Lt1 top end overhaul

[JOATMON]

I recently completed a top end overhaul on my Camaro and thought I would share the build up through a series of photos and comments. There were many setback aggravations but it's nearly complete. Perhaps what I learned may help others in the future.
Nolan

[myltwon]

That's awesome can't wait to see pics

[JOATMON]

The engine build was a comedy of errors from the get go. The previous owner knew what he wanted but was paying folks to work on it. This is a 385" stroker(.040 over), all forged bottom end,AFR 210 heads, comp xfi292 cam and other assorted goodies. When I bought it the valvetrain sounded bad, it stunk bad at idle and sometimes smoked a bit ot of the tailpipes. But at WOT it was a beast. I played around with it for awhile and figured out some of the random misfire issues and got it running better but it had more issues.

[JOATMON]

The misfire issues were caused by his mechanic putting stock LT1 spark plugs in the AFR heads and also a couple of bad plug wires that sometimes fired and sometimes not. I had run into the spark plug issue once before on a different engine. Stock heads use a tapered seat spark plug, AFR heads use a gasketed seat spark plug. I put a set of gasketed seat plugs in along with a set of wires I custom built to go over the valve covers. Ran alot better but it still stunk and smoked some times. I was actually losing compression from the plugs leaking because the tapered seat plugs were tightened against a flat seat.

[JOATMON]

I finally decided that the engine seemed to run like it had an internal vacuum leak and made plans to pull the intake and investigate. While I was at it I planned to check out the valve train noise as well.

[JOATMON]

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[JOATMON]

Yep, It was what I thought. The rear four ports (5-7 and 6-8) were leaking internally. Ports were very oily. The 5-7 reminded me of another issue I discovered while doing the plugs and wires. By chance I happened to notice that the #5 and #7 fuel injector plugs were hooked up reversed. It actually ran like this, LOL.

[JOATMON]

The heads on this engine are AFR 1057's. AFR says DO NOT use GM LT4 intake gaskets, they will leak. Use AFR 6860 with a little bit of silicone sealant on the port bottoms. Guess what was installed on it? I think all the ports leaked slightly but the rear four were the worst because the engine slants back and the oil drainback really flooded the rear four ports.

[JOATMON]

The more I looked the more I found. The rocker arms were running all over the valve spring retainers. At this point I started looking closer at the valve spring setup and discovered several valve guides on both banks that appeared to be worn badly. I could push on the springs and make the valves move side to side in the guides. Well hell, its time to pull the heads to have them freshened up.3820938210
The clay was a good way to check clearances that are hard to see.
These are Crane Gold rockers.

[JOATMON]

The heads were a real pain in the ass to pull. I got some help after I had cut myself all up trying to get to all the hardware and bolts. Finally out;38211

[JOATMON]

Take notice of the rear cylinder combustion chambers. Oil build up= heavy deposits.

[JOATMON]

In addition to being the wrong intake gaskets, they didn't have any sealant at all, they were installed dry. The upper intake was oil fouled too from a PCV valve that was sucking oil. The PCV system was not set up correctly neither. The hose that normally would run between the valve cover and the throttle body was gone and they were running a breather on the valve cover. This setup was allowing un-metered air flow into the throttle body.(The stock setup is using airflow that has been measured by the MAF sensor)

[JOATMON]

I bought new valve guides and new valve springs. The valve springs that were on it were way too stiff for a hydraulic roller. Brought the heads to a friend to do the guides and valve job and got a disturbing call a couple of weeks later. He had a problem pressing the guides out of one head, the valve guide bosses cracked on a bunch of the guides. It looked as though it might be okay with some grinding done on the cracked area, but one boss broke so badly that there was only about 3/4" of material supporting the guide. The guides came out of the other head with no cracking issues. We decided to buy one new bare head. He took responsibility for the damage, he didn't charge me anything for all of the work and he gave me $400 cash towards the cost of a new bare head. Good Man in my book. Had to wait near two months for the new head(custom order).

[JOATMON]

Broken head, new head382123821338214
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[JOATMON]

It appears that the factory presses in the valve guides, then does the CNC port work. The guide bosses and the bottom of the guides are cut down pencil shaped, so I can see where they could easily break when replacing guides.

[JOATMON]

I don't have a pic of the piston tops but they were extremely caked with carbon from all the oil burning. It was a big chore to clean them and I got sick from breathing all the brake cleaner and B12 Chemtool I used to clean them. After I got feeling better a few weeks later, I used a respirator to finish the cleaning.
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[JOATMON]

I'm not sure why my photos came up as an attachment in post #14???
Now on to the valve train. I don't have a photo but I found the lifter spider had several bent fingers. I'm extremely lucky that the dogbones didn't come off the lifters. After doing some research and some measuring to verify, it appears that when you get above approx. .350 lobe lift you are gambling with the dogbone and spider setup. The flats on the lifters that locate the dogbone come very close to hitting at max lift and very close to dropping out of the dogbones on the base circle of the cam. Howards and maybe others make replacement lifters that have a longer flat area to help with this, but I opted to buy tie-bar lifters. 38217

[JOATMON]

Here's where I mocked up the valves with check springs to figure out proper pushrod length. It gets much deeper as I gained my PHD in rocker arm geometry so I'll stop here and continue later.38218

[fullforce]

Wow, very nice build...or RE build!

