Setting Valve Lash & Preload on GT40 Heads
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- Опубліковано 4 жов 2024
- Set Valve Lash and Lifter Preload on Cylinder heads! In this video I finally finish installing the heads by setting lash and preload. I show proper procedure, share tips, and crucial information regarding lash and preload when using hydraulic lifters.
Good video, no music, straight to the point. Subbed.
Hello. Yes sir! No BS is what I'm going for with this channel. Glad it helped and thanks for commenting and subbing!
The better technique for setting preload is moving the pushrod up and down until there is no play. If you twist them and don't stop tightening until the rocker arm won't move you've already suppressed the lifter slightly without knowing it and applied unintentional preload and the torque value will be reached too soon. I see 90% of people use the twist method, but if you think about it the goal is really to start with no zero up and down movement.
Right, good tip there. I didn't adequately convey what I was doing in the video, but I was putting pressure up/down as well in the twisting motion, but it wasn't that apparent. Thanks for this!
Good one
The twist method is exactly what I did. The engine wouldn't start. I checked EVERYTHING from the coil to injector pulses to BAP signal. Once I backed the valves off a little, it fired right up. Now, I get to go back through and adjust them properly. With the "up and down" motion, and not so much the "twist" motion.
That said, I've never seen anyone get to zero lash and then torque to 20 lb/ft. It's always 1/2 turn, 3/4 turn or 1 1/2 turn. Made no sense to me.
Hey bud thank you ,your way of explaining finally I understand until watching your videos I was lost no body explains it in detain in order.
Lol, you’re 100% right! Have to watch 10 videos to get an answer. Glad this one helped!
This video has cleared up so many questions for me, I will be using this before I set my lash this week. Might get new pushrods though as mine are the older original ones. Thank you so much!!
You’re very welcome! If the old ones are in good condition, I’d re-use them. Did you change lifters or rocker arms? If not, re-use is totally acceptable. Unless you have concerns on their condition and/or history. Glad the video helped! Thanks for the comment 👍
Very good explanation of the adjustment proceedure. Thank You.
Glad it was helpful! Thanks for commenting 👍👍👍
Great video I like how you explain the firing order and turning the flywheel thank you again
You’re welcome!
I was actually looking for a video like yours to adjust my valves on my 91 fox. This helps unlike anything I've found. Lol
Awesome! Glad to hear that. Best of luck on your fox!
I think this video is what I was looking for after a couple of days of reading my notes and looking online. I have an engine similar to your 302 HO in my 1966 F-100 truck that the previous owners installed. I did check lifter preload last in 2020, but since I changed oil a couple of weeks ago, it seems noisy. I added 5 quarts of 10 30 synthetic this time with filter change. There are so many conflicting ideas about the amount of turn and even the torque for the rocker bolts, though 20 ft lbs seems to be the common standard. Some say that even 3/4 turn is too much, others that 1/2 to 1 full turn is okay, but 1/4 is too little. I have pedestal mounts, like here, but others have studs with nuts. I think I bought longer pushrods at 6.300 and used .040 shims mainly, others at .032 or .020. But I need to recheck after 4 years of infrequent use. I plan to use the top dead center on compression stroke technique this time, a little less confusing at age 76. Also, if this doesn't improve the noise, I may use an additive or switch to 15 40 oil. Thanks for the video. Dave
Hello, Dave. It sounds like you know what you’re doing. At 76, you’ve got more knowledge and experience than most. More or less, setups like ours only require the correct torque. However, I consider setting preload/lash to be a good best practice to simply make sure everything is set correctly. A person can discover potential problems when taking the long path, so I think it’s worth while. Best of luck to you, sir! Thanks for your time and comment, I appreciate it 👍
@@FastFixUA-cam I started out turning the engine by the balancer / crank bolt using a 15/16" socket with a short extension and long handle rachet wrench, to top dead center for compression #1 cylinder, but I found it easy to get confused or distracted following the firing order and turning the engine 1/4 turn. A better method, for me at least, is: SET INTAKE WHEN EXHAUST BEGINS TO OPEN. SET EXHAUST WHEN INTAKE OPENS AND STARTS TO CLOSE. I went right down the valves for cylinders 1 thru 8 in that order, rather than the firing order, using the above printed on a card in the compartment. I also drew a diagram of which valves were intake or exhaust to refer to. I think this way is safest. The truck runs better and quieter, even more so since I replaced the plugs gapped to .050". The shim kit from Ford Performance provides: .010, .020, .030, .040 (10 of each), cost about $20. I ended up using 15 shims at .040", 2 at .035 (from previous owner), and 1 at .030". To torque to 20 foot pounds, it took 1/2 turn or a little more, maybe 2/3 turn from finger tight with no play. I hope to take the truck some miles on the turnpike on Saturday to a truck show and another on Sunday, put on by the Cadillac and Lincoln clubs.
