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Valves hitting the pistons?

 
88MonteClone
I love my Chevy Chevette!
Posts: 8
Joined: 03/12
Posted: 03/11/12 06:15 PM

Hello everyone, new guy here looking for help with a small dilemma. Ok here is my set up in detail. 350 sbc 4 bolt main,bored .30 over everything is brand new... Scat 3.480 - 9000 crank, 5.7 Scat forged rods, forged Probe -4cc pistons with two valve reliefs, Melling HV oil pump and pick up, Moroso wind-age tray, 7qt Moroso oil pan, Lunati (60103)Hydraulic flat tappet 504/525 lift cam, Lunati true double roller timing chain, Lunati hydraulic lifters, Proform one piece hardened push rods, Brodix IK200 aluminum heads, 2.02 intake/1.60 exhaust valves, Lunati 630' lift springs, full roller rockers 1.5 self aligning.... 10:5 compression.... Hopefully that's all you need to help me out, Ive been seeing a lot of people say they don't give enough info LOL. Problem is when put at 0 valve lash and clayed to check the clearance, my intake doesn't hit the piston but my exhaust valve is JUST hitting it, not by much but it is definitely not enough clearance, I did not use solid lifters when clay testing could this have thrown off my readings? The timing chain is lined up dot to dot for standard timing. Should i just grind down the exhaust valve relief in the piston a couple thousandths? Any tip tricks etc would help a new comer out, thanks guys  
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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 03/11/12 09:34 PM

88MonteClone welcome:

NO DON'T GRIND ANYTHING DOWN, UNLESS WHEN YOU FIRE YOUR ENGINE IT WILL BE IN PIECES VERY QUICKLY.DON'T GO ANY FURTHER.................

The  valves come the closest to the piston in the OVERLAP CYCLE. Thats when both valves are open and off their seats at the same time. Isky Cams Years ago refered to this as the fifth cycle. In this OVERLAP CYCLE the piston is chasing the exhaust valve. You know that as it did touch! you can only imagine how fast this happens when the piston is going a 100 plus MPH trying to hit the valves. Confused  

So listen up and I will get you out racing and have fun. I will get you thru this but there is NO easy way out now. If your engine is assembled you will have to take it apart, to Fly-cut the pistons........

If you are in a Mock-Up assembly your in better shape....But the pistons will still need to be FLY-CUT...There is no way around this......How much we have to figure out...With steel rods you will want .060 on the intake valves and .080 on the exhaust valves for valve to piston clearance.

To determine how much you need to FLYCUT your pistons you need to assemble one side only. First you need to install two light valve springs. NOTE: You can remove the outer valve spring and use the inner most spring and reassemble the two valves. Install and use the #1 piston as you were putting the engine together for final assembly. Put modeling clay approx 1/2" thick across the vavle reliefs, Install your head gasket. Install your head you NOTE: don't need to torque the head bolts down just use the bolts around the #1 cylinder but make sure they are snug. Install two solid lifters, install the push rods install,the rocker arms and adjust for zero lash.
Rotate the engine slowly in a Clock Wise direction making two complete turns...

Remove the head very slowly and then check your depth of the clay. Make note of the depth and then you want .060 on the intake valve and .080 on the exhaust valve. Let us know what that figure is and we will help you determine the FLYCUT you need. Confused

Guess what you left out information also....LOL... Confused

1.What are you running for quench area.
2.What type head gasket and ist thickness.
3.How tight is your deck. Are you running a .020 .030 deck. That all gets determined for the valve to piston clearances.
4.You didn't mention if your assembly was balanced. It will need to be rechecked again.5.Did you deck the block?

The build sounds nice but I have a question. The Lunati Cam number you gave us 60103 specs, out at .489/.504 .227/.233. You have it as .504/.525. and no duration.
Let us know what the correct part/number is on the Cam.  Confused  Shocked  

One more thing that is very important I don't know why you have so much Valve Spring Pressure but you will need to break that New Cam in with very light Valve Springs,or you may rub the Cam Lobes of before you even get started. Cool All this is do to the lack of ZDDP inour engine oils.

