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I thought I changed this?
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Discussion Starter #1
Ok peeps, this one's got me scratching my head, so it's time to turn it over to the masses before I wind up spending serious amounts of $$$ on what could be a simple fix !!
302, 1970 block, with late 70's D80E heads (yes, i know they're rubbish!)

Now, I bought myself a new cam.
http://www.atlanticspeed.com/productcart/pc/viewPrd.asp?idproduct=6488&idcategory=169
I changed out all the timing gear, and valve springs, gave the valves a little precautionary grind, and re-assembled everything.

All went well, it started and ran fine, and I've managed to get it set up properly, and it's idling a treat !

Here's the rub tho.
There was an awful lot of valve clatter.
When I took the valve covers off, some of the rockers (pedestal mount) are so loose they can be shaken about. No way I can even get them near the pushrods, never mind set the lash correctly.
I ordered 0.060 oversized pushrods, which seems to have solved the problem on one head, a couple are a little long, but that could be sorted by shims.
however, half the rockers on the other are still way loose. I reckon I'd need another 3mm in length at least.


Now, I, and my friends are mystified why some of them, and on only one head, would be so far out.
After all, all I've really replaced is the cam, nothing else has changed.
Could it be a deck height issue ?
Could I have installed something incorrectly ? (visual inspection suggests not)
Could it be that the head gaskets were really so much different that the head would sit much higher ??

I did wonder if removing the head and having it skimmed (milled?) would drop it by enough to bring it close (perhaps the other has already been done, that's why it's ok)

Yes, I could order custom pushrods, but I can't figure why it's so far out. I expected to have to change the rods, but not by that much ! This isn't a situation I've heard of, and a Google search isn't exactly bringing up an influx of people with similar problems.

I have a couple of spare heads with push in studs which I was going to have modified to run screw in studs and roller rockers, but that's an expensive fix !!

Any ideas ?:bloated:
Anything I could or should check first ?
Thanks in advance.
 

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Sounds like the best thing is going to be the other heads to use adjustable valve train. The new cam may have a slightly smaller base circle (often happens with higher lift and duration). Another thing is changing rocker positions, the previous owner may have run into that as well and had the pedistal milled. Or it could just be a matter of the reduced base circle. The factory rockers were rarely uniform, same with the pedistals. They were designed to create a little bit of preload when fully bolted, this is why I am thinking reduced base circle. Avoid high revs until you get it fixed or you will be buying yet another cam and lifter set.
 

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I thought I changed this?
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Discussion Starter #3
Thanks, base circle or deck height seem to be the only plausible explanations at the moment.
I think the p.o may have built the motor from bits he had lying around, so it's very possible he's messed about with things. I was careful to refit everything in the same place, but if the base circle's different, then that wouldn't matter.

The only other thing I could think of was maybe a lifter issue, if the lifter pistons were jammed or something, but although I could see one or two failing, I can't see 4 or 5 ! Especially brand new ones !
Might pull the lifters out and have a look before i start pulling it to bits again.

I'm not really running it, it ran to break in the cam, and it was on the first idle I noticed the valve noise, so I'm hopeful it should be ok, it won't be run at all now until I get something sorted.

Cheers,
Bob

Sounds like the best thing is going to be the other heads to use adjustable valve train. The new cam may have a slightly smaller base circle (often happens with higher lift and duration). Another thing is changing rocker positions, the previous owner may have run into that as well and had the pedistal milled. Or it could just be a matter of the reduced base circle. The factory rockers were rarely uniform, same with the pedistals. They were designed to create a little bit of preload when fully bolted, this is why I am thinking reduced base circle. Avoid high revs until you get it fixed or you will be buying yet another cam and lifter set.
 

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see if you can purchase or borrow an adjustable pushrod for checking length needed when ordering custom pushrods.
Map the tolerances and see if it increases front to rear or rear to front or has any pattern whatsoever. It could be a head out of spec when cast that you never noticed before because of the crapulent but forgiving stock stuff, or could be the deck, or could be the base circle as mentioned.

Knowing is half the battle. Gather data to know.
 

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Yes sirs, couldn't agree more. Me thinkst your PR are a weee bit short! To many unknowns to risk it. Get the adjustable PR I think you will be days ahead. Lacking that a dial indicator with a magnetic base and some careful calculations could save the day. I doubt you really would have to invest much - just the time to figure out how long and where. Sounds like you have a stash of shims around - that's rare! There is another recent thread on here with a guy having the same issue - pretty much the same thoughts though. Good luck Bob! Let us know how it goes. - OH, and watch that you don't have spring bind - especially if you have to shim any.
 

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I thought I changed this?
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Discussion Starter #6
Ok, had another good look at it today, when I tried the oversized rods, it was just a quick fiddle, because time was against me, I just stuck 'em in, and was gonna check the lash properly later.

Pretty much every single rocker is loose, and they all require new pushrods, and, although I'm guessing, and not scientifically measuring, almost every single rod would require to be of different length.

