PRV engine: what breaks at what speed question

[deloumis]

I own a prepped Delorean and also an Alpine, and prepared some PRV engines.
Changed 3 engines in my delorean. Also remember that odd-firing prv are quite different even in little things from the late even-firing, even if seems similar. For example different ( bigger ) oil pump, different rocker arms, different liner base diameter, rods etc etc... So the blocks seems similar and match some mouting holes, but different animals.
In an aspired preparation PRV the biggest numbers i know are 293hp for N/A 2.8 from Renault when they run the car in the 80s rally, and one who did 307hp from a PRV 3.0lt N/A last year, with modern technology and EFI.
For getting this numbers you need compression around 11,5:1, 300+ degree cams, direct throttle intakes, some lightining and RPMs. After around 8200rpm stock valve springs start to bunce, and can hit the pistons. For gettin 9000rpm safely you need with the high numbers cams also reinforced springs.
On an evenfiring N/A than the oil supply is adeguate: there are lot of difference in rocker arms, lubricating passages on the axis of arms etc, and an oil bath for cams in the head castings.
Early Odd-firing lacks lot of this things: so could be better.
This are pistons i have now on the shelf for an evenfiring N/A PRV prep, CR aroun 11:1.

comparison with stock.


In Turbo preparation, Peugeot at Lemans run also around 900hp from PRV. Not so reliable tought, and was quite different head castings etc.
But for a normal turbo PRV, the biggest problem I found is the oil supply start to get weak: tollerances are not so good in the old PRV, better in the newer ones, so when getting hot, the oil supply start to loose pressure, if you have a very hot engine, and an addictional oil use, like a turbocharger. That's why i found so important that late evenfiring has a better, bigger, oil pump, and i went with a twinturbo in my delorean using a late evenfiring PRV. Late prv also has cross side bolt for reinforcing. Quite indistructible, apart the oil problem. I just saw one time a cracked liner, and bent rods, on a Renault Safrane buturbo, but was caused by a poor lubrication.
So, just take car of it: good oil cooler and good oil.
The PRV oil pump surfaces are integrated in the block, so if get damaged, you can't do anything but change the entire block.
The 24v version, the first one, had a rocker arms problem with get ruined for poor lubrication, and the parts ruined the oil pump. Late one has ceramic follwers, so is
more good.
But still idraulic followers, wich is not good for rpm, and you can max put in a 260deg cams.
I prefer the 12v version, much more easy to find, work, find and make performance parts and reliable.

Will those pistons work on an odd fire PRV? Where could I find some of those? I'm assuming they are forged.. what different cam options is there available?

[cineman]

Will those pistons work on an odd fire PRV? Where could I find some of those? I'm assuming they are forged.. what different cam options is there available?

Nope, this are made just for evenfiring 2.8 PRV ( like volvo B280 ), they have a different rod pin diameter from the oddifiring. I did made this here from an Italian manufacturer, sending him also an head casting.
This pistons has 2 spherical pocket for the spark, they are 6 identical, so i can use them both on left and right of engine, turning them.
About cams, the grinding company I use has charts for PRV for : 268, 280, 292, 296, 304deg, new from billet or regrinded.
If someone is interested in a new set of cams from them i can enquiry, send me PM. regrinding would be difficult with shipping, from other side of ocean
Rocker ration is more around 1,5:1 if i remember right. The grinder can make new cams with 11mm lift at the valve.
Remember that you can't just put in a different cams and go, and that a cam is quite like a bedcover... if you pull too much you loose down

[Squall67584]

Any possibility of having those pistons made for an odd fire 2.8? What else needs to be replaced/upgraded for an engine to last with those?

[Grover]

High compression pistons are already for sale through:

http://www.delorean.eu/catalog/index...19f099bdb5a126 (I just bought these, nice set)

and Josh at DPI has his own custom made variant of High Compression Pistons as well (his are over-sized a bit, requiring a slight honing of the piston liners)

[Delorean Industries]

High compression pistons are already for sale through:

http://www.delorean.eu/catalog/index...19f099bdb5a126 (I just bought these, nice set)

and Josh at DPI has his own custom made variant of High Compression Pistons as well (his are over-sized a bit, requiring a slight honing of the piston liners)

Ours will only be available as a set with our reproduction over sized liners shortly as well. Standard size pistons and liners available too.

[EarlHickey]

http://www.delorean.eu/catalog/index...19f099bdb5a126 (I just bought these, nice set)

The site at that link reminds me of reading an asian hot rod magazine, and probably not one I'd spring for a sub. Not just that it's upside down and backwards, but..

'you buy fast cam go with nice piston'

and that's all you need to know!

Mind boggling!

[dmc6960]

The site at that link reminds me of reading an asian hot rod magazine, and probably not one I'd spring for a sub. Not just that it's upside down and backwards, but..

'you buy fast cam go with nice piston'

and that's all you need to know!

Mind boggling!

Ed Uding, owner/operator of DMC Europe, can speak decent English but cannot write in it. Most of his written English is done with a translator so a little give with the grammar is necessary. I rebuilt my engine myself in 2009 using his high compression pistons and fast cams along with several other engine modifications recommended by him for a high-power naturally aspirated DeLorean engine (2.85L odd-fire). I put out over 200hp at the crank.

Ed has also blown up 3 different PRVs experimenting with high-revving components for high-revving power. With a setup he installs only at his shop, you can have an 8500rpm revving PRV putting out 250+ hp if memory serves me right.

[EarlHickey]

Ed Uding, owner/operator of DMC Europe, can speak decent English but cannot write in it. Most of his written English is done with a translator so a little give with the grammar is necessary. I rebuilt my engine myself in 2009 using his high compression pistons and fast cams along with several other engine modifications recommended by him for a high-power naturally aspirated DeLorean engine (2.85L odd-fire). I put out over 200hp at the crank.

Ed has also blown up 3 different PRVs experimenting with high-revving components for high-revving power. With a setup he installs only at his shop, you can have an 8500rpm revving PRV putting out 250+ hp if memory serves me right.

Don't get me wrong....... it's the complete lack of component specifications and disclosure of pertinent details that completely turn me off.

You know the guy, great. I don't and for all I know his "fast cams" have merely had their base circles made smaller using a bench grinder or are machined from recycled coat hangers in China.

Nice pistons.... I think I read somewhere that the nicer ones weren't made of recycled PBR cans by child slave labor.


The coated skirt pistons posted prior at least have the company's name prominently displayed. It's possible they all came from the same place, but, I'm not going to be the one to pay to find out otherwise.

When I buy a piston set from Keith Black, Arias, Venolia, or even the well established European manufacturers, I can get complete disclosure prior including certified materials used, heat treatment, weight, all dimensions.... ect.

Should this be important to a non-hands on gearhead that merely hands over cash to pay somebody else to install parts in their engine or car?

It's certainly not my place to tell somebody else what should be important to them.

[dmc6960]

It's certainly not my place to tell somebody else what should be important to them.

Then perhaps this forum is not your place.

I dont understand why your tone to everything is so condensing. If your such a hotshot who knows how to do everything without help from anybody, then stop asking for everything.

You want to know why people aren't posting 100 pages of engineering specs on every product sold? So people like you don't just take the information for themselves after the developers of such information spend a LOT of money and time on the product.

[jawn101]

Then perhaps this forum is not your place.

I dont understand why your tone to everything is so condensing. If your such a hotshot who knows how to do everything without help from anybody, then stop asking for everything.

You want to know why people aren't posting 100 pages of engineering specs on every product sold? So people like you don't just take the information for themselves after the developers of such information spend a LOT of money and time on the product.

Amen.