cyl head back from machine shop - ugh! Really?

[inline6]

I've been working on a project to install a cam and switch over to 44mm Mikuni's for almost a year now. I just got the head back from the machine shop yesterday and while inspecting things today, I found more and more that is upsetting.

 

First thing is I provided the guides and asked for them to be shortened and tapered (I gave specific instructions on how much and where the taper should start and end). When I picked up the head, that had not been done because they didn't think it would be a good idea - the guides need the strength - they might crack, or something to that effect. Given all the porting I have done to make this thing breathe as much as possible, and that I have a 4 cyl head on a shelf where the guides were tapered just as I desire (and it ran for over 30k miles with no issues), I was disappointed. I only have machine work like this done maybe every 10 years, so I wanted it done right.

 

Removed rocker arms and checked to make sure the cam rotated by hand. It does. Good there.

 

Next, I cut a piece of hard wire to 1.68" length (spec provided for installed height by the cam manufacturer for the springs which they also provided) so I could quickly check the installed heights. Eyeballing it, I see some differences that look to me like possibly close to a millimeter. Really? .030" to .040" off? So, I decide to disassemble all the valve spring assy's to measure the installed heights.

 

The first one I do is an exhaust. After removing the collets, retainer and spring, I push the valve down a bit to inspect the valve and seat work and The valve seat is galled on one of the cuts! I did the same for a second exhaust valve - ughh. Same thing. See the attached pic.

 

I stopped there. Honestly, I think a shop that would let work go out like this isn't worth taking it back to. I mean, obviously I could go back and try to get them to do it right, but quite frankly, I am scared to let them try. Until I decide whether to give them another shot or not, they shall remain nameless. They don't know anything about my issues with the work yet, and the last thing I want to do is complain and moan on a forum about such and such machine shop and then not take it back to them so they never have a chance at correcting the problems.

 

So, now I have tried finding a recommended machine shop near me and I am not happy with the result. Who are known performance Datsun head builders left that I can trust to do good work? Rebello and Sunbelt and BRAAP (don't know his business name) are options in my head at the moment. Also:

 

I'd like to take the valves out, but don't want to wreck the seals... Do I need to find a straw or something to cover the collet grooves so I don't damage the seals?

 

Can the intake guides be punched back out and machined the way I want and reinstalled? Or should I just leave them alone because the work to taper the guides isn't worth the increased flow difference?

Edited August 8, 2010 by inline6

[john turner]

Inline6.....

 

If you want someone who truly knows his beans about cylinder head and manifold porting I would like to recommend to you Brian Maloney. I've known Brian for more than 20 years and he is very knowledgeable in the field having worked primarily on Ford, Dodge and Toyota NASCAR race engines. He also has his own independent shop.......Maloney Competition Porting in

Martinsville,Va.

Brian has worked on L series engines, and did great work on my 240z.

Give him a call at 276-252-8676. Feel free to use my name if you wish.

 

Regards, John Turner

[inline6]

I got in touch with Bryan at Maloney Competition systems and had him fix the head. The level of detail is incomparable.

 

Bryan determined that the head (already milled by the previous shop) had a slight bow to it (flat edge on original top surface showed this).

 

L series owners should know that having warped heads is common and something that the machine shop should look out for. Before any remachining is done, the head needs to be checked for straightness, and then corrected via heating, if at all possible, on a perfectly flat surface to get any warp out of it. If your shop doesn't have experience doing this and the head is warped, IMO, you are asking for trouble by proceeding with machining.

 

Since my head had already been milled on the head gasket surface, (and the head was still bowed on the top surface, that meant that the cam towers were out of alignment. He meticulously milled the cylinder head surface where the cam towers touch the head (not the whole top of the cylinder head, to account for the warping, which realigned the cam tower holes. Though I could turn the cam by hand before, now it turns with very little effort. That frees up some horsepower...

 

Additionally, he fixed the seats by recutting them, took out all of the intake guides that had just been installed (one of them was cracked by the way) and machined the ends of the new ones like I wanted, and installed and sized them to fit. Finally, my combustion chambers were cc'd, and 1,2 and 4,6 were modified to match 3 and 4, as they were larger (thanks to the slight bowing/warping of the cylinder head (see, I told you that you should have it straightened before you machine any surface!)

 

He also determined necessary lash pad sizes and then cut oversized lash pads (the only ones that were available at the time) to the sizes needed in a mill, and did final assembly.

 

We're about to start on the bottom end now. I hope to have that done by June.

 

Thanks John for the recommendation. If anyone is interested in having Bryan look at their stuff, he is interested in more L series work. As John stated, he is in Martinsville VA. Next time I go there, maybe I'll take some pics of his shop and put them up here.

Edited April 2, 2011 by inline6

[Tony D]

And the shop we should avoid is...

[inline6]

The first round of work was done by Citizen's Machine Shop - Richmond VA. I did not go back to give them a chance to correct things. With the type and number of problems I discovered when I looked it over, I decided I'd be more comfortable just taking it elsewhere.

Edited April 3, 2011 by inline6

[Tony D]

I would agree, that it left like that... well, giving them a chance to 'make it right' belies an overly generous outlook.

 

I once had to decertify a local distributor after a disatisfied customer called us (The OEM) directly for service. I went to the site and from what I saw, could draw a very clear picture of what happened on site. Not revealing this to the customer or the distributor, I let them both have their say.

 

Curiously, both stories followed each other very carefully. The difference being the distributor service manager told me they were a 'problem customer' and that they had 'six inspections before anything left the shop'...

 

As I decertified them for our product line I used the old Demming Quote: "You can't inspect in quality!" Meaning, if the guys doing the work don't care enough about their work to take the time to do it right, no amount of inspection will make them change. And that is what I see here...

 

Sometimes, you just don't give the guy that second chance. If they didn't get the BASICS right, that's pretty sad!

 

 

Curiously, in my instance of decertification, the customer wasn't necessarily complaining about the COST of what was done, just that the cost kept going up more times than he had authority to change his initial P.O. Both admitted 'it was a blank check P.O. just don't change it more than 2X after the initial quote'---in other words quote me a new machine price, and when you come in below that we all look good. Amazing guys get so stuck in their ways that they can't accomodate that kind of request. Then you get guys leaving monkey prints all over the machine, broken and stripped fittings, piles of rust and dross all in the tray on the machine... Not professional at all. And in all this, I was the 'bad guy' because I decertified all the technicians who worked on the machine, as well as the distributorship. An ounce of prevention was worth the thousands of dollars of 'cure' which was to send all the guys back to classes back east (which they 'already knew anyway') and make them jump through process hoops to regain their certifications within 90 days. Only to do so poorly in the intervening years that the OEM ends up buying them out, and firing most of the management in the Service and Aftermarket Parts Department. "Hey man, I warned you something like this could happen..." Good to hear you got your head rectified by someone who cared enough to do his job right the FIRST time.