ThorLoki

I am in need of advice.
My mechanic informed me that my 1979 3.0L engine has a burned intake valve on #1 cylinder (leak down test). Compression test on other five cylinders indicated they are within 10% of each other. The engine ran strong before this, started first time every time. I am debating whether to have a top end valve job done or sell the engine the way it is and upgrade to a 1984 3.2. The estimate to do a top end valve job is $8,000. The cost for the 3.2 is about $7,500; installation is another $1000-$1500. Installation costs is dropping the 3.0l, valve adjustment and oil change on 3.2, modification of 915 bell housing to accept 3.2 sensors, rewire engine compartment. So out the door for the 3.2 would be about $9,000. When I work the numbers they are about break even. I have no documentation on the mileage on the 3.0l engine, odometer indicates 120,000. PO said engine and tranny were gone thru about 25,000 miles ago….don’t trust him. I can probably sell the 3.0l for high of $2,000 which would bring the bottom line cost of the 3.2 down to about $7,000. The 3.2 has 94,000 miles, leak tested, and will come with a 90-day limited warranty. Limited warranty is for engine internals such as bad valve, rod knock, chain tensioner failure, low oil pressure, etc.
My question is: Considering the increasing cost and availability of older 3.0l parts is it cost effective to just do the top end valve job or pay the extra and upgrade to a 3.2 with 94,000 miles with a limited 90 day warranty?

JonSnow83

I say 3.2. Or else invest more $ and rebuild the 3.0 with carbs and increased displacement. Where's it located?

upier

Personally I don't like to spend that much on a simple repair. I would go the upgrade route. Haven't you ever spent a couple grand on a repair and was ticked off because it was just back to normal?

ron mcatee

Be aware that the 3.2 has had valve guide problems in the past. If they've never been changes, you may have to do a "top end" on it. I'd keep the 79 3.0L that it came with. Just my opinion.

CW-VIESOCK

I second this.

If your 79' is original, keeping the numbers matching may make a difference in your future with the car, plus, you know what you have now and know what needs to be done to make it right. An unknown motor is just that and your theoretical bottom line may flip in the other direction, significantly for the worse.

Good luck...

race911

$8K on a top end (meaning not going below the cylinder heads, and certainly not taking into account upgrades/peripheral repairs) is still pretty strong money today. Figure a shop has 25-30 hours in the job + $2-2.5K in hard parts/sublet machine costs. Do the math from there. Once the heads are off, it's pretty easy to see who had his hands where along the way.

JCP911S

Been this route.

First, $8,000 for a valve replacement on a 3.0 sounds ridiculous to me. Get another estimate.

Second, engine replacements always end up costing more than you think. $250 here, $300 there for parts and fittings. Integrating the DME into the SC electrical system... oil lines... I've been through this.... add $3K.

Third, $7,500 for a used 3.2? And it is a used engine which could also require a rebuild.

IMHO your mechanic is trying to rip you off.

Now Porsche rebuilds are not cheap, but I'd guess a top-end should be more like $4-5K. Find a better shop and just rebuild your existing engine and keep your car original.

Ed Hughes

No way would I pay $7500 for a used 3.2.

Build the 3.0 the way you want it, and have a new motor.

The Brewmeister

^ These last three opinions come from some of the most experienced members on Rennlist.
Their opinions back up my opinion. I'm with them!