Cylinder head Guru required!

[Berlin]

...Preferably in the Newcastle :)

... So I bought a new Cylinder head for the GSXR 600 K3 race bike.. a very very special cylinder head. So Special it comes gas flowed and ported with machined pistons so the valves don't self destruct on them. It also comes with variable cam timing and serious cams and should add about 20BHP to the bike.

All I have to do is fit it! This has the distinct possibility of going very, very wrong, very, very quickly. :D

The Very helpful Paul from the Dyno centre (www.dynobike.co.uk (http://www.dynobike.co.uk) Excellent service today! Very clever man!) managed to sort out the glitch in the fuelling today. Just in time to see it all come apart and have to be completely set up from scratch again! :) At least I'll get a couple of practice days out of it before the strip down.

So, is there anyone that fancies holding my hand during the surgery? I can pay with as many cups of tea as you can drink and hold things extremely steady if required. Even if its by phone! :) Should it not explode on start up, you'll get your name on the ever expanding list of forum member sponsors on the fairing! :)

Now as this is valve timing and very technical, I'd prefer someone who obviously has some knowledge of this kind of thing and not someone who once changed an inner tube in a Raleigh Chopper but feel free to come around and watch the goings on if you're interested.

So then, What's a 1.3 degree piston/valve overlap all about? I have solder for squish! :)

Cheers,
Carl

[Berlin]

Blimey! The Org is Guruless! :D

Anyone have any info at all on this sort of stuff?

Online links? Rumours? Blokes down the pub?

C

[ophic]

*bloke down the pub mode*

Isn't it just a case of getting the camshaft in the right place in relation to the crank?

[ThEGr33k]

Im not too up on cams unfortunately. As for over lap, that sounds like the hardest thing to work with. You need to know the cam degree's so you can get them both bang on.

Unfortunately I don't know much about all that either, all i can say is the best for my engine is 106/109 and im not certain what that means.

Maybe I should come along to find out something? When you planning the surgery? If i got my bike back I could come and point at things...

[Berlin]

You're most welcome to the surgery! :)

Google's great...

http://www.compcams.com/Technical/TimingTutorial/

http://www.camshaftshop.com/camshaft/78-checking-piston-to-valve-clearance

If these were standard cams I'd not have a worry in the world doing it myself but as the pistons are machined to match them then things are obviously very, very tight in there :) Each cam has an adjustable gear cog at the end meaning it's possible to stuff things up very easily! :)... and there's no marks to line them up either, even if you know where TDC is. (panic!)

I'm praying that where they currently are is the right setting for my engine block but as the donor bike was running a super thin yoshi head gasket I'm not sure they will be.. unless I also run a super thin Yoshi head gasket?

It looks like I need a "Degree Wheel"! Anyone got one? :)

C

[Berlin]

More interesting info...

http://www.r1-forum.com/forums/showthread.php?t=183617

[punyXpress]

Any idea who did the head work & the source of the cams, Carl?
Failing that, if you establish the middle* of the period of maximum lift & time that at TDC you'll minimise the chance of a valve/piston interface.
* They're often not symmetrical
Dont blame me if/WHEN it goes bang, but just adding to the plot.

[ThEGr33k]

http://www.alcester-racing-sevens.com/cam_timing.htm

Something else that might help.

Cheers for the reading, I think I did once learn a lot of this but it had gone. :(

Do you know what timings the cams should be at? Anyway to find out? I think that once you have all the gear it should be reasonably easy (in theory anyway) to test what they are at and adjust. Once you measured the first time you'll know exactly how far out. Turn them then test again and should be sound. :smt045

Oh and be glad you are only doing 2 cams! Id love to make sure mine were at what most Aprilia engine people recon is best (106/109) for all round performance but man, id have to slot the gears and well mess around a whole lot. Maybe ill get another engine and "blue print" it to a low level...

Anyway, I digress.

Let me know when you are doing it mate and id love to come and see whats goin on!

Cheers

[yorkie_chris]

I've got a minimal knowledge of such things.

If it was already all timed up for "bolt this lot onto a stock bottom end with X base gasket and Y head gasket" then that will probably be OK.

However if you building it from bits (i.e never been together, god knows what machining done to head, barrel and base.) then you need to think up target squish numbers, maybe CC the head and pistons to find CR and then figure out what valve-piston clearance is acceptable.


Lot of this is figuring out numbers. If somebody else already worked these out life is FAR easier!

[Berlin]

The only marks on the cams are a small "PP" inside the end of one of them pressed into what looks like alloy inside the end of the shaft.

They were together but the previous owner took them apart (DOH!). The shims and cam fittings are now rattling around inside the rocker box cover.

C

[yorkie_chris]

You mean removed the cam sprockets from the cams?
That is major PITA if so.