So i have stock pushrods and do what you did. I did rotate engine twice and my pushrods got loose. Could this just be because lifters were compressed and have no oil pressure? Or do you think I need longer pushrods?
Hello. Have you changed anything in your valve train? If not, no you don’t need longer pushrods. The push rods shouldn’t be loose to the point of losing contact with the rocker arms. Did you set valve lash as described? Also, if you have stock rockers, you likely don’t need to set lash. Simply torque them to the required poundage and you’ll be all set. What engine are you working on?
If I fail to see your reply, please start another comment. UA-cam doesn’t make it easy for me to track replies unfortunately.
So I have a 302 from a 93 mustang, added gt40 heads and cam with 540 lift. I did upgrade springs. I ran 6.250 pushrods and set lash and torqued down to 20lbs, everything was good. I rotated engine and pushrod got lose. Granted this was only on cylinder #1. Now my pushrods are loss, I did get a pushrod checker and feel I should be running 6.350 pushrods. Does this sound about right or did my stock lifters get compressed?
Hello. How lose did the pushrods get? Was there a gap between the pushrod and the lifter? If so, you’ve got something out of spec. After everything is torqued, you should be able to twist the push rods around, but there should be no up and downward play between the push rod lifter and rocker arm. Also, did you use factory rocker arms? If you used aftermarket ones make sure that you are setting correct lash and Torque to those. The rocker arms from the factory can be simply torque down, you don’t really need to set lash at all, but if you’re using aftermarket rocker arms, it could be a completely different story. It could very well be that you need a longer push Rod if you’re doing everything else according to spec. It could also be true that you have a lifter that’s stuck and compress down. If the other push rods are just fine, I would remove that lifter on cylinder number one and see if it’s seized. Best of luck to you! Feel free to reply and let me know how things go or if I totally the mark on my answer.
Why are we doing all this when we have pedestal mound rocker arms??? All you need to do is bolt them down to 19 lb and you're done.
Hello. Yes, you're correct. I suppose I wanted to be precise knowing full well the torque value would provide all the precision I needed. Still, I thought it might help others to learn the process for rocker arms mounted in different ways. Thanks for commenting!
3:05 gawhdamn now im a math wiz, thanks 👍
😂😂😂. Hell ya! Got to love the maths. Thanks for commenting 👍👍😂
I'm confused ur talking about valve lash and shimming.....on a standard torque to spec pedestal rocker. What is the achieved goal??
To have consistency. That’s it. I know it’s not required to do it this way, but I figured what the hell. On a previous build (same engine) I just torqued them to spec and left it at that. This time I wanted a way to measure my inputs considering the head change….again, not necessary, but it makes my brain happy. Thanks for the question.
The picture of the firing order had the same order for both style engines
Regular 302 1,5,4,2,6,3,7,8
302 h.o./351 1,3,7,2,6,5,4,8
Right, but the picture is indicating the HO motor which shares the same firing order for 302 and 351. I know there’s different firing order for the non-HO motors because the camshafts are different. Thanks for the comment 👍
I installed a cam in mine. I did this exact method to adjust the valves but now my valves are not closing. The guys at comp said I could use the stock pushrods but clearly something is wrong. I don't think shims will fix my problem
If the valves aren’t closing, yes you’ve got other issues. If the valves are not closing, the pushrods are too long.