[JOATMON]

I ain't gonna lie, the rocker arm setup confused the hell out of me. I was attempting to get the rockers up and off the valve spring retainers. After inspecting the Crane Gold rockers there didn't appear to be anything wrong with them. I got it in my head that because the AFR heads use plus .100" valves that I simply needed a longer push rod to get the rockers up. The reason for longer valves is to provide space for a taller spring to allow a real high lift cam, for anyone wondering why. I've done other small block Chevys with stock type heads and valve lengths and never had any issues with rocker clearance or alignment. These heads in addition to the longer valves also have the port locations somewhat changed and the valve layout is spread out to allow bigger valves.(2.08/1.60)

[JOATMON]

When I mocked the rockers up I couldn't get them off the retainers. the clearance was too tight when the valves were closed. It finally dawned on me that the spring and retainer package was designed to use lash caps. the lash caps got the rocker up higher but not by much. If you look at the photo in post #18 you can see the line I drew across the rocker arm centerline. I was trying a mid lift technique to determine proper push rod length. With the valve exactly at the middle of its lift it appeared I needed a ~7.40" pushrod. But keep in mind that measuring for pushrod length in this fashion will produce different numbers with different rocker arms and will not necessarily have the roller tip centered on the valve tip. In my case the roller was way too far out on the valve tip. I compromised with a 7.30" to get the roller tip centered. 7.20" is the stock length.

[JOATMON]

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This was my initial pattern with the Crane rockers, my simple old faithful spring compressor. Pattern is a bit difficult to see using a dry erase marker, I later tried using lipstick and found it to be the ultimate pattern marker. I would like to claim I thought of this first, but I'm sure someone did it before me. LOL

[JOATMON]

I actually put the rest of the valvetrain together using the Crane rockers. The rocker alignment was a compromise on being centered left to right even with adjustable guide plates. (the original build had fixed guide plates!) It's a real pain to do rocker/guide plate alignment with a mirror and a flashlight. Earlier I mentioned the other paths of oil migration into the combustion chambers, well another path on these heads is through the intake rocker studs. You HAVE TO put sealant on the intake rocker studs because they are drilled all the way into the intake ports. Vacuum will literally suck oil through the stud threads from the top of the heads.
Well after running the engine, the valve train still sounded horrible. Then I discovered a problem I hadn't noticed, AFR had not ground out the casting flash on one exhaust pushrod slot. It must have been missed on QC check. I missed the bad alignment because of the difficulty of working with a mirror. I wound up having to pull the intake again and VERY VERY carefully grind out the casting flash without getting any in the engine.

[JOATMON]

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[JOATMON]

I decided that I needed a different style of rocker because I still had a bare minimum clearance as far as rocker to retainer clearance and in the pushrod slot to pushrod area. I got it in my head that a set of long arm Crower rockers would cure all my clearance problems. This was considering that AFR claims you can run straight rockers on these heads. So I called and talked to the Crower folks and they agreed with the long valves and lash caps, the center to center measurement at the top of the stud to the top of the valve tip was so much closer that a backset rocker was just what I needed.

[JOATMON]

Well I put it together again figuring the Crowers were gonna be the ticket. I had to drop down to a 7.2" pushrod to get a decent center pattern on the valve tips. I tons of clearance between the rockers and retainers, but the push rod to head slot was very close(about .015" using a piece of wire as a feeler gauge). I ran it again and the valvetrain noise was unacceptable. It seems the pushrods were just slapping the heads further down in the pushrod slot.

[JOATMON]

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Notice how close the clearance is on the pushrod

[Camaro96]

Nice build thread. Seeing more and more flawes in there castings that have left the factory. The difficult part is that they make the best set of heads for the LT1.

Sent from my Moto Z (2) using Tapatalk

[Injuneer]

Do you think an offset lifter would clean up the pushrod geometry?

[JOATMON]

Offset rockers coming up, it's fixed now. I like to do photos to help people. But I've had too many beers to continue tonight. I've read alot of your posts and appreciate your troubleshooting skill. I was just checking in to see if I was just talking to myself. Stay tuned.
Nolan

[JOATMON]

The Crower rockers are high quality heavy duty units but simply would not work on my intake valves. The exhaust rockers worked out perfect. It was a $636 mistake on my part. There are SBC applications that these will work on but not on mine. I kept believing what AFR says in their footnotes. This is a copy/paste;

ROCKER ARMS: The Air Flow Research 180, 195, 210 & 220
aluminum heads are designed to use standard pushrod location
rocker arms (offset rockers are not required). Clearance between
rocker arms and the retainers should be checked. For high RPM
stability, the Jessel or T & D shaft systems are recommended. AFR
stocks a complete line of standard and shaft rocker arms for your
convenience. AFR suggest for the 227 & 235 you use a shaft mount
rocker and offset lifters or a .050” offset intake rockers. With the
.050” offset the intake rocker arms will be at a slight angle and the
roller tip will not be perfectly parallel or centered on the valve tip. The
245cc only accepts a shaft mount rocker system with an .180” offset
intake lifter required.