Have you got a new cylinder block or are you getting yours honed or what?

[Berlin]

Nope, Cam sprockets are stiull on the cams but I don't know what they are set up as.

I've got the head, cams pistons and conrods. I also got the crank and barrels. But the big end was "rumbling" so probably needs new shells.

I'm planning to buy another K3 engine and graft it all onto there so I still have a spare engine should this one decide that we had the settings wrong when it goes together :)

C

[yorkie_chris]

Spare engine is a good idea :)

Good you got barrels, that way you should be able to keep pistons matched to their bores (save you honing yours and replacing rings). Have a careful look for any scuffing though as sometimes a knackered big end allows the pistons to move around you get scuffing damage on skirts and alloy smeared into bore.

[Lozzo]

So basically you've got slotted cams and you need to time them to suit the crank position. It's all quite simple if you have a degree wheel and lots of patience. Just remember to make sure you know your advance from your retard and never ever turn the engine on the starter before you've slowly turned it over by hand to make sure there's no piston/valve interface. I'm sure I've seen a page somewhere on the net with an idiot's guide to timing slotted cams, a google search should find it.

The supplier of the head/cams should have given you baseline values to work with, and final adjustments can be made with dyno runs in between to get it running spot on.

[embee]

I haven't looked at the linky guides, so apologise if this repeats stuff unnecessarily. Anyway, FWIW...

If starting with "unknown" bits, you really need to go through the procedure from basics, otherwise it could end in tears.

Minimum kit you need is a degree wheel, I have a Wassell one sitting right here in front of me. You can make one with a little basic computer skill and a graphics app of some description, or I'm sure you can find something online. I haven't got a scanner handy so can't reproduce the one I have right now, but if all else fails I could arange it. Print it off and laminate it, the one I have is stiffish but flexi plastic, about 190mm dia.
http://i258.photobucket.com/albums/hh268/Hi-vis/IMG_4244Small.jpg

Then you need a Dial Test Indicator (DTI), the type with a plunger rather than a "finger", and a stand to fix it to the top of the engine somehow. The usual is to use a magnetic base and bolt a piece of steel onto something handy if it's all alloy around it.

Get some light weight springs which will replace the stock valve springs, something you can press with your fingers easily. Places like Screwfix etc have selection boxes usually.

Build the bottom end up with crank/rods/pistons/barrels so it'll turn. Fit teh camchain and some form of tensioner (can be manual). Build the heads with the light valve springs.

Set the TDC using the timing wheel. Use the DTI to find a suitable piston "drop" each side of TDC, say 2mm down, note the wheel degrees difference and halve it, reset the wheel to zero at half the difference (e.g. if -2mm clockwise gives 58deg, and -2mm a/cw gives 46deg, diff is 12deg, half is 6deg, turn engine to 52deg and then re-zero the wheel, that's now as near as damn-it true TDC). Don't move the timing wheel again!

Fit the heads with a known thickness gasket, no real need to torque it at this stage, a tight nip will do.

Fit DTI above one valve, zero the dial, push valve down with fingers and determine the clearance. Do this for each valve to be safe. Make notes systematically.

For checking valve timing clearances, set the crank to the nominated "Maximum opening point" (MOP) for the cam, fit the cam. Using the DTI, set it to full lift as near you can judge. Use the same principle for checking the MOP as for setting TDC, turn crank a/cw until DTI on the valve reads say -2mm, note crank angle, turn c/w until DTI reads same valve drop, note angle, MOP is then half way between (usually near enough anyway assuming symmetrical cams). It might be necessary (certainly desirable) to always turn the crank in its proper direction for the camchain tensioner to work properly, but with light springs you can often get away without having to do this.

Repeat for the other cam. Carefully turn crank to TDC, set up the DTI on each valve and check the clearance again. You'll probably want to check clearances at different cam timings, or do a cam lift curve measurement exercise while it's set up like this.

The amount you need to allow for expansion and rod stretch will vary engine to engine, someone must have a min value for an SV.

The minimum valve/piston clearance won't be at TDC, so you would be advised to check the clearance each side of TDC, turn crank a couple of degrees at a time and measure/record clearance, you can then plot a curve of clearance vs crank angle.

Checking "bump" clearance between piston/head is probably easiest done with plasticene in the home workshop. Add small cones of plasticene to the piston crown at strategic points (squish areas etc), lighly smear the head chamber with oil to prevent the plasticene sticking to it, fit head (easiest without cams to start with), turn engine through TDC slowly,remove and measure thickness of plasticene. Record on a drawing or large photo for future reference.

I've seen a case where a piston part number laser etched into the crown had transferred to the head squish area perfectly readably after a run at max RPM, that's close.

