Sad but true, the Cam was off enough to have Valves and Pistons meet in a rather unjoyous occasion!:cry
Well, it's off to Paragon to order new pushrods, and over to the local shop to have a five angle valve job and maybe a couple of valves (they don't look bent, but might as well do the whole nine yards...)
So sorry to hear about the "untimely"meeting of the valves and pistons. I haven't been on in a couple of weeks or I would have added my two cents. I had the same problem when I bought my 62 last year. Went crazy trying to find the problem until I pulled the front timing cover and discovered I could touch the timing chains together. Being in a rush to enjoy the new toy, I only did the top end. To make a long story short, a word of advice, if you're not sure of the miles on the motor, and judging by the condition of the timing chain, I would certainly think about dropping the pan and looking at the bottom end while you're waiting for the valve job or any other parts. I ended up having to locate another 327. I could have saved myself many hours of doing the top end twice if I had done it right the first time and checked everything out from the start, especially not knowing anything about the miles on the motor when I bought it. Good Luck, use fender covers, A Fellow 62 Owner
I actually did look at the bottom end already. The oil was clean (no metal of any kind) and the rods were tight. The motor was burning pretty clean until our unfortunate demise so I feel pretty good about the rest....
The advice is good regarding the fender covers. I use extremely soft packing blankets (they are much larger and easier to wash) but were removed in most photos to show more of the car and less blue rags!:
Thanks for the advice, I'm sure we'll be swapping stories again!
As long as you've done you're homework on the cylinders and crank with regards to the bearings and journals, you should be good to go. I also used to do quite a bit of wrench turning in my younger days, it's amazing what you can forget when you're in a rush to get back to the good old solid axle days. I made so many stupid mistakes doing mine it's not even funny now, six months later!:cry Nobody ever said going fast was cheap.
I'll check back to see how you're making out.:crazy
I've been down this road before with my 61 283 2x4 (carters), duel points. I diagnosed the problem as fuel system after much frustration. I removed the fuel lines and then rand the engine by manual gravity feed pouring fuel into a funnel with a hose running to the "Y" that splits into the duel carbs. Once it ran great that way and knowing I had a new fuel pump and the fuel lines were clear of obstruction back to the tank, I traced it back the the inside tank pickup where I found serious sludge and obstruction in the line and end sock. GOOD LUCK
Well, after much cussing and such, it looks like the crank gear is mismarked!!!!
With the marks aligned as discussed (see previous posts) the intake valves hit the top of the piston and bend the push rods. Didn't have this problem before replacing the timing set.
Comp Cams verifies I have the correct set.
The crank gear does have the A 0 R keyways and I do have it on the 0 keyway currently. You can't put the Cam gear on wrong, and the Crank gear only has timing marks on one side...
I've done about 15 engine rebuild over the years and this is my first time with timing problems!ad
Any advice for me?
I would like to avoid degreeing the cam (standard alignment should have been fine) and I really don't like foolin with the balancer (since I have an untapped crank) but I am sure this is my problem.
Especially since it is obvious that the valves are opening way early (exhaust valves opens near the middle of the power stroke and the intakes are full open at TDC during the Exhaust/Intake transition stroke. I would tend to believe that we set the crank gear to the Advance keyway...
You should see that carb spit up gas like a baby on bad formula!
1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
I assume that you backed off the valve adjustments so the cam would turn freely when you installed the gears. How did you readjust the valves? I don't recall you stating if the cam was solid or hyd.
Back off all the valves so they aren't opening and set one cylinder only for checking purposes. If solid lifters, set them loose, about .030. If hyd set them at 0 plus 1/4 turn. This will make sure that they aren't too tight. Make sure that you adjust them on the base of the cam lobe, fully closed. Then turn the engine again by hand and check for valves hitting. Don't force it. I hope you don't have any bent valves from before or Donna will get to pull the heads. You will want to do a compression check after you get the timing problem solved to look for any cylinder with very low or 0 compression, bent valves.
If they still hit,I know that you don't want to hear this, but I don't see any other choice other than to pull the front cover off again and verify the timing marks. You're right that the cam run in the engine before so too much lift can't be the problem. If you still have the old gears compare the mark locations with the new ones. Or get a set from the Chevy dealer to compare and return them later.
The problem should show it's ugly head after these checks. If you have to pull the front cover again check the cam for brand markings. Might get lucky. If that 340 hp short block still has the original cam it will be the 097 Duntov. Valve clearances are .012 intake and .018 exhaust. With the condition of the removed timing set it could be that you have the original cam in the block. Doesn't sound like it has ever been rebuilt before.
So, we have properly set the clearance at 1/4 past slight friction on the bottom of the lobes (no sweat) and yes they do hit.
So pulled the heads (Donna loved that 65 ftlbs of torque!) and sure enough, the lifters are coming up with the pistons.
