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cam degree questions: guru's?

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Hi all,

 

I am planning to degree my RHC cams.

The are the adjustible type.

 

I have 3 questions:

1) Of course i don't want the gears to slip. What is the torque spec on the gear bolts?

2) What is a good way to hold the gear and cam while torquing the gear bolts?

3) What type of loctite? I assume hi strength 2701?

 

Thanks for any info!

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1)  The bolts are 6mm from what I have seen,  The heads will be marked with the strength. 8.8, 10.9 or 12.9.  8.8 can go about  84 inch pounds. 10.9, 100inch pounds and 12.9, 120 inch pounds.

 

2)  Don't know.  Never done it.  I suspect the motor compression via the cam chain will hold the cam well enough to tighten the bolts.   If the wrench handle crosses the cam center, it takes less effort to hold the cam.

 

3)  Should be fine

 

 

What spec are you going to use for cam center?  Hot Cams numbers or something custom?  Are you looking for something special with cam settings or just making sure it is right on the advertised number?  When I was checking cams a few years back, the cams were very close to the Hot Cams specs, I made no adjustments.  I only have the slotted gear in the IN cam.  I later ordered a matching EX cam but it got substituted with a newer cam so no slots.

Edited by Noble

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Thanks Noble.

 

RHC 187 EX 

RHC 208 IN

 

I got them used but very low miles.The degreeable version. They were predegreed 

The previous owner removed the sprockets to inspect the bolts so they are not pre-degreed anymore.

 

Trying to get in touch with Ron Hamp because no-one seems to know the official LCL spec of the RHC208 cam.

 

Will be used on my +5 or +4mm stroker build.

I will have to decide on which one to use, i have the luxury of owning both.

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Hey J, Your 208 cam is almost the same cam as the Web 539 with .007 thou more lift. .407 lift and 280 @ .020 and 258 @ .050.  The 187 has .356 lift with 277 degrees @ .020 and .257 @ .050, This is close to what I'm running, but I have more on the ex. side. There's no big secret in the lobe center numbers. You should stay close to the manufactures recommendations but It's not gonna kill your horse power if your off a few degrees. You can move the power band around degreeing but the main characteristics of the cams are determined by the duration, the time in degrees the valves are held open and when they open and close. The more duration the cam has favers top end HP at the cost of some low end power. You can advance the cams to add bottom end or retard them to kill off some bottom and maybe help the top. I've moved the cams all over the place without making a whole lot of difference you can feel. I've been at 104/108  108/106 and everywhere in between.  I would stay away from low lobe centers like 104 without keeping an eye on your valve to piston clearance. The bigger the lobe center number the more valve to piston clearance you will have. I would set your combo up at 106/106. That will run like crazy with your engine combo and be a safe place to start.  Use red Loctite and tighten the bolts to Nobles specs. You can hold the engine from turning with the alternator rotor nut on the left side. One more thing, with the 208 intake cams lift, your going to need to replace the guides with shorter ones so the valve spring retainers wont smash the crap out of the guide seals. You can push the stock guides down .030 to gain the needed clearance but I would instal new Kibblewhites. Let us know how it's progressing.

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for the record here on tt.

 

I got this from the source (eddie)

RHC 208 IN LCL is 108.

He also says the stock guides  and seals clear no problem with the 208's lift.

 

RHC 187 EX LCL is (found on the net) 104 LCL.

But i think i'll go 106, just to be on the safe side for clearance,

and because james says i won be able to tell the difference,

and because if it makes a difference it will most likely favor mid range and take a little top off.

I like that anyway.

Edited by jhondius

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I'm running 108/104 on my current setup (welded sprockets), runs great.

On my other set I was running 106/104 (187/187), adjustable gears, but this setup worked great.

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J, I just read what you got from Eddie and I say he's wrong. The 208 with .407 lift will smash the seals. I just went down to the shop and measured the lift on a head with stock valves. The head has had the valve seats cut before so the valve sets deeper in the seat and has even more retainer to seal clearance than stock. The  spring retainer contacts the seal at .395 lift. You should have at least .020 thou. clearance at full lift. This stuff needs to be checked building a Motor like this. Yours might be different but I don't think so. Please check it to make sure. Also, don't try to run stock springs with that much lift, they will coil bind.

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Thanks james,

apreciate your effort a lot.

I am confused. You are obviously right.

But i do trust eddie too.

My head is an ssw ported +1mm in with rhc valves and springs. So the springs are good for the lift i think.

Eddies reply concerned general ssw heads that most of the time have this setup i think.

He says plenty of room. Weird.

I think the rhc valves are a tad longer then stock ones. So the shims are thinner.

Maybe cam base circle is smaller too?

Could this make a difference?

I am no experienced engine builder so trying to grasp it all.

Best is to measure of course.

But how? I think i will have to remove a valve? I think i need a valve compressor for that?

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the ferrea rhc +1 valves are 82.65mm long.

now how long are the stockers...

searching..

Edited by jhondius

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If you head has longer valve stems, that will give you the clearance you need. I thought you were using a stock head. If Eddie built it, he should know what will work in it. Let me know how it runs.

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Just read your last post, As far as I know, the 1mm over Ferreas are the same length as stock. That's what I use.  If the valves in your head are longer, they had to have been ordered special. Just checked Ferrea's website,The Ferrea stock size valves are also 82.65mm in length. both with a 1.70 tip length.

Edited by james509

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They are normal rhc ones.

Regular ferrea's with a coating AFAIK.

 

But think i have read a post by eddie here on TT that the RHC's are longer then stock and need thinner shims.

Cant find that post now.

??

 

Anyway Eddie should know.

But it would be wise (and fun) to measure.

 

How do i go about measuring that?

valves out of the head, cams in, find clearance and subtract valve top size?

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There are several ways of measuring that. I removed the springs and installed a very weak spring i got from the hardware store then measured how much travel it had until the retainer hits the valve seal. I used a dial indicator, vernier calipers work just as well.  

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i feel very stupid but i dont get it.

there is a bucket over the valve and retainer. So i cannot see or access the space in between the retainer and seal can i?

Even without bucket i could not get in there i think?

Plasticene?

Edited by jhondius

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You can measure or calculate valve movement to coil bind and/or valve movement to spring retainer/seal contact.  Compare that to lobe lift of the cam.  The cam base circle is less then 180 deg so you either have to use the manufacturers spec for lift of measure lift by rotating the cam against a dial indicator.

 

You can measure spring installed height. Then compress a spring in a vise to the installed height, measure the distance between the coils and calculate how much more it will compress to coil bind. Or just coil bind the spring and measure the length.  Difference between installed height and coil bind is the max a valve will move.  Of course you can not use a spring to coil bind.  There has to be some space remaining between coils at full lift.   I do not have  good number for that.  Maybe 1mm at each coil.

 

To measure spring retainer to stem seal, instal the retainer with no spring or a very light spring and measure how far the valve will move.

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Now i get it.

Just push the valve down and measure the travel.

silly me.

The cam lift is 10mm.

The rhc spings are up to that task.

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