[PontiacLars]

Need to replace some valve guides in my Speedmaster cylinder heads.
Anyone know correct replacement guide?

[steve25]

You’re going to need to get a valve job done on whatever guides that get replaced so why don’t you let the shop that does the valve job order up the guides also?

[Formulas]

Curious .... what happened to original guides?

my bet is top shelf materials were not used to start with on the originals,
propably be best to replace all unless its mechanical damage

[PontiacLars]

They are worn. I am replacing valves, springs and everything else with quality parts. Valve stems have pitting after roller rocker contact after only one summer with driving. Junk.
Will be replacing all the guides.

[Schurkey]

Originally Posted by PontiacLars

They are worn. I am replacing valves, springs and everything else with quality parts. Valve stems have pitting after roller rocker contact after only one summer with driving. Junk.
Will be replacing all the guides.

You should be thinking about replacing the "Junk" cylinder heads.

[performerrpm]

Originally Posted by Schurkey

You should be thinking about replacing the "Junk" cylinder heads.

do you own a set? have you had them in your hands? why on earth would you describe them as "junk" ?


are the parts he is replacing junk? sure, which is why most buy them bare. i have edelbrocks and a couple sets of speedmasters. i would buy the bare heads, or even complete heads on black friday before investing in iron originals all day long unless i needed a specific cast number for my car...which i myself dont.

[PontiacLars]

Castings is nice. No issues there, but should buy bare and use better hardware.
I know about the Speedmaster scam situation, but I have owned these heads for years, before all this drama happened.

[Formulas]

you should leave the replacements up to the machinest tell em to use proven good stuff or get measurements from him and go from there on your own there is differences besides materials some have a shoulder to set press in depth along with hose barbs (like) at the seal area to get a good seal bite so the seals dont lift off during use..

you dont want questionable yellow metal straight tube material thats fo sure

i use a piloted spot face'r to trim down guide heights in either the bowl or valve area

[Schurkey]

Originally Posted by performerrpm

do you own a set? have you had them in your hands? why on earth would you describe them as "junk" ?


are the parts he is replacing junk? sure,

Made in Communist China, filled with recognized junk parts. You think they spent extra money to perfect the casting? Or did they cut corners on everything except the casting? Can you see the heat-treating? Have you checked the purity of the aluminum? Heaps of "invisible" stuff goes into making a casting, and all anyone seems to care about is flow at peak lift.

The fact that they come from Speedmaster should be all you need to know. It's all I need to know.

[performerrpm]

Originally Posted by Schurkey

Made in Communist China, filled with recognized junk parts. You think they spent extra money to perfect the casting? Or did they cut corners on everything except the casting? Can you see the heat-treating? Have you checked the purity of the aluminum? Heaps of "invisible" stuff goes into making a casting, and all anyone seems to care about is flow at peak lift.

The fact that they come from Speedmaster should be all you need to know. It's all I need to know.

I mean theres plenty threads here on PY that testing has been done on the casting...in fact, the owner at pontiac speed shop cut one of the castings in sections to test it, i believe there were hardness test done as well. plenty of sets in use now, in fact pontiac spreed shop post vids pretty often on his fb page them on his motors but with upgraded parts.


like i said, i will buy and run these over iron heads all day long, and you stick with your iron D ports.

or completly bypass the void these heads fill and skip to a nicer head..edelbrock/Kre..etc...for the money,you can beat them...as far as china stuff is concerned, i hope your running around barefoot and naked since just about everything you buy is made in china...you just decided to pick on the op's head brand......i bet you disagree cloning gto's too...lol

[steve25]

I am confused here!
The OP says he has owned the heads for years ( post 7 ) yet has only put one Summers worth of driving on them ( post 4 ) ?

[Formulajones]

Originally Posted by steve25

I am confused here!
The OP says he has owned the heads for years ( post 7 ) yet has only put one Summers worth of driving on them ( post 4 ) ?

That's not unusual Steve as most just don't drive these cars much. Others in the build phase take some time.
So I figured it would take a while before problems from the heads would show on this forum, that is if anyone even bothered to post about it. It's well known the parts used in the heads are sub par. Valve seats are another issue with some other engine brands where higher volumes are sold that have been documented.

Thanks to the op for being up front.