I know there is a lot of information but if you follow it, and if you don't understand some of it let me know. You have a lot of money in your build and I don't want to see you bend the valves or worse break a valve and blow the engine up. Or rub a lobe off the cam. Follow Lunati's directions for Cam Break in and you will be OK.............. This is serious when your to this state of your engine assembly. Confused

Thanks, Bob  

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88MonteClone
I love my Chevy Chevette!
Posts: 8
Joined: 03/12
Posted: 03/12/12 10:32 AM

Bob, thanks for taking the time to answer my problem here.I am running 93... The cam is a Lunati 60104, not the 60103 sorry bout that. My head gasket is a triple layered steel gasket 4.060 in bore  and .040 compressed. My block has never been decked. Yes my full assembly is balnced... How do you know i am running a lot of valve spring pressure? I ordered a couple solid lifters and a degree wheel to see if the problem is still there after i check with those, to tear down and rebuild the engine again would be nothing but a pain do to the fact that i have put it together 3 diferent times thanks to wrong pistons then I had to tear it down again to put ARP studs in the main for the windage tray instead of bolts.... but if I have to it would be better safe than sorry LOL I will repost in about 2 days with the progress. If I have to they all will be removed and taken to machine shop for some fly-cut... thanks for your help, Bob!  
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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 03/12/12 01:48 PM

88MonteClone

Believe this when I tell you if you are building a Hi-Revving Chevy Small Block, and you will be twisting the engine over 6,400rpm and above you can expect to do a Mock-Up maybe three times.Without supplier problems. Then the forth or fifth time your ready to button it up for final assembly.

Now one more thing if you are going to degree your cam DON'T FLYCUT THE PISTONS YET. the pistons will get closer to the valves.
Sometime when you degree the cam you move the timing sequence of the valves and piston events. In other words if your cam is off a couple degrees your Valve to Piston clearance will close up and get even tighter. While you are waitng for the the Degree wheel JUST FOR HA-HA's advance your cam 2*degrees at the crank. Then assy the head the way you would to check your V/P clearance. Then look to see what the overlap cycle did to the valve timing event. Confused  Shocked

Good the assy is balanced you can buzz your small block and not worry about it shaking itself apart! Confused
Good on your M/L head gasket..040 you will add to your deck clearance,and V/P clearance.
It wouldn't hurt to put a straight edge across the deck of the block. Start at the top and slowly move it down and if you see any space between the straight edge and the block slide a thickness gauge between the two. If you have .002 or less thats OK. I'll get back to you in a few about the valve springs I have something I need to do! Grin  Cool

If you want your small block to live if you have to put it together 3 more times to get all the clearances correct so beit! Remember when your out running the FREAKIN LITTLE rice burners You can say I built my engine I didn't have it built. That a lot of guys can't say. They say it but they know the truth! It's a good feeling to know that it was your build. Just take your time and don't rush it!

Thanks Bob  

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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 03/12/12 02:54 PM

88MonteClone:

Your valve springs will be OK to use. You need to follow Lunati's Cam Break In Procedure and follow it to the T. You don't want to rub alobe off the cam. What has happened to engine oils as the ZDDP has been taken out of it. The ZDDP is the addative that was added to engine oils to help with the high valve spring loads of Hi-Performance cams. It was taken out because the new catalytic convertors can't handle the blow-by and it harms the cats. If you had a roller cam you wouldn't be concerned. Thats why all new engines today have roller cams installed. The only oil that has some ZDDP left in it is a 15/40 weight Diesel engine oil....I actually run that in my 86 Monte SS when I do the oil changes.
So as we said in the day Keep on Keepin ON.........I'll get you thru this just stay with me. Then you'll need to tune the engine..... Grin  Cool

Then we will have to make sure that your valve train geometry is correct! Confused

Bob  

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88MonteClone
I love my Chevy Chevette!
Posts: 8
Joined: 03/12
Posted: 03/13/12 05:51 PM

