Cam replacement on 850 2.3/2.0

[woz]

Hi all - as part of the Lusty Heartthrob renovation project, I picked up a 2.0 Auto estate in the same paint code (saved me loads in painting costs)
Before it gets weighed in I thought I might nick the cams - is it straightforward mechanically to drop them on the top of the T5 engine?(Same model year 20v engine). If its a PITA job I wont bother, as it sounds like the gains are mythical/marginal at best.

But it looks to me like I can lift the cams, in their carriers and timing wheels complete - swap them across and retime then (as per other detailed threads on here) without too much grief. Can anyone who has done it confirm or deny? And if so will I need two cam locking tools or do they fail to be of use once you have the assembly completely off the head?

Its slightly hypothetical until I get both engines covers off and measure the cam lobes for wear.

Cheers Woz

[MoleT-5R]

The cam carriers as you mention are really the cylinder head and the cam cover, so really if I'm reading your post right regarding "lifting the cam's, in their carriers and timing wheels complete - swap them across and retime", then in essence your just doing a straight head swap ?? I'm not sure on 2.0l 20v cams, as the ones most try to get are the 2.4l 20v ones, they may be the same but I do doubt that, but they also may work but I know nothing really on the 2.0l other than some block differences.

[woz]

Thanks Mole that is helpful - I will look into it some more. I have a spare head with cams so will pull it apart and see what happens.
Sounds like a cam swap is really that - a cam (only) swap, but I would need to take the head off to release the pressure of the valve springs and replace the followers - I assume they should go with the cams?

Cheers Woz

[MoleT-5R]

worth checking up on the 2.0l head though as afaik the difference between a 2.3l and a 2.0l is the stroke as the bore is the same, so may be a possible swap but compression ratio could be an issue dependant on the head chamber volume.

[Doingitsideways]

Straight head swap is out.
Don't forget the exhaust valves are sodium filled on the turbo engines.

Can't help with the 2.0 cam profile I'm afraid.
Haynes book of fantasy may help here.

I have N/A cams in mine, but I think they're from a 2.5.
They have good lift, but the overlap on each cam needs dialling out with an angle guage afterwards

[MoleT-5R]

Straight head swap is out.
Don't forget the exhaust valves are sodium filled on the turbo engines.

Can't help with the 2.0 cam profile I'm afraid.
Haynes book of fantasy may help here.

I have N/A cams in mine, but I think they're from a 2.5.
They have good lift, but the overlap on each cam needs dialling out with an angle guage afterwards

Good point Steve, hadn't got around to thinking about the valves, I was still pondering whether it would just bolt on with no issues, but I'm sure there'd be differences in the chamber volumes that would affect the compression ratio, but no need to ponder no more as it's not worth the time if the valves are not up to it. Would be interesting to see some data on the 2.0l 24v cams though as they would be a cheap source of supply...:)

[woz]

ould be interesting to see some data on the 2.0l 24v cams though as they would be a cheap source of supply...:)

Haynes only quoes the ift values for the cams I think. The chamber volumes will definitely be different - bit one suspects that material could be removed - I will need to check the deck height of the heas. Thats not what I am intending though. I should have perhaps phrased my real question as "do I need to take the head off to swap the cams over?

Its throuwn up some interesting thoughts though... thanks for all the input.

[Doingitsideways]

In a word, no.

The base of the head stays put.

[MoleT-5R]

In a word, no.

The base of the head stays put.

as Steve said, leave the head alone and just swap cams, but I'm still thinking the 2.0l ones don't give the same timing and lift of the 2.5l n/a ones people normally want !!

[woz]

Thanks guys, I found a tech exploded drawing of it and it all makes sense now, the head is in two bits, the top bit comes off, then the cams lift out. The botoom bit of the head (with comb. chambers etc.) stays bolted on the block. My manual only has cam data for the 2.0 and 2.3 versions., The n/a cams have more lift but appear to be the same in all other respects. I will do a comparison with 2.5 cams when I can.

Thanks for all the input. It seems such an easy swap I may well give it a try. However, not expecting much benefit, otherwise Volvo would have done it. I expect I will give the head a bit of a rework, improve teh flow round teh seats and valve heads etc. Then after an RR session try changing the cams at that stage so I can see exactly what makes the difference, on the basis of only changing one thing at a time.

[MoleT-5R]

next comes the decision on how many degrees to offset them, there has been a few threads over the years on this and may be worth a look, I did read the thread again on RT's yellow peril and Russ claimed in that, that he lost bhp on the dyno when he fitted n/a cams, but that really wasn't a fair test as it had previously been dyno'd with some reprofiled cams in.

[MoleT-5R]

Rereading that thread again, 525bhp is not to be sneezed at on n/a cams though there are a fair amount of other supporting mods and stand alone ecu... a big build and big budget to match I'd guess