So, I'm not going to take any chances with it.
I've managed to source a pair of spare heads, for a good price, so rather than messing about with what's on, I'm going to convert them to screw in studs, and run with guideplates and roller rockers.

I'll also have the heads skimmed a little to bring the c/r up a touch.

It's not going to be cheap, but at least I'll know it's right !!!

Sucks that I've got to take it all apart again, but with the benefit of hindsight, I should've just done that in the first place !! :ego:

I guess the lesson I learned was not to mess about with what was actually a really sweetly running 302 !!!!
 

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Did you prime the lifters before start up? I have seen dry lifters collasp and stay stuck down. I now prime the oil system with a pump sprayer connected to the oil sender after installing parts suck as hydralic lifters. I would pull the intake and look at the preload on the lifters before popping your heads off.
 

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I thought I changed this?
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Discussion Starter #9 (Edited)
The casting numbers on the block decode correctly as being a 302, I can't remember them off the top of my head, but it was a 1970 block, most likely Torino.
**EDITED** found em.

D10E-6015-aa. OM2E.

From what I can see, the 351's pushrods are around an inch longer, that would be just too much.


I can only presume that someone has messed about with stuff to make it fit, and I don't want to take any more chances. It's already costing much more, and taking much longer than expected.
In all honesty, If I'd known beforehand it was non adjustable rockers, I'd have left well enough alone !!

Slightest of possibilities it's a 351W and not a 302 block? Higher deck height ~ longer pushrods needed. Don't recall if the intake ports and bolt holes for a 351W would match up to 302 heads. Ran a quick yahoo query, and found this: http://answers.yahoo.com/question/index?qid=20080711220805AAEmBgo.
I didn't prime the lifters, Comp advise against it.
From their website.

"It is not necessary to “pre-pump” hydraulic lifters full of engine oil prior to installation and valve
adjustment. It is actually undesirable to do so as the “pumped up” lifters will cause the valves to open during the adjustment process, rather than positioning the lifter plunger in its operating position as it is supposed to do. “Pre-soaking” hydraulic lifters in a bath of engine oil is a good
idea but not mandatory.
"

I soaked them in fresh oil for 24 hours before installation.

If I remove the pushrods and look down with a torch, I can see that everything looks in order down there, but I will definitely have an inspection before I remove the heads again.

That said, i've already ordered the rockers and stuff, so by hook or by crook it's getting done !!!

Did you prime the lifters before start up? I have seen dry lifters collasp and stay stuck down. I now prime the oil system with a pump sprayer connected to the oil sender after installing parts suck as hydralic lifters. I would pull the intake and look at the preload on the lifters before popping your heads off.
 

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^^Atta boy! Like the go get it attitude. Screw in studs will make your life much easier. Good ol' 20/20 hindsight will get you everytime!
 

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I thought I changed this?
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Discussion Starter #12
In Scotland we say "buy it cheap, buy it twice".

My grandpa used to say things like "I can't afford to do things the cheap way" and I never knew what he meant until years later.
 

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I thought I changed this?
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Discussion Starter #13
One more question !! :wave:

The other heads arrived today, actually, for the price, they're not bad. Got some new valves in them, and look like they've already had a litte fettling.

Managed to remove all the press in studs today, after a little patience and cussing !
Actually, with the exception of the two which sheared off, it was a little scary how easy they came out ! :uhoh:

Spoke to my machine shop too, so everything's ready to rock.

Before I send them off to the shop, I just want to double check that I still need to have the stud mount bosses milled by 0.230".
Seems the holes are pretty much the right size to be threaded for the 7/16" studs. Can anyone clarify if this is, in fact the case ?
I did find information online, but this referred to having the pedestal mount bosses re-engineered, not studs.

Cheers,
Bob
:beer:
 

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Well done! You did two things right. #1 you read the instructions and #2 you did not fill the lifters with oil. That is a bozo no - no but some people don't know how to read the directions.


The casting numbers on the block decode correctly as being a 302, I can't remember them off the top of my head, but it was a 1970 block, most likely Torino.
**EDITED** found em.

D10E-6015-aa. OM2E.

From what I can see, the 351's pushrods are around an inch longer, that would be just too much.


I can only presume that someone has messed about with stuff to make it fit, and I don't want to take any more chances. It's already costing much more, and taking much longer than expected.
In all honesty, If I'd known beforehand it was non adjustable rockers, I'd have left well enough alone !!



I didn't prime the lifters, Comp advise against it.
From their website.

"It is not necessary to “pre-pump” hydraulic lifters full of engine oil prior to installation and valve
adjustment. It is actually undesirable to do so as the “pumped up” lifters will cause the valves to open during the adjustment process, rather than positioning the lifter plunger in its operating position as it is supposed to do. “Pre-soaking” hydraulic lifters in a bath of engine oil is a good
idea but not mandatory.
"

I soaked them in fresh oil for 24 hours before installation.

If I remove the pushrods and look down with a torch, I can see that everything looks in order down there, but I will definitely have an inspection before I remove the heads again.

That said, i've already ordered the rockers and stuff, so by hook or by crook it's getting done !!!
 
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