Swapping the Cam AGAIN- good thing! - S-10 Forum
 
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post #1 of 14 Old 07-06-2015, 08:56 AM Thread Starter
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Swapping the Cam AGAIN- good thing!

Hey Folks,
As many of you read, I just rebuilt my 2.8 in my 85. I put comp cam's cam, rockers, lifters and springs. Cam 16-232-4 and 1.6 rockers. It didn't have much bottom end so I decided to put in a crower cam, 0304. I pulled it apart yesterday, good thing I did.

Cylinder number 4, the push rod plate is slightly out of tolerance(too narrow of an opening for a push rod). The push rod had rubbed on one side and put a deep groove into it. With another few hours of running the push rod would have failed. This was my initial assumption.

After I got it apart I noticed that four of the push rods had been slightly deformed. The round ball end was shaped into a "tit" form. It had shaped itself into the opening of the lifter. Obviously it had way too much pressure on it.

The comp cam states .425"/.425" lift with 1.5 rockers. 1.6 would obviously be more. I am wondering if this cam and rockers is just a bad combo? I thought I was very careful with lash and did not have them too tight, but that is another possibility. I ordered a new set of push rods yesterday. I have already installed the new cam and hew lifters from crower. I am going to re-use the rockers. The new cam is .386"/.387" lift(IIRC) This should have a bit less strain on the push rods.

I'll post some pics in a bit of the push rods.

BTW - anyone who want to take a cam out of the 2.8l v6, plan on removing the radiator and the AC radiator looking thin, there is no way to get the cam out without doing it.


85 S10 Durango 2.8L extcab rwd 36k actual miles.
"true wisdom is knowing you know nothing" Paraphrased from Socrates
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post #2 of 14 Old 07-09-2015, 01:21 PM
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Re: Swapping the Cam AGAIN- good thing!

If you are going to run 1.6 rockers with a decent sized cam you will have to cut the pushrod guide plates deeper so you do not run into the side loading of the pushrod like you have experienced. Be careful not to widen the opening, just cut the plate deeper, as the width of the opening is what keeps your rockers aligned on the valve tip. Also what valve springs are you running?

I ran a 0.464/0.479 Crower in mine and with the proper springs with no chance of coil bind at a 1.7" installed height, and cut pushrod guides i had no issues with GM rods and that motor has been run hard for 60,000 kms

1986 S10 PU "SCLB" 2WD 355 TH400 3.73 8.8"
Dart 215 headed full roller 355, Full manual TH400, Killduff Lightning Rods, 150 shot of spray, homemade traction bars
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post #3 of 14 Old 07-09-2015, 04:00 PM
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Re: Swapping the Cam AGAIN- good thing!

Gears, Good to hear that you're still around. Haven't seen a post from you for a while.

Sorry for the jack Kricket

S10 addiction:
1)'82 S10, 383, 700R4, Shorty
2) '85 S10, 3.4, 700R4 4x4 stretch cab (Redneck)
3) '90 S10 2.5, 5 speed shorty
4) '91 S10, Built 3.4, 5 speed shorty (Voodoo)
5) '92 S10, 2.5, 5 speed shorty, (Barbie)
6) '92 S10, 2.5 5 speed, Shorty
7) 1979 LUV, Buick 3.8 V6, TH 350 Shorty.
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post #4 of 14 Old 07-09-2015, 07:09 PM Thread Starter
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Re: Swapping the Cam AGAIN- good thing!

Gears,
Thanks for chiming in. I am running the comp cam 980-12 springs.

I did change my cam to a milder lift and a great lobe separation. The advertised lift on my cam is .386/.387. It is crower cam number 0304.

Do you think I would need to do anything with the guide plates with this cam, those springs and 1.6 rockers?

85 S10 Durango 2.8L extcab rwd 36k actual miles.
"true wisdom is knowing you know nothing" Paraphrased from Socrates
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post #5 of 14 Old 07-11-2015, 10:57 PM
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Re: Swapping the Cam AGAIN- good thing!

From my experience anything with a larger then stock cam and 1.6 rockers needs the guide plates cut a bit on these motors. The only way to check is get a solid lifter and set it down there. Turn the motor over and see how close the pushrod gets to the end of the guide plate opening

MadMax yeah im still around haha. I havent done much with my S10 though as moving out and simply being 21 has taken up too much of the funds.. Shes sitting at work with no motor or trans and the box is off and interior gutted lol

1986 S10 PU "SCLB" 2WD 355 TH400 3.73 8.8"
Dart 215 headed full roller 355, Full manual TH400, Killduff Lightning Rods, 150 shot of spray, homemade traction bars
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post #6 of 14 Old 07-11-2015, 11:34 PM Thread Starter
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Re: Swapping the Cam AGAIN- good thing!

Hey Gears,
Thanks for chiming in. Here is some info that I have come up with my reading.
Stock cam gross lift is .395 intake and .410 for exhaust.
My cam is .386/.387 but that is with 1.5 rockers. With the 1.6 rockers it is more like .411/.413 - very close to the stock configuration.

