shims and tappet clearance

[Machi san]

Hi chaps

What is the recommended tappet clearance for cg13 using 260* 10mm lift kent cams?

What's is the clearance on stock cams?



Also where do people get they're new shims from for reshimming? I have access to a lathe and a surface grinder. I could make new ones from silver steel if its suffice?


Cheers
Kev

 

[frank]

i set mine to 10" thou kev (.25mm, all 16, cold)
and be careful about using fatter/heavier ones, me, baguete and stani have had them spit out
far safer to grind the lip off the bucket and fit the shims underneath imo (and much quieter too)

 

[Machi san]

Ace! Thanks frank!

Have you got a pic of the lip that I need to grind? Just trying to plan ahead so I can fit them asap without too much down time!

Where do you get your new shims from? Do you have any for sale?

 

[frank]

i put mine on a broom stale and ground the lip off freehand kev, then put the bucket in the drill and held it down on some emery (you can use a bolt with a rubber bush that expands into the bucket)
and you have to chamfer the top shim so that it sits fully into the top of the bucket btw
the shims are £6 a pop iirc, so i just gather what i can from scrap engines, i dont have many spare tho tbh

 

[Machi san]

Hmmm ok thanks frank

Iam starting to think that going down this road maybe a bad idea. I don't think this is within my comfort zone and I can't really justify spending 100 on shims.

I will get some quotes from some of the local tuning shops and see how much to get someone else to do it.



Out of interest is the drill and rubber bush bit just for re-lapping the face of the bucket?

 

[frank]

how much was ground off the cams kev ?

 

[Machi san]

Too be honest frank I have no idea, iam waiting for superls to send them down to me.

Do you think its possible that I may not need any shims?

 

[frank]

Too be honest frank I have no idea, iam waiting for superls to send them down to me.

Do you think its possible that I may not need any shims?

my pipers had 1.75mm took off iirc, and i had to grind some shims down to the same amount and add them under the buckets (i tried the surface grinder and they kept flying off the magnetic table lol, and used a belt sander in the end :grinning
autosprint remove 2.5mm so its a more straight forward stock extra shim job
i have some late cga3 buckets which have no shim atall (but are thicker), i,ll measure them when you get the cams

 

[Machi san]

Ace that's brilliant Frank, thankyou very much

Just so you know I do have access to lathes, mills, surface grinders, cylindrcal grinders ect ect so modding stuff is fine, as long as I have a plan and have a decent idea in my head what iam doing

 

[Machi san]

Hey Frank I should have the cams in my hands in the next day or two.

Did you want me to get you the measurement from the cam centre line to base circle diameter? And also centreline to full lift on the lobe?

Or did you want different measurements?

Thanks
Kev

Ps I have an rb25det neo engine which has solid lifters, you wouldn't know if they were the same diameter?

 

[frank]

Hey Frank I should have the cams in my hands in the next day or two.

Did you want me to get you the measurement from the cam centre line to base circle diameter? And also centreline to full lift on the lobe?

Or did you want different measurements?

Thanks
Kev

Ps I have an rb25det neo engine which has solid lifters, you wouldn't know if they were the same diameter?

just the base circle diameter will do kev, stock are 32mm, my autosprint one is 27mm, and my piper ultimate one ranges between 28.4 and 28.6 fwn

 

[Machi san]

Thanks frank, ill let you asap.

Lol at piper scams and they're .2mm tolerance haha its not hard to use a grinding machine accurately. We have a cylindrical grinder from the 70s and it hold .005mm without much trouble

 

[will930]

Im making a set of buckets for me with my spare set then when mine are out i can mod them too if u want

 

[Machi san]

Im making a set of buckets for me with my spare set then when mine are out i can mod them too if u want

Let me know about the mods and have you got any pics? Sounds like it could be an option

My cams have 29.6-29.8 base circle diameter and 9mm lift

My pm box is full atm, need to get on a computer to delete them. So thanks scott if you read this ill pm you tomorrow when I get onto a computer. Cheers

 

[frank]

Let me know about the mods and have you got any pics? Sounds like it could be an option

My cams have 29.6-29.8 base circle diameter and 9mm lift

My pm box is full atm, need to get on a computer to delete them. So thanks scott if you read this ill pm you tomorrow when I get onto a computer. Cheers

they,ve taken just over 2 mm off then eh kev.
the late cga/cr shimless buckets are 2mm smaller than a cg bucket and shim (or 1/2 a mm bigger that a cg bucket only.
and the late cga/cr valves are 2 mm longer to suit.
so a good option would be for you to fit the longer valves to your head and fettle a tad off the end of the stem (a few thou) to get the clearances bang-on

 

[Machi san]

Sorry frank I didn't realise you had replied to this thread!

Thanks for the info, iam going down to the breakers yard in the next couple days to source out the bits I need to put my car on injection.

Iam also making a new carb manifold so if the new manifold cures the running problem and improves economy at all then I will keep carbs, if not ill be putting injection on it.

Iam having nistune installed on my driftcar next month so I will be picking his brains about nistune on the micra with maybe a td04l or an rb25 ceramic turbo or a t25. Not sure yet though.

I just want about 120hp turbo engine with decent fuel economy on the cruise.

Cheers
Kev

 

[superls]

what are you doing to the gallon on the carbs, i was at about 32 going back and forth to work, have you replaced everything ignition wise? i doubt a manifold would make any difference as i honestly had none of the problems you are having.

 

[Machi san]

Hi scott,

I replaced the spark plugs twice. Denso ones made it worse. Iirc I have bosch or ngk in there now. I also fitted new leads.

I haven't changed coil or rotor arm.

I have tried to buy a new dizzy but can't find any for sale as of yet.

The rolling road guy said it isn't a problem with coil breaking down or anything like that. It is a wiring problem or a duff dizzy BUT he said that the air leaks don't help. I have air leaks on both carbs where the bolt down and also a leak on one runner where it bolts to the head.

On the dual carriageway I managed 26mpg cruising at 60 in 5th. I didn't accelerate hard once because I had the dog with me. If I drive it fast the economy drops to like 12mpg.

My 300hp rb25 driftcar can do over 22mpg on the limiter whilst drifting on track.


I have decided to give up on the carbs and making new manifold ect. Just gonna get injection fitted asap.

Am I right in assuming that it'll be around 90-95hp on standard injection with the free flowing exhaust?

 

[superls]

well the mis firing wont help mpg at all, but that is really bad, the wiring to the dizzy and coil is so simple its hard to believe that its wrong, for the sake of about £8 i change the cap and rotor arm.

the coil wiring should be easy as i say, positive to coil when ignition is on, and then the dizzy makes and breaks the earth to the coil for the spark, thats it, change the rotor arm and dizzy cap.

blue hylomar will stop the leaks on the flanges and thick paint will block the others up, then let us know what happens

and if you go injection, i think you can expect around 90bhp but at 40mpg