EQ Cast heads (Not a Mopar ) A SAGA nonetheless

-
R

RAMM

Well-Known Member
Joined
Nov 22, 2010
Messages
2,818
Reaction score
3,835
Location
Ontario, Canada
Chevrolet 5.0L 305 1996-2002 Vortec Cylinder Head - Assembled (Pair) - EQ Cores & Recycling

Built a nice 355 for customer in a 2bl class that also uses a 4bl for certain races. This is a fairly high compression 11.7 1995 1 pc rear main block ISKY SFT cam Mahle flat top, 6" Scat Rod, Stock cast crank build. I used the fabulous EQ 305 Vortec casting with a QualFast 1.84"/1.5" Stainless valve and little did I know this is where 4 weeks of delay and effort (cost) would stem from. I'm going to post this now because I had a huge post previously written and didn't save it and it vanished which is a real piss off.

2bl'602crate.jpg
 
I've used these heads only two times prior but had astonishing results. They feature a cast in guide "vane" ,Vortec runners, raised exhaust ports, beautiful bowls and a racey S.S. I have never ported a set of these or even touched them with a die grinder. They flow a whopping 218cfm from .500"-.600" After a .020" cut the chambers were 57-57.5 cc's. Would you ever use these heads on a 350 or even 383 stroker? I have but it was more of a happy accident. J.Rob

EQ305Vortec.jpg
 

Dyno day arrives Jan 25th and the customer and his buddies were in attendance and I break the engine in with the automated dyno cycle and break in springs. I change the springs to the Isky 235D's and we're ready to see what this engine's really got. We're listening to the valvetrain with the stethoscope and checking lash after every 5 minute cycle and everything is looking good. Perform a couple of pulls to 5000/5500/6000 rpm and it makes a real good 416hp @ 6000rpm. We decide to try the 4bl and bolt on the prepped 650 my buddy GB built and fire it up. My friend Joe is as paranoid as I am and puts the stethoscope back on as it doesn't sound quite right. Joe says #8 sounds noisy and we shut it down and pull the cover. Our day is over as #8 intake is stuck open. WTH!? We've run this thing all morning and early afternoon at this point. J.Rob
 
The customer leaves for a 2hr drive home and I tear it down and figure if its happened on the passenger side then it is probably happening on the drivers side and pull both heads. Wow, 2 intakes were so bad I had to cut the valve heads off and tap them up through the guide. Usually if a valve sticks its the exhaust not the much cooler intakes. Anyhow, I worked through the weeknights and proceeded to ream an extra .0005" and then hone all of the guides for a nice smooth cross hatch and confirm guide clearance with my gauge pins. I ordered a new set of 1.94" S.S. valves from QualFast and machined them down to 1.900" .Re cut the intake seats , polished the stems on everything and installed Cometic head gaskets so in the off chance this happens again I can clean them and reuse them. All of this at no charge to the customer of course. No fault of his. J.Rob

galledvalvestems.jpg
 
So the following Saturday comes and I'm back on the dyno with my buddy Joe and two other witnesses. We fire it up and it sounds just like it did before--awesome ....as I'm checking timing and turning the distributor it starts to run really rough. We shut it down and now two exhaust valves are stuck open!!! WTF!? It ran for 50 secs total. We never had an exhaust valve issue before. WTH is going on here? So foolishly we tear the heads off and because I had some 1.50" exhaust valves in stock we put a couple of bronze liners in the guides and two new valves and reassembled. We refire the engine at about 1:30 p.m. and nervously warm it up. It sounds great and we run it for about 10mins at different RPM's almost doing another break in cycle. Everything checks out and we proceed to make our first test to 5000rpm with the 4bl. Nope as soon as it reached 4500rpm it dropped a cylinder and I shut the run down. Two more exhaust valves seized but not the new ones. Now I'm re-thinking career choices and take the cylinder heads back off. J.Rob
 
Now I'm questioning metallurgy, oil type, fuel (D109), timing, rocker geometry, karma....Everything. I wound throwing pretty much everything at it. I knew I could improve the rocker geometry by machining the rocker bosses down .100" and moving to a shorter pushrod. So that's what I did while I waited for the new set of pushrods and Black Lightning Nitrided 1.94"/1.50" valves to come in. J.Rob

Rockermachining.jpg
 
NC Engine Builder said:
That SUCKS. but I dont trust the china blend iron they pour with, so I ALLWAYS install guide liners in any new iron head I use. Knock on wood, I havnt had any issues so far.
Click to expand...
Yeah I did boil it down to an incompatible material issue. The lower quality stainless did not play well with the unknown alloy of cast iron. The story does have a happy ending however. Lol J.Rob
 
As @NC Engine Builder says I proceed to install bronze liners in all guides, ball broach them and hone them for size and cross hatch. I did not increase the intake seat size out to the 1.94" head size and decided to put a steep "top cut" on the valve face sort of the opposite of a back cut. Clean everything up and reassemble but by this time I had the shortblock off the dyno and in the assembly room. This past Saturday was the next available opportunity to finish this off and by this point I'm treating this as a full blown R&D project and I figure if it fails-it fails and I will build another. As luck would have it, the engine runs like it should have from the outset. Makes 455ft/lbs 431hp on the 4412 and 479ft/lbs 466hp on the 650. Rev's like a chainsaw and we put a total of 23 pulls on it. Moral of the story is like Richard says install bronze liners right from the start. Total cost to the customer was a serious time delay but that was it. It taught me a lesson I won't soon forget. These heads are awesome though.Makes me wish I was Chevy guy sometimes. J.Rob
 
What a bummer. I’ve said this about a million times.