When I finally realized that my old eyes were not tricking me and the footnotes were hogwash, the road to success was just ahead.

[JOATMON]

After I did more research in various rocker arm catalogs, I noticed that Scorpion offered .100" offset rockers specifically for AFR heads but they didn't address the plus .100" valve length and I'm running a .080" lash cap.
Harland Sharp had a set originally designed for the old Canfield 220 heads with plus .100" length valves. The featured .150" offset intakes and a roller tip relocated .030" back to compensate for the longer valves. I did some ballpark measuring and found ~.130" difference between the stud center to centers and the valve center to centers.
I called Harland Sharp and talked to a fine gentleman and discussed my problem. He sent me both .100 and .150" offset to do some test fitting.

[JOATMON]

I ordered a custom set from Harland Sharp. All 1.6 ratio, all roller tips relocated .030" back, 8 straight exhaust rockers, 4 left and 4 right offset at .100".
It took some grinding on all the guideplates to achieve proper tip alignment.3823138232

[JOATMON]

After a bunch of tedious fitting, especially having to use a mirror to do the rear most cylinders. Also ordered a set of heavy wall 120* tip pushrods. 3823538236Final result;
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[JOATMON]

I forgot to mention the Harland Sharp rockers are designed to provide a generous amount of clearance between the rocker and the springs and retainers.
Hat off to Randy Jr. at Harland Sharp, this wasn't his first rodeo with providing custom built rockers that work.

[JOATMON]

oops double post

[JOATMON]

In between waiting for parts I had to address some maintenance and clean up items. Replaced the leaky water pump(put a new Summit pump on a clean housing I had), MSD distributor(had MSD rebuild it just to know it was all good), rebuilt the alternator myself. Replaced the worn out motor mounts. Ordered a set of 42lb. injectors(up from 30lb), had the PCM tuned for the bigger injectors. New valve covers which I addressed in another thread. Also replaced the power steering pump and hoses. Damned rebuilt pump failed on start-up had to replace it again. Not long after I got it running, I had a no start situation and found the coil had failed, had to replace it too.

[JOATMON]

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[JOATMON]

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[JOATMON]

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[JOATMON]

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[JOATMON]

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[JOATMON]

Well folks I guess I'm gonna have to hold up on this thread until the forum admin can figure out why my photos are disappearing. I posted them, saw them and now they are gone replaced by an attachment script that does not link. I'm having trouble using the "reply to thread" button. It keeps dropping down to the quick reply box. On the few occasions that it worked I was able to get to the manage attachment screen which should allow me to upload more than one photo at a time, but it won't work. So from the quick reply box I can only click on the photo attachment icon and load oneeeee photooooo atttttt aaaaaa timeeeeee, its such a slow process its aggravating, then after that agonizing process a bunch of my photos have disappeared. Weird that some are still there, they were all uploaded the same exact way.
Nolan

[Injuneer]

meissen

[fullforce]

When I first opened the post earlier the pics popped up and then dissapiered... it was very strange
That you for sharing

[meissen]

Well folks I guess I'm gonna have to hold up on this thread until the forum admin can figure out why my photos are disappearing. I posted them, saw them and now they are gone replaced by an attachment script that does not link. I'm having trouble using the "reply to thread" button. It keeps dropping down to the quick reply box. On the few occasions that it worked I was able to get to the manage attachment screen which should allow me to upload more than one photo at a time, but it won't work. So from the quick reply box I can only click on the photo attachment icon and load oneeeee photooooo atttttt aaaaaa timeeeeee, its such a slow process its aggravating, then after that agonizing process a bunch of my photos have disappeared. Weird that some are still there, they were all uploaded the same exact way.
Nolan

Which browser are you using? Try clearing your cache and seeing if that makes it better? Otherwise when you click Reply and it takes you down to the Quick Reply box, click "Go Advanced" and you'll have the full reply functionality including the Attachment Manager to upload multiple images at once.

Posting a test image to see if it "sticks"
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[JOATMON]

Hey, I use regular old google chrome. I'm anal about clearing my history which should clear my cache. I clear it every time I finish using the browser and sometimes I clear it between websites. Just now when I clicked "reply to thread" which should bring up the screen with a title block, it just jumps me to the quick reply section. I'm also having problems with the time out period when I take too long to type a post. I have to log out and back in and click the auto save to retrieve my typing. Sometimes it's all there and sometimes just a portion of what I typed is there. Is there anyway you can make the photo links work. Are all those photos lost in cyberspace? They were all uploaded direct from my computer. Thanks for help, Nolan