Still think I need to do something with the guide plates? I would bet not, but I sure would appreciate you thoughts.

I got the truck all the way back together today. It sort of fired up on the first try. Ran, rough, coughed a bit, and died. I am going to mess with the timing a little tomorrow. It should be running within an hour of me starting on it. And if course another break in will be done.

More to come...........

85 S10 Durango 2.8L extcab rwd 36k actual miles.
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post #7 of 14 Old 07-12-2015, 01:38 PM Thread Starter
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Re: Swapping the Cam AGAIN- good thing!

I have the truck running now. It idles smooth, but is a bit touchy on the timing. It has a very narrow range for a sweet spot. Also, if it is at idle, it is touchy for acceleration. I am pretty sure the carb needs to be re-jetted to a slightly richer jet. Same with the idle fuel mixture. After it cools, I'll get back to it. Time for a break now.

85 S10 Durango 2.8L extcab rwd 36k actual miles.
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post #8 of 14 Old 07-15-2015, 04:48 PM Thread Starter
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Re: Swapping the Cam AGAIN- good thing!

I finally have the timing set correctly, the carb adjusted well, and all of the little things corrected. She runs AWESOME!!!!!!!!!!!!!!!!! That cower cam, 1.6 rockers, edelbrock intake, and the weber carb make a great combination.

Now the fun begins. I get to start thinking paint, interior mods, subwoofers, cb's etc.

till later
mark

85 S10 Durango 2.8L extcab rwd 36k actual miles.
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post #9 of 14 Old 07-16-2015, 09:04 AM
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Re: Swapping the Cam AGAIN- good thing!

Ha! If you ever feel like swapping to the 4bbl too it's pretty easy. Just swap the tops!



1984 xcab s-10 3.4L GM crate engine 91 S10 TBI swap w bored intake, Edelbrock headers. 2" Rough Country Lift. Custom exhaust, shift kit, e-fan.


EFI swap https://www.s10forum.com/forum/f106/...e-help-513616/

My build thread (3.4L)https://www.s10forum.com/forum/f106/...stions-427168/
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post #10 of 14 Old 07-16-2015, 11:59 AM Thread Starter
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Re: Swapping the Cam AGAIN- good thing!

I already have the top. I was considering it, but I didn't think there was a 4bbl that was small enough to work right on this motor. The smallest 4bbl I could find was the holley 390cfm.

Do you think the 4bbl would give more performance over the webber 38dges? I may just look for one and see if I can find it.

mark

85 S10 Durango 2.8L extcab rwd 36k actual miles.
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post #11 of 14 Old 07-16-2015, 04:01 PM
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Re: Swapping the Cam AGAIN- good thing!

See I don't know Mark...I never had the Weber. The 390 works well. That's what I used. Max seems to like the Weber better overall...Im just curious.



1984 xcab s-10 3.4L GM crate engine 91 S10 TBI swap w bored intake, Edelbrock headers. 2" Rough Country Lift. Custom exhaust, shift kit, e-fan.


EFI swap https://www.s10forum.com/forum/f106/...e-help-513616/

My build thread (3.4L)https://www.s10forum.com/forum/f106/...stions-427168/
Quote:
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I had to cut my nut in half .
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post #12 of 14 Old 07-17-2015, 10:09 AM Thread Starter
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Re: Swapping the Cam AGAIN- good thing!

I'll keep my eyes open for a holley. If I find a used one for cheap I may get it and see how it works. I looked on line, $466 for a new one is more than I am willing to "try" something. I see a used one on the bay(needs rebuilt) for about $125.

85 S10 Durango 2.8L extcab rwd 36k actual miles.
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post #13 of 14 Old 07-20-2015, 01:06 PM
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Re: Swapping the Cam AGAIN- good thing!

If the truck is automatic, you'll have to have some valve covers that don't have the cable mounts on them...or cut them off yours. If you are stick, no worries. Some of that cabling sucks by the way. Bracketry can be a PITA if you don't have the sucky kit that came with the intake. You might be better off fashioning your own.



1984 xcab s-10 3.4L GM crate engine 91 S10 TBI swap w bored intake, Edelbrock headers. 2" Rough Country Lift. Custom exhaust, shift kit, e-fan.


EFI swap https://www.s10forum.com/forum/f106/...e-help-513616/

My build thread (3.4L)https://www.s10forum.com/forum/f106/...stions-427168/
Quote:
Originally Posted by Racer_X View Post
I had to cut my nut in half .
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post #14 of 14 Old 07-23-2015, 08:43 PM Thread Starter
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Re: Swapping the Cam AGAIN- good thing!

I already had to modify the stock brackets to get the edelbrock intake to work. Until I get that dialed in perfectly, I am not even going to consider he 4bbl. Also, I just bought my second s10, so I am at least temporarily satiated.

85 S10 Durango 2.8L extcab rwd 36k actual miles.
"true wisdom is knowing you know nothing" Paraphrased from Socrates
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