It’s way easier to lose money doing this than make money.

You really can’t charge the customer so you eat the loss.
 
I forgot to mention that the exhaust seats needed to be re-cut because the seat was 1.375" diameter or something ridiculously small. The seats were off of the back side of the valve near the stem OOTB. That was a disappointment. It's not like these heads are all that cheap either. So between needing 16 guide liners installed and re-machining the valve seats which in this case I did not pass on to the customer. The heads are pretty costly--thank goodness they make tremendous power. Oh forgot to mention best power was at a low 30* total timing which is a great indicator of a fast burn. J.Rob

20250104_110929.jpg
 
NC Engine Builder said:
Really impressive numbers!
Click to expand...
For a head that only flows 218 cfm unbelievable. about 5 years ago I wound up doing a build for a young fella that 5 years before that he bought these same heads for a 305 he was planning on hopping up--the build took many turns and he brought me a whole 383 rotator and a block. I thought this thing was going to be an absolute turd and rpm like a diesel. Nope, Made 445hp/482 ft/lbs and he could not be touched on the street. After a few years he wanted aluminum heads and put on a set of Profilers and his father bought the EQ 305's and had me build him a SFT 383 with a single plane--Results were 473 HP/ 473 Ft/Lbs. Pretty stout for a 305 head with a 1.84"/1.50" valve and barely 220cfm. J.Rob
 
RAMM said:
They flow a whopping 218cfm from .500"-.600"
Click to expand...
I'm curious to see what some port work would do with the dyno numbers. With it making those numbers with a 170cc port volume, there's probably not a lot of room for improvement. This post adds a whole lot of relevance to "port shape vs. flow numbers argument."
 
A picture of the intake port. Looks a whole lot like the rather unremarkable stock six digit casting number low end 305 castings.
1740411993393.png
 
Garrett Ellison said:
I'm curious to see what some port work would do with the dyno numbers. With it making those numbers with a 170cc port volume, there's probably not a lot of room for improvement. This post adds a whole lot of relevance to "port shape vs. flow numbers argument."
Click to expand...
These heads are probably one of the best examples this. I intend to order another pair and "work" them to about 240cfm and then test them versus a more conventional aluminum cyl head with about 280cfm . Should be interesting. J.Rob
 
oh wow, that's nightmare fuel right there.

you have any WASG's on the underlying cause or just the ol' "it is what it is, and it all sucks"?
 
VERY interesting, but when I read stuff like this I think, "what chance" do us backyard guys have? When you cannot buy stuff like this ad depend on any quality, many of us don't have the money or resources for a big machine shop. In in this area (N end of idaho) there isn't a lot of resources. Many more "rebuilder" machine shops won't take this kinda thing on, precisely because of the liability concerns
 
67Dart273 said:
VERY interesting, but when I read stuff like this I think, "what chance" do us backyard guys have? When you cannot buy stuff like this ad depend on any quality, many of us don't have the money or resources for a big machine shop. In in this area (N end of idaho) there isn't a lot of resources. Many more "rebuilder" machine shops won't take this kinda thing on, precisely because of the liability concerns
Click to expand...

Yup. Not many shops can take hits like Ramm just did and survive very long.

And, finding guys that can do this work is getting harder every day.
 
RAMM said:
These heads are probably one of the best examples this. I intend to order another pair and "work" them to about 240cfm and then test them versus a more conventional aluminum cyl head with about 280cfm . Should be interesting. J.Rob
Click to expand...
When it comes time and you don’t care to, show us the as cast configuration of the port design. Is it supposed to be a duplicate of the Vortec stuff? The short side of the port must be magnificent for it to work that well.
 
Last edited:
Sort of related:

20-25 years ago, before the circle track crate motors had taken over here, we used to build a bunch of SBC circle track engines.
When they became legal, we started using Vortec heads(original GM back then).

After the end of the first season, during the freshen ups of several of these engines it was discovered that the intake guides were all worn out. All of them.
Almost no exhaust guides showed any issues.

These all were brand new heads to start with that got a hone job on the guides and were run with Ferrea 6000 valves.

All the heads in for freshening got 16 liners installed, as well as any new heads for new builds.

With the liners installed, the heads would go a few seasons of racing before showing any appreciable guide wear.
 
Great numbers from a 355.

The aussie EQ mopar heads are well known for seized valves as well unless bronze liners or guides are installed.

Tough way to learn about the vortech heads having a similar issue. Sorry you had to waste all that time.
 
How much valve guide clearance is recommended to avoid these issues? I have the Aussie EQ heads with no liners.
 
DMC_78 said:
How much valve guide clearance is recommended to avoid these issues? I have the Aussie EQ heads with no liners.
Click to expand...
Its not a clearance issue which I proved because when I added clearance it made the problem WORSE. It's the alloy itself, prone to galling because it's ductile (soft). They are not the same iron as the TooWoomba castings. J.Rob
 
You must log in or register to reply here.
-
Back
Top Bottom