Volvo adjustable rockers source?
Discussion
I read here http://www.pistonheads.com/xforums/topic.asp?h=0&a... and I have been told elsewhere by an engine builder with some experience of Rover V8, that adjustable rockers from Volvo can be used in the Rover V8. Can anyone provide more details on this please? Which model Volvo do they come from? Is the complete Volvo rocker gear used, or are just the rockers put on the Rover rocker shaft or what? Are the Volvo pushrods used, or something else?
Cheers, Pum.
Cheers, Pum.
Cheers Matt - you mean the old 240 saloon car box thing?
OK, this is where my knowledge is rudimentary, and I'd appreciate input from the knowledgeable people that inhabit these forums. My engine is suffering low compression on some cylinders. It was a recon short engine not too many miles ago, retaining my old but good heads. Rhoads hydraulic lifters were fitted at that time with adjustable pushrods. All was working fine. The reason for the adjustable pushrods was so that pre-load could be set for each valve independantly, instead of the one-size-fits-all approach of rocker shims.
Two reputable places have examined the engine for the source of the current low compression without completely striping it down, and reckon the block, cylinders and bores are fine and not causing compression loss. They both reckon the loss is through the valves.
The first de-coked the heads and replaced the former adjustable pushrods (a couple of which were split) with standard pushrods, and setup the rockers with shims. Whilst the heads were off they check the bores and pronounced them fine. The compression problem remains, but may have moved about the cylinders a bit.
The second reckons that without adjustable pushrods or adjustable rockers the pre-load cannot be properly set on all the valves. They say this is due to the inevitable uneven wear of the varous parts involved. So when new, all the valve stem lengths etc would have been fine with the crude adjustment available from shimming the rocker posts, but now the engine has had some wear, shimming cannot get all the clearances and setting close enough.
I don't fancy adjustable pushrods again as I really didn't like the way they split after a few years. So I'm looking at adjustable rockers as the alternative to be able to get the valve gear adjustments right on every cylinder and hopefully then cure the compression problems.
As far as adjustable rockers go, it's either Yella Terra, which are out of my price range, or something more mundane, like the Volvo rockers which I orginally enquired about.
Thought and wisdom gratefully received.
OK, this is where my knowledge is rudimentary, and I'd appreciate input from the knowledgeable people that inhabit these forums. My engine is suffering low compression on some cylinders. It was a recon short engine not too many miles ago, retaining my old but good heads. Rhoads hydraulic lifters were fitted at that time with adjustable pushrods. All was working fine. The reason for the adjustable pushrods was so that pre-load could be set for each valve independantly, instead of the one-size-fits-all approach of rocker shims.
Two reputable places have examined the engine for the source of the current low compression without completely striping it down, and reckon the block, cylinders and bores are fine and not causing compression loss. They both reckon the loss is through the valves.
The first de-coked the heads and replaced the former adjustable pushrods (a couple of which were split) with standard pushrods, and setup the rockers with shims. Whilst the heads were off they check the bores and pronounced them fine. The compression problem remains, but may have moved about the cylinders a bit.
The second reckons that without adjustable pushrods or adjustable rockers the pre-load cannot be properly set on all the valves. They say this is due to the inevitable uneven wear of the varous parts involved. So when new, all the valve stem lengths etc would have been fine with the crude adjustment available from shimming the rocker posts, but now the engine has had some wear, shimming cannot get all the clearances and setting close enough.
I don't fancy adjustable pushrods again as I really didn't like the way they split after a few years. So I'm looking at adjustable rockers as the alternative to be able to get the valve gear adjustments right on every cylinder and hopefully then cure the compression problems.
As far as adjustable rockers go, it's either Yella Terra, which are out of my price range, or something more mundane, like the Volvo rockers which I orginally enquired about.
Thought and wisdom gratefully received.
Edited by Pum on Thursday 6th September 14:29
To be honest if you've got hydraulic followers then you've got a range you can set the pre-load over which from memory is 0.25-0.6mm.
When I last built my previous engine I used a combination of the shims and swapping the push-rods around to get them all within this tolerance.
I too had Rhoads lifters in mine (wouldn't use them again) but I also had cro-moly tubular pushrods which may vary more than the standard rover ones.
I don't think you need to got the expense of the Volvo rockers (if you can find 2 sets or course as they're quite sought after)
Also if you've had pushrod troubles it may be that the valve seats are little burned if the valve has been held open during combustion.
Now this may sort itself out with time, but you may be better off whipping the heads off and re-grinding the valves.
Best of luck with it
Matt
When I last built my previous engine I used a combination of the shims and swapping the push-rods around to get them all within this tolerance.
I too had Rhoads lifters in mine (wouldn't use them again) but I also had cro-moly tubular pushrods which may vary more than the standard rover ones.
I don't think you need to got the expense of the Volvo rockers (if you can find 2 sets or course as they're quite sought after)
Also if you've had pushrod troubles it may be that the valve seats are little burned if the valve has been held open during combustion.