I am gonna buy some of the lunati add. for my break in oil, what oil would you recommend I run after the break in, i was thinkng 5w 30 or 10w30....royal purple but of course. The guys over at Lunati couldnt help with the problem either, told me to buy new pistons that will fit... I bought some low tension springs and tried applying the clay method again and it ended up the same low clearance reading, i was thinking possibly shorter push rods? Im currently using the stock 7.8 5/16 length one piece chrome moly hardened push rods.... The Deck is nice and level all within .01, Just gonna have to wait and degree the cam? Advanced it 2 degrees and still didnt clear...If the degree on the cam is good what steps would we take out of curiousity, thanks again for all the help, for the hell of it i have made a list of the whole motor top to bottom, me not stating enough info kinda inspired me Cool

65' Small block chevy 350
Bored and honed .030 (355cubes)
4 Main bolt
New Scat 9000 3.480 balanced crank
New forged 5.7 Scat rods with Arp bolts
-4 cc/2 Valve relif forged probe balnced pistons floating wrist pins
Arp main studs
10:5:1(ish) compression ratio
Moroso windage tray
Melling high volume oil pump and pick up
Arp oil pump stud
7 Qt Moroso oil pan
Lunat Voodoo Cam 504/525
Proform hardened chrome moly push rods
Proform full 1.5 roller rockers self aligning
Brodix IK200 Alluminum heads
Triple steel .040 head gaskets
2.02 intake 1.6o exhaust stainless steel valves
64 cc cumbustion chamber
Comp cams rocker arm studs
200 cc intake runners
Lunati 630 lift valve springs keepers and retainers
ARP Head bolts
Lunati true double roller timing chain
Weiand dual plane gaped air intake manifold
ARP manifold bolts
Holley 770 Aluminum Ultra Street Avenger Double Pumper
MSD 8.5 wires
MSD Pro Billet Distributer
Champion Spark plugs
Tall aluminum fabricated valve covers
Electric water pump
Proform wire loooms
High torque starter
Proform timing chain cover
Proform harmonic balancer
Every bolt pan to carb is ARP
Should make about 455HP and 450 Lb's torque

For the car so far...
Rear
7.5 GM rear eaton posi unit
Richmond 3:73 gears
BMR boxed lowers
BMR double adjustable uppers
2" MBR solid sway bar
Hotchkis 1" lowering springs
70/30 Lakwood drag shocks
Proform 10 bolt diff. cover
Stock driveshaft with Lakewood performance U-Joints
Stainless steel Brake lines/Braided

Front
All polyurethane bushings
1 1/4" sway bar
Lakewood 90/10 drag shocks
Moog coil short springs heavy duty
Belltech 2:drop spindles
Quck ratio 12:1 stearing box
New idle arm/pitman arm/center link/ inner and outer tie rods with adjusting sleeves/ new upper and lower ball joints / summit calibers and drilled and slotted rotors/ all stainless steel braided brake lines

all i can think of as of now LOL keep on keepin on, Bob  
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88MonteClone
I love my Chevy Chevette!
Posts: 8
Joined: 03/12
Posted: 03/13/12 07:58 PM

After doing a few hours of research on the Lunati Voodoo cams like most of their other cams they are ground 4 in advance right on the cam, if I were to retard it 4 would it then put it into standard timing?  
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pepsi1
Big Block power for the win
Posts: 940
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Posted: 03/13/12 10:37 PM

All the cam makers do that because the cam under load retards itself. Also it done by the cam manufacturer so they can get their lobe centers.... When you get your degree wheel you'll see what I mean. But if you advance the cam as I explained earlier the Valve to Piston clearance will get closer. If you want to listen to what someone else is going to tell you then Please let me know,as I don't really have time to explain myself to him. Or debate what he has to say.  You have a valve to piston clearance problem and it is a problem that comes from doing engine building at this level. If you did a Mock-Up you would have found that early on,now because the engine is assembled you are pissed I understand that OK. Grin  Cool  

Ok that being said don't be You have a nice 88 Monte Carlo SS.You've totally rebuilt it. When we get your engine package all together and tuned up your going to have a nice ride. You put a lot of money and time into it. Thats why I want you to make sure that your engine has the correct clearances so after you break it in and start spinning it will stay strong each time you run it through the gears. The only thing down the road is a step-up with a Currie 9" Ford rear with 31 or 33 spline.