[mgarblik]

I have my hands on my first set of Speedmaster heads in my class at the college. The cylinder head class starts in January at which time we will have some flow bench numbers and detailed impressions. The student bought the complete pair set-up for hydraulic roller cams. First impression is they are nowhere as "finished" as the Edelbrock heads out of the box. Pulled a couple valves out to look at the ports, seats and guides. Seat installation looks good as well as the guides. The ports are "incomplete", in so much as burs are removed so they won't cut your fingers but they are truly "as cast". Areas under the seats are kind of a mess visually, port floors are lower than an E-head. It appears they get the "extra" seat pressure by installing .240" of shims under the springs. They do not come with official spring seats or cups, just shims. The seals look nice. Valves are non-branded, I assume Chinese. They need a bunch of hand work to be brought up to Edelbrock standards IMO. But the much lower cost if the castings are good is very attractive. There is NO EXCUSE for the Edelbrock Pontiac heads to be the most expensive head in their catalog. Pontiac fans like us, through 15 years of constant badgering created the entire "niche" aluminum head market for Edelbrock, and this is how they thank us. Speedmaster may be an inferior head, but at least they are putting some pressure on them.

[PontiacLars]

Originally Posted by steve25

I am confused here!
The OP says he has owned the heads for years ( post 7 ) yet has only put one Summers worth of driving on them ( post 4 ) ?

Reason is I have collected parts for my engine over some years and finally got to build and drive it this summer.
Before even mounting them I installed spring cup locators and upgraded valve retainers and locks. I also ported them.
Now after one summer of driving the guides are shot and there is visible pitting on the valve stems. Never tested the spring pressures, but installed at 1.800 install height. Throwing it all in the bin and will replace with Ferrea valves, PAC beehive springs now.

[steve25]

Ok👍

[mgarblik]

Originally Posted by PontiacLars

Reason is I have collected parts for my engine over some years and finally got to build and drive it this summer.
Before even mounting them I installed spring cup locators and upgraded valve retainers and locks. I also ported them.
Now after one summer of driving the guides are shot and there is visible pitting on the valve stems. Never tested the spring pressures, but installed at 1.800 install height. Throwing it all in the bin and will replace with Ferrea valves, PAC beehive springs now.

After a season of running, I would be very interested to hear what the seat pressure is on those springs @ 1.800. Because my students are on a pretty tight budget, I would like to send him out the door with these springs if they don't go to hell right away. He is going to run a flat tappet cam. Removing 2 of the shims gets him in a safe zone @ 125-130 seat pressure on new springs. But I certainly don't want them at 90-95 lbs. after a run in.

[steve25]

Don’t forget about the harmonic resonance of a spring(s) .

The springs not only must control valvetrain mass, but there own mass.

You can find that with cheap springs you can have the needed seat and open pressure yet have surge taking place at certain rpms in the cams power range.
That makes not only for a poor power curve, but a valvetrain that beats itself up at these surge rpms.

The higher the resonance frequency of a spring the less you have to worry about surge, and Beehive/ conical springs have a high resonance point which is what you want.

[mgarblik]

The springs that came on those Speedmaster heads have more space between coils at max lift than I want, around .100" I like around .060" That helps greatly with surge, but it is what it is. Interestingly, I have never had a conventional spring break in a stock or lightly modified engine, but I have had dozens of factory beehive and several performance beehive springs break over the years. So there seems to be a trade off between reliability, surge/bounce and spring type. I have some possible beehive candidates here at home. If any have the right specs., I will donate them to the student's engine. We only get a Pontiac through the class every couple years, so I do give them some extra help when possible.

[steve25]

Where are the Beehives breaking ?
The first coil on these types of springs take the hit of most of the valve lift used and the coils on down after that top one absorb progressively less and less.

[mgarblik]

Originally Posted by steve25

Where are the Beehives breaking ?
The first coil on these types of springs take the hit of most of the valve lift used and the coils on down after that top one absorb progressively less and less.

Just like you mentioned, the majority of them break in the first coil or coil and a half. But I have seen OE beehives break all over in various places without any real pattern. The old GM 3100-3400 V-6 engines would sometimes break them in 3 pieces. I guess after the initial break, the coils would get intertwined and crunched a second time. I understand the advantages. Quality springs from PAC or equivalent would probably eliminate most breakage. Beehives were marketed extensively as far back as the early 1980's. Erson pushed them hard until reports of breakage seemed to sour racers on them. Then the OE's started using them again in the mid 1990's. They are cheap to manufacturer and are very compact. Attractive to OE's trying to save a penny anywhere they can.