Inlet cam touches the head when turning cam

[cliokongen]

Never experienced a problem like this before!

I am in the process of building an engine at moment.
Removed lifters and thought id better check to see if cams would spin freely in the head - just to be sure. Luckily i did!

Exhaust cam spun smoothly.
Inlet was a different matter.
Cam lobes are hitting the inside of the head - just at the egde where lifters are fitted.

Pictures attached. Luckily no harm was done to the cams.
Cams are Piper RW16VBP285H.
When measuring the lobes on the inlet cam they are bigger than on the exhaust cam. The exhaust spins freely in the inlet cams place.
Dont get it as the inlet and exhaust on pipers website has the same measurements.

Will it be possible to grind off just a little bit to make them move freely?

Michael

http://i50.photobucket.com/albums/f312/Cliokongen/Motorprojekt/Knastskrabcyl-3.jpg

http://i50.photobucket.com/albums/f312/Cliokongen/Motorprojekt/Knastskrabcyl-2.jpg

http://i50.photobucket.com/albums/f312/Cliokongen/Motorprojekt/Knastskrabcyl-1.jpg

http://i50.photobucket.com/albums/f312/Cliokongen/Motorprojekt/Knastskrabcyl.jpg

[MAXIBOY]

how many lobes touch the head mate...out of eight

[cliokongen]

how many lobes touch the head mate...out of eight

6 lobes touches the head.
I think the contact is minimal - might only be 0,5 millimeter.

This is far from ideal - but never seen this problem before.

Michael

[cliokongen]

4 lobes mate... :-)

Michael

[stan]

common on higher lift cams, you need to remove material from the head so as to give a couple of mm clearance.

[cliokongen]

Thanks Stan....

Cams doesn't seem to have such a high lift on paper - making all this work necessary.
Anyone got experience with these cams?

But anyway - quite simple - just need to grind away a few mm and debur the edges.
Anything else i need to take into account? (of course removing valves before grinder action and cleaning head thoroughly afterwards.....)

Michael

[stan]

what lift do they give?

around 11-12mm and you need to relieve the head.

remember there are always casting variations aswell, so this will account for part of it...

[cliokongen]

what lift do they give?

around 11-12mm and you need to relieve the head.

remember there are always casting variations aswell, so this will account for part of it...


They "only" lift 10,87mm
2,18mm @ TDC

Strange...
How do i effectively measure the cam to check the lift.
Already checked the engraving on the cam - it should be the correct ones.

Michael

[stan]

measure the height of the lobe, then subtract the base-circle diameter from this figure..the remainder is cam lift.

check all of them, Pipers have a tendency to have a bit of variation.

[cliokongen]

measure the height of the lobe, then subtract the base-circle diameter from this figure..the remainder is cam lift.

check all of them, Pipers have a tendency to have a bit of variation.

Maybe my measuring are a fair bit out - used a std. digital vernier which is far from ideal... So did it a couple of times - this is the average:

Lobe: 43,33 43,33 43,34 43,33 43,32 43,32 43,32 43,32
Base: 32,00 32,00 32,04 32,03 32,03 32,00 32,00 32,03

Avarage lift: 11,30 which is far from the 10,87 stated by Piper....
Very strange.....

Michael

[cliorod]

Stan
If these are "high ~ lift" and fouling on the casing etc. :oops: :oops:
Would he not be as well,for checking piston crown to valve clearance :wink: :wink: ~~Last thing he wants is these two items coming in contact with each other :( :cry: :shock: :cry:
Rod
What sort of clearances do you work too ,on a dry build
:roll: :roll:

[cliokongen]

Rod,

I am going to check clerances - using the dry build/play doh method :-)

I would like to know something about clearances too.....

Michael

[stan]

clearaces for what exactly?crank runing clearances, ring end gaps, bore/piston clearances??

are you running std pistons? the last convo we had you were thinking of forged high comp?

[cliokongen]

Sorry Stan........
Impressed with you being able to remember that... :-)

Using Wössner 11,2 Cr pistons.
Looking for minimum alowed valve to piston clearance.

Dont think it will be an issue - valve pockets are quite a bit larger on the Wössners compared to the std. pistons.

Michael

[cliokongen]

Pictures of the build here:
Text is in Danish - just read the pictures.... :-)

http://www.renaultklubben.dk/forum/forums/thread-view.asp?tid=1641&start=326&posts=340

or

http://s50.photobucket.com/albums/f312/Cliokongen/Motorprojekt/

Michael

[stan]

you want around 1mm of valve/piston clearance.

with the pistons you have, you will have about 8mm of clearance. so if your cams require 2.5mm of lift, you will have about 5mm clearance...acres! on stock pistons however, you only have about 3.5mm...so with the same cams, you would be on the verge of clearances isssues.

[cliokongen]

Excellent - thanks mate! :-)
Acres! LOL

Anyway - got the lifters, valves and the rest out of the head.
Let the grider action commence... :-)
Any final advice....?


Michael

[stan]

not really..just make sure u clean all swarf, and de-burr the edge of the follower bore.

[cliokongen]

Material removed - cams are now spinning freely.
Next - get the head a proper clean before fitting valves again.

Michael

http://i50.photobucket.com/albums/f312/Cliokongen/Motorprojekt/Slibe03Small.jpg

http://i50.photobucket.com/albums/f312/Cliokongen/Motorprojekt/Spner04Small.jpg

http://i50.photobucket.com/albums/f312/Cliokongen/Motorprojekt/Spner02Small.jpg

http://i50.photobucket.com/albums/f312/Cliokongen/Motorprojekt/Spner05Small.jpg

http://i50.photobucket.com/albums/f312/Cliokongen/Motorprojekt/Frdigtop01Small.jpg

http://i50.photobucket.com/albums/f312/Cliokongen/Motorprojekt/Frdigtopmedknast-derkankrerundtS-1.jpg

[stan]

looks good pal, how much clearance have you got now?

[cliokongen]

About 1mm - 1,5mm - hard to actually see anything from any angle... :-)
Getting a feeler blede under there is impossible...

Just hope it will work witout any problems.
Considering the lift i measured is a fair amount larger than stated by piper i worry that the lift is to much for hydraulic lifters?

Michael