sumner2k3
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Registered: 12th Jan 06
Location: South Wales Drives: Clio 172
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can i use cam caps off my old head on a different head? both redtop heads.
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Stu_22
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Registered: 25th Mar 02
Location: Luton
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not supposed to as they are machined to that head
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craig_s
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Registered: 5th Mar 06
Location: Birmingham Drives: mk4 astra gsi
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it's not ideal but has been done before.if you are going to do it yourself andnot take it to a proper engine builders when putting them on keep checking that the cam turns ok everytime you tighten a cap down fully.best to do it with the lifters out of the head.no gurantee the caps fit the journals correctly though.if your not sure get it done properly.
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sumner2k3
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Registered: 12th Jan 06
Location: South Wales Drives: Clio 172
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so if i get it done properly then it will deffinatly be ok to do?
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craig_s
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Registered: 5th Mar 06
Location: Birmingham Drives: mk4 astra gsi
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yeah a proper engine builders would check the tolerances of the cam jounals against the cam caps.then machine them if need be.obviously if the too loose theres not much they can do.there wont be a lot of difference between caps anyway.as people swap cams over all the time.if you buy a set of reground cams for instance they will not be exactly machined to fit your head but will be fine.
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sumner2k3
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Registered: 12th Jan 06
Location: South Wales Drives: Clio 172
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ok thanks mate
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Limecat
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quote:
Originally posted by sri power
yeah a proper engine builders would check the tolerances of the cam jounals against the cam caps.then machine them if need be.obviously if the too loose theres not much they can do.there wont be a lot of difference between caps anyway.as people swap cams over all the time.if you buy a set of reground cams for instance they will not be exactly machined to fit your head but will be fine.
Sorry but I do not see what changing cams has to do with cam caps?
Yes you may have a slight amount of play on the studs when you put the cap on but it centres on the journals before it is tightened down.
The caps are line bored specifically to the head, it isn't ideal but as pointed out people have done it in the past. Personally for the risk involved of it 'nipping' I would get a head which is fitted with the original caps (saying that you have no guarantee!)
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sumner2k3
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Registered: 12th Jan 06
Location: South Wales Drives: Clio 172
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i only have 2 or 3 missing so if i use all the original ones and the 2 or 3 off the other head do you think that would be orite?
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Limecat
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Depends on the 'slop' on those 2 or 3 to be honest. Maybe stick them on with a cam in place, make a location mark, take them off, remove the cams and then refit lining up the location mark (use a scribe etc) and then use an internal vernier and take as many measurements as possible to check how true it is?
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sumner2k3
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Registered: 12th Jan 06
Location: South Wales Drives: Clio 172
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i have absolutly no clue how to do that lol ill have to take it to the place thats curruntly rebuilding my head and see what they'v got to say about it
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Limecat
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Thats the best bet, they are far more able to assess it than people on the internet are TBH!
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sumner2k3
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Registered: 12th Jan 06
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thanks for help anyway mate.
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craig_s
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Registered: 5th Mar 06
Location: Birmingham Drives: mk4 astra gsi
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quote:
Originally posted by LETGSI16V
quote:
Originally posted by sri power
yeah a proper engine builders would check the tolerances of the cam jounals against the cam caps.then machine them if need be.obviously if the too loose theres not much they can do.there wont be a lot of difference between caps anyway.as people swap cams over all the time.if you buy a set of reground cams for instance they will not be exactly machined to fit your head but will be fine.
Sorry but I do not see what changing cams has to do with cam caps?
Yes you may have a slight amount of play on the studs when you put the cap on but it centres on the journals before it is tightened down.
The caps are line bored specifically to the head, it isn't ideal but as pointed out people have done it in the past. Personally for the risk involved of it 'nipping' I would get a head which is fitted with the original caps (saying that you have no guarantee!)
well if there is so much difference between cam caps you would not be able to swap cams over so easy.yes there may be slight differences in caps but not a lot.if cam caps are so specific to each head then cams must be too yet you can fit any other cams into any head
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Limecat
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Thats because if you have the original caps they are line bored to a specific size. If you swap the caps about you may end up with it not being matched, essentially having an offset hole. It has nothing to do with the cams though.
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craig_s
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Registered: 5th Mar 06
Location: Birmingham Drives: mk4 astra gsi
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so how can the caps differ so much yet you can swap cams from head to head?i agree there might be some difference but not much.and cams have everything to do with it as it's the caps that hold them in and if they are so different then you would not be able to swap cams from head to head.
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Limecat
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What you are missing is that the caps are basically 'halved', ie. the cap is fastened to the head, line bored and then removed, hence why they are numbered etc. So if when each head is line bored you will get manufacturing tolerances depending on how true it runs, by then mixing and matching parts you are then installing further tolerance issues.
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craig_s
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Location: Birmingham Drives: mk4 astra gsi
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the same with cams then.as they will have there tolerances to fit correctly.so if they do how can you swap them from head to head.my point is that the tolerance you are stating on the cam caps must match the cams for them to run smoothly.i'm not syaing that swapping caps is a good idea just that it can be done.and theres not as much difference as every one makes out.
[Edited on 23-01-2008 by sri power]
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Limecat
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quote:
Originally posted by sri power
the same with cams then.as they will have there tolerances to fit correctly.so if they do how can you swap them from head to head.my point is that the tolerance you are stating on the cam caps must match the cams for them to run smoothly.i'm not syaing that swapping caps is a good idea just that it can be done.and theres not as much difference as every one makes out.
[Edited on 23-01-2008 by sri power]
No. Imagine a circle that has been dissected smack bang across it's horizontal axis at the point it's diameter is at it's maximum. That is basically your head and your cam cap.
Now bear in mind that on that head and cap you have 2 vertical holes that locate the head and the cam cap together?
So you have the tolerance from the initial instance, plus the tolerance from the second process. Say you took a cam cap that had a 1mm difference (I wouldn't envisage that difference between any but it is something you can visualise) and you then put that on a head that doesn't have that difference, you have a total circle that is offset by 1mm at it's mid point?
Do you get me? I am struggling to explain it despite being a trained engineer. If needs be I will knock up some things in paint to explain it, but I am crap with it.
A cam is just turned at one point on it's mounting faces/journals, so if that mic's up thats it.
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craig_s
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Location: Birmingham Drives: mk4 astra gsi
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i get what your saying now.you mean that the journal in the cap could be slightly offset i.e. slightly more to the right or left compared to another one.i was talking about the acual depth/circumference off the jounal in the cap matching the cam.i agree with what you are saying now we are talking about the same thing.i done a couple of years as an engineer machining cylinder heads and so on.
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Limecat
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Yes, thats what I mean chief, as it would cause it to nip up. 
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