The fun starts when you want to assess cam timing changes, so do as many measurements as you can while it's all set up for it, once it's built in anger you want to be able to simply refer to your records.

That's a start anyway.

[Berlin]

Thanks Embee! I'm going to have to read that a few times before it makes complete sense! I've still had no joy tracking down base settings.

More good stuff on this...

http://www.factorypro.com/tech/tuning_cam_timing_tuning_proc.html


C

[Berlin]

After lots and lots of reading I think I'm getting the hang of this now and quite enjoying being out of my mechanical comfort zone.

I still haven't managed to identify the cams yet but I have found out they should be in the 104-106 range for the initial set up and depending on what comes out from the lift graph(I have to plot) maybe as high as 107 to 112.

Feeling a lot more confident about this now.

Thanks for the help! :)
C

[Lozzo]

After lots and lots of reading I think I'm getting the hang of this now and quite enjoying being out of my mechanical comfort zone.


You never improve if you don't push your boundaries.

[gfewster]

As you bolt it all together in the manner that you think is correct, apply a layer of engineer's blue to the top of each piston.

Then turn it over gently by hand, take it all apart and check there is no blue on any of the valves.

[Berlin]

It looks like there'll be *LOTS* of putting together and taking apart on this one! :)

And I'm presuming you can't get away with doing it for only one cylinder. you have to do them all?

C

[yorkie_chris]

Doing them all is safest.

[Red Herring]

You never improve if you don't push your boundaries.

This is true, but you don't win races without recognizing your weakness either.

Much as I admire Berlins adventure there is no way i would be taking on this job myself, and I've been stripping and building my own engines for the past 20 years. It's one thing to strip a standard engine and rebuild it to manufactures specification, or even to replace tuned parts with similar parts from the same tuner, but to take various parts from different sources and put them together yourself you either need to be very very good at checking everything (and have all the necessary instruments to do it), and have some idea (usually from experience) what the relative gaps and clearances should be, or you'll end up with a very expensive pile of spares shortly afterwards.

The problem with tuning engines is everything has to be matched together to the optimum clearance, and these figures aren't written down anywhere, they are the closely guarded secrets of engine builders and are what their reputations are built on. Just about anybody can throw together a powerful engine, not many can make it last a race distance....and 20bhp on a 600 is right up there with the best of them.

I guess it depends on how much you have invested in this build Berlin, and what you want to use it for. If you look at the economics having it put together by an expert would cost you less than one race weekend, how many DNF's is that worth?

[Berlin]

£160 for spare engine (std)
£65 delivery
£150 for sexy head, pistons and cams etc
£80 for new thin head gasket

Putting it together myself and finding out it does put out 120BHP at the rear wheel...

Priceless! :D

If it goes pop, its been a useful learning curve and I feel I should be able to get it to at least start being an engineer and all that :)

Optimising the exact valve timin to the half a degree may take a little while on the dyno.

I've also ahd a bit of a result identifying the cams. They're Kent cams and I now have the base settings for the angles. I've also found out the springs and valves are Crescent Suzuki monsters.
The cams were special order and not in the Kent catalogue! Someone knew what they were doing!

C

[yorkie_chris]

Chemical engineer? :-P

Getting it to start is the easy bit, finding out whether it explodes when you hit rev limiter at full throttle...

[Berlin]

And you think an engine is mechanical engineering?

Designing and machining the engine is mechanical engineering.

What happens after that is pure chemical engineering! :)

Fluid flow dynamics for both fuel and air, fuel injection, heat exchange, combustion, Oil pumps, fuel pumps, ram air, and thernodynamics are all chemical engineering.

You make the cogs, I'll make them turn ;)

C

[fastdruid]

Both Mechanical and Chemical Engineering are nothing more than lots and lots of maths. :)

Druid

[yorkie_chris]

And you think an engine is mechanical engineering?

Designing and machining the engine is mechanical engineering.

What happens after that is pure chemical engineering! :)

Fluid flow dynamics for both fuel and air, fuel injection, heat exchange, combustion, Oil pumps, fuel pumps, ram air, and thernodynamics are all chemical engineering.

You make the cogs, I'll make them turn ;)

C

Fuel can burn as much as it wants when valves just got eaten by piston, you won't go very far ;)

We do fluid mechanics, basic heat exchange, turbomachinery inc pumps, compressible flow and thermodynamics as part of mechanical course :)
Thermodynamic cycle of how engine works is less interesting than it sounds!

[ThEGr33k]

Id love to be doing the course you are doing Chris.

As to Berlin, now you have a rough idea where you want to be im sure you will be fine! :)

[yorkie_chris]

+1 now you know where you're going with it rest is safety check.

Check squish and map piston-valve clearance with those degree numbers, I'd check one and if clearance is miles then leave others.