Yes, have a professional do it for you....Well, had a moment to play with it. Backed out all the lifter preload, still can't get the intake valve to seal at the proper time.
I ended up hooking up the leak down tester and running only like 20 psi of air in to the cylinder. Enough to hear it but not enough to do the actual test. I then slowly spun the engine around by hand, several revolutions, both listening to the hissing and, since I don't have the intake manifold on, watching the lifters raise and fall. Also, I decided to try it on the the worst cylinder. The one that had the previous leak down test of 72psi being put in and only reading 20 psi staying in.
As I turned the crank, very slowly, there is one very small moment where the intake valve seals and no air comes out of the runner, but, instantly, the exhaust opens and the air starts coming out of exhaust. Even looking at the 4 stroke animations, it seems there should be a good amount of time that both intake and exhaust valves are sealed as the piston compresses the mixture. I don't have that.
Here are some things I'm thinking-- before I pull the head off.
1. The heads came from marketplace with the TFS stronger springs already installed. I took them off during cleaning, re-measured the height and re-shimmed as required. If I recall, most places required 1 more 0.015 shim then they previously had. Could I have messed something up here that would cause my issue?
2. In the TFS spring instructions, it said the keepers for the springs come in 2 bags-- 1 for exhaust, one for intake. The keepers were already on the valves when I got the heads. Could the previous owner have mixed them up? Would that cause my issue?
3. Can the cam be so much defective that it doesn't open/close the valves at the right time? Does that even happen?
Any other ideas? Thank you!
Engine Engine rebuild suggestions
- Thread starter JulianR
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If I bought a set of used heads, unless I got them from a machine shop, that'd be what I'd do, now a trick a guy taught me was to take brake cleaner or some alcohol and spray on the back side of the valve, we did this with the head off, and looked on the combustion side for wetness.
Just spit-ball'n
Just spit-ball'n
I wasn’t talking about the preload. I mean completely back the rockers off so all of the valves are closed. This is where the springs are exerting all of the closed pressure they have on the valve. Pressure up each cylinder and listen for leaks at the intake and exhaust ports of the heads. If any of them leak then you have a problem. The used heads I bought had six valves that leaked at the seat and another three or four that leaked up through the guides. Several hundred dollars later they were good to go.
Moral of the story is take used heads to a shop and get them checked before you install them.
Moral of the story is take used heads to a shop and get them checked before you install them.
Just a quick update. I did end up pulling all the rockers off and re-doing the leak down test. The air was still leaking out on the intakes on all cylinders.
Unfortunately, I don't have the money to take the heads to a shop. My wife would kill me as is if she knew how much this is costing me. Anyway, I took the head with the worst reading off, and after doing more research online about valve lapping, I re-lapped the valves. This time I used a drill (online opinions differ on the goods and bads of this approach). I also decided to spend $50 and get new intake valves. Alex's store online is great. They had the lowest price, fastest shipping and all the info I needed to choose the right valves. http://alexsparts.com
Anyway, I used an old valve from each cylinder and lapped it about 20 times in one direction, 20 times in the other. Then, I'd put the New valve in with spring and spacers, flip the head, spray wd40 over the valve face and cover the intake port with a towel and blow 100psi air in. At first, I saw big bubbles. I'd repeat the lapping. After a 2-3 rounds, the bubbles were small. I figure I shouldn't push my luck and I'd stop there. 1 cylinder even fully sealed.
To be sure I'm on the right path, I took the old head that I took of the mustang in disassembly, still covered in oil and carbon, and ran the same air test on 4 cylinders. 3 out of 4 had bubbles coming out. Again, this is from a running mustang. So, I figure the new heads should do ok. Maybe later I'll have some money for the AFR heads, or decide to get the gt40p ones to a shop, but for now, they should run.
For comparison, the new leak down test numbers are in black:
Here's and example of the old valve and seat after lapping:
Unfortunately, I don't have the money to take the heads to a shop. My wife would kill me as is if she knew how much this is costing me. Anyway, I took the head with the worst reading off, and after doing more research online about valve lapping, I re-lapped the valves. This time I used a drill (online opinions differ on the goods and bads of this approach). I also decided to spend $50 and get new intake valves. Alex's store online is great. They had the lowest price, fastest shipping and all the info I needed to choose the right valves. http://alexsparts.com
Anyway, I used an old valve from each cylinder and lapped it about 20 times in one direction, 20 times in the other. Then, I'd put the New valve in with spring and spacers, flip the head, spray wd40 over the valve face and cover the intake port with a towel and blow 100psi air in. At first, I saw big bubbles. I'd repeat the lapping. After a 2-3 rounds, the bubbles were small. I figure I shouldn't push my luck and I'd stop there. 1 cylinder even fully sealed.
To be sure I'm on the right path, I took the old head that I took of the mustang in disassembly, still covered in oil and carbon, and ran the same air test on 4 cylinders. 3 out of 4 had bubbles coming out. Again, this is from a running mustang. So, I figure the new heads should do ok. Maybe later I'll have some money for the AFR heads, or decide to get the gt40p ones to a shop, but for now, they should run.
