No valve clearance? HOW

[Tiki2777]

Ok guys, I'm in a bit of a doozy... I'm putting together my 6 bolt engine build and I'm hitting a giant wall with my valve to piston clearance. For starters I have 9.0:1 Manley pistons onto Manley H beam rods, bored .020 over. My ptw is .0035 as per Manley specs. Now...onto the issue:

We clayed the pistons to check valve clearance. The cams I'm using for this are fp4rs. The block was decked 6 thousandths and the head was decked 3 thousandths. Mind you I have not checked the actual height of both the head and the block because of lack of calipers big enough, but I may be getting some from a friend soon. The piston sticks out at tdc above the deck at about 8 thousandths. I'm planning to run my new cometic .051 gasket and to test the clay we used my toast .052 Mitsubishi gasket.

When first claying the pistons. We found that the intake was a hair away from smacking the piston and the exhaust was about 20 thousandths of clearance...so in order to avoid donation issues and reordering gaskets I took the pistons to get fly cut a tenth of an inch deep (100 thousandth cut to ensure it clears both intake and exhaust) and turning the engine over was easy and it did not bind, we did the clay test three times before pulling the slugs.

Now after reinstalling fly cut pistons, we redid the clay test almost 5/6 times...here's where it gets weird. The intake is still a hair from clearing the piston and the exhaust hardly touches the clay. We had made custom solid lifters and also tried using regular pumped up lifters..No dice. We used a milwaukee probe and watched through the spark plug hole the clay just get pushed away from the intake side.

Wouldn't it have bound and not turned over well prior to not getting cut?? Taking a hundred thousandths off did nothing? How???

 

[1990TSIAWDTALON]

I am not sure that I didn't experience the same thing and my problem was the fact I didn't bleed my lifters after they soaked in oil for a few hours. I spoke with Bogus on here and he explained I needed to take every lifter out and bleed it by putting a paperclip in the center hole of the lifters and pressing down the relief valve to let oil out. My valves were hanging open was my problem though are yours? I bent six exhaust valves just rolling the motor over by hand. Not sure if any of this info helps but I am relaying my recent experience.

 

[Tiki2777]

I am not sure that I didn't experience the same thing and my problem was the fact I didn't bleed my lifters after they soaked in oil for a few hours. I spoke with Bogus on here and he explained I needed to take every lifter out and bleed it by putting a paperclip in the center hole of the lifters and pressing down the relief valve to let oil out. My valves were hanging open was my problem though are yours? I bent six exhaust valves just rolling the motor over by hand. Not sure if any of this info helps but I am relaying my recent experience.

Holy cow! You bent valves by hand rolling it! I've never heard of that.
But anyway, I'm testing the clearance on my engine, so by popular common knowledge I thought you are supposed to use a solid lifter to test max lift also at zero lash. I tested someone else's theory with using a pumped up lifter...so am I supposed to use a bled lifter then?

 

[Archer Fabrications]

Have you checked your valve stem install height?

Are you using standard length rods?

 

[Tiki2777]

Have you checked your valve stem install height?

Are you using standard length rods?

I have standard size h beam Manley rods...and I have not checked the valve stem installed height. Reason being is the head came from a running car.

 

[motomattx]

Your lifters when running will never be fully extended like your solid lifters are, thats where I would have to say your problem with measurements lies, your lifter setup seems like it has been inconsistant throughout your checks. Your valves to rockers always require a certain amount of clearance at minimal, most engines have antyhere between 3-10 thou depending on design and whether its intake or exhaust, of course some engines run alot more or less depending.

 

[Tiki2777]

Your lifters when running will never be fully extended like your solid lifters are, thats where I would have to say your problem with measurements lies, your lifter setup seems like it has been inconsistant throughout your checks. Your valves to rockers always require a certain amount of clearance at minimal, most engines have antyhere between 3-10 thou depending on design and whether its intake or exhaust, of course some engines run alot more or less depending.

So do you think I should test it with bled lifters then???

 

[motomattx]

I would bleed a lifter, then put it in a container of fresh oil, pump it until its full, install it in the head, let it sit for several hours or overnight, then turn the cams over five or six times to get it closer to its actual practical operating position and measure that way, of course I would do this with two intake and two exhaust lifters not just one at a time.