Now this may sort itself out with time, but you may be better off whipping the heads off and re-grinding the valves.
Best of luck with it
Matt
Interesting, though probably tedious suggestion on swapping the rods around - thanx Matt. Due to this onoing problem I haven't used the car much, and hopefully haven't burned the valve seats. If valve gear adjusts/remedies don't fix it then I guess the next step is to take the heads off and have a look at that.
BTW, I've copied this thread to the Major Mods forum, which may be a better place for further discussion of this.
BTW, I've copied this thread to the Major Mods forum, which may be a better place for further discussion of this.
The group A Rover SDI rocker gear used steel posts,Volvo 240 rockers and thicker shafts.On the twin plenum road cars the ajusters are spot welded up and you have to grind them off(fun job!)then fit new adjusters avalible from John Eales,who also has some spares.The push rods are also different.You can run the cheaper chevy 350 high rev lifters with this set up.I used solid lifters in my 5.5 and a 404 cam which seames to like reving more with no hydraulics to worry about. Sets seem to come up on ebay now and again,make sure you get the push rods with them.or buy a TP vitesse and break it like I did!.
Edited by topsparks on Thursday 6th September 22:26
Thanx for the further info chaps.
I'm just trying to understand the problem and figure out what the options are to fix it, Rev-erend. First workshop to have a go at it said it was valve gear, decoked the heads and set it up with standard rockers, shims and rods. Now my regular mechanic also says it is probably valve gear, and that the lifter preload is way out, so he wants to fix that before investigating further - sounds reasonable to me, so my question is how best to setup the preload on every cylinder properly. As I understand it, my options are adjustable rods or adjustable rockers, now the engine is no longer new. Am I missing something?
I had adjustable rods and didn't like the way they seemed to fall apart after a couple of years, so my preference is adjustable rockers if I can source them at a reasonable price. I am concerned at buying something I don't know what it is, which was the source of my original enquiry.
I'm just trying to understand the problem and figure out what the options are to fix it, Rev-erend. First workshop to have a go at it said it was valve gear, decoked the heads and set it up with standard rockers, shims and rods. Now my regular mechanic also says it is probably valve gear, and that the lifter preload is way out, so he wants to fix that before investigating further - sounds reasonable to me, so my question is how best to setup the preload on every cylinder properly. As I understand it, my options are adjustable rods or adjustable rockers, now the engine is no longer new. Am I missing something?
I had adjustable rods and didn't like the way they seemed to fall apart after a couple of years, so my preference is adjustable rockers if I can source them at a reasonable price. I am concerned at buying something I don't know what it is, which was the source of my original enquiry.
Give Rob Robertson a call and discuss this at V8 Developments ..
http://www.v8developments.co.uk/
Whilst something like Yella Terra adjustable roller rockers may do what you are asking for - I feel that you should talk with a true expert in the field - who will be also to sort thru the stuff you have been told and sort out the good from the bad.
Like you cr - if it varies too much across cylinders - I would say it can only be rings or valve seats ..(unless cam timing was so badly out..)
http://www.v8developments.co.uk/
Whilst something like Yella Terra adjustable roller rockers may do what you are asking for - I feel that you should talk with a true expert in the field - who will be also to sort thru the stuff you have been told and sort out the good from the bad.
Like you cr - if it varies too much across cylinders - I would say it can only be rings or valve seats ..(unless cam timing was so badly out..)
350Matt said:
This is a little off-topic but is it possible to fit Chevy roller followers to the rover?, Admittedly you then need a roller follower profile cam as well, but that can be over-come
Matt
I doubt it as they are single bolt per rocker arrangement so You'd have to do a fair amount of work or make base plates to clamp them onto.Matt
Boosted LS1 said:
350Matt said:
This is a little off-topic but is it possible to fit Chevy roller followers to the rover?, Admittedly you then need a roller follower profile cam as well, but that can be over-come
Matt
I doubt it as they are single bolt per rocker arrangement so You'd have to do a fair amount of work or make base plates to clamp them onto.Matt
Matt
Cheers. I think I've sourced some decent adjustable rockers, probably of the Volvo type, cheaply. I think I'm more into the question of whether the valve train is to blame for the low compression on some cylinders. I guess my way forward is to get the valve gear all set up right, and recheck compression. I shall also see about a leak-down test.
Pum said:
Cheers. I think I've sourced some decent adjustable rockers, probably of the Volvo type, cheaply. I think I'm more into the question of whether the valve train is to blame for the low compression on some cylinders. I guess my way forward is to get the valve gear all set up right, and recheck compression. I shall also see about a leak-down test.
Personal as i said in the major mod forum i do believe you are looking in the wrong place with the valvetrain, before you go and blow any money on tasty valve train do a leakdown first... Gassing Station | Griffith | Top of Page | What's New | My Stuff