Edelbrock E-Street cylinder heads

Automotive powered airboat discussion.
Post Reply
hdsadey
Southern Airboat Member
Posts: 285
Joined: Sun Jul 01, 2012 7:42 pm
Location: venice fl.

Edelbrock E-Street cylinder heads

Post by hdsadey »

So I was running the boat today at the house, I start it every week or so and let it come up to temp, letting it idle when BANG!!!! Sound like a rod came loose! Thought it was coming from the right bank, pulled valve cover and nothing out of place. Started it several times to try and locate the hammering. Pulled the fuse on fuel pump and turned the engine over. A noticeable dead hole sound was coming out. Pulled left valve cover and there it was!
20190929_171951.jpg
No. 8 exhaust rocker stud broke at the poly lock. There is only about 10 hours on this engine. I can only assume Edelbrock is using low quality fasteners with so little time on them. No coil bind, factory seat pressure from Edelbrock and not high rpms. ARP studs will be replacing these right quick!
02 Predator 12' 0320 Lycoming
2019 Circle H 408 Windsor DD Sig Series 74"
99 Donzi 16 Classic 350 Vortec

flcracker9
Site Supporter - III
Site Supporter - III
Posts: 538
Joined: Mon Aug 11, 2014 10:05 pm
Location: Loxahatchee

Re: Edelbrock E-Street cylinder heads

Post by flcracker9 »

I think your assuption is correct! I'm running Twisted Wedge heads on my SBF (street/strip Mustang), and before I ever installed the heads, I replaced all the studs (with ARP), springs & retainers (Comp Cams) with better quality units. Even though you are spinning 3000rpm where I'm spinning 7000, I think most of the aftermarket aluminum heads skimp on these items.
12' Open Palm Beach, IO-0470-L 260hp, 72" NGQ

SWAMPHUNTER45
Site Supporter - III
Site Supporter - III
Posts: 3033
Joined: Thu Nov 21, 2013 11:38 am
Location: Naturecoast, Florida

Re: Edelbrock E-Street cylinder heads

Post by SWAMPHUNTER45 »

I think it's a unusual occurrence as Edelbrock does their own castings and has a really good reputation. I know a few guys running the RPM series heads and only good things to say.

Going with an ARP upgrade is a great idea just look at everything real well because Edelbrock in my experience has been US materials not Chinese crap like some of the cheapie sets out there. Could you gain any info from looking at the broken stud?

hdsadey
Southern Airboat Member
Posts: 285
Joined: Sun Jul 01, 2012 7:42 pm
Location: venice fl.

Re: Edelbrock E-Street cylinder heads

Post by hdsadey »

The E-Street stuff is offshore parts to my understanding. They are trying to compete with all the other cheap Chinese heads. The machining is done here. Since I was trying to keep the port size to a minimum, the E-Street was the best option. The heads perform wonderfully but the hardware has it's issues I guess. The RPM series is completely domestic sourced. I unthreaded the broken piece today, looks like it maybe had a stress fracture and just popped off. Glad I wasn't out in the woodadds when it happened! ARPs ordered today.
02 Predator 12' 0320 Lycoming
2019 Circle H 408 Windsor DD Sig Series 74"
99 Donzi 16 Classic 350 Vortec

SWAMPHUNTER45
Site Supporter - III
Site Supporter - III
Posts: 3033
Joined: Thu Nov 21, 2013 11:38 am
Location: Naturecoast, Florida

Re: Edelbrock E-Street cylinder heads

Post by SWAMPHUNTER45 »

https://video.search.yahoo.com/yhs/sear ... tion=click

I would inspect everything really close on tear down. Look for galling or discoloration in area of the break.

Edelbrock has done some "off brand" work for a former Cadillac aftermarket vendor and we have found them to be an excellent casting. Never used their hardware but I would almost bet they are getting a unbranded ARP bulk because they really pride them selves on a quality product.

Keep us in the loop and I will try to run your break past Mr. Branch.

hdsadey
Southern Airboat Member
Posts: 285
Joined: Sun Jul 01, 2012 7:42 pm
Location: venice fl.