Those are a single contact rocker there is no setting lash or preload just tighten them and torque I’ve done it on 4 on my 5.0s and I’ve never had an issue
I think you still have to set lash and preload. How else can you determine if you're reaching final torque within 360 degrees (or less) of rotation?
Cause it’s a single contact rocker it’s not a roller rocker once the pedestal is tightened and torqued that’s it
And if you think you have to do that then you don’t know they aren’t a pedestal roller rocker just stamped steel and you’re putting stamped steel on a big cam it’s gonna shatter those eventually big cams need roller rockers and majority of comp cams recommend 1.7 roller rockers
@@ponyboywils9950 the cam is mild to mild-aggressive in range. The stamped steel rockers will be fine. They have plenty of strength for my setup. Thanks.
No they don’t they will shatter guaranteed
I have a 4.9 that the head has been decked .065. do I need to shorten the pushrods or add shims to it?
Hello. Decking the head doesn’t usually require you to change pushrods or add shims. You’ll get a slight compression bump however! Or, you can install thicker head gaskets to make up for the difference. However, it’s negligible on most applications. Full blown race stuff would require more attention, but assuming you’re not building a 2000hp motor, you should be gtg. Thanks for the question!
Are both ends of the pushrod the same one side of my old ones seems more worn than the other end does it go to the rocker
Hello. I like to keep all my pushrods synced to their corresponding lifter and rocker arm. That way the machining that occurs through natural wear process is maintained. In your case, it sounds like abnormal wear on one pushrod. If I were you, I’d try and find which lifter or rocker that pushrod was mated to and replace both. Otherwise, you’ll need to try and figure out which lifter or rocker arm paired with that pushrod and use them together in your build. Make sense? Please let me know if not. Thanks for the question.
Thank you!
You're welcome!
Are you sure the reason you didn’t use the roller rockers isn’t because the gt40 heads require some machining to employ them?
Hello. No, the heads don’t require any machining. The roller rockers come factory from Ford on the Cobra Mustangs. Thanks for the question.
Hey man awesome video! Quick question! What springs did you use? As well as what pushrods ?
Hello. Pushrods are factory length from Ford Racing. Springs are from Comp Cams, but I don’t remember the part number. It really doesn’t matter though. When choosing springs, make sure they match your cam. Sorry if that doesn’t help much.
Hi do you have any paper version of What you’re doing in the video
Sorry, I do not.
My rocker arms became loose and I tried titinig them but thay still became loose I'm I doing something wrong
Yes, I’m sure you’re missing a step along the way. Make sure you’re tightening the rockers when you have zero lash when the valve is completely closed and the piston is at TDC. If you’re not exact when you do this, your rockers won’t remain tight. Double check the recommended torque setting for your rockers as well. Too little torque and they’ll loosen up quickly. Also make sure you’re applying the recommended torque within 3/4 of a full turn of rotation. As described in the video, if you’re having to go beyond a full 360 degrees of rotation to reach the torque number for your rockers, you’re going too far and need shims. Hope this helps.
I have a 1990 I'm gonna be replacing the push rods and lifters will this be the same for hrdrolic lifters and stock heads and do I need to soak the lifters in oil ?
Hello. Yes, the same. My setup has the hydraulic lifters. In this video, I took extra measures for consistency, but with rockers like this, all you have to do is tighten them to their final torque and you’re good. No need to make sure that you’re hitting final torque within 360 degrees of rotation on the bolt. Of course, make sure the valves are at TDC before tightening.
Soaking the lifters in oil is optional, but something I do. It certainly doesn’t hurt anything.
@@FastFixUA-cam so after I torque down the bolts on number one you torn the engine over 90 degrees then just fallow the firing order
@@brianrohm6757 correct! You got it.
