different cam covers

[T5frankie]

Are 850 and v70 cam covers different? my v70r had a leak so i put the cam cover off the 850r onto it, trouble is the cams wouldnt turn at all when bolted down, so after fitting it all and sealing it ive hadto take it all back off again

[Jamest5r]

Nope both 5234 enginges

[T5frankie]

Nope both 5234 enginges

so what is the problem?

[Jamest5r]

so what is the problem?

Something's stuck

[T5frankie]

Something's stuck

thanks for that lol

[graemewelch]

check you havnt nipped a oil seal or sumit daft

[960kg]

Any engine which uses the actual alloy direct block for bearings eg: cam cover for the camshafts....the cam bearing surface is line bored all in one go with the cover in place, so therefore although the same engine you cannot swop the covers due to the tolerances allowed when doing the in-line bore.

It`s obvious in your case that the tolerance on the swopped cover is all one way and the tolerance on the head is all the other way so the cams have jammed up!

Or

You have tightened up the cam cover bolts in the incorrect sequence for even tightening to exaggerate the effect.

[T5frankie]

Any engine which uses the actual alloy direct block for bearings eg: cam cover for the camshafts....the cam bearing surface is line bored all in one go with the cover in place, so therefore although the same engine you cannot swop the covers due to the tolerances allowed when doing the in-line bore.

It`s obvious in your case that the tolerance on the swopped cover is all one way and the tolerance on the head is all the other way so the cams have jammed up!

thanks keith, i have now taken that cover back off and will refit the original one after i make sure the filler neck is properly in place, although i have seen a small missing piece of metal on the 850r one now

[Jamest5r]

Any engine which uses the actual alloy direct block for bearings eg: cam cover for the camshafts....the cam bearing surface is line bored all in one go with the cover in place, so therefore although the same engine you cannot swop the covers due to the tolerances allowed when doing the in-line bore.

It`s obvious in your case that the tolerance on the swopped cover is all one way and the tolerance on the head is all the other way so the cams have jammed up!

Or

You have tightened up the cam cover bolts in the incorrect sequence for even tightening to exaggerate the effect.

I swopped a leaking cam cover for a random one donate by Claymore without a problem.

[siamblue]

Can the cam covers bend if undone in the wrong sequence?i know camshafts can snap because of not undone correctly,also what sealant are you using on the faces?

[960kg]

I swopped a leaking cam cover for a random one donate by Claymore without a problem.

Not being rude at all James as you have done far more than me with our Volvo`s......but if you know anything about the production of engines you cannot swop these parts over due to the reason i mentioned.

You swopping a cover was purely by chance it worked as the tolerances were in your favour.........i have known cams to knock out because the bearing clearances have not been within limits and the lower oil pressure caused just knocked them out...........i am not just talking Volvo`s here but other makes with the same design.

It is very bad practise to swop these parts especially on any engine let alone a tuned one

As said you take your chance but how long would it last nobody know`s!!

[partsforvolvos.com]

as above, defo cant swap them between engines due to being for that head only.

[Jamest5r]

Not being rude at all James as you have done far more than me with our Volvo`s......but if you know anything about the production of engines you cannot swop these parts over due to the reason i mentioned.

You swopping a cover was purely by chance it worked as the tolerances were in your favour.........i have known cams to knock out because the bearing clearances have not been within limits and the lower oil pressure caused just knocked them out...........i am not just talking Volvo`s here but other makes with the same design.

It is very bad practise to swop these parts especially on any engine let alone a tuned one

As said you take your chance but how long would it last nobody know`s!!

as above, defo cant swap them between engines due to being for that head only.

I must of been lucky then as mine fitted perfectly with no leaks and that was 2yrs ago and it's been tested with over 50 full boost(26psi) runs on the rollers

[MoleT-5R]

From my foundry and machine shop experience I can agree with 960's comments, The way these parts are cnc machined these days tolerances are to 0.005 mm ( Think that's still our current limit ) which in theory is why James was able to swap his cover with no troubles as each part is replicated to exacting tolerances, BUT from time to time on the casting side things go out tolerance ( casting tolerances vary dependant on part/customer etc) Casting tolerance is way more than machining at approx 0.05mm, say things went out slightly datum wise on the cam cover whilst casting, this would have a knock on effect as the cam assembly is machined ( thus the parts may not fit as well if inter changed) Then the foundry guys may be asked by quality to adjust the datums to bring the parts back to spec, the afore mentention parts could still be within the manufactures tolerances but not exactly the same as the 1000's made before them or after them if the datums are adjusted, so it would be luck of the draw inter changing these sort of parts, as with Frankie it was to tight on the cams on another it could go the other way and be to loose (we are only talking fractions of factions of mm) or you could be lucky.

[Jamest5r]

Random cover.....



Cleaned up.....







Notice I left the belt on as well when doing mine

[graemewelch]

same with the tdci rocker covers. they are prone to cracking and they cant be swaped around either. lost of of how many ive welded now