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-   -   Xe268 wiped lobes (http://www.hotrodders.com/forum/xe268-wiped-lobes-214952.html)

1969chevyss 02-18-2012 10:41 PM

Xe268 wiped lobes
 
Hey guys I have a 355 short block with a xe268h cam stuffed in her. I have a set of vortec heads that I will get new springs to accomodate the extra lift. My question however is this, are there any other good lifters besides the ones that comp cam recommend(812-16) that will help me prevent the chances of my cam going flat. I have been doing a lot of reading and this seems to be a reaccuring problem with this grind. My next question is for my vortec heads, what sprints can I use that will drop right in without any machine work. I read that z28 springs from northern for 525 lift will work, just would like to get you guys opinion on the matter. Thanks in advance.

F-BIRD'88 02-18-2012 11:31 PM

Quote:

Originally Posted by 1969chevyss
Hey guys I have a 355 short block with a xe268h cam stuffed in her. I have a set of vortec heads that I will get new springs to accomodate the extra lift. My question however is this, are there any other good lifters besides the ones that comp cam recommend(812-16) that will help me prevent the chances of my cam going flat. I have been doing a lot of reading and this seems to be a reaccuring problem with this grind. My next question is for my vortec heads, what sprints can I use that will drop right in without any machine work. I read that z28 springs from northern for 525 lift will work, just would like to get you guys opinion on the matter. Thanks in advance.

the springs are not the lift limit issue. The valve guide boss to retainer clearance, is the issue for more than stock valve lift.

many of the `Z/28`style stock diamete4r replacement hi perf springs will fit the vortec spring pockets if you remove the inner damper.

But you still have to deal with the retainer to guide boss clearance.

GM LS motor Z06 springs and comp 787 retainers can be used.
again verify retainer to boss clearance.

ComP cams extreme failures. Use high quality GM hyd lifters.
Use a oil additive high in Zinc and moly dysulfide
Zddp and or Moly slip and or GM EOS.
Order a custom grind comp cam version of the XE268 Say on a 108LSA instead of 110.... much better cam grind and finish quality when done in house.
( you`ll probabily make a bit more power too. )
Buy a Isky Mega cam instead. I find them much better quality.
( you`ll probabily make a bit more power too. )

Isky cams are made in house. I find the Isky stuff high quality and the flat tappet stuff lives.

Comp sells way more of these XE268H-10 cams than they can make inhouse. Who knows who is doing their high production contract work.

The GM Heavy duty `taxi `hyd lifter with the special alloy face is the best production SBC hyd flat tappet yu can buy.

Aparentl;y back in production I don;t have a current GM part number for you.

I have a comp XE284H-10 cam in my car and so far no issues. Proper break in procedures and zinc-moly oil aditives are a big help. My cam was made in house for me, at Comp.

Comp offers a extra cost cam lobe hardening treatment `Nitriding`that is said to offer better flat tappet cam endurance and run in.

Call them.
www.molyslip.com

1969chevyss 02-18-2012 11:43 PM

How much is it to have a custom grind done?

F-BIRD'88 02-18-2012 11:50 PM

Quote:

Originally Posted by 1969chevyss
How much is it to have a custom grind done?

According to Comp only slightly more than a off the shelf cam.

Special orders ( custom grinds ) don`t upset them`.

They custom gind cams every day, there.
Call them for tech advice.

1969chevyss 02-18-2012 11:56 PM

Thanks for the reply, I will definitely give them a call Monday and see if they recommend the custom grind. I will go and price the z06 springs and comp 787 retainers.

327NUT 02-19-2012 12:33 AM

As F-Bird says, if you listen to guys that don't do any research they will rawdog Comp Cams all day long. In reality when Johnson and a couple other lifter mfg's quit making lifters for a while a chit load of cheap crappy Chinese lifters came across that were made of inferior material....hence wiped out lifters and accompanying cam lobes. Johnson is back in business but if F-Bird says use the GM lifters then use them, he is a man that knows of what he speaks.

