2.8 V6 camshaft choices?
Discussion
I cannot find a recent thread on this on here or on 'wedges'.
I have just started a rebuild of my 'spare' 2.8 engine. I wondered about fitting a slightly 'hotter' camshaft while I was about it. No problems getting one from Burton and others. If I fitted one it would need different springs (readily available).
But is it worth it?
I know the tuning potential of the 2.8 is limited by breathing so just how much more would the fast road cam give? What downsides are there on this engine?
I do intend to fit a rev limiter as the new balanced engine may rev a little more freely and they do not like over revving.
Experience?
I have just started a rebuild of my 'spare' 2.8 engine. I wondered about fitting a slightly 'hotter' camshaft while I was about it. No problems getting one from Burton and others. If I fitted one it would need different springs (readily available).
But is it worth it?
I know the tuning potential of the 2.8 is limited by breathing so just how much more would the fast road cam give? What downsides are there on this engine?
I do intend to fit a rev limiter as the new balanced engine may rev a little more freely and they do not like over revving.
Experience?
I'm by no means an expert but I have read that a hot camshaft alone won't make much noticeable difference, I recon that with rebuilding the engine to standard spec you will be pleasantly surprised at how many escaped horses you are able to recapture. I'm sure someone much better informed will be along shortly to correct me.
Top Gear TVR said:
I can think of a lot more important things to spend £200 on if your going to try and get more horses you have to go a a lot further than changing the cam imho Thanks for the views so far. The stripped engine has been to the specialists today.
It is an engine I bought off ebay, supposedly good, out of a 2.8i Capri. To my surprise the crank seemed perfect and the specialist has confirmed it has had a replacement crank and has done so few miles that nothing at all needs doing at the bottom end, although I am going to re-shell as a precaution.
The bores are just a little too bad for honing only so we are going for a +0.5mm rebore as I acquired some +0.5 pistons a couple of years ago and because this size is apparently seen as giving optimum capacity for the 2.8.
The cam is marginal so a new one will be going in, and that means new followers as well. The specialist was of the view that a 'hotter' cam wouldn't be an advantage unless I was using the car for track days. The loss of response on 'fun' country roads would outweigh any gain.
I think we are going to concentrate on getting the components balanced as far as possible, getting the heads flowing as well as possible ...and then fitting an electronic rev limiter, just in case. (set at 6000)
He has also strongly advised replacing the big end bolts and nuts with later, stronger, ones. They certainly look pretty puny!
I had thought of a 2.9 but the masochist in me feels I would like to get a 2.8 really right! (and as pointed out above the changes from Jetronic to EFI are not that simple). If I was to change completely then mine is the green S1 with the V8 bonnet....it would be tempting as that RV8 is such a lovely engine.
It is an engine I bought off ebay, supposedly good, out of a 2.8i Capri. To my surprise the crank seemed perfect and the specialist has confirmed it has had a replacement crank and has done so few miles that nothing at all needs doing at the bottom end, although I am going to re-shell as a precaution.
The bores are just a little too bad for honing only so we are going for a +0.5mm rebore as I acquired some +0.5 pistons a couple of years ago and because this size is apparently seen as giving optimum capacity for the 2.8.
The cam is marginal so a new one will be going in, and that means new followers as well. The specialist was of the view that a 'hotter' cam wouldn't be an advantage unless I was using the car for track days. The loss of response on 'fun' country roads would outweigh any gain.
I think we are going to concentrate on getting the components balanced as far as possible, getting the heads flowing as well as possible ...and then fitting an electronic rev limiter, just in case. (set at 6000)
He has also strongly advised replacing the big end bolts and nuts with later, stronger, ones. They certainly look pretty puny!
I had thought of a 2.9 but the masochist in me feels I would like to get a 2.8 really right! (and as pointed out above the changes from Jetronic to EFI are not that simple). If I was to change completely then mine is the green S1 with the V8 bonnet....it would be tempting as that RV8 is such a lovely engine.
Mine is a 2.9 not a 2.8 fitted with a Piper "Fast Road" (their mildest) cam, I'm convinced it pulls better at higher revs with no detriment lower down.I went for the far cheaper regrind rather than ground from a new blank option.
