When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
My 1981 4.5l is toast. Scarring in one cylinder wall, took it to a machine shop and they did not even want to touch it. Called Roger and he said if an oversize piston is available from Porsche they are about $500.00 each. This engine then immediately became scrap. So...I'm not going to mess with a Porsche engine unless I find a 4.5 or 4.7 for free that runs. Chevy LS motor is calling. So, I'm interested in reading all the Chevy engine installations in the 928 - any help here to steer me towards those threads?
I was looking into the Texas Performance Concepts set, since it is mostly off the shelf parts other than the adapter plate setup.
I don't have any specific experience with this, but they did send me a spreadsheet of the parts needed, as well as a pricing breakdown for the list.
I am cautious of the Rengade kit since my understanding is that it uses a custom clutch and flywheel.
Having custom hard parts doesn't bother me much, but custom wear items is a recipe for disaster if the manufacturer ends support for the part, or goes out of business.
That all said, no personal experience with this yet, as my engine actually runs, much to my surprise, so I'm using it as it sits until it proves unreliable.
If it does grenade, it'll likely be replaced as the repair prices are hefty in the Porsche side of motoring.
To compare cost fairly. A used engine 928 vs LS, both with zero issues with either engine it's cheaper to go with a used 928 engine. No mods to the car or rest of components.
However looking at the cost of a New crate LS engine VS a rebuilt 928 engine cost can be astronomically different.
Call Precision Motor Works ask for a "rebuild" you will understand the true cost involved with Properly rebuilding
that engine. That price doesn't include any shipping any accessories any of the while you're in there cost.
Call summit racing ask for a crate LS engine they will deliver it finished and new. But you still have another pile of stuff that has to be done. Computer fuel supply program mapping etc. HP depends, 928 vs LS is just how deep your pockets are.
LS has more hp off the shelf. LS is cheaper ..
928 engine is proper 928 is pure..
Either way this debate will never end it all depends on what you want. Do your homework and educate yourself on the true cost.
Disclaimer, I am by no means anyone that has knowledge of anything. But I do know I spent more time than you can imagine planning on a build. I do know I own an LS built 928 as well as 💯% stock 928's. I do know my LS can be worked on anywhere by almost anyone. My 928 cannot and will not be touched but by only a select few. This subject will go on until the end of time. Just a morning rant.
I'm thinking the time involved will be considerably higher with the LS swap.
I'm certainly blue-skying it, but the way I see it the motor is going to come out either way. If the 928 motor goes in to get a cylinder redone, it's going to have be torn down to the block, and there are a ton of WYAITs, etc. I wasn't thinking of an LS crate motor, but rather a takeout from a junkyard. The 5-liter LS from the early 2000s in stock form has about the same power as the stock 16v motor. My thinking was that the time spent putting in the conversion kit for the LS would be offset by the time spent tearing down and rebuilding the 928 motor. (This assumes that the LS doesn't need a significant rebuild.)
I don't have any Renegade experience so can't speak to a 928 conversion, but...
I recommend that folks budget somewhere around 3-4x the major parts costs so they can cover all the rest of the conversion stuff needed. The LS deserves a gearbox to match, for instance, so you'll end up shopping for the 928 Motorsports Corvette gearbox conversion.
There's a thread from a member in OC California that shows the ton of additional fabrication work needed to get a conversion to look and feel like it belongs in the 928. The time talent patience and funding needed for that project make a great yardstick. The OP here has lots of fab experience so the project may be the perfect fit for him.
Personally, I'd be shopping for a good used 4.7l or hybrid 5l to drop in.
Renegade kits START at 2K and can easily double that. Add the cost of the engine, then all of the accessories, associated wiring, Exhaust. The list gets bigger. I've seen conversions cost as much as 10K and that started with a free engine.... The thread started like this... My 928 engine is toast, and I have this SBC or LS motor laying around. I'm going to convert it because the 928 engine is complicated and expensive. The cheapest and fastest solution is to drop in a used engine. My bet is that if you have a day job that keeps you busy, and you start now by ordering a LS kit this project will have a birthday this time next year, not be done, and you will have significant money and time invested. And the car will be worth less. Doing an engine conversion because it is cheaper is a fallacy.
$500 LS3 and a conversion kit? Overall it's probably about a wash...
No LS3 is $500. Even if it is blown up.
Renegade in Las Vegas has the kits or parts that you need and the clutch comes from Kennedy and they are not going anyplace same as Renegade. They have successful businesses.
You will save money over the factory Eng. Rebuild if you do the install yourself. If you have to go to Renegade it will cost you Big money plus parts but much less than getting a 430HP built factory 928 ENG.
Bob B
$9136.14
Start
$9500. Plus, Free Shipping in the 48-States, 1 to 3 Day Delivery to Most Locations
CHEVROLET PERFORMANCE 19370414 - LS3 6.2L 430HP E-ROD SYSTEM
That's zero mods. From here it's as fast as you can afford.
Super chargers Turbo chargers hamsters in a wheel.
My Adult rational decision , I would find a compatible year 928 that's been abandoned or wrecked with under 100k clocked. Pull engine do a top end and refresh fuel lines etc..
Use the donor for all your tidbits then Chuck it or sell off to the next vulture. .That's the proper way
My inner child says drop in the LS add headers tweek the tune drop in turbo chargers pound it with HP and have a super fun toy. Something about strap on horse power
$25 k in 928 motor -VS- $25 k in LS motor what does that Dyno sheet look like ?
$ for $ in the long run there is "the never ending debate".
If buying new, for approx another $ 1,000 look into the LS3/525hp (NA) motor that comes with a hotter cam and better flowing heads. A rolling laptop tune will get you approx 560hp at the crank. As an added bonus the LS motor is lighter (-150lbs) and sits further back in the engine bay (a result of its smaller size). IIRC the LS comes with a 2 year MFR warranty. T
My 1981 4.5l is toast. Scarring in one cylinder wall, took it to a machine shop and they did not even want to touch it. Called Roger and he said if an oversize piston is available from Porsche they are about $500.00 each. This engine then immediately became scrap. So...I'm not going to mess with a Porsche engine unless I find a 4.5 or 4.7 for free that runs. Chevy LS motor is calling. So, I'm interested in reading all the Chevy engine installations in the 928 - any help here to steer me towards those threads?
I've got to tell you, this post left me shaking my head, in wonder.
Whoever is planning on buying a 38 year old car with an engine that most likely has over 150,000 miles on it and expects the bores and pistons to be perfect and all be good enough to be re-used, needs a little dash of reality.....
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
06-18-2019, 07:46 PM
LS Engine!
