the lvferraripilot engine rebuild thread

Oh dear Chris looks like this motor is going to be together this weekend . John you have certainly shown us how to get on with it !!!

 

Picked up the heads. Man they are pretty. Very smooth and shiney deck. pics coming. Waiting on my timing gear bearings to show up........ I ordered them over a week ago now.

 

snapped a pic a few minutes ago.
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WOW

 

Very nice. But please educate me....what is the purple stuff around the valves?

 

Ain't it the truth.

John, those look soooo sweeet!

I have to bow to you my friend cause I'm not worthy.

 

IIRC, it's called bluing spray and it helps the machinist know the radius of the cut. I am sure this is not the complete answer so anyone feel free to chime in.

 

Ran into a small snag today. The exhaust seats were cut a little too deep making the exhaust stem sit up too high. It sits so high that when the shim bucket is placed it gets in the way of the base circle of the cam lobe itself and has zero clearance. What a mess. I am not entirely sure how the machine shop is going to fix this. Perhaps it is a matter of removing .020 or so from the valve stem?

 

Blue stuff is dykem. It's hard to see the material removal on bright metals like aluminum so the machinist uses the dye to identify the before condition. It's useful to dye and then scribe material also for lower tolerance applications to give one a witness line to cut/mill to

 

How much valve stem sticks past the cotters ? Shortening the valve stem is not a problem . When I was rebuilding a Honda RC30 V4 bike motor we could not get different size schims and the Ferrari machine shop at the time set the valve clearance by machining the valve stems !!!

 

Hits the bucket itself as in you have a 3mm problem or hits the shim that sits is in the top of the bucket? I suspect its the latter because I just don't see any way to grind 3mm out of the seats.

So, pop the shims out and check the clearance that way then check what shims are available and see if you are still in a useable range. If not shortening the stems a little is ok just watch that the bucket has clearance to the spring retainer. Beyond that you can have the seats replace.

 

Here's what I'm dealing with. The exhaust stems have quite a bit of room to remove material so I am thinking I will be ok. The bucket, not the shim, literally poke out a good .020 from the bottom of the cam bearing bottoms. I have no idea if they cut the seat too deep/removed too much material from the valve mating portion or if the valves are too long. Ferrea has made umpteen thousands of these valves so I suspect it is not the latter.

On the opposite end, the intake valves will require another .040 shim to get them into spec so it appears they cut those either very shallow or something else.....
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John what paste are you using on the cam bearings ?

 

The cam won't touch the bucket I don't think. Pop the shims out and see what you have.

 

more info. Removed shim from bucket and found the the cam shaft portion has .010 clearance from the bucket, but the base circle has no clearance and upon rotation the lobe itself comes into contact with the bucket. The bucket has a depth of .120. After measuring all the cam specs, I am coming up with the base circle being .008 in the bucket. Not sure how much will need to be removed from the stem to correct this. .030-.040 sound about right?

Dave, I am using Lubriplate 105 engine assembly grease. I like the stuff.
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Some pics of the cuts themselves. It appears the shop sprayed with red dykem first, made a cut, sprayed with blue dykem, then made another cut. I have no way of telling how good a job they really did.

The stock intake valve with its respective cuts is shown compared to the Ferrari 'super-flo' valve which they claim flows much better. The second back cut of the 'super-flo' valve appears to be 2-3 times wider compared to that of the stock. Can anyone make sense out of this?
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John are all the exhaust valves at the same depth ? In a previouse pic the third combustion chambers ex valve looks to be deeper ( may just be the pic !! )
Possibly you could back cut the valve to narrow the seat width on the valve as long as the seat in the head is on the outer diameter of the valve seat ( does that make sense ? )
How wide are the seats in the head ?

 

Ex valves all measure up about the same (within .002 of each other). I follow what you are saying regarding essentially swapping areas of the valve which meets the seat which pushes the valve out a bit. The machinist would know once it's apart if that can be done, but the easiest way is probably cutting down the stem a bit.

The seat diameter at the widest area is about 1.398 (35.52mm).

 

OK I think I have this intake valve back cut thing figured out. The stock intake valve shows a much steeper angle of back cut while the Ferrea valve shows a more shallow cut (Ferrea says 18 degrees) which is also a bit longer. I can see how this type of cut provides a smoother contour at the throat yielding more flow.

 

Maybe try dropping the stock exhaust valve in? It could be a problem with the new valves??

 

I agree the issue is probably with the new valves. Plenty of room atop the valves to remove a bit of material to correct this. No worries.

 

My thought was maybe compare to the stock valves....it is possible that the new valves were just plain made wrong. It happens.

Also, if the valves are truly sitting a couple mm deeper than they should be you'll need to shim the springs back to spec installed hieght. Also also if the exhaust valves are sitting 2 mm deeper than they should be you've added about 2 cc to the combustion chamber volume id my math is right.

 

How far above the top of the spring retainers (not the keepers) are the valve ends? That - a reasonable clearance & wear allowance is the max the valve stem ends can be safely trimmed.

Doesn't look like there is 2mm it reads like you need, but hard to tell from the camera angle.

You don't want the shim bucket to ever contact the retainer's top, even after wear.

BTW, standard shim thicknesses are supposedly 0.015", 0.030", & 0.060". However, depending on the mfg, the mfg. tolerences will surprise you. When I was looking into shims for my SC project I found that one mfg's tolerences for the 0.060" shim was +0.000/-0.006 thou. & another was something like 0.060 +/- 0.005". These were 'precision' shims! Found this out the hard way when out of one set of 50 0.060" shims, a very large percentage measured 0.054", & IIRC NONE were over 0.056".

Step back & think about this some:
To compensate for the shop's machining error you're now shimming your valve springs & trimming valve ends. I know it will be painful, but you seriously should consider having the shop get another set of valve seats & machine them correctly.

 

Thanks for the input guys. First thing I will do is have the machine shop compare the stock ex valve to the new one to see what the heck is going on there. It could be that the stem is too long, or the seating part of the valve itself is just that much different that it required a different style cut (unlikely).


I measured the stem height to the retainer with a delth gauge yesterday, and all valves show .084 extra room before the retainer has contact. I suspect a safe amount of removal to be no more than .070. I will have the shop check the installed height of new one vs old to decide what the best plan of action might be.

 

Agreed.