Bob  

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88MonteClone
I love my Chevy Chevette!
Posts: 8
Joined: 03/12
Posted: 03/14/12 08:34 AM

Degree wheel will be in today sometime and I will let you know how everything turns out with it... I think retarding 4 will put it at standard timing and give me the clearance I need to assemble to full engine, the degree wheel tells all! Will post later tonight...  
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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 03/14/12 01:17 PM

OK but be carefull as to what your doing. You can try advancing or retarding the cam, but you will also loose the perforamnce of the cam. You can retard the cam 4* to 6* you will pick up some clearance but maybe a couple thousands.  You can replace the cam if you don't want to flycut the pistons....Good Luck! Grin  Cool

Bob  

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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 03/14/12 01:36 PM

Try these two sites....Valve to Piston clearance is the traugh the piston has to give you that Valve to piston clearance.Good Luck...........

www.centuryperformance.com/checking-and-settingpiston...

www.fordmuscle.com/fundamentals/pistontovalve  Look at the pictures then you'll see why it's such a critical clearance..............  

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88MonteClone
I love my Chevy Chevette!
Posts: 8
Joined: 03/12
Posted: 03/14/12 05:31 PM

So I went with a 4 degree retard and it clears the pistons at .90 at exhaust and 80 for the intake.... the cam was ground at 4 advance when at strd. timing, so when it was dot to dot it wasn't at standard it was technically at advanced 4, so I retarded 4 and it put it truly at standard timing!So the clearance was fine, just had to balance the advancement in the cam by retarding the timing! All is well now and the build will be completely together by Friday night, will post pictures! Thanks for all the help Bob  
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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 03/14/12 06:27 PM

88Monteclone Your welcome.

Did you order the cam that way or did you purchase it from a circle tracker. Usually their the ones that do that with cams. But anyway I'm sure you mean .100ex. and .080in. clearances. It's really a nice ride you have.

Like I said we have a 1986 Monte Carlo with 55,000 original miles on it. We are the original owners. My oldest son has a 1986 MC also. We built a 350 for about 12 years ago. He did put a 9" Ford rear in it with 3:90 rear gears. We knew the 7.75" rear would not hold up to what he was punishing it with. He still has it.
He has run it and it runs 11:22 118MPH.1/4 mile. Grin  Cool

I think the earlier Monte SS's had 3:73 gears. After that they went to a 3:42 Rear gear. A young guy I met who actually became part of our family had a 1988 Monte SS and it had 3:42 posi gears. I know if you came across a Buick Gran-National Rearend  and it's reasonable, they will hold up pretty well they are also a 8.5" as you probably know. Even with the HO 305 they run good. But it's still not a 350.

Go have fun that's what it's all about. Take care and I can't wait to see pictures........... Cool
Thanks
Bob  

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88MonteClone
I love my Chevy Chevette!
Posts: 8
Joined: 03/12
Posted: 03/15/12 10:34 AM

The cam itself comes with a 4 degree advanced ground in...

Those both sound like some sweet Monte's! The rear casing is just about the only thing i haven't invested in to much. I do plan on putting in a Ford 9" in the future, but for sake of finishing it I will just suck it up with the GM small guy! Video and pictures saturday or sunday!  
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pepsi1
Big Block power for the win
Posts: 940
Joined: 03/11
Posted: 03/15/12 01:17 PM

Yeah that's the weak link in the Monte Carlo. I was fortunate to have 3rd members, so he had to order the case and the axles.  

All I ever did to our Monte was put a shift kit in it. It shifts very hard at wot.

Well good luck with your's and have fun.....  

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