cylinder heads problem

post a picture on the base of the camshaft

 

go to you engine builder and take a good Close up pic on the base of one lobe

 

Snowsport1,
you may want to have a browse through some of the pictures in the following thread. It may highlight any obvious problem with the valve seat setting and shape you have. The reason for inadequate or too much valve shim clearance can be quite subtle.
http://www.ferrarichat.com/forum/206-246/228842-cylinder-head-removal.html
http://www.ferrarichat.com/forum/206-246/222622-valve-shims-cam-wear.html
Kevin

 

Did the supplier of the heads, and person who machined the valve seats also supply the valves (I assume the valves are new) ?
Kevin

 

The most common shim used on these is around the 3.60 - 3.85mm range. If your cam has been reprofiled (-1mm) then the current max shim you would require is about 4.60 to 4.85mm, which as you say is close or outside the range of shims available. I am not 100% but I am sure you cannot regrind the cams, if they are screwed then you need new ones

You could try and ring Ron at Superformance UK (he is on holiday at the moment back on the 12th I think) he has built over 100 of these engines so can give you some useful info.

What is the dimension across the lobes. Each cam is stamped A or S,

A=inlet should be 36.7mm or S= Exhaust should be 40mm

 

Wouldn't this cause the thick shim issue? If the seat has not been put into its depression fully it will sit proud of its proper position and require a thicker shim, no?

Can you send the head shop a photo of the seat not fully seated and ask them if that's how it's supposed to be? Maybe the worker who did it had too much wine at lunch.

 

Yes, first easy check is the cam lobe dimensions (as per Tony's suggestion). In reprofiling the cam, meat can't be added, only lost, increasing the distance between the cam follower and cam lobe.
The comment that troubles me though is the one about the valve seat inserts not sitting high enough in the head. I don't see how the valve seats would have not been pushed in properly. Once in, the seats do need facing to match the valve. I assume that was done? With the problem magnitude you indicate, if its a valve seat issue, I would have thought the problem was visible. Your engineer says it is. Can you take some photos and compare with those in the thread post above?
Kevin

 

I have seen very experienced engine builders get these wrong. I would only trust Ron to do my engine. Give him a call, he is a really nice Italian. There is only a finite amount you can remove from cams, if they were bad then regrinding them can makes matters worse. Get some dimensions of news ones and compare. The dimensions I gave I believe are correct.
Tony

 

Are they a well known German company, if so then name an shame them. This is not the first time they have been just a bit arrogant. I gave up but fortunately it was for only a £100.00

With this we are talking serious money. They fully understand alright, they took your money quick enough without to much trouble.

 

Keep us informed if you don't mind, post some pics and I will speak to Ron about it.

Tony

 

In addition to Kevin's fantastic information I ask that you read the following posts:

Dino 246 Restoration Blog: The right shim: Blueprinting the valve train

Dino 246 Restoration Blog: More shim talk: Images of the blueprinted head

In here I discuss the importance of not going to thick or thin on the valve shim. From what I am reading it looks like your heads just plain were not built properly. 6500 Euros is a mountain of money for a pair of 6 cylinder 2 valve heads so nothing short of a perfectly blueprinted set of heads should be acceptable at that price and even then a massive premium is being paid.

 

This sounds very familiar, unfortunately.

 

if your cams are 1 mm smaller you can not use them go get a set of n.o.s cams, the biggest problem you have is the valve seats if they are not fully pressed in it means they are not fitted correct, and they can come out, the ring is skraping of aluminium from head make pressure fit to loose, some people use a big hammer to have them fitted over the years i have done loads of dino heads, i use only a special tool and with hand force have them fitted with correct tolerance
return those heads to that german man and buy your parts from superformance there is no Point to buy from germany he have the same parts as Colin but is more expensive and he is very arrogant, the only good part he have is the 246 head gasket its superior from other gasket, i have tested them very hard i do race engines

 

Is the valve seat a tapered fit or straight? I have heard the bore in the head for the valve seat is a slight taper.

 

spot on....