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Patiot Heads..Promaxx problem

Tstorm

Member
Joined
Dec 15, 2008
Messages
12
Location
Philadelphia
Corvette
1981 Silver Coupe
Hey all,

I have not posted alot on the forum but I read often. You guys are great!
I need to vent though. I purchased a set of Patriot heads about 2-1/2 yrs ago, then the problems started. First, I could not fit the rocker arms under the stock valve covers as they interfered on the intake side. Gave them a call then, they said "never heard of that". These are SBC Freedom heads and they obviously changed the geometry. No problem, i got out the old grinder and moved on. Now I do not drive the car as much as I would like, so there is about 125 miles on these heads. Since install I have had the following issues;
- snapped rocker stud, 3 bent push rods, 1 pushrod bent so far it snapped about half way around, 2 pushrods wore through guide plates allowing the rockers to rotate off the valves.

I have assembled a few engines in my time, so I am pretty sure I set the valves correctly. Used the pushrod length tool with some marker on the valve to get the correct pushrod length. Adjusted while on the stand to get close. Fired it up to get the lifters pumped up, then adjusted agian while running.

I just explained this to the "salesman" Jason Collins at Promaxx looking for some technical info, any issues they know about or the like. The response I recieved was, well less than customer friendly. Basically told me he is one of the new owners and since they purchased the companies asssets from the bank they are not liable. But he did ask what I would do to fix them and told me "we will see" WOW.

Sorry for the long read. I think my problem is the valve springs. The cams lift does not exceed the advertised max lift on the heads, but I cannot think of anything else that would cause these issues. I also know they had problems with their springs. Any ideas? And a final word of caution on dealing with these folks, just don't do it!! Thanks....
 

Mac

Well-known member
Administrator
Joined
Feb 13, 2003
Messages
5,475
Location
Ottawa, Canuckistan
Corvette
1973 coupe L82 (gone as casualty of divorce)
I'm having a hard time visualizing an issue that would cause so many problems with pushrods yet not related to adjustment. Your mention of the geometry being changed sounds has me wondering... Sometimes change isn't a good thing, if you get my drift?

Mac
 

bill81vette

Moderator
Joined
Jan 17, 2004
Messages
4,321
Location
Troy,NY
Corvette
1981 dark blue metallic
Perhaps the geometry WAS off,go back to the OEM heads.
you could take the heads to a machine shop you trust and have them checked to see if the geometry is in fact off.
then your suspicions would be confirmed! at least you would have proof that they are off.
 
Joined
Jan 12, 2004
Messages
424
Location
Lakeside in Monmouth, Maine
Corvette
75 Stroker 4spd Frame Off, 05 Cpe 6spd
Perhaps the geometry WAS off,go back to the OEM heads.
you could take the heads to a machine shop you trust and have them checked to see if the geometry is in fact off.
then your suspicions would be confirmed! at least you would have proof that they are off.

Excellent Idea!

Although hard to do, try not to get too angry with the new people that bought Promaxx. They were not in control back then.

You gave the old owners a call 2 1/2 years ago, then want some help now from the new owners 2 1/2 years later. Warranty is more time based rather than mileage based.

Please don't get upset with me, but I think you took too long to try to resolve this with them.

Chuck M
 

Hib Halverson

Technical Writer for Internet & Print Media
Joined
Jan 10, 2001
Messages
13,453
Location
CenCoast CA
Corvette
71 04 12 19
That the rocker arms' pushrod ends interfered with your valve covers is more likely a problem with either the rocker arms, valve lift or the valve covers than it is a problem with the heads.

The pushrod guide plates wearing could the guide plate manufacturer's faulty materials or process but it also could be because of the bent pushrods.

A rocker stud failure could be a faulty stud, but it also can be caused by interference between the rocker arm body and the stud. This happens when the rocker arm is a faulty design or the valve lift is more than the rocker supports. It's possible stud breakage could be caused by valve spring coil bind.

Bent pushrods can be caused by faulty pushrods, but it is more likely to be caused by a valve train problem such as excessive spring pressure, valve spring coil bind or valve train instability in certain rpm ranges.

Bottom line...while it's possible there's a problem with cylinder heads, I'd be worrying a lot more about some sort of valve train problem than a problem with the heads.
 

Tstorm

Member
Joined
Dec 15, 2008
Messages
12
Location
Philadelphia
Corvette
1981 Silver Coupe
Hey Guy, Thanks for your replies.
Bill, you have an 81 and you know those heads were the cause of the stock 185 hp. I had never seen such restricted heads before. As far as the folks from Promaxx, I expected they would not replace the heads, I was not looking for that. I was however looking for some explanation based on their experience as to what may be the issue.
As far as the geometry change, I think the rocker stud centers have been moved up towards the intake thus changing the fulcrum of the rocker arm to allow for the additional lift in the valves. I guess what I am trying to say is that the push rod center is not on center with the lifter bore. Although the lifters can obviously tolerate some miss-alignment by design, I think the move they made on the rocker stud pushes the rocker to push rod mate to far up. This is the only reason I can think of as to why the rockers where hitting the inside if the valve cover, by almost .095". This is the kind of information I was looking for from the guys at Promaxx. I am not sure where to go from here if this is really the case!
 

TimAT

Well-known member
Joined
Sep 8, 2007
Messages
708
Location
Gladstone Missouri
Corvette
1969 LS-7 BB
I've heard of a couple of guys that had pushrod/rocker/valve alignment problems. Not necessarily with your heads, but problems.
Have you checked and measured the rocker stud location with a known good head? I'd look to at the placement of the guideplates too. They might be off and causing the pushrods to set at an odd angle or rubbing on the holes in the heads.
 

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