You can also do a search function on this forum..."cam break in" or something of that nature and you'll get all kinds of info. Most very good and then some not very good.

F-BIRD'88 02-19-2012 12:43 AM

You can ask Comp cams tech about the `Johnson lifters.

I believe its either Johnson or Stanadyne that make the GM HD lifters with the hard alloy face. Comp probabily sells them too.
You just have to ask.

Thats what the tech line is for.
I`ve found them very help full.

I used the common speed pro HT-817 hyd lifters on this cam.
No problems.

I don`t have big problems with cams.

I like this stuff
www.molyslip.com

1969chevyss 02-19-2012 11:03 AM

From what I've been reading, Johnson makes alot of people lifters, trick is to find out which ones. I found a guy name Mike Jones from Jones cams and they sell Johnson lifters. I think even the Speed pro are made by them too, but I will do some calling around and find out for sure. I went on Summit and found these GM Performance lifters for a 350 sbc part number 12371044. Not sure if these are the ones that you were referring to as the GM Heavy duty or not.

DENCOUCH 02-19-2012 11:25 AM

I am running an Isky Mega cam & I like it a great deal.. great street manners.
Vortec heads w/ the z28 outer springs... verify clearances tho.

fBird88 recommended the set-up. Fun when the TH350 grabs second & the tires break loose (note: NOT chirp!).

Me like!

Studebaker 02-19-2012 12:57 PM

Comp Cams
 
Compcams flat tappet hydraulic failure rate is unacceptable. They know there is a problem and their answer is to keep their fingers crossed and hope for the best. I really like the Compcams grinds but I would not use anything from Comp again. When a cam fails, this requires a complete teardown. Will Comp stand behind the product. Hit and miss. If they know the XE series has high fail rates, why woudn't they nitride all cams in this series. It's simple, it's about customer service and doing the right thing, not excuses. How many out there are using Comp xe series cams? Did your cam fail?

CNC BLOCKS NE 02-19-2012 01:47 PM

When ordering a flat tappet cam always order a P-55 cam core and use only GM lifters with the steel bottom and use a good oil.

I use a lot of flat tappet cams in my circle track engines never been an issue in 38 years.

I use CENPECO 20/50 oil which has 2300 PPM of zinc.

stich626 02-19-2012 01:49 PM

Quote:

Originally Posted by Studebaker
Compcams flat tappet hydraulic failure rate is unacceptable. They know there is a problem and their answer is to keep their fingers crossed and hope for the best. I really like the Compcams grinds but I would not use anything from Comp again. When a cam fails, this requires a complete teardown. Will Comp stand behind the product. Hit and miss. If they know the XE series has high fail rates, why woudn't they nitride all cams in this series. It's simple, it's about customer service and doing the right thing, not excuses. How many out there are using Comp xe series cams? Did your cam fail?

comp,cams failures are caused by lack of correct oil, and the fact that they have a problem with a line of fakes, being sold as comps.
We've never had a camp.s go flat, but we use the correct oil, liter springs for break in, and buy directly from comp. bypassing the chance of being sold a fake(counterfit) . that a major speed shop is halking.

techinspector1 02-19-2012 01:51 PM

Geez, what is it with you knuckleheads and these extreme grind cams?????:spank:
Have you not heard and read enough horror stories yet?????:spank:

stich626 02-19-2012 01:56 PM

Quote:

Originally Posted by techinspector1
Geez, what is it with you knuckleheads and these extreme grind cams?????:spank:
Have you not heard and read enough horror stories yet?????:spank:

I've been using rollers for the last few years, flat tappets are not woth it anymore

LATECH 02-19-2012 02:03 PM

1 Attachment(s)
Quote:

Originally Posted by techinspector1
Geez, what is it with you knuckleheads and these extreme grind cams?????:spank:
Have you not heard and read enough horror stories yet?????:spank:

I have NOW. LOL, I have been leaning toward the crower 60918, or lunatis 60901lk. I think the crower is a tad rowdier, but not much.
It will be for a 400 pontiac (389 block @4.120) zero deck,82 CC heads , if anyone GAS. :thumbup:


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