Earthad58

So I've built many small blow Chevys over the years and this is my first olds, bout a beautiful 69 cutlass from a guy who restored it back to original. Engine was rebuilt in the 90's and has 60k on it. Engine ran good but not a powerhouse by any means, so I pulled it, cleaned and installed a new oil pan to replace bottomed out one, Installed hooker headers and a pypes exhaust system and a howards .275 dur .501 lift flat tappet cam and lifters. I had my engine builder go through the heads, perf 3 angle valve grind, new bronze mag valve guides, double springs and hardware for the new cam, he also machines guides to for posi lock valve guide seals on intakes and umbrellas on ex. He also honed each valve guide for a nice finish. I installed heads and re assembled the engine, went to fire for break in and couldn't get the car started, after awhile of messing around realized I wired the dist cap clockwise like a sbc, so got that taken care of and fire it up, revved to 2500 and after about 2 mins head a loud clacking so I shut it down. Refired and sound was gone so finished break in, drive the car maybe 5 miles that night then parked it, drove the car prob another 10 miles easy the next day when I noticed a tapping sound and idle got rougher yet, we'll I kept driving and it got louder and louder so I headed home thinking cam went flat, found #4 cyl back pushrod was bent pretty bad, so I've replaced it with a new one and I'm also replacing all the rockers and bridges which will be in tomorrow, before I try and put it back together any ideas why it bent? I checked all the other, they were straight, put a dial indicator on rocker with new pushrod and seems to be the same as another rocker so I believe cam is still okay ( pulled lifter to check and it all looks good). Why just one pushrod? I reused the pushrods that were in it, who knows if they were stock or cheap replacement I do t know, should I have shimmed rocker pedestals? I'm not used to non adjustable rockers.

Earthad58

Also the machinest took .003" off the heads to clean them up, I used felpro gaskets, and the machinest said that the valves were on their last grind, as they have already been ground a few times, if this has anything to do with with it. Also reading up other posts I did soak my lifters in oil over night but did not pump them up, just pulled em out, put moly on them and installed them. I'm really kicking myself for not having the machinest not install studs so I could use adj rockers, although I don't know if I can do that anyway due to the fact my car has ac and the ac brackets don't allow me to use any taller valve cover than stock.

Oldsmaniac

Was lifter preload checked? Most cam manufacturers suggest breaking engine in with only 1 valve spring to reduce chance of wiping out a lobe during breakin. I am thinking you possibly had a valve hung up in guide?

Earthad58

I did not check lifter preload, it did baffle me how the bolt on rockers worked with different cam profiles, milling etc but could not find really any useful information online as to checking that, basically have read that " bolt em on and tq em down" and " that's what hydraulic lifters are for is to adjust theselfs", sarcasm... But really I have yet to find any kind of specs. Also the weird thing is why just one pushrod?

Earthad58

You may be right on the guide, supposedly they were all individually sized and honed but who knows if the clearances were correct

Oldsmaniac

When heads are milled, cam changed, etc the just bolt em down goes out the window. There is a good bit of play in the lifters but preload must be checked and possibly different length pushrods will be needed or rocker bridges shimmed. If valves are not all the same heights you have varying differences.

Earthad58

I will definately check valve stem height today with a straight edge. How does one go about knowing what the lifter preload should be, and how to check lifter preload?

MDchanic

Did your machinist machine the valve seats so that all of the valve stems were the same height?
And was it the correct height?
Did you lay a straightedge across the valve stems to see that they were all the same?

Non-adjustable valves only work if the other parts are in the right places.

Welcome to ClassicOlds.

- Eric

Oldsmaniac

Ideally you only want enough preload to keep the rockers from tapping. Something like .025 would be what I would look for. With minimum preload as the rockers wear you will get a tapping so really you dont want to have the bare minimum. It is easier to check preload with intake off and lifters drained down. Since they are spring loaded you can bolt the rockers down when both valves are closed till you see the lifter plunger start to move down. The bolts will still be relatively loose and a feeler gage can be used under rocker arm bridge and head surface to measure gap. This is where you will see if pushrods are too long or too short and if shimming will do what you need or pushrods need replacement.