 

[jakelandry]

You did mention you haven't checked the actual head thickness. I don't do machine work or anything but from the heads I've had worked I would venture to say it's been cut before if it only required .003 taken off. It also could be cut crooked.

 

[1990TSIAWDTALON]

Bleed that lifter (HLA) or it will not compress like mine did and yes I bent them rolling it over by hand...brand new engine soooo 200 later and new set of exhaust valves, luckily didn't hurt the intakes. It surprised me that it took so little to slightly bend them and they wouldn't seat anymore hence no compression. Not to mention new head gasket, exhaust, intake the whole dang nine yards.

 

[BogusSVO]

You said you had the pistons fly cut .100 ?? Also the pistons were .008 above the deck.

So now the pistons should be .098 in the hole.

And look a bit more like Evo pistons, if they were flat cut, and the top ring should be very close to what is now the crown of the pistons.

Or did you have the valve reliefs fly cut .100?

Or was a decimal misplaced? and you ment .010? and the pistons are now .002 below the deck?

You did set the timing belt on correctly when you clayed the pistons?

Not just bolted the head down and rolled the cam over.

If you just rolled a cam over while the piston was at TDC, you will have an issue, Keep in mind the 4g is an interference engine and bends valves when the belt breaks.

This is why you have to have the timing belt on when you clay the piston, so both the crank and cam relationship is kept as it would be running and the closest point then can be measured.

 

[Tiki2777]

You do realize the solid lifters purpose in this case is to set zero lash adjustment... In between a fully pumped lifter and a bleed lifter

You said you had the pistons fly cut .100 ?? Also the pistons were .008 above the deck.

So now the pistons should be .098 in the hole.

And look a bit more like Evo pistons, if they were flat cut, and the top ring should be very close to what is now the crown of the pistons.

Or did you have the valve reliefs fly cut .100?

Or was a decimal misplaced? and you ment .010? and the pistons are now .002 below the deck?

You did set the timing belt on correctly when you clayed the pistons?

Not just bolted the head down and rolled the cam over.

If you just rolled a cam over while the piston was at TDC, you will have an issue, Keep in mind the 4g is an interference engine and bends valves when the belt breaks.

This is why you have to have the timing belt on when you clay the piston, so both the crank and cam relationship is kept as it would be running and the closest point then can be measured.

Yes sorry about that, I had the valve reliefs of the pistons fly cut 0.100.

And yes, always the engine was timed and rolled over with the timing belt on. It just doesn't make any sense how my exhaust almost barely touches clay now and my intake is a hair from smacking the piston still.
Any insight on the lifter issue? I thought using a bled lifter will never give appropriate results. Thanks

 

[bastarddsm]

When I've done mine I always use a solid adjustable lifter, and light weight test springs on the valves. Then adjust the lifter to 0 clearance. I can't imagine you really have 0 clearance on the intake side.

Double check that you have it timed right.

 

[Tiki2777]

I'm still thinking in the back of my mind that it could be a timing issue, particularly regard the cam gear markings in relationship to the top of the cylinder head, for whatever reason it didnt want to line up exactly (mind you I was using the jay's racing cam gear tool to help hold the two in place). it either was a couple hairs below the head line or a hair above. Any tips on getting the timing marks to line up with the head easily and with each other?

Also, a good idea when cranking the engine (this is for you 1990talon) is to use a smaller length 1/2 drive and removing the spark plugs to avoid fighting the compression so you are less likely to bend the valves by hand (still unsure on how exactly you did it, but I guess its possible if you keep cranking even after feeling significant resistance).

 

[1990TSIAWDTALON]

Yes to clairify, I set my pistons at mid-stroke and rolled each cam over by itself to make sure that everything felt ok only to hear a "ting" when I did it and then looked at my HLA's and some were still holding pressure and were full of oil. That tiny amount of exhaust valve being open was just enough to let the intake valves touch the lip of the exhaust valves that were in a semi-open position. My stupid mistake and one that I will never do again and Bogus lined me out on it so thanks to him for his input.