Re: Edelbrock E-Street cylinder heads

Post by hdsadey »

I did some reading, apparently the heads are cast in the states but the valvetrain parts are crap. Also they advertise .550 lift capability but it's highly recommended not to go over .500 cause the 1.250 springs can't handle it. And definitely no rpms over 5500. Ugh!!!!
02 Predator 12' 0320 Lycoming
2019 Circle H 408 Windsor DD Sig Series 74"
99 Donzi 16 Classic 350 Vortec

User avatar
keys2pines
Southern Airboat Member
Posts: 123
Joined: Thu Jun 28, 2018 10:55 am

Re: Edelbrock E-Street cylinder heads

Post by keys2pines »

I'm running the same heads, haven't had an issue, bad batch maybe?
12x6'8" Frank Barnes deckover, 383 DD, 72" Sensenich JM
Our keys house for rent, 10% off for SA members https://rentalsfloridakeys.com/view-uni ... /#image-10 :usa:

SWAMPHUNTER45
Site Supporter - III
Site Supporter - III
Posts: 3033
Joined: Thu Nov 21, 2013 11:38 am
Location: Naturecoast, Florida

Re: Edelbrock E-Street cylinder heads

Post by SWAMPHUNTER45 »

That cam you had ground I remember you could not go roller and went with a Mechanical Flat Tappet so what is the lift on that?

If the stud was not defective and a geometry issue or other dynamic caused it and then you reinforce the prior weak link (ARP) your moving the fail point. Next would be a push rod, rocker tip or cam lobe.

I don't know but that just seems like an odd fail if there is no obvious defect to the stud. If the cam is close to that lift and you shimmed to set heights then maybe it lost range and is bottoming out. Odd to happen at start up but that is a time with low lubrication. On another thought could the rocker have hung up on anything ? I assume it is a needle bearing type rocker does it float free and is it tight or sloppy? Just things to look at in the event the stud was not the root cause of the problem.

This is a way out theory but something we risk with our monster cams. With weak valve springs it could jump the lobe and if you were extremely close to a fail point the added stress may cause something to break. It is a very remote likelihood but I don't know your cam. Normally the push rod would be the fail point with that type of issue but if you had some big heavy hardened rod it may find a weaker link in the stud if like you feel it is a substandard component. Keep us in the loop curious what you find.

SWAMPHUNTER45
Site Supporter - III
Site Supporter - III
Posts: 3033
Joined: Thu Nov 21, 2013 11:38 am
Location: Naturecoast, Florida

Re: Edelbrock E-Street cylinder heads

Post by SWAMPHUNTER45 »

Found your old data HD that said 504' lift with 1.6 ratio rocker. So that is well within your range if no ratio change or alterations?

hdsadey
Southern Airboat Member
Posts: 285
Joined: Sun Jul 01, 2012 7:42 pm
Location: venice fl.

R9e: Edelbrock E-Street cylinder heads

Post by hdsadey »

Maybe a bad batch! Lobe lift is .3150 with a 1.6 rocker is .504. I doubt .004 is the tipping point. They advertise .550 capable. No shimming. Ran them straight outta the box because of the low lift number. My fault for not making sure. It's Edelbrock for Pete sake, not ebay coke can heads. It's coming off the boat here shortly. Gonna get rechecked and dynoed in house this time. I just measured the broken piece, .375 roughly. It was about .060 recessed in the poly lock. Let's call it .425 should have been enough. ARP are longer so that won't be a concern going forward.
02 Predator 12' 0320 Lycoming
2019 Circle H 408 Windsor DD Sig Series 74"
99 Donzi 16 Classic 350 Vortec

SWAMPHUNTER45
Site Supporter - III
Site Supporter - III
Posts: 3033
Joined: Thu Nov 21, 2013 11:38 am
Location: Naturecoast, Florida

Re: Edelbrock E-Street cylinder heads

Post by SWAMPHUNTER45 »

I checked with Mr. Branch for you and he said that if you have 100% ruled out coil bind or the springs being to heavy that most likely the stud was over or under treated in the hardening process. That said, he commented if you replace it and suffer another valve train failure such as a push rod or cam fail you missed the real problem.

He said to check your push rod measurement as that can effect your geometry. As such it can cause an off center (side push) alignment. In addition he advises that in his experience with Edelbrock heads he found incidents with valve guide binding due to positive pressure seals being used. This type of a seal is very efficient but can starve the guide of oil and in tight spec heads can lead to a bind. Generally the valve will stick open but not always, he raised it as a item you may want to check in your R&R.

Post Reply

Return to “Automotive Power Only”