MDchanic

Lifter preload should be somewhere between about 0.020" and 0.050" (you will hear different numbers, and they are not critical - that's the point of hydraulic lifters).

You check them the same way you would on a Chev., more or less:
If you have a stock valvetrain, with 5/16-18 rocker bolts, you turn the engine to TDC compression of each cylinder, loosen up the rocker bridges on that cylinder, then tighten each with your fingers until the slack is just taken up, then see how far the screw will turn until it bottoms - it should go about half a turn (somewhere between ⅓ and ⅔ is great). If it bottoms before that, then you don't have enough preload (pushrod not long enough). If it bottoms much after ⅔, you've got too much preload (pushrod too long).

A bunch of fancy machine work is useless on an Olds if the machinist didn't set the valve stem heights correctly when it was all said and done.

- Eric

olds 307 and 403

Was it an exhaust valve by chance? This is very common, the center exhaust guides need more clearance due to the heat from the cross over, valves stick and bad things happen.

Earthad58

Thanks for the info guys, I got a lot to check today, I also ordered all new rockers and bridges which should be in this morning so I'd like to get those on as my machinest pointed out the pretty decent wear on the rocker valve face. Also as far as coil bind and guide to retainer clearance, how do I check this without removing the springs?

Earthad58

And yes I believe it was a exhaust valve in the center

Earthad58

If that's the case do you think I would need to remove the heads and have the guides resized/honed? Valve moves freely now.

Oldsmaniac

If it was the guide it may have been a one time thing/borderline issue and could have worn itself in so to speak. If it were me I would check everything I could and try again before pulling head(s). The dual valve springs may be a bit of overkill in your application and they put more stress/pressure on valve train parts.

Earthad58

That's my plan, I really done wanna pull the heads again, and the valve spring are a very light dual spring, I believe something like 85lb pressure

Earthad58

So after checking valve stem height on the pass side with a straight edge and feeler gauges the valve that bent the pushrod was almost .090" lower than the rest, and there was another exhaust valve that was around .050" lower than the intakes, no wonder why that pushrod bent, I has rockers tightened down on them the the valves closed and the real low valve the rocker would wiggle where the intake rocker next to it wouldnt really,maybe a slight wiggle, I snugged both bolts down by hand and then I got maybe 1/4 turn till it was tight, and the one next to it I got 1/2 turn

MDchanic

You need to talk to your machine shop.

As a person who has built a lot of "Brand C" engines, you can be excused for not having experience with non-adjustable valves, but it's your machine shop's job to know how to machine heads for engines with non-adjustable valvetrains, including not only Oldsmobile, but also contemporary Buick, Pontiac, and MoPar.

Also - are you sure that those two valves are actually closed?
If you give them a rap with a mallet, they should open and close smartly.

- Eric

Earthad58

I did speak with him, and he is a friend of mine and he felt awfully bad, completely forgot we were working with non adj setup, so he offered to make it right, but I believe at this point I'm just gonna order a adjustable kit and be done with it

Earthad58

He said he did remember one valve being shorter that the rest and he was gonna make sure he installed it in the deeper of the seats but spaced it

80 Rocket

I would verify that figure. Is it 85lbs on the seat? If so, you don't have enough spring pressure. When you say dual spring, do you mean a spring with a damper inside?

Something doesn't sound right here.

MDchanic

That should work, just be sure you have enough clearance under the valve covers.

- Eric

Earthad58

It's an actual dual spring, not the damper type, and that's what I was told it was a real light dual spring, he said it was like 85lbs of seat pressure, this motor wasn't meant to spin high rpms, my oiling system can't handle ot

Earthad58

I think I'm gonna order the mondello roller tip kit, it's $299, the comp cams kit I've been hearing comes with too short of pushrods

80 Rocket

That would be the same exact kit as the comp cams one, except marked up a bit by them. Also, pushrod length really needs to be measured to be sure......otherwise you end up with broken pushrods.

