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Wrong cam caps for head...worried. (NON DSM but same nexus)

4gfun

Supporting VIP
2,008
52
Dec 10, 2007
Ask Me, Virginia
This is a non-dsm question, but the expertise is so high here, the Focus SVT community is not as strong, and I am comfortable here....

It is not as bad as it sounds but it could be.

History:

I bent the valves on my FSVT when doing a timing belt job due to a failed OEM ford tensioner coming apart.

I grabbed the valves, springs, bucket tappets (pain in the neck) from a junk head that was warped and put them into my old head that worked just fine.

Problems:

I left the project for many months and I am not sure which cam caps go to which head. I did mark the order though.

So as it sits, I have a 50/50 chance of getting it right by guessing which set is which.

I am also not completely sure which set of cams is which. In the DSM world I don't think this would matter much. As a matter of fact, I'd assume that most of us would take advantage of that and use dial calipers on the cams and/or see which was less worn.

I am not bringing this to a machine shop. Not around here anyways.

What would you do?

Thanks!
 

o0GuitarKid0o

Proven Member
1,040
108
Dec 12, 2013
Winnipeg ,MB, MB_Canada
My understanding is that each cam cap was machined for that specific journal on the head.( line honed at the factory) any discoloration on one set?(burnt oil ect..)
You may be able to see the differences between one set vs the other. As one set might have 100,000 and the other set might have 300,000.

Any scoring on them? You can possibly look on the head and see that the lines from debris coming in contact with the bearing surfaces line up if that makes sense

Youll need a line hone if you cant figure it out as these aren't all made equal.

Did you take pictures at all of the cam caps on the head?
Same numbers on them I assume?

You can try putting them on (tourqed to spec) and get a bore micrometer to measure the inside diameter with the cams off.

Then grab a OD micrometer and measure the cams bearings. Minus your two measurements and get you bearing oil clearance and compare that to what ever the spec is.
Make sure you take the X,Y,Z measurements not just one .
Anyways someone will chime in with more experience
 
Last edited:

4gfun

Supporting VIP
2,008
52
Dec 10, 2007
Ask Me, Virginia
That is a fantastic idea man as far as marks etc! Not sure if I have pics but that is a good idea too!

I forgot to add that both sets are in the right order, just not sure which set is which.

I read that I can put the cam caps in and see if either set binds but I didn't want to inject any bad ideas into the thread.
 

1990TSIAWDTALON

Moderator
8,442
4,336
Nov 14, 2013
Independence, Kansas
I would put one set on and put the cams in the head and see if they spin easily, then try the other set for comparison. I would think you could tell the difference, but the only safe and sure way is like @o0GuitarKid0o said, a line bore on it.
 

4gfun

Supporting VIP
2,008
52
Dec 10, 2007
Ask Me, Virginia
Is a line bore a marking due wear or is it something else that I am looking for? Just wanted to clarify.

Or is a line boring having a machine shop hone them. Thank you.
 

ThunderChild

Supporting VIP
3,762
1,121
Jan 5, 2012
Rathdrum, Idaho
I would inspect the heads and caps carefully for any witness marks as @o0GuitarKid0o said, as that seems the simplest and most hopeful course of action.

Line boring is done by a machine shop to bring things back into proper alignment and uniformly straighten the bore if other work is done, or the cam/crank bore is out of spec (such as wrong caps for the cams).

Can you post some pics of the two heads and cap sets for us?
 

4gfun

Supporting VIP
2,008
52
Dec 10, 2007
Ask Me, Virginia
https://www.dragzine.com/news/engine-machining-101-getting-started-with-your-engine-build/
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This is really cool. Nice article. So that's how they do it. I'd sooner trust a monkey then to let them take my money around here. Going for broke here. I'd better find those markings or get this worked out.

FSVT head replacement and timing is a minefield anyways, so I am ready to live with whatever happens.
 

4gfun

Supporting VIP
2,008
52
Dec 10, 2007
Ask Me, Virginia
Maybe I am not tracking here, but if we swap used cams willy nilly isn't that effectively the same as using the wrong cam caps? Another way of asking the question is...If I have identified the correct camp caps, can I use either set of used cams?

Thanks.
 

1990TSIAWDTALON

Moderator
8,442
4,336
Nov 14, 2013
Independence, Kansas
The journals on the cams will be the same size in diameter so you can swap bumpsticks, willy nilly. Just can't mix the cam caps. :thumb:
 

4gfun

Supporting VIP
2,008
52
Dec 10, 2007
Ask Me, Virginia
The journals on the cams will be the same size in diameter so you can swap bumpsticks, willy nilly. Just can't mix the cam caps. :thumb:
ohhhhhhh....well time to try and enjoy myself with an additional option should I verify the correct cam caps...which in reality I am 90% sure of anyways.
 

4gfun

Supporting VIP
2,008
52
Dec 10, 2007
Ask Me, Virginia
Get a dial bore gauge and start mixing and measuring.
That's a good idea. I will research the tool and then come back if I need help. Hopefully the fsm has specs.
 
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