Toowoomba Metal Technologies in Australia.
Valve / seat height concern
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Re: Valve / seat height concern
Automotive Machining, cylinder head rebuilding, engine building. Can't seem to quit
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Re: Valve / seat height concern
If the ebay seller is AAA MidWest they are a division of EQ.
EQ has the replacement marine castings for the GM 217 casting which flow very well and compared to the Dart iron eagle out of the box they are a better head for a stock type build.
They use a std. 1.250 OD spring and are good for about .500 lift. DO NOT try to put a 1.6 exh. valve in them. It can be done but I have hit water doing it and they don't flow any better anyway. They are a very good head for the money but you can get better heads that will work with the vortec chamber from Dart. I use them on marine builds as the machining accuracy is more like a HP head should be where the EQ head needs some work as does the Darts but that is why we get heads bare and make them right
But as mentioned the tip heights should be with in +/- .005" max. There is room to touch up seats and correct the heights but I have seen where the exh. seats are higher then the intakes causing some flow loss at overlap as the seat height difference allows incoming air/fuel to be scavenged out the exh. at overlap causing a power loss.
We found 10 HP by correcting that minor issue making the valve faces parallel to each other when seated in the chamber to help keeping comp. the same hole to hole
EQ has the replacement marine castings for the GM 217 casting which flow very well and compared to the Dart iron eagle out of the box they are a better head for a stock type build.
They use a std. 1.250 OD spring and are good for about .500 lift. DO NOT try to put a 1.6 exh. valve in them. It can be done but I have hit water doing it and they don't flow any better anyway. They are a very good head for the money but you can get better heads that will work with the vortec chamber from Dart. I use them on marine builds as the machining accuracy is more like a HP head should be where the EQ head needs some work as does the Darts but that is why we get heads bare and make them right
But as mentioned the tip heights should be with in +/- .005" max. There is room to touch up seats and correct the heights but I have seen where the exh. seats are higher then the intakes causing some flow loss at overlap as the seat height difference allows incoming air/fuel to be scavenged out the exh. at overlap causing a power loss.
We found 10 HP by correcting that minor issue making the valve faces parallel to each other when seated in the chamber to help keeping comp. the same hole to hole
Real Race Cars Don't Have Doors
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Re: Valve / seat height concern
I find the same thing and as I to only get them bare I treat them as a very good core head I don't have to install seats in.Keith Morganstein wrote: ↑Thu Mar 22, 2018 6:40 pmThey are the importer/distributor of the castings. I didn’t know they offered complete assembled heads or who is assembling them.
I use the castings, but buy them bare and they need prep before assembly. Often the guides are too big (I.D) and I put liners in, then a valve job.
Looking at them from that stand point they are a bargin when you consider the cost of getting heads from a wrecker then cleaning and maging and pressure testing they are a steal at that price.
I realize most guys consider them a freshly machined head ready to assembly like other heads they need work to get them perfect.
Valve manufacture choice also has a lot to do with consistent margin thickness's so when comparing and checking I go from the chamber face to the tip and compare the lengths the longest valve measured this way will have the shortest installed tip height. And thats another issue some are made with a .250 groove to tip length others are about .280 to.300 creating a non symmetrical tip height situation that leaves guys pissed off with the parts they just got.
I simple tool is a 2" machinists square. It can be used to check face heights in the chamber and when compared to the tip heights they should be the same it the chamber measurement is flush. That allow's you to set the stop on a level head and machine to the same depths keeping the chamber depths all the same thus it helps to keep their volumes all the same.
very important on restricted engines that are teched all the time when the win
Real Race Cars Don't Have Doors
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Re: Valve / seat height concern
FIFY.
I don't know who machines them.
Re: Valve / seat height concern
Same people that use to be Pro Top Line.
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- midnightbluS10
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Re: Valve / seat height concern
AFAIK, they're cast by Precision Foundry in NZ. I'm guessing theyre the same people?
JC -
bigjoe1 wrote:By the way, I had a long talk with Harold(Brookshire) last year at the PRI show. We met at the airport and he told me everything he knew about everything.It was a nice visit. JOE SHERMAN RACING