Hey guys. I have gt40p heads ready to go in tomorrow. The problem is when I bought the heads, the guy I bought them from said they had a valve job and the springs were running on a fcam. I figured the springs must be new. I asked him if they were good he said itll be fine they were running on an fcam, again. So that was a while ago, everythings dandy, i rip apart my motor, heads are ready to drop on tomorrow morning, and im talking to the guy and he tells me the springs are STOCK! I get alittle scared. I dont have the time or money to swap springs. These springs have been supporting an fcam for 5k miles, so they should be good with my bcam right? Im using 1.6 rockers so the lift shouldnt go up. The guy I bought them from said the guy he bought them from took them to a machine shop, had a valve job, and cleaned them up. THing im thinking is, if you do that work at a machine shop, somewhere in the conversation he had to have told them how much lift the cam he was using had, and they would tel him he needs new springs. The guy didnt tell him the springs were new but is their a chance they are if they ran with an fcam for 5k miles? SHould i just keep the rpms low till i can afford springs? Thanks.
I know you guys are gonna say take them to a machine shop but i dont have the time or money to do that.
I know you guys are gonna say take them to a machine shop but i dont have the time or money to do that.
ahhhh this is not good, so how did they support a fcam for 5k miles?! Itll be about a month before i can get new springs, i have to buy new headers, insurance time, 50 bucks for the gym, and a 200 dollar ticket, IM BROKE
Well don't go on my word. Lets wait till someone with a tad more know how chimes in.
Hey don't fret anyway. Bills have left my gt40 irons sitting in the corner of my room now for like 10 months. Looks like another winter they won't be doing much other than collecting cobwebs
Hey don't fret anyway. Bills have left my gt40 irons sitting in the corner of my room now for like 10 months. Looks like another winter they won't be doing much other than collecting cobwebs
mob...valve spring pressure is extremely important,especially for performance.
At this point,you need to know what pressure you have now...and if it`s not enough,you need to upgrade the springs.
The correct valve spring pressure is critical.
If they are just stock replacement springs,they may/probably won`t handle higher rpm use with a B cam.
Valve springs cannot be taken for granted,they are a critical component.
If they are weak you will know it.
Check them.
(TFS makes a valve spring kit for stock heads if you need new springs fairly cheap).
At this point,you need to know what pressure you have now...and if it`s not enough,you need to upgrade the springs.
The correct valve spring pressure is critical.
If they are just stock replacement springs,they may/probably won`t handle higher rpm use with a B cam.
Valve springs cannot be taken for granted,they are a critical component.
If they are weak you will know it.
Check them.
(TFS makes a valve spring kit for stock heads if you need new springs fairly cheap).
I dont have time to get them checked. What does valve float feel like? Im gonna keep them in the lower rpms till i can get the tfs kit.
you're pushing your luck, and trust me, you're gonna try it just once or twice to see if you have float, and that's all it'll take and kaboom.
don't install them until you get new springs. those gt40p-explorer valve springs don't really rev past 5k, and you're asking for trouble. I bought and installed the tfs valve spring kit from summit at slightly over $100, and I've only running a HO stock roller cam with my p heads.
don't install them until you get new springs. those gt40p-explorer valve springs don't really rev past 5k, and you're asking for trouble. I bought and installed the tfs valve spring kit from summit at slightly over $100, and I've only running a HO stock roller cam with my p heads.
Forgot to mention that since these are used heads,it`s a good idea to take them to an experienced engine builder to have them checked over for possible defects before installing them.
It would be a severe pita to go through a head swap and find out that something is maybe wrong with the heads.
It would be a severe pita to go through a head swap and find out that something is maybe wrong with the heads.
mob said:
What good will that do you? A camshaft goes through it's entire range of lift at all rpms, so keeping your rpm's low won't save you.
I ran GT-40P heads for a while, and I was concerned about the stock springs as well. The Ford Racing Tech Dept. told me the stock springs were only good to .450" lift. I thought I would be safe with a .447" single duration cam, but in less than a year I had all sorts of valvetrain problems related to the springs.
Do it right the first time, or expect to pull the heads again in the near future...that's an awful lot of work for not getting it done the right way. You think it is expensive and time consuming to do a spring swap? I had to replace all of my lifters and pushrods AND springs because I didn't to springs the first time.
Trick Flow sells a spring upgrade kit for SBF heads, they are the same springs they use on the Twisted Wedge heads and I installed that kit on my old GT-40P heads. They were good to .542 lift I believe, and they weren't just a single spring like the stock GT-40P springs they had dampners as well. The kit wasn't expensive and the install was easy with a rented valve spring compressor from the local auto parts store. Never had an issue again, it ran really well.
if their only good to .450 lift then how did they run with a fcam for 5k miles? Is it very likley that their not stock?
mob said:
I guess you would have to take them to a shop and check the pressure specs with a spring testing machine to know for sure,unless the previous owner can give you a definite answer and a part number on the springs.
mob said:
Mob, don't goof your project up. Look at the facts. The guy you got the heads from, at no point in your explanation of your situation did you say he said that the springs were upgraded...you just assumed they were. He said they ran with an F cam, but all you know right now is he didn't say the springs were upgraded and later said they were stock. Don't assume the head shop did something to the heads (installed stiffer springs) if the customer didn't specify it. Don't assume because they made it 5000 miles that things are in better shape than you think, remember they only made it 5000 miles not 50,000. If you look at the facts, you know that you really know nothing about the springs. Almost all aftermarket springs designed for performance cams at the very least have a dampner. If your springs are just single springs with no dampner, than they are more than likely the stock springs. Do it the right way the first time, get them checked.
the springs probably arent any worse than the stock e7 springs. and your b-cam ran fine with them. if these springs are stock chances are that the motor was lower milage than your heads stock heads were. plus the b-cam doesnt have much lift anyways. i would have them checked out sometime
i bought my thumpers and had them torn down and inspected. turned out they had 2 bent valves and i had some spare valves laying around.
would have been bad if i threw them on with bent valves.
i bought my thumpers and had them torn down and inspected. turned out they had 2 bent valves and i had some spare valves laying around.
would have been bad if i threw them on with bent valves.