Help: Builing a Street 408

[bobcowan]

1. I find the pry bar type compresser to be difficult to use on the bench. I like the kind that looks like a big C clamp.

2. What you're looking for is piston to valve clearance. I set to vero lash and then back off 2-3 turns. If clearance is going to be a problem, you'll be able to see it then, before the valves actually contact the pistons. Even if turning by hand, you can damage a valve if the clearance isn't there.

3. The issue is with the hydraulic lifters. They're designed to collapse a little bit under use. When there's no oil pressure, they will collapse a lot more, and you'll never get full valve lift.

[donraye]

Originally Posted by bobcowan

1. I find the pry bar type compresser to be difficult to use on the bench. I like the kind that looks like a big C clamp.

2. What you're looking for is piston to valve clearance. I set to vero lash and then back off 2-3 turns. If clearance is going to be a problem, you'll be able to see it then, before the valves actually contact the pistons. Even if turning by hand, you can damage a valve if the clearance isn't there.

3. The issue is with the hydraulic lifters. They're designed to collapse a little bit under use. When there's no oil pressure, they will collapse a lot more, and you'll never get full valve lift.

Thanks Bob, That's helpful to know.
The lifters I'm using are actually from another engine and are still full of oil so they will not colapse. Is that going to be a problem since as they are "pumped up" and will not collapse at all probably? Will that make adjusting the valve lash or rockers a problem using them on the cam and roller rocker install?
I think I read in my cam installation directions from Comp Cam that it was "not desirable" to use lifters filled with oil for the cam installation. Anyone know about that? I would really like to know before I use them if that is going to be a problem or not.
Don

[bobcowan]

Originally Posted by donraye

Thanks Bob, That's helpful to know.
The lifters I'm using are actually from another engine and are still full of oil so they will not colapse. Is that going to be a problem since as they are "pumped up" and will not collapse at all probably? Will that make adjusting the valve lash or rockers a problem using them on the cam and roller rocker install?
I think I read in my cam installation directions from Comp Cam that it was "not desirable" to use lifters filled with oil for the cam installation. Anyone know about that? I would really like to know before I use them if that is going to be a problem or not.
Don

Yes, they will collapse. Just watch the plunger when you rotate the engine. Even when filled with oil and the engine running, they will collapse a little bit. That's the design of a hydraulic lifter.

I don't install my lifters with oil in them. I coat the bodies with assembly lube, and put a littl on the rollers. Before engine start I spin the oil pump with a drill motor until oil comes up to the rocker arms. That tells me the lifters are now full.

[J Persons]

If you have an extra hydraulic lifter, disassemble it, clean it in carb cleaner and fill it with epoxy, then re assemble. It will act as a solid lifter for checking purposes. No worries about the lifter collapsing under spring pressure or anything. Just be sure and don't install it in the engine during final assembly.

If you have stud mounted rockers and hydraulic lifters, you can gain 200 to 300 more RPM if you adjust the lash so that it's at 0, then lock it down. This will put the lifter plunger at the top of its travel, and will prevent lifter pump up at high RPM. Adjust the valves at operating temp. Trade off is they can sometimes be noisy.

[donraye]

Hi all, I have just about every big and little thing for the 408 build now and have just pulled the 351 out of the car, so I will be starting the buld soon.
I will be robbing a lot of periferals from the 351 but some things will not transfer like the flywheel and the balancer which are both 28.8 oz. external balance and I will need neutral balance since the 408 is internally balanced.
But the question I now have for anyone is:
I have a perfectly functioning 10.4" OEM type clutch and pressure plate set-up with only 1,700 miles on it. I need to know if it will stand up to the 500+ crank HP of the 408 or not.
It will not be raced but of course there will be the glorious at least occasional "lead foot" (as one reason I have a Cobra to begin with!).
Will I need to just forget about the OEM clutch and get a Centerforce (or some other) that has about 90% more holding force than the stock unit? Or can I get by reasonably well with stock?
I hate to spend the extra dough at this point but would would hate to be replacing the clutch soon to put one in then even more!
One reason i hate to go to a new clutch pressure plate, etc. is that I think it will make the intall harder since the bellhousing/tranny are still in the car and the onld broken in clutch would mate up a lot easier than a new one when I put the new engine back in. I would that make that much difference? Was hoping to not have to disturb the stuff still in the frame/car.
Don

[bermblaster41]

I have a 408 in my cobra. Building a fair amount of power. I had the same decision as you to use a known good used clutch. The last thing you want to do is pull the trans because your clutch won't hold. I went with a new clutch from ram. Not sure if I would go with their product again. Requires a great deal of leg strength to push it in. {I have a hydraulic clutch} I am sure others will chime in on their choice and which one has an easier pressure but still holds. Far as unbolting your clutch you will have to due to the pressure plate is bolted to your flywheel. A clutch alignment tool can be purchaced at any auto parts store. Hope this helps. Berm!

[carmine]

On a cobra being so light you really dont need anything bigger than 10.5 dia for clutch. Also makes it That much easyer to push the clutch peddle.