I know rolling road figures can be a bit debatable but it came up with just short of 185 (184.9 I think it was) so bang on the 14 gain that Piper claim plus 0.9 gained by grinding out some of the biggest casting lumps in the inlet ports
.
I know rolling road figures can be a bit debatable but it came up with just short of 185 (184.9 I think it was) so bang on the 14 gain that Piper claim plus 0.9 gained by grinding out some of the biggest casting lumps in the inlet ports
.Hi Mike, thanks for that, appreciated. When you fitted that cam did they recommend any other associated changes, e.g. valve springs.
I am going to have to get a cam anyway and the cost of a fast road cam over a standard cam isn't enormous, but did you have to make any other changes?
I will be 'porting' mine but I believe the bigger issue will be exactly matching the inlet manifold to inlet ports rather than port 'polishing 'as such. I have yet to check the heads in detail to see how manifold and port align.
I have been advised, to my surprise, that there are heads around with two different sizes of inlet valves! Fortunately the heads I will be using have the larger 42mm valves. Those are b...y enormous valves, no wonder 4 valve heads are so much better!
I am going to have to get a cam anyway and the cost of a fast road cam over a standard cam isn't enormous, but did you have to make any other changes?
I will be 'porting' mine but I believe the bigger issue will be exactly matching the inlet manifold to inlet ports rather than port 'polishing 'as such. I have yet to check the heads in detail to see how manifold and port align.
I have been advised, to my surprise, that there are heads around with two different sizes of inlet valves! Fortunately the heads I will be using have the larger 42mm valves. Those are b...y enormous valves, no wonder 4 valve heads are so much better!
greymrj said:
When you fitted that cam did they recommend any other associated changes, e.g. valve springs.
did you have to make any other changes?
I opted for the kit,so new followers and valve springs fitted.did you have to make any other changes?
Straight swap no problems.
Recommended clearances are wider than standard.... it rattled like a right old nail so I now have valve clearances set a couple of thou less than standard, still not exactly quiet!
I guess big manufacturers (Ford) put a lot of effort into cam design, to get a good balance of performance, economy and quiet operation
Bugger!!! I bit the bullet and spoke to Piper and ordered the same kit. They have since rung back...no 'blanks' left for the 2.8 'big' cam! B* B* B* 
So I went on to Burton Power who assured me they can sort one out! I have now sent the old cam to them so they can decide to rebuild or replace. Which ever I get, the cam will come back with all followers and valve springs.
'Big' cam you may ask. Only recently found out there are two. The identifying feature is the cam journal at the front of the engine. Later 2.8 engines have a 43.9mm journal, older ones a 41.9mm journal. I believe the cut off was 1982/3 but if you are rebuilding a second hand engine, or are unsure of the origins of the engine in your car, you might need to bear this in mind. You have to measure the No1 journal, the others are slightly smaller.
So I went on to Burton Power who assured me they can sort one out! I have now sent the old cam to them so they can decide to rebuild or replace. Which ever I get, the cam will come back with all followers and valve springs.
'Big' cam you may ask. Only recently found out there are two. The identifying feature is the cam journal at the front of the engine. Later 2.8 engines have a 43.9mm journal, older ones a 41.9mm journal. I believe the cut off was 1982/3 but if you are rebuilding a second hand engine, or are unsure of the origins of the engine in your car, you might need to bear this in mind. You have to measure the No1 journal, the others are slightly smaller.
Yep, the 2.9 cam goes the other way round, is driven by a chain, has different cam lobe centres and order...otherwise just about the same! Thanks for the offer but do you mind if I pass on it!!
Surprising just how different the 2.8 and 2.9 are when you get down to it. Apparently the 2.9 crank is OK for a 2.8 for some reason, just a minor grind on one dimension apparently.
Surprising just how different the 2.8 and 2.9 are when you get down to it. Apparently the 2.9 crank is OK for a 2.8 for some reason, just a minor grind on one dimension apparently.
When this is finished I will have 2 spare blocks, 3 spare cranks (one of which has been re-ground and is like new), 2 camshafts, 6 heads, 3 flywheels etc etc etc. I think I will keep the equivalent of one spare engine and see if I can get a bit of cash back off the rest, and a bit of space. A late summer sort out I should think! Although Colognes are still coming up on ebay they are certainly getting less readily available and I am trying to ensure I have enough stock to keep this S viable for a long time yet.
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