Camshaft

[LUIS COLCHETE]

Hi!

 

Can i set up A15 camshaft H50 on my A12 engine block instead a12 camshaft?

 

 

[datzenmike]

I don't see why not. What head are you using?

[LUIS COLCHETE]

I need your help, i have some many questions...

 

I make a new engine with a ISKENDERIAN regrind A12 cam, twin carbs, double springs, an A14 cylinder head on A12 eNGINE and it works well in a couple of minutes, after that it looses power, and the valves gains clearnces, after a while i had adjust them and new clearance, in a couple of minute a total clearance 0.70mm.

I dismantle the engine and i found the original rocker arms valve opener has wear, loose material, the regrind cam have only shadows i think its ok, but im afraid it gains wear.

Please let me know install normal a14 Valve Springs? Buy a reforced rocker arms ? Double springs can make this? Lack of oil on cylinder head?

 

 

A12 actual cam performance is:         WITH THE ISKENDERIAN GRIND

 

My A12 actual cam performance is:         WITH THE ISKENDERIAN GRIND

 

total intake timing   248º                                            266º

open before tdc       14º                                              24º

close after bdc         54º                                              62

 

 

total exhaust timing   248º                                         266º

open before bdc         56º                                            62º

close after tdc             12º                                            24º

 

Please let me know the performance of A15 m10 camshaft,  i saw a new one if is like my reground one i will buy it.

[datzenmike]

When you looked at the rocker arms did they have oil on them?

 

Does the oil supply hole in the block line up with the hole in the head??

[LUIS COLCHETE]

Thanks for your replies.

 

The springs have some oil, but i think insuficient
I have no oportunity to make the test on oil flow because i took of the engine of, when i have the oportunity i will assembly a starter and test the oil passage. Now im geting ideias and knowldeges from you with experience and trouble solutions. 

The valve stem its ok no damgages, i notice the valve springs are stacking solid at full lift, the engine is very stuck it is dificult to move it with a wrench on cranckshaft pulley, but when i removed the rocker arns, the engine moves slowly with no prison.
 

 

 

 

Thanks Again

Luis

 

 

Posted on: Yesterday 9:14

[G-Duax]

Take some time, and go through Kameari's web site.

They make wonderful things for the little 'A'.

 

http://www.kameariengineworks.co.jp/

[LUIS COLCHETE]

Hi!

 

The problem which cause wear on rocker arm was the valve springs

"This item is worthy of middle class specifications enough.(To about 8,000 rpm spec)
They are Valve Springs popular very much in JDM.
The double valve springs control Valve Surging at the time of high rpms.
It supports; cam lift - 6.5mm, valve lift - 9.4mm"


And the cam lift is 0.298" or 7,57mm that is i saw on paper..


Cam lift 7.57mm is bigger than the spring can suport????

 

My camshaft has wear too. i need regring again another one...................

i bought on ebay a new  A15 h50 to send to iskenderian

This time I must buy a elecrical fuel pump, because its a late camshaft and my a12 block it is a early one, i saw a nismo 17010-A7600 17010-A7601 and this model is for Carburetor vehicles requiring a low pressure pump and to replace factory electric or mechanical pumps
1.3L/min @ 29kPa/4.2psi

Mikuni recommended fuel pressure is 2.84 - 4.98 psi


I think this fuel pump is perfect and i dont need a regulator, please let me know 


and i will order the springs from Iskenderian to avoid any doubts.

Im counting with your advices

 

 

Luis

[Crashtd420]

As far as the fuel pump the best suggestion I have is install a simple fuel pressure gauge and actually check what you get for pressure....

I installed a recommended carter fuel pump on my engine and was actually about 2 or 3 psi over what my weber wanted and caused a rich and flooding issue.... once I installed a regulator and set the pressure I needed things ran so much better....

I'm not saying you need a regulator but it's best to verify the actual output not just trust what they say....

 

Goodluck with the cam and spring issue...

[datzenmike]

Use an oil with high ZDDP level such as Shell Rotella T or T4 15W40. Today's over the counter oils are formulated for roller rocker cams and don't need as must zinc scuff protection additives. They don't provide enough protection for our engines. Valvoline, Castrol racing oils do, but you have to ask and look for it.

[sebpv]

Mike would you suggest the same oil on a newly rebuilt engine? I have Mobile oil awaiting on my shelf until i drive the truck. Worst case Ill use it to collect the crap for the first 500km

[Crashtd420]

The biggest thing is if you have a flat tappet cam setup you need the extra zinc...

 

Has the motor ever been ran?

You may wanna use a break in oil first....

[datzenmike]

Yup. Mobil makes a racing oil I think. Cams need anti scuff protection ALL the time. That start up and hold the revs at 3K for a new cam is bullshit. That's old news for a V8 swhere the cam does not get direct oil lubrication and relies on cast off from the spinning crankshaft just below it. The L series has oil forced through the cam lobes... it gets plenty. Rockers and cam lobes can 'break in' while they are driving you around.

 

Myself, I would never use a specific 'break in' oil. Run what you plan to run for the life of the engine OR cheaper high level ZDDP oil initially because you are going to change it right away anyway. It's more important to get the oil and filter used on the initial start up changed within a couple of hundred miles. Then run your favorite high level ZDDP oil.

[Stoffregen Motorsports]

To answer the original question, you have to figure out if the distributor drive is in the same location on both cams. The early A12's had the distributor up front. Later, with the rest of the A series lineup, they moved the distributor rearward and the cam style changed.

[LUIS COLCHETE]

hI!

i taken measures on camshaft with more precision, and the cams are ok, but some have some shadows and one have a litle material dent.

Please give me your opinion? Its a big deal? or take the risk and assembly it with this material dent on cam? The lifter will make some pressure in all cam and will toutch the dent too, im afraid the lifter will increase the cam dent?

Thanks

Luis

 

[DanielC]

If the valve springs stack up solid, that is there is no space between the coils at full valve lift, that is very bad.  At best, it will force all the oil out of metal to metal contact places, like the camshaft lobes, and follower, and these parts will wear out very quickly.  At worst, it will bend the pushrods, break rocker arms, or in some other way make other things break.

 

With the valves at held at full lift by the camshaft, there still should be room in the springs, for the valves to open more.

[datzenmike]

The cam lobe will take on a very shiny polish from the lifter rubbing against it. This is what I see here.

 

 

This is wear...

 

[LUIS COLCHETE]

Thanks

 

Please see this best picture,the first arrow shows a litle dent (i dont know if comes with it or was a material porosity) The second arrow shows a shadow

 

But the cam has no wear... Please give your opinion 

 

[datzenmike]

The indent I don't know unless there when put in.

 

I think the shiny parts are just natural polishing of the cam by the lifter. Select an oil with lots of ZDDP in it. Racing oil or diesel oils still have the correct level. ZDDP is a zinc anti-scuff additive crucial to prevent wear on non roller cams like yours.