engine from Porsche for less than that... There is no way in hell I could justify spending 2x the whole cost of my car on an engine rebuild... I would just buy a whole new used car at that point... woo hoo 1000th post

No crates here, and BTW you can't get a crate for under 20k in the states, I tried. If you want a pro job 15k is the intro price, I checked with all the best builders. My engine is 100% new sans the crank, rods and chain boxes. (also had the trans and CIS done.)

[RWebb]

Tom gave you great advice. A common problem is the guy who hogs out the ports. IF you race, you can figure how big you want he ports by determining the rpm on each part of the track that you will be running at.

For AutoX or street use, you want ports that are not too big...

[zevenbergena]

Originally Posted by RWebb

Tom gave you great advice. A common problem is the guy who hogs out the ports. IF you race, you can figure how big you want he ports by determining the rpm on each part of the track that you will be running at.

For AutoX or street use, you want ports that are not too big...

Im figuring running mostly auto-x and DD use, and want to eventually get into DE events as my driving level matures.

Thanks everyone for the inuput- the retainers, etc. advise is helping me better understand what it is I really want vs. what I read would be cool to throw in the motor "while Im in there" anyway. Of course I am set on performance and an enduring motor, but would definately like to shy away from thing where I wouldn't see a great benefit.

It makes sense to leave the port sizes alone, and just have everything cleaned up. I can't think of a reason I wouldnt be able to use the original p/c's, I plan on doing a pre-emptive rebuild before anythig breaks hopefully,

So now Im looking at leaving the p/cs alone, go for the regrind, leave the heads alone in terms of specs, and go with stock springs/retainers/ etc. I have 187,000 on the motor, do I budget replacing springs at this point or are they still reliable? I do plan on buying Waynes book as I get closer to a build date, and Im sure this will answer a whole lot of questions I might have where Im at right now. Besides muddling through engine build posts, does anyone have any good forum resources available to guide me through this entire processs? The wants vs. needs vs. unneccesary bits during a rebuild type threads...

[martj]

Web cam reverside Cali has the cam. As far as cost 7500 is more like it. I just installed new studs, rings. clutch. lt wt fly wheel. valve job used oil cooler with webcam cams for that number.

[yelcab1]

All I said was $5K is not going to do it.

With your $3K cost, my guess is ported head valve work is going to for for $1250 by somebody good. That leaves $750 for the cam and rocker work.

OK, now add:

$150 for engine oil change (twice)
$100 gear oil
$500 gasket kit
$100 misc chemical, rags,
$100 tune up kit, belt, plugs, cap, rotor

And if you break anything ... like a ring, plug wires, a sensor or two, ... it will be $7K before you know it.