Michael_D

Contrary to popular belief, cutting a seat concentric to the guide insert bore – to spec, is not as easy as it sounds. It is not something any machine shop can, or should do. You need good machinery, and a deft hand running the machinery. I am not just being a parrot either, I owned an early model Serdi and for the life of me, could not get the damn thing to cut a seat that I was happy with. Ended up selling the stupid thing. There are machine shops that specialize in automotive machine work, and then there are job shops. There are also shops who specialize in large runs, and they have CNC machines for repeatability. Some auto machinists will have a combination of both. You won’t find many job shops that have Sunnen or Newen machines though…..

Any of the shops mentioned in this thread, or others… CAN do good work. Most probably do, and do so consistently. But sometimes things just happen and the product that leaves the shop is not up to snuff. All experienced engine builders know this, and that’s why they blueprint. Disassemble and inspect, measure and log everything – that’s part of what blue printing an engine is. Trust, but verify….. Either that or drop your car off and pay a shop to do everything and provide you a warranty. Or, you could buy a set of heads from a shop, and pay them for a couple hours of their time inspecting (with instruments), the cylinder heads and documenting their findings.

I just mentioned AI, because they have a killer CNC program for these heads and they just make great power. But if you are less interested in peak power, and just looking for improved reliability, then AHP, WCCH, LPE will be just fine – but you should still verify the quality of the machine work done.

Would you (or anyone) assembling a short block after sending the block and rotating assembly out for machine work, and not check cylinder taper and piston clearance, bearing clearance, crank thrust, or ring end gap, etc....??? No, so why do so many just bolt down a set of cylinder heads without verifying the machine work?

realcanuk

And there it is.... The truth of the matter...

Its about the valve geometry being right and the combination of parts. It has to be 10s of thousands of cars running around out there on the streets, and racetracks, running much more aggressive setups than being done here, that don't use these super guides.

Nothing against using them, or touting them because someone did, but to say they are "best" or the only solution is just wrong.

There are many great shops out there that can do a proper job on heads. Speak to them and use whichever one you feel most comfortable after doing so. That usually works out for me.

FSTFRC

Good choice Matt!

outhouse

And given a choice with softer PM guides, bronze and the harder PM guides on a table, most of you will install the harder guides despite the rhetoric posted.

realcanuk

Only rhetoric here is in favor of the harder guides. But like I said, everyone should do what makes them feel most comfortable.

Unreal

Nope. I would not. Especially at a drastic price increase.

MTPZ06

Agreed Michael, and there's lots of chatter on treating/polishing OE Ti intake stems...versus new coatings...versus new aftermarket Ti intake valves. My rebuild went the treating/polishing OE Ti route, and knowing that there are opinions out there that this still may not be enough to reduce the abrasiveness of the stem; I chose the hardest material (MS90) simply for increased longevity.

I'll take your word for it Michael...and leave the cylinder head machining in more capable hands than myself. Knowing runout is an issue, even on brand new off the shelf OE GM LS7 heads; Kohle's high standard here was another reason for my choice on AHP. I wasn't in the pursuit of max HP on this car...just longevity and reliability.

injfuel

You have to rely on someone sometime , I just can't agree that if I pay to have an engine assembled and I get the shortblock home and tear it all apart checking Ring gap , rod and main clearances , torque specs , I mean why did I pay them in the first place , wish I'd have read more on AI when I joined in November , but most of the current threads were about WCCH and AHP , I didn't like lingenfelters program for the heads

Unreal

Or aftermarket heads. Other options I would strongly look at is Mamo TFS, WCCH brodix, WCCH AllPros, etc. More money, but a better head IMO if you want to open your options up.

Michael_D

Read my comments again. I said, if you are assembling a short block. If you buy one assembled from an engine builder, it will normally come with some form of warranty, and a build sheet that will have all measurements noted. If it doesn't come with a build sheet, it should be broke down and inspected. Have you ever seen that with a set of rebuilt heads? But yes, the end user will eventually need to trust someone, if they are not builders themselves.

realcanuk

You lost me. Heads done by a good shop should come with a spec sheet showing everything they did.
Most guys aren't capable to double check that type of work, and like you said, you have to have some trust.

MTPZ06

Very true...I'm interested to see more MMS builds. I've also seen a few Mast 285 head builds lately that make real good power.

Michael_D

Will it note guide clearance and seat runout for every hole? Spring height and loads for every valve? No. So you have to either take it on faith, inspect yourself, or have someone else check for you.

realcanuk

Should give spring heights and pressures for every hole at least.

Not many guys are capable to check these things... that's why they are using a shop. If you don't trust the shop doing it, you are using the wrong shop.

Unreal

I had the install height written on the heads. IMO that should be standard practice.

Michael_D

No, not each hole. If you did see that, every one would by slightly different. I spend ALOT of time blueprinting heads. I go so far as swapping locks and retainers, trying to get each set as close to target height I can. I have not ever seen all 16 identical. But again, that takes time, and end users will not want to pay for that.

realcanuk

I don't know the practices of all the shops. I can tell you I just had my heads done, and they cut the valves stems to make sure they were all identical heights.
I always marveled at how many places claim to install springs at the correct heights, without asking for cam specs. How does that work ?

And you are right... the spring heights will not be identical, but will be very close assuming seats and work was done right.

Michael_D

cutting/grinding the stems will affect total stem height for rocker geo, but not spring height. That's fixed to the lock grove. There is a window for optimal height and lift and coil bind distance. I prefer 0.060-0.080. Some "builders" will accept more. I wait till I have the cam specs and train components identified before I spec a spring.

fattiremike

Basically, if I'm going to do it, I'm only to do everything I can to only do it once. From what I researched about the MoldStar guides is that it is a material that actually gets harder with use and (hopefully) will last longer than PM. No one really knows why the LS7 heads drop valves. The data is all over the place. Some say exhaust valve quality control, some say bad cylinder head geometry. So, the way I see it, the Ferrea SS valves take care of the valve quality control problem and the MoldStar guides can stand up to possibly bad geomety a little better than PM. Hope this helps.

Dan_the_C5_Man

A buddy servicing his heads found up to a .030" variance in the spring pocket / base cuts.. Luckily that doesn't add up to much of a loss or gain in spring pressure, but if you were shimming right to the edge for coil-bind and you didn't measure EVERY cylinder pair (like most of us would not do..).