Now, you know that the valves are suppossed to lift a little early to account for good gas scavenging and swirl mixture and all that, BUT, these guys are way early.
Last time I had the cam gear off, there were no end markings on the cam. The lifters are HYD and still have a nice convex surface with no appearant wear. Obvious aftermarket replacement.
The pistons look like the original hightops (Maybe 10:1?) and the cylinders still have obvious crosshatch. Since the car WAS running the plugs nice and tan with no oil usage, I believe it is in good shape, though I am still suprised by the chain slack.
I agree with you that the lift is not the problem. I have new stock pushrods and they are the same as the old ones.
The pistons do have a tiny nick in them where they made contact. I know that stress of smacking valves can put in unseen stress cracks, so I am carefully evaluating them. I have seen piston explode at 6000 rpm from this sort of thing.
However, the valves aren't bent at all, so my guess is the stock pushrods were weak enough to really absorb the damage and thus the pistons are probably fine.
Okay, tonight we'll finish disassembly and give another update tomorrow.
Rick & Donna:
I've never had my hands on a 327/340 ... but I think that might not matter here. It seems that maybe this car's original cam may've been solid ... but now it has hyd lifters? Also, it may appear motor's never been built. BUT... Could it be there is now a non-original, aggressive cam in her ... one that might very well need to be degreed-in? Maybe old TG set was installed NOT @ zero ... maybe it was indexed well enough with the old floppy TG set ... but not with new set. Also, could it be the lifters have not bled off sufficiently prior to setting preload ... maybe they're gummy inside? What do you think ... you too Tom? BTW, you guys have the patience of Job!
1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
It's obviously had a cam change. But to what? 327/340 used the Duntov 097 solid lifter cam. The cam would have had to be retarded :Silly significantly to avoid the intake valves hitting. That doesn't sound right. It sounds like the engine is fairly fresh except for the timing set. :confused Also sounds like the right pistons for the 340. They are the same as FI short blocks. Should have plenty of valve relief for a fairly agressive profile. It might be our old friend the 327/350 hp hyd cam.
Since you have the heads off and you will be taking the front cover off again have you considered pulling the cam out and checking for GM casting numbers? How did the engine sound before? Mild lope, smooth, choppy lope? Maybe we will learn something during the teardown.
BTW It is easy for me to have patience with this project. It isn't my car! :L :L :L
Thanks you guys for the ongoing help! It actually makes it a lot easier to be patient when you can have diatribe with others....:TALK :TALK
So far we have not seen any marks on the end of the cam. I will be pulling the cam Thursday Night (too much work at the day job to get home in time for wrenching):cry
1. The lifters are bled down and not gummed up...
2. The pistons do have large valve reliefs (only the intakes are tapping the pistons)...
3. The motor had no lump to the idle. It did run like a raped ape before, but idle was smooth...
4. Heads have not been milled...
5. Block has not been decked...
6. With the heads off, it is obvious that the lifters are rising too early..
So, We continue our journey into the macabe:eek
I will update on Thursday night.
BTW Tom, I bought the GM Casting Book and the Corvette Vin Book.!!! Great Purchase!
I have a Holley 3310-4 from a 66 425HP 396 Chevelle
and the intake is from 65-67 Camaro/Chevelle iron 4bbl holley setup.
As you know the heads are LT1. So maybe the previous owner was putting in an interesting cam??? But again, It seems to be a mild grind... Very streetable
:L :L GREAT!!! Tom, you're so darn right ... and I'm just as sure your humor does help R&D through their trials.
This thread is a PERFECT example of how CAC helps me too ... I find R&D's problem very interesting (maybe entertaining in a gearhead psyche). As I try to think through R&D's problem, I not only reaffirm my own limited knowledge, but it also opens the synapses to new thoughts & possibilities too. I'm a firm believer in "two sets of eyes are better'n one."
I anxiously await to hear what R&D find/do ... same goes for GWTILL's big block ('81?) swap!
Since I am going to be down n the motor so ddep, I might as well entertain the replacement of the cam and lifters.
Obviously, I will mike the old one and see if the wear is acceptable and if it is an interesting cam, I might keep it. However, more ponies is not a bad thang!:cool
We're open to suggestions.
BTW I will be keeping that Holley 3310-4 and Intake for now, as the FI unit is gonna hit me for about $8K!!!
So a little lump is okay with the 4-speed as there are no vacumm accessories or stall convetors to deal with. The biggest problem is still the 210 degree water temp....
LASTLY, Rob, if you're out there...
The guys bring up a great point regarding the usefulness of this thread. I have several digital pics that I would like to add to the thread that probably would be useful (to show folks following the thread in the future,) documenting the issues. Is it okay to add some kbytes to your server? If so, how can we do this?