XE 268H cam
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Joined: Jun 2003
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From: New Fairfield CT
XE 268H cam
Got everything put back together last night after the no oil pressure fiasco. Yesterday`s post. Thank you to all that responded! The new issue is my idle. I have a comp xe268 in the new 350. I can not get this cam to idle at a usable rpm for my 400 Auto trans(750 rpm). This is a 9.5 compression engine with 2.02 heads.
I`ve read all the current and archived posts. What I was thinking of doing, if I can`t get it right tonight was to install a set of variable duration lifters. Years ago I installed a set of the Crane VBL on a 75 350 camaro rebuild, that I installled a high duration cam (350/350) chevy cam in and I still drive that camaro every summer. Has anybody out there every installed a set of Roades VDL on a Comp 268? How did it preform? Man I can`t seem to get this engine any road time!
I`ve read all the current and archived posts. What I was thinking of doing, if I can`t get it right tonight was to install a set of variable duration lifters. Years ago I installed a set of the Crane VBL on a 75 350 camaro rebuild, that I installled a high duration cam (350/350) chevy cam in and I still drive that camaro every summer. Has anybody out there every installed a set of Roades VDL on a Comp 268? How did it preform? Man I can`t seem to get this engine any road time!
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Joined: Sep 2004
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by 71stockray
Got everything put back together last night after the no oil pressure fiasco. Yesterday`s post. Thank you to all that responded! The new issue is my idle. I have a comp xe268 in the new 350. I can not get this cam to idle at a usable rpm for my 400 Auto trans(750 rpm). This is a 9.5 compression engine with 2.02 heads.
I`ve read all the current and archived posts. What I was thinking of doing, if I can`t get it right tonight was to install a set of variable duration lifters. Years ago I installed a set of the Crane VBL on a 75 350 camaro rebuild, that I installled a high duration cam (350/350) chevy cam in and I still drive that camaro every summer. Has anybody out there every installed a set of Roades VDL on a Comp 268? How did it preform? Man I can`t seem to get this engine any road time!
I`ve read all the current and archived posts. What I was thinking of doing, if I can`t get it right tonight was to install a set of variable duration lifters. Years ago I installed a set of the Crane VBL on a 75 350 camaro rebuild, that I installled a high duration cam (350/350) chevy cam in and I still drive that camaro every summer. Has anybody out there every installed a set of Roades VDL on a Comp 268? How did it preform? Man I can`t seem to get this engine any road time!
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Joined: Jun 2003
Posts: 143
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From: New Fairfield CT
Stock stall speed converter. I used this cam because Comp assured me it whould work fine with my stock converter. If I thought this was going to be a problem, I whould have changed the converter whene the engine was out, which was 2 weeks ago!
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by 71stockray
Stock stall speed converter. I used this cam because Comp assured me it whould work fine with my stock converter. If I thought this was going to be a problem, I whould have changed the converter whene the engine was out, which was 2 weeks ago!
what is your stall speed? put your foot on the brake and give it gas when it wants to jump out of its own way note the rpm....on my engine/700r4 swap it was at like 1400-1500 rpm.....my idle in park was about 500 rpm higher then when it was in gear....my 2500 stall speed converter which incidentally was recommended by every reputable person i asked fixed the problem....and yes i did have to go back and do this portion of it over again and it did cost $$$
i'm using a 4 bolt main, final CR of 9.25 :1, fuelie heads, xe268h, performer, headers, speed demon, true 2 1/2" duals
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From: At my Bar drinking and wrenching in Lafayette Colorado
71 -
I have the same cam in my car, and I've tuned dozens of Vettes with the XE268 on the Tuning Tours. The cam is not that big, and it has a pretty smooth idle to it - just a slight lope. It runs just fine in auto cars with a stock converter - no problem. It will idle fine at 700 rpm. I don't think you need a converter - your problem is someplace else.
Recommend you check and verify your initial timing versus total timing: Your initial should be in the 18-24 range. If you're running vacuum advance, you need a very light vacuum advance control unit (like a VC1862 if you have HEI or a VC1810 for a points-type distributor) and you need to run it off a manifold vacuum port. If all this checks out, you might want to check your carb setup and mixtures: you should be running a tad richer than stock for your setup.
The Rhoades lifters will only Band-Aid your tuning problem. That cam isn't big enough to warrant bleeding off any lift or duration.
Lars
I have the same cam in my car, and I've tuned dozens of Vettes with the XE268 on the Tuning Tours. The cam is not that big, and it has a pretty smooth idle to it - just a slight lope. It runs just fine in auto cars with a stock converter - no problem. It will idle fine at 700 rpm. I don't think you need a converter - your problem is someplace else.
Recommend you check and verify your initial timing versus total timing: Your initial should be in the 18-24 range. If you're running vacuum advance, you need a very light vacuum advance control unit (like a VC1862 if you have HEI or a VC1810 for a points-type distributor) and you need to run it off a manifold vacuum port. If all this checks out, you might want to check your carb setup and mixtures: you should be running a tad richer than stock for your setup.
