DAPSUPRSLO

iTrader: (14)

After attempting to put my combo back together with Harland Sharp non adjustable rockers and my Comp Cams 239/246 .649"/.613" 106lsa 106icl cam, 5.3 litre heads cut .030" I have found that because of the use of two different lobes (new comp lobe/XE-R comp lobe) I need to much variation in preload between the intake and exhaust lobe on my setup. I can't get this adjustment by using shims because the Harland Sharps are a commons paired shaft system (i.e. you must shim the exhaust and intake the same). The stock system would not be useful either for the exact same reason, you shim the intake you have to shim the exhaust.

I know I could fix the problem with an pushrod length checker and a set of custom pushrods but would rather go a head and get some adjustable rocker arms.

I am looking at several of the shaft systems and the Jesel SS series adjustable has caught my eye more then any other. My questions with this system are do you have to clearence the pushrod whole with them and do you absolutely have to get the valve cover spacers with them? I would rather not have to clearence the pushrod holes if possible based on the fact that I just put one of my heads back on and don't want to have to get another set of head bolts and maybe a head gasket as well (motor has not been run). Also, do I have to get a set of 7.050" pushroods or close to? Could I just use the 7.4"s and adjust to get the proper preload my comp r lifters need or does the change in geometry mandate the use of the much smaller pushrod? Thanks.

wrlowry

iTrader: (1)

1ST-- jessel super sports are non - adjustable
2nd -- I did the super sports on a '99 TA -- No push rod to hole problems(1.7)'s 7.40 comp push rods.

3rd -- valve covers '99 center bolts , drivers side remove filter baffle in rear, mill or grind couple of high spots.

pass side remove tin baffle, mill,grind dimpels for coil bolts( 1/4")off

this info is for The supper sport series (1.7 ratio)

Note: instrctions on Jessel site (LS1)- BECARFUL with bolting the rails on, with the logo to the springs, this will have you install to wrong.

eallanboggs

iTrader: (1)

The Comp Cams Pro Mags ARE adjustable and don't require any of the modifications as mentioned above on rocker covers as needed with the Jesels. The are NOT shaft mount if that is a MUST for you, but are very high quality. You can't go wrong with the CC Pro Mags. They use guide plates which keep the pushrods straight which in turn prevent the rockers from pivoting. The guide plate require you to run hardened pushrods.

DAPSUPRSLO

iTrader: (14)

The SS series now offers and adjustable version. This is fairly new so they may not have been available when you decided to purchase yours. Sounds like I better cal Jesel to make sure that I don't have any issues with it. Thanks for the information.

LASTLS1

iTrader: (7)

Jesel shafts are nice. But I did need to gut my valve covers and grind the holes for the push rods. Aslo, I ground a little on the head where the rocker meets the edge of the head. It didn't touch, but it was very close. I didn't like the whole shimming thing. The adj. seemed the only way to go. You do need valve cover spacers with them too.

DAPSUPRSLO

iTrader: (14)

Are you running the SS series or the Y2K or some other series?

racer7088

You can but different length pushrods very easily. Many heads are like this although usually inline valve ones use the same pushrod lengths on both valves.

You may have different length valves or something in those heads because the base circles should not be that different?

DAPSUPRSLO

iTrader: (14)

I assembled the heads and I know they are not different length. They are Manley valves. I would rather go ahead and do the shaft system right now and this is a perfect time considering i need the adjustability.

I bet the base circle on this cam is significantly different. I should have measured. The only way to get this kind of lift is to shrink the base circle so I am sure that is what they did (comp that is).

racer7088

What is the lobe lift or those two different lobes?

DAPSUPRSLO

iTrader: (14)

Just divide by 1.7 but as taken from the cam card it is .3830/.3610

racer7088

Well the lobe height can be different off of the edge of the cam bearing depending on the master used to grind it but if they are both the same then you only have .022 difference in how far down the lifters go. You can get .025 different pushrods.

DAPSUPRSLO

iTrader: (14)

I don't see how that would be given the fact that that is the total reduction in the lobe lift from the intake to exhaust valve. Are you saying that the base circle of the cam will be reduced exactly the same as the difference in lift? Also, wouldn't the difference be divided in 2 because we are only talking about one side of the total difference of the base circle. Please provide an explantion for the numbers you have posted for educational purposes.

Like I said, I know I could run different sized pushrods with a pushrod length checker but there will be no margin for error. With the shaft mount rockers I will be able to adjust for this error.

DAPSUPRSLO

iTrader: (14)

Anyone else have any input?

LASTLS1

iTrader: (7)

I think they were the mohawk or pro series shaft mount adj. I think they were around $1200.00 I can't remember.

DAPSUPRSLO

iTrader: (14)

That would make sense, I don't believe you have to do the modifications, except valve cover spacing, to run the SS series.

Blktie8

iTrader: (1)

It looks like a lot of Harlan Sharp users are about to jump ship or already have.
I would like the adj. Jesels or T&D but with the valve cover spacer do you have to relocate the coils to clear the alternator
It looks like the alternator would be in the way
Also need longer plug wires
Wonder how many have used Jesels and who have used the cc pro magnums.
The pro magnums would increase the lift a little 1.75 ratio
Thanks John

racer7088

The base circle is simply being reduced by double the amount of lobe lift difference you have if the lobe peaks are the same. Some times the cam grinders will use the same base circles though and vary the lobe peak or lobe nose heights. The lobe peaks or noses can only get so high as they have to be able to be put in the engine therefore the base circle must become smaller to get bigger lobe lifts.

An LS1 cam has a 2.166 or 55 mm journal so half of that is 1.083 and with say .370 lobe lift and the lobe say .013 away from the outer diameter of the bearing for clearance to go in the motor you would now have the roller riding at 1.083 - .013 - .370 = .700 or another wards riding .700 inch away from the cam center line or on a 1.400 base circle.

If you went to a .395 lobe you'd now be on a 1.083 - .013 - .395 = .675 or another wards riding .675 inch away from the cam center line or on a 1.350 base circle.

Now even though your base circle is .050 smaller the lifter really only goes .025 lower in the bore or only needs a .025 longer pushrod.

Hydraulic lifter preload is NOT that important and does not need to be exactly the same or anything between intake and exhaust or anything so don't worry so much about that!

Still if you have way more difference than that you probably have different valve heights too so run a straight edge over all the valve tips and see if they are the same. It's very easy.

Jason99T/A

iTrader: (21)

I agree with what Erik said above. You may have the same length valves from Manley, but inconsistencies in the valvejob can make the tip heights vary quite a bit. Some head porters will sink the exhaust valve more than the intake valve as well. The easiest thing to would be to lay a straight-edge over all the valve tips to check this. If they are varying quite a bit, send the heads to the machine shop to have the tips cut to the shortest one. On our high-end solid roller stuff, we equalize all the tip heights. This makes setting the valvetrain geometry and pushrod length much easier!

Jason

DAPSUPRSLO

iTrader: (14)

I did check the installed height and it didn't very more then .013" from best to worse. Thanks for the advise guys.

Unaffliated Racing

iTrader: (15)

If he had a stock style lifter the difference in base circle wouldn't be a problem..but it is since he has a pro magnum lifter...preload is very strict.