 

[Tiki2777]

Yes to clairify, I set my pistons at mid-stroke and rolled each cam over by itself to make sure that everything felt ok only to hear a "ting" when I did it and then looked at my HLA's and some were still holding pressure and were full of oil. That tiny amount of exhaust valve being open was just enough to let the intake valves touch the lip of the exhaust valves that were in a semi-open position. My stupid mistake and one that I will never do again and Bogus lined me out on it so thanks to him for his input.

Yea that really sucks man, luckily thats in the past for you, right now I'm in the middle of my own mess :/

Anyways, the pistons' valve reliefs were fly cut, not the piston itself. I'm also starting to wonder how accurate the valve relief angle is with respect to the actual valves, because the actual 'clearance issue' identified with the clay is always on the very edge of the valve, not the middle of the valve.

 

[BogusSVO]

Tiki... the timing has to be off, or you ended up with a cam that was severely ground off the center.

You have the FP4R cams, I did not look to hard for that cam card, But found the FP4 cam card

file:///C:/Documents%20and%20Settings/HP_Owner/My%20Documents/Downloads/101400_FPCam4%20(1).pdf

Then looking at some info that Bastard posted,
http://www.dsmtuners.com/threads/delta-hks272-regrind-info.464400/

The FP4 has an Intake lift of .415, and the delta .394 so thats .021 more on the FP4

Then if we add the .008 that your pistons are out the deck

That adds up to .029 tighter clearance.

Bastard used a composite HG .039 thick, and you used a MLS HG at .052

so that adds .013 to your clearance.

So a base difference of .016 tighter

(yes, I know head thickness has not been taken into account)

Bastard says .005 was cut from his head, But head thickness is unknown on both his head and yours.

But looking at Bastards post, with the gears zeroed, he has .150 clearance

Assuming that factory valve relief depths are similar on both brands of pistons

so .150-.016 =.134 clearance should be about where you are.

Back to the heads now, lets assume Bastards just had a first cut of .005 making his head thickness 5.195

Then lets assume your head is milled .020 past min spec of 5.185 making your head 5.165 so you would be .030 tighter

You still would be around .100 valve to piston clearance.

BUT

If the timing belt is off by one tooth and one valley appox 10* Advanced

Bastard comes up with .050 Intake valve to piston clearance @ 12*

You would have just what you are finding, next to nothing for clearance.

So with the guessing and assumptions aside, The timing bet must have been set up a tooth or so off.

 

[Tiki2777]

Here's a link to the fp4r cam card Bogus:
http://store.forcedperformance.net/merchant2/graphics/info/camcards/dsmfp4rv2.pdf

These seem to have a considerably faster valve accel. rate (like the fp'x series of cams) from what I've read, could that have anything to do with it as well?
I might be getting a set of adjustable cam gears to see if I can degree out some of this.
I realize that these cams are VERY aggressive and push the limits of the stock valvetrain, but I still am clueless on why cutting the reliefs 0.100 didnt affect the intake clearance.

 

[BogusSVO]

I know I used the FP4 with a lift of .415

I now see the FP4R have a lift of .440

so that would make the piston to valve .025 tighter.


Now have you checked the crank marks against true TDC?


If you had some sort of clearance on the intake valves before the fly cut, ,you should have that + .100

Also the engine should have locked up before the fly cut.

 

[Tiki2777]

I haven't checked the crank marks against true TDC, so that could be an issue and I'll try to go check that as soon as I get the chance. Also, I need to talk to my machinist about the valve reliefs just for the hell of it to see if he can help too.

 

[Tiki2777]

UPDATE:
'TDC' wasn't correct due to the timing plate being installed backwards by a friend of mine helping me with an engine install, luckily I caught this.
After having the valve reliefs fly cut and the timing set correctly, there was over 150 thou of clearance on the intake and even more for the exhaust.
In addition to some of the others that posted in this thread, you do not use pumped up lifters to check for valve clearance, you will end up hanging your valves open even on the base circle of the camshaft, there's a reason solid/adjustable lifters are necessary.

 

[motomattx]

You definately should never turn an engine over with fully extended lifters period, you must always allow them to bleed down overnight.

 

[1990TSIAWDTALON]

And another note...I let mine bleed for two weeks in various positions and still had some pumped up. I figured a day or two would be enough . Mine were 3g revised versions btw.