The Rhoades lifters will only Band-Aid your tuning problem. That cam isn't big enough to warrant bleeding off any lift or duration.
Lars
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by lars
71 -
I have the same cam in my car, and I've tuned dozens of Vettes with the XE268 on the Tuning Tours. The cam is not that big, and it has a pretty smooth idle to it - just a slight lope. It runs just fine in auto cars with a stock converter - no problem. It will idle fine at 700 rpm. I don't think you need a converter - your problem is someplace else.
Lars
I have the same cam in my car, and I've tuned dozens of Vettes with the XE268 on the Tuning Tours. The cam is not that big, and it has a pretty smooth idle to it - just a slight lope. It runs just fine in auto cars with a stock converter - no problem. It will idle fine at 700 rpm. I don't think you need a converter - your problem is someplace else.
Lars
hey thats great news for you from Lars ....i guess i had different issues going on that pushed me into a higher stall speed converter....
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From: New Fairfield CT
xe268 cont.
OK Picked up a new RPM meter last night. Checked idle speed last night, here`s what I got, Vaccum holding at steady 15 at idle of 725. Shift in gear on the TH 400 and drops to 450 and engine starts to stumble. Can this be caused by another reason other than a bad torque converter? Everthing else seems OK. this TQ worked fine on the old engine.
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Tech Contributor
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From: At my Bar drinking and wrenching in Lafayette Colorado
Torque converter has nothing to do with it. I think you have a timing issue. You need to be running at least 18 degrees initial timing with 36 total. If you're runing vacuum advance, you should be running manifiold vacuum, but you MUST use a very soft vacuum advance unit (see part numbers in my previous post) that pulls its full advance range in at less than 8 inches of vacuum. If not, you have to run ported vacuum in order to keep the timing from retarding when you put it in drive: If you are running manifold vacuum on a stock-type vacuum advance unit, you will have lots of vacuum advance when you're in neutral, but the timing will retard 16 to 20 degrees when you put it in drive. This will cause the problem you're having.
Last edited by lars; May 26, 2005 at 09:38 AM.
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From: At my Bar drinking and wrenching in Lafayette Colorado
71 -
Do you know what vac advance unit you have? What code is stamped into it? I can tell you for sure if this is the problem or not if you post me the code.
But switching to ported vacuum will identify and cure the issue if this is what we're looking at. When you swap over to the ported vacuum source, first verify that there is no vacuum signal provided at idle. Then, with the vacuum adcvance hooked up to ported vacuum, you will need to re-set your idle speed and idle mixtures for the new timing setting. Once done, drop it in drive and see if the rpm drop is in the acceptable range. I think you'll see a bit of a difference in the way the rpm behaves...
Lars
Do you know what vac advance unit you have? What code is stamped into it? I can tell you for sure if this is the problem or not if you post me the code.
But switching to ported vacuum will identify and cure the issue if this is what we're looking at. When you swap over to the ported vacuum source, first verify that there is no vacuum signal provided at idle. Then, with the vacuum adcvance hooked up to ported vacuum, you will need to re-set your idle speed and idle mixtures for the new timing setting. Once done, drop it in drive and see if the rpm drop is in the acceptable range. I think you'll see a bit of a difference in the way the rpm behaves...
Lars
Last edited by lars; May 26, 2005 at 11:13 AM.
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From: New Fairfield CT
I will try this tonight. Can not wait to get this new engine out of the garage and out on the road for Memorial weekend. Vette season has allready started in the neck of the woods. I will also check the # on the advance unit.
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by lars
.....If you're running vacuum advance, you need a very light vacuum advance control unit (like a VC1862 if you have HEI or a VC1810 for a points-type distributor) and you need to run it off a manifold vacuum port.
Lars
Lars
well good news for me my local NAPA parts store finally has the VC1862 in its warehouse and i will pick it up tomorrow...the price is $16.89 it will replace that Proform adjustable unit i have ....i have been delaying getting the unit since the shipping charges cost more then the actual unit and the parts store recommended to try the "hunt and peck" method with them until the ware house got restocked....so now i have a weekend project also....
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by bobs77vet
well good news for me my local NAPA parts store finally has the VC1862 in its warehouse and i will pick it up tomorrow...the price is $16.89 it will replace that Proform adjustable unit i have ....i have been delaying getting the unit since the shipping charges cost more then the actual unit and the parts store recommended to try the "hunt and peck" method with them until the ware house got restocked....so now i have a weekend project also....
well thinking about my install of the new vacuum canister...any reason i can't do this with the distributor in place? thks bob
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by Nate 76x
It's easy to replace the can with the hei in place. There are just 2 screws and a slot for the advance lever.
sounds like a plan!!!!
Melting Slicks
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From: Sodertalje/Sweden
Originally Posted by lars
, but you MUST use a very soft vacuum advance unit (see part numbers in my previous post) that pulls its full advance range in at less than 8 inches of vacuum. .
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by Corz
listen to lars 
thats about the only advice I can give
thats about the only advice I can giveyup....good advice to go by if your are tinkering on the vette
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From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by BB wowbagger
How much does the MSD Dist require in vacuum to pull in full advance?
Lars