For comparison, the new leak down test numbers are in black:
Here's and example of the old valve and seat after lapping:
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Question on hoses. Now that I'm getting closer to the final touches, I'm noticing there's different size hoses that I've cut and need to replace. The biggest issue is they are pre-formed hoses which makes them special-- and Expensive!!! What do you guys do about that? Spend the money or is there a way to get a cheap hose and form it?
Thanks!
Thanks!
Next dilemma the gt40 intake came with 8 injectors. I tested them and 2 didn't click when voltage was applied. I know they have a better spray pattern, but I believe I'd need to buy a plug adopter, like $30 and 2 injectors. Also, they're called ev6, and I saw a set for sale, I think Advanced Auto Parts brand for like $68. Otherwise I'm seeing other brands full sets for like $250.
On the flip side, I rebuilt my stock injectors from my running mustang and found that one injector wouldn't click when voltage was applied. Finally after about 10 tries it did, but I don't want to risk running that injector.
So here's my question. Do I need to spend $200+ for a quality set? Can I get just one stock injector replacement for under $50 (which brand), or is the ev6 set for $68 fine to use? I saw a review there said that injector leaked and hydrolocked the engine, I don't want that
On the flip side, I rebuilt my stock injectors from my running mustang and found that one injector wouldn't click when voltage was applied. Finally after about 10 tries it did, but I don't want to risk running that injector.
So here's my question. Do I need to spend $200+ for a quality set? Can I get just one stock injector replacement for under $50 (which brand), or is the ev6 set for $68 fine to use? I saw a review there said that injector leaked and hydrolocked the engine, I don't want that
Stock injectors on the Foxes are EV1's. I believe the EV6's will fit but like you mentioned you will need plug adapters. You may want to see if anyone on here has a set of 19 lb/hr units or a few spares that they would sell.
Take your set of EV1 injectors and send them to a cleaning, rebuild, and tuning outfit.
There's no way in hell I would run an adaptor for EV6 injectors. That introduces 32 new potential points of failure to help you pull your damned hair out.
There's no way in hell I would run an adaptor for EV6 injectors. That introduces 32 new potential points of failure to help you pull your damned hair out.
I can't afford to pull my hair out-- I'm already bald 
I'm seeing some New Old Stock on eBay for about $40 for the original injectors. Sorta leaning that way now. Also, there's so many brands of EV6 injectors everyone is selling, I'm not feeling comfortable spending the big bucks on unknown brands.
I'm seeing some New Old Stock on eBay for about $40 for the original injectors. Sorta leaning that way now. Also, there's so many brands of EV6 injectors everyone is selling, I'm not feeling comfortable spending the big bucks on unknown brands.
I'm sure I do, but my other concern is spending money on 30+ year old injectors. If they don't flow evenly, I may be chasing gremlins later. I'd bite the bullet and get all new 8 injectors, cuz it's easier now to replace than later. But at $260 @ lmr.com, they're still either re-manufactured or people say some fail in the reviews. On the flip side, you got ebay and amazon selling 8 for like $60 NEW-- but also with mixed reviews.
Do you have a recommendation of basic #19lb OEM replacement? It also looks like the new ones have 4 holes instead of the 1 mine have.
Do you have a recommendation of basic #19lb OEM replacement? It also looks like the new ones have 4 holes instead of the 1 mine have.
I got new/rebuilt four hole injectors on E Bay and it totally changed the performance of my 90 LX. I started the car and got a high idle. I had to bring it down and the car took off.
keel
Active Member
I am running a TFS1 cam, GT40 three bar heads, and GT40 intake with 19lb EV1 injectors and a stock fuel pressure regulator with zero fueling issues, at least as far as I can tell. I also am running a stock throttle body, MAF, and airbox though which most people would have probably upgraded for a few extra horses when running a combo like mine. Not sure on what you're planning in that department.
Don't know what the duty cycle is at my power level but it is probably pretty close to the limits of how hard you want to push the stock injectors.
Don't know what the duty cycle is at my power level but it is probably pretty close to the limits of how hard you want to push the stock injectors.
keel
Active Member
Ideally, you don't want your injector duty cycle to be at or near 100%, which is why LMR says they're good for 285 horses. I think that is around 85% duty cycle. I wouldn't be surprised if you and I surpass 285HP with a combo like this but its not going to be much more at all, probably around 300HP max.
LMR has excellent customer service but the common auto parts they sell like sensors, injectors and stuff are repackaged and inflated
You do realize that the ratings are in fwhp not rwhp. I ran out of injector at 306 rwhp on my old 306 and that was with 24 lb/hr injectors at seal level.
Stay away from the Amazon injectors. Tubers post videos of those injectors a lot and they are inconsistency and do not come with data sheets so they are about impossible to tune.
Stay away from the Amazon injectors. Tubers post videos of those injectors a lot and they are inconsistency and do not come with data sheets so they are about impossible to tune.
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