If you don’t do this will the car run I replaced my cam in my 1978 302 now I can’t get it in time
Technically no , you don’t have to do this. On the 302 you ca. tighten to factory specs and be good.
Regarding your issue. Check the firing order compared to you plug wires. Then, make sure you’re starting the #1 cylinder on the compression stroke or it won’t fire.
I just turn the motor until a rocker loosens all the way and then tighten all the ones that are loose, then turn the motor over until more loosen up then tighten them, then turn the motor over and tighten the loose ones until none are loose.
Hello. Yes, that works too. I wanted to show newbies the most “accurate” way to adjust in case they didn’t understand how engines work. Good suggestion, thanks!!!
@FastFixUA-cam great job sir! 🤠
This guys seems nice but shouldn’t be giving advice.
Those are positive stop bolt down, there is no adjustment.
Thanks Andrew. I’ve heard from others saying the same thing. But doing it this way doesn’t hurt anything. If it did, I’d take down the video. If anything, it’s a good best practice IMO. So I take your point, but I wanted consistency in preload within 360 degrees having changed heads. I realize it may not be necessary, but it makes my brain feel better knowing all was done the same. Thanks for the comment.
Consistency comes the fact that they all tighten to the same exact height.
If you changed heads you need to check with a pushrod measuring tool if they are the right length in order to assure proper preload
Thank you! I said the same thing to this guy
@@iqinsanity how does one check to make sure they are done right in a vehicle that has ran? Meaning my lifters are pressured up?
Tdc 1 on the balancer?
I guess 🤷♂️
man you dont set preload on pestle mount rockers lol you just torque them to 20-25 foot pounds and your done!
Yeah I hear ya. I just wanted to show how lash and preload are done regardless of the necessity to do so. Of course torquing to 25ft lbs IS all you need to do and completely acceptable, but I wanted to factor in degree of turn as well. Plus, a video torquing these to 25ft lbs is pretty boring…. Thanks for the comment 👍
@@FastFixUA-cam ah ok makes sense!
What cam did you use?
Hello. Com Cams 35-514-8
Did you have to chip the computer, or the maf did the adjustment?
Had to chip the computer. The cam totally threw it off. Was basically undriveable with the stock tune.
Any company you recommend for that chip?? Sorry for all the questions, I'm pretty much going with the same setup
No prob. Channel is pretty small, so it’s easy to get to the comments. I got my tune from Bama via American Muscle. It’s been a while since I got this, so there might be better alternatives to chipping the computer. FYI. www.americanmuscle.com/sct-4-bank-computer-chip.html
And if you dont upgrade the valve springs on the gt40 heads you will have lag at the bottom end and it will drastically drop at top end. P.S. you don't adjust these. Lol
Right. Per your last comment, the springs are very important and often overlooked or not taken seriously enough on some builds. I took great care to make sure they were perfect on this build. 👍
Your in the wrong position start at 6 o’clock and tighten up to 3 o’clock and that’s it!
I see what you’re saying, but what I did wasn’t wrong. Just overkill.
@@FastFixUA-cam yep not wrong just a little confusing as UA-cam has plenty of it
@@brunoburtoni8479 can’t argue with that
Not old. Just young a long time ago. 🤣🤣
🤣🤣👍
@@FastFixUA-cam Like I was young 55 years back.
Where did you find or purchase the stock stamped Ford rocker?
Hello. The rockers I used were from my original engine. I didn't need to source them. I would assume they'd be available at your local parts store or even Summit Racing or similar.
Fast Fix
Lol 10 4. The current engine in my Fox runs great and has about 100k on it. I am building a second engine on the engine stand. I laugh because I was planning on using the rockers from the original engine like you did. But I thought if I could purchase a new set at a good cost I might do that. Thx for the quick response
Oh, I gotcha. It’s a legit question. Sometime cheap stuff is out there if you know where to look. Cool on your project. You’ll like the added power.