Also, about your spring pressure, while RPMs are a factor for spring pressure......the lobe intensity also plays a factor. Springs with 85lbs on the seat are only good for a stock type profile cam, which the cam you have is most certainly not a stock type lobe. I would most certainly verify what you have. I never heard of a dual spring with so little seat pressure.

About a stock oiling system. I ran my small block up to 6500rpms for 5 years. Completely stock bottom end. My cam was slightly smaller and less aggressive than yours, but I did have single springs with a damper that had about 110lbs on the seat and almost 270 open, I believe (it's been a few years now).

All in all, I would stay away from Mondello Performance Products if you can help it because of the very horrid reputation they have. I would buy the Comp Cams kit, but verify the correct pushrod length (the pushrods in the kit may work, you don't know until you measure). I would also find out what you have for a spring. You would need to verify installed height in the heads and also the spring pressure at that installed height.

Earthad58

We'll valve did smack the piston and bent it, so heads are off and headed to the shop, puttin all new valves in and were building our own adjustable rocker set for the problems to make things right which is pretty cool he's doing that, I called comp cams and they said their pushrod length was 8.5". I didn't know mondello was comp, that's why I was gonna go with him to make sure I got the right stuff but nvm, were gonna machine the heads for 3/8" studs and build out own

cutlassefi

Exactly. Shoot for 100-110 on the seat and 275 open.
And I offer a full roller rocker kit to your door for $270.00. Not roller tip, full roller, minus pushrods

Earthad58

Awesome, we'll I've got guide plates and 5/16" -3/8 studs just need rockers and pushrods

Earthad58

How much for just rockers?

olds 307 and 403

Well that sucks, can't put chebby specs in an Olds motor and expect it to live. The sticking valves have happened to a few. At least he is making it right, mention the extra clearance on the center exhaust guides, isn't it .0025"?

80 Rocket

This is a good price^^^^

Buy these and verify pushrod length and then buy pushrods.

Your valves that smacked the pistons were exhaust valves and that was because you had too tight of clearance. Olds 307 and 403 is close, I'd do .0025 on the outer exhaust and .0028 on the inner for the exhaust stem clearance.

Earthad58

Yeah he feels super bad, knowing him he won't sleep tonight, these things will be buffed to polished chrome in the morning lol, and honestly it wasn't that he really screwed up, the valve heights were actually correct, or very close to it other than the bent valve. When we took them apart too they seemed to fit very well in all the guides, he said he did give the center ones a little more clearance, were still not 100% sure why it happened other than maybe the bad rockers and stuff, so everything else seems to check out just he knew I was on a budget and salvaged my valves that were in it since they still had life left in them but he did a lot of work to try and salvage them so new valves and a adjustable valve train should have this thing singin in no time!

Earthad58

I may be jumping the gun here but I was gonna order pushrods tonight, mondello kit uses a 8.6" pushrod and the comp kit is a 8.5" so they say, I found a hardened set for a killer deal that is 8.550" and was thinking if go that route. Does anyone seem to think this will work or do I need to get a pushrod checker my the machinest and check them once I get my new rockers? I have the comp guide plates and the same stud both kits use.

80 Rocket

Hell, I don't know.......if your guides were done properly then maybe your lack of spring pressure caused you to loft a valve into the piston. All I know is that proper guide clearance does not cause stuck valves. With your combination, it is impossible for valves to touch the piston no matter what you did for decking, head gaskets, milling, etc. A bad rocker would not cause a valve to hit the piston.

Maybe I'll start a shitstorm again, so be it, but to me it sounds like your machinist buddy lacks experience with an Olds engine......and no offense, but so do you. The fact you think you can buy a pushrod set without measuring tells me that you.......and your machinist......are a little wet behind the ears when it comes to establishing proper rocker arm geometry.

The fact that your machinist friend said nothing of 85lbs on the seat says something as well. Could this be another case where someone is an absolute phenomenal machinist.....but not an engine builder?

