598 turbo motor keeps breaking the head

Guys,

Keep having issues with the turbo motor. First time out, the rocker stand got pulled out of several of the threads in the heads. The heads were never heli coiled and the rockers were bolted to the factory alumium tapped holes. With 1200#'s of open pressure it pulled out the bolts. So, heli coiled all the holes, replaced the broken timing belt and bent valves, double checked all the pistons, and put it back together. This last time out, the car left hard, pulled the wheels, set the front end down and got on top of tires which spun them. The motor made about 22#'s boost at 8500 rpm, and pulled the aluminum perch out of the #2 exhaust stand. The heli coil was still attached to the bolt, it literally broke the head. The valves never hit the pistons, and all the cylinders were firing so no hydraulic problem.

Any ideas?

This is the Exact reason I do not like Shaft rockers for heads that are set up for STUDS on shaft setup it put all the stress on the individual stud mounts, when you use studs and a girdle it spreads it among all 8 studs and another thiing is Heli Coils are junk.......


I have fixed more Heli coils than not....because they are a bandaid fix....


JMHO
Randy

A rocker system with a subplate/stand that runs the lenght of the head is a much better concept. The two thick washers under the stands are not helping matters .

Lem,

Does anyone make a plate rocker system for the TFS A460's? I bought the T&D's at the advice of one of Kaase's guys. I really don't want to have to change heads right now, but I could deal with getting new rockers. The washers don't help at all, but in order to get the right angle T&D tells you to add washers based on your cam size...and our cam is BIG.

Thanks

Chappy

Anyone have any photos of a full stand setup for A460's? I have thought in the past of welding all the stands together on the heads with some heavier duty metal than what I have now.

Any ideas?

Thanks for the phone call Lem. Gonna talk to T&D right now and let you know what answers I get.

Send me the engine and I'll test it under various racing conditions and try to find the problem. Could take me a few years

Hope you get it fixed.

use longer bolts and weld 3/16 or 1/4" stock vertical to the stands ... not flat like you did

D. Sea wrote:Send me the engine and I'll test it under various racing conditions and try to find the problem. Could take me a few years

Hope you get it fixed.

Right now you wouldn't get any testing done. LOL.

DanH wrote:use longer bolts and weld 3/16 or 1/4" stock vertical to the stands ... not flat like you did

Thought about that as well. I did some research and found that TFS has started drilling the threads deeper and supplying longer bolts to be used with this setup. Unfortunately my heads are older and don't have this.

Lem,

Spoke to T&D...said they can make me a one piece stand that will connect all the intake rockers. Then individual stands for the exhaust that butt up against the intake stand. Also they will correct the stand height on the exhaust side due to the larger installed height on the springs...so no more shims.

Of course I have to send them the head and wait 4 weeks for them to make it...and it's gonna cost some money...but what's money at this point anymore. Gotta get this expensive engine fixed so I can actually race it.

Did you ask them why they didn't design them correctly the 1st time
Ask them if this will be the design going forward. Be sure to weld the exh. stands to the long bar when you get things aligned.

Like what Lem said, the two washers under the stands did not help any at all. They appear to be .070" thick, so that's about .140" worth of shims, which greatly reduced your number of threads of engagement. If you are going to continue to run this set-up, then the stand hold-down bolts, (which are likely ARP 12 point bolts), needs to be longer so that you'll engage more threads down deep in the head. Make sure you use long helicoils and redo if necessary.

Also, be advised that with blown or turbo engines and the greatly increased cylinder pressure, the exhaust rocker arm and pushrod are under even greater compression load than normal. The exhaust valve does not want to open, so therefore it's more likely to rip an exhaust rocker pedestal out, than an intake pedestal.

I see that you are using the TFS BBF 3 head which is the 18 bolt version. That's good and I'm sure you're using all 18 bolts to help hold the head gasket.

Be advised that W.W. Engineering has a new TFS A-460 18 bolt head in house, and is currently working on a new one piece stand for this head with shaft mounted rockers. They are almost done. The W.W. version will be one piece across the intakes with four individual stands for the exhaust, (like the suggested T&D). The W.W. version will use the longer 1750 body rockers which reduces the amount of roller sweep across the valve tip. Because of the longer bodies, the pushrod side of the intake rockers gets into and makes contact with cast valve covers and notches have to be ground in the valve covers up next to the intake manifold. Sheet metal fabbed valve covers should be no problem.

Hope this helps,

Charlie

We did several things inthe past to eliminate this issue. The first is to weld or do whatever you can to tie the rockers together. The exhaust has to fight the spring pressure and the 22 lbs of boost to open. We also put in longer studs on the exhaust that ran into the top of the port and then put a pin in it so that you had to shear the pin before you started to pull the threads.

