PRV cam identification

Any experts on PRV cams here? I've got three I need help identifying:



From left to right (edited for anyone who needs this info in the future):

1) Box marked 1277821. It has a distributor gear, so it's a LH cam. The end by the distributor gear is "skinny" at 24.8mm. The intake and exhaust lift are both 5.08. Part number search says it fits B27A/F 75-79 260.

2) Volvo OEM in a tube marked 1269979-9. It has a distributor gear, so again, LH cam. The end by the distributor gear is "fat" at 32.41mm. The intake and exhaust lift are both 5.99. Part number search says it fits B28F 80-86 260/760.

3) Unipart box marked GKC-25. It has a lobe where distributor gear would be, so LH cam. The end is "fat" at 32.41mm. The intake and exhaust lift: are 5.96 and 5.42 (give or take, and I’m not sure which is which). I can't find any info about Unipart GKC-25. It fits B280F 87-90 760/780, corresponding to Volvo 247958.

I don't know the duration or any other info, as I only have a micrometer. Here's some more pictures and feel free to ask any questions. Thanks for your help!!!

PM JohnLane. He will know. Forum expert on PRV engines.

All are distributor side cams.

Those with gears are for odd firing engines.

Lowest lift will be B-27f.

Cam with no gear is B280f. That looks to be a mechanical profile...

The hydraulic cams have a visibly different look to the nose on the lobe with a different finish on the cam lobes.

I have used the hydraulic cams/rocker arms in odd-firing heads with an even-firing three liter bottom end. Made nice runners! Someone no doubt wondered years later why it had a B-30 distributor cap.. May also have wondered how it had the perfectly smooth idle.

Thanks for the PM and response here John! I was able to find lift information for B27F and B28F cams online... 5.08mm for B27F and 5.99mm for B28F, so in the picture above, the cam on the left is a B27F and the one in the center is a B28F.

The third cam (on the right) has me puzzled though. If you look at the lobes in the last two pictures, they're only offset by a few degrees (unlike the B27 and B28 cams). That would mean on a 12 valve engine that the intake and exhaust would be open at the same time. I'm thinking that this must be for a 24 valve engine? Any thoughts?

My mistake... That cam will be for the driver's side of the engine.

So, with the difference in the fat and skinny ends of the odd fire cams, they aren't cross compatable? Would need to know so I wouldn't order a performance set from the wrong place.

The flywheel end of the cam is different to drive a vacuum pump via eccentric on the driver's side and a fuel pump on the passenger side + a gear to drive a distributor.

With EFI that is programmable none of the lumps and bumps are needed. Though the late three liter even-firing engine has a lump used to tell management where #1 is... For sequential fun...

Knock sensors get bolted to the block in the valley.

Ohhhh the fun we can have with these.

sisu_slay said:

So, with the difference in the fat and skinny ends of the odd fire cams, they aren't cross compatable? Would need to know so I wouldn't order a performance set from the wrong place.

Click to expand...

Is anyone offering cams that work? The last set I tried was a spectacular failure. That was many years ago.

monkecmonkedo said:

Thanks for the PM and response here John! I was able to find lift information for B27F and B28F cams online... 5.08mm for B27F and 5.99mm for B28F, so in the picture above, the cam on the left is a B27F and the one in the center is a B28F.

The third cam (on the right) has me puzzled though. If you look at the lobes in the last two pictures, they're only offset by a few degrees (unlike the B27 and B28 cams). That would mean on a 12 valve engine that the intake and exhaust would be open at the same time. I'm thinking that this must be for a 24 valve engine? Any thoughts?

Click to expand...

There are "only" 4 cam bearings so the stub behing the dizzy gear is hanging free.
Small angle between lobes on the even fire cam: Think how the rocker arms look like and you will have your 180 degr difference..

M

JohnLane said:

Is anyone offering cams that work? The last set I tried was a spectacular failure. That was many years ago.

Click to expand...

I will repost here what I pmd you.

I would avoid any small time machine shops that grind their own customs, very few people can get it right, but there are options. Aussiefrogs people say you can go all the way up to 310 degrees duration and 10 degrees of lift and still be a tractable engine.

Dbilas shop in Germany has a nice selection to choose from in their alpine section and can even give you a set of matching valve springs.

http://www.dbilas-shop.com/Products...V6/New-camshafts:::7_2504_2812_2836_2837.html

Simon auto in Germany also has a set of 296 degree cams

http://www.simon-auto-shop.com/shop/cgi-bin/shop.dll?AnbieterID=16&bnr=241257&Hauptseite=detail.htm

And if you don't want to make a trip to your closest DMC shop for a stage 2, deloreans european website sells them individually. They also have both high compression and turbo forged pistons too with divits for the valves.

These are 283 degrees of duration

http://www.delorean.eu/catalog/product_info.php?cPath=20_139&products_id=38063

m nordin said:

Small angle between lobes on the even fire cam: Think how the rocker arms look like and you will have your 180 degr difference.M

Click to expand...

Yeah I figured it out. I'm not used to looking at V6 rocker-based cams. The profile seems odd, until you think about how the cam rotates in relation to the rocker arms/valves for each head and that they're mirror images of each other with regards to intake and exhaust valves. Thanks for the response!