If you don't find the exact cause of your problem, you are destined to repeat it. Please, please don't take this as me trying to be critical of you or your friend......I am only trying to help.

Earthad58

Why would you think it's not possible for the valve to hit the piston if stuck open at the top of the lobe? And yes I am learning Oldsmobiles, I knew nothing about them prior to buying this car so bear with me I'm trying to learn and use the knowledge I have of other engines to help me out here. As far as the pushrods go, mondello sells only one length pushrod for their small block olds, same with comp... So why is it such a big deal me asking about pushrod length? They did the research already I'm just basically copying one of their kits...I can respect constructive criticism just back it up, explain why

Earthad58

And to clarify, this engine was built as. Cruiser with a muscle car sound... It's got 2.56 rear end gears and is a #'s matching car, so it was not built with intentions of spinning high rpms or building max hp, just a good driver that sounds killer and runs well

67 Cutlass Freak

Do not buy any push rods yet. Purchase an adjustable push rod, so you can set up your valve train geometry correctly, than measure the adjustable push rod. Order a full set at the perfect length.
How did your machinist figure out that he set up the valve stems to the correct stock height? Does he have the Olds specific valve stem height gage tool?

Earthad58 you said - " I checked all the other, they were straight, put a dial indicator on rocker with new pushrod and seems to be the same as another rocker so I believe cam is still okay ( pulled lifter to check and it all looks good). Why just one pushrod?"

At what point in time did you realize that you had a bent valve? You said with the dial indicator the rockers all looked the same. How is your machinist measuring valve stem to guide clearance? You do realize most aftermaret valve stems are generally thinner than the stock OE type valves? Your machinist may have to install another set of guides. Did your machinist install guide liners, or full bronze guides? I just saw a set of heads on Sunday that they did inserts on and the metal around the sleeves was cracking and breaking off.
The other suggestion I have for you would be to purchase new stainless steel valves that are slightly taller than stock. This would open up your options for aftermarket spring choices. I sure hope you are replacing the springs as well.
You might want to spend some money on Bill Travato's book about building Oldsmobile Performance Engines, or Mondello's Technical Reference Manual. It's not uncommon for the Olds engine owner, to have to educate their machinist on what it takes to make an Olds live.

Hope it all works out for you.
Please keep us all poste, Dave - The Freak

67 Cutlass Freak

We must have been typing at the same time. Do not bank on Mondello doing the research for your engine. There's many different options for push rod length. FORGET ABOUT USING MONDELLO PERFORMANCE PRODUCTS.
They have the absolute worst reputation for customer service.

You should contact John at Rocket Racing, or Bernard Mondello. There's other vendors that could help you as well including Mark (CutlassEFI).

Don knows what he's taling abou. I now he's just trying to help you. I'm pretty sure everyone here wants to see your engine perform well and you not to spend too much more money.
Dave - The Freak

Earthad58

Yeah I didn't check the right thjng, I checked pushrod travel/lifter travel to make sure cam lobe was good not actual valve travel. I did talk to him today about the installed valve height, I told him I had the chassis service man and the spec Is supposed to be in there, he then pulled out a old book he had with it in there, we got to talking and he's built quite a few olds 455's over years, I've seen quite a few engines he's built that just plain work, I know everyone has their opinions but the fact is this guy knows his stuff, he may be a little rusty on olds stuff and I will talk to him more about the valve springs he chose and why, also he put in all new bronze guides, said they were the good stuff. I appreciate your guys patience and help, I have faith in him that he will get it right this time, he really does know his stuff. When I brought the heads back we removed springs and checked all valve installed heights and they were All within .005" of each other most were spot on other than the bent one, also the previous owner had two different shops do head work (valve jobs) on these abs did a shoddy job and me being on a right budget right now we made most of the stuff work, (my vales) which he did warn me this was the last go aroubd with these valves before needing replaced.

Earthad58

And yes he has this tool with a tube on one end and a dial indicator on the other that you slip over the valve and it bottoms in the spring seat and tell the height, that's what we used today