This is what a properly designed subplate looks like for the C460 head . I do understand that the A460 stuff can't be as good but most of what is available for A460 heads could be waaay better.

This is a pic of psfracer's P51 build that he has posted here. Notice that the shaft system looks like what chappy89 needs.....which T&D seems to already know how to make.

Damn that's some nice stuff there. I talked to my motor guy today...he finished repairing the head already. We looked at the setup now, and we all agree that the washers are screwing me. He suggested longer bolts if we stay with the current setup, but I think I am going to go ahead and get T&D to make me some one piece stands. I don't want to have ANY more problems.

Thanks again Charlie and Lem for your help and quick responses. I know the WW stuff is nice, but its another 1500-1600 bucks, and I would have to sell my current setup. I am going to post some pics of the rockers I have now, and see if you guys think they will suffice with the one piece stands.

Thanks again

Ryan

[quote="Lem Evans"]This is a pic of psfracer's P51 build that he has posted here. Notice that the shaft system looks like what chappy89 needs.....which T&D seems to already know how to make.

T&D already knows how to make it for sure...but because its custom and not the ordinary setup, it will take 4 weeks. The cost doesn't even matter any more.

Chappy how is this a custom set-up? you would think if they have an a-460 head the could do a mock-up and if it bolts down to that one why wouldn't it work on your heads? Maybe i missed something but i dont understand something here?

lghting94 wrote:Chappy how is this a custom set-up? you would think if they have an a-460 head the could do a mock-up and if it bolts down to that one why wouldn't it work on your heads? Maybe i missed something but i dont understand something here?

Its a custom setup because T&D does not provide a one piece stand unless you send them your head. If you order their shaft rockers for A460 heads, u will get the individual stand type. The only way they will make a one piece stand for A460's is if you send them your head. So this makes it custom.

lghting94 wrote:Chappy how is this a custom set-up? you would think if they have an a-460 head the could do a mock-up and if it bolts down to that one why wouldn't it work on your heads? Maybe i missed something but i dont understand something here?

It's W.W. Engineering in Dawsonville, GA that already has a new TFS A-460 head "in house" and is currently working on a new one piece stand,,,, not T&D.

Charlie

the Coug wrote:This is the Exact reason I do not like Shaft rockers for heads that are set up for STUDS on shaft setup it put all the stress on the individual stud mounts, when you use studs and a girdle it spreads it among all 8 studs and another thiing is Heli Coils are junk.......


I have fixed more Heli coils than not....because they are a bandaid fix....

and that theory you provided awhile back in another pissing match thread is why I went with that exact set-up....


JMHO
Randy

and that theory you provided awhile back in another pissing match thread is why I went with that exact set-up....

Ok that clears it up some thank you Charlie and Chappy. I still dont understand why T&D would make everyone that wanted a set of one peice stands to send them the heads to make them off of but oh well it is their business and their funds doing the devolopment.

lghting94 wrote:Ok that clears it up some thank you Charlie and Chappy. I still dont understand why T&D would make everyone that wanted a set of one peice stands to send them the heads to make them off of but oh well it is their business and their funds doing the devolopment.

Im with you on that. I guess they developed the original system and didn't make any drawings or keep the head they used to design their setup. So anytime someone wants one they have to send in their head. U would think after the first time they did it they would make drawings or something. Hell, I would let them use my head as a template if they would give me a little something off the price. LOL.

138 wrote:

the Coug wrote:This is the Exact reason I do not like Shaft rockers for heads that are set up for STUDS on shaft setup it put all the stress on the individual stud mounts, when you use studs and a girdle it spreads it among all 8 studs and another thiing is Heli Coils are junk.......


I have fixed more Heli coils than not....because they are a bandaid fix....

and that theory you provided awhile back in another pissing match thread is why I went with that exact set-up....


JMHO
Randy

and that theory you provided awhile back in another pissing match thread is why I went with that exact set-up....

I can tell you with certainty that there is no rocker/stud girdle setup that withstand the kind of pressures and rpm that my motor sees. I ran a similar setup on a small block turbo street car that turned around 7800 rpm and made about 1200 HP, and I broke several Crane Gold Race rocker arms which caused all kinds of bent valves. I will never run rocker/girdle setups for high rpm/big power combos.

We turn this motor to 9000 rpm, and it will go to 10K if I wanted it to. Our springs have 400#'s on the seat and over 1200#'s open. Plus throw in 35#'s of boost from twin 88's on the exhaust side...and you have a recipe for disaster for a rocker/girdle setup. Maybe others have tried it and been successful...but Im not going to risk my 40K investment. That's why Im a little pissed that T&D didn't make me aware that they could do this when I bought the rockers...and Kaase didn't make me aware either. 6 months later and 2 times damaging parts at the track, and now I find out about this. Makes me want to quit racing...but I love the rush too much.