Tearing Down and Starting Over...

[Stretch32]

First I just wanted to say thanks for all the earlier help regarding a damaged crank shaft plug (that caused an oil leak) and my lower spark plugs that were hit by my pistons. The major specs of the engine I built are:

- displacement of 2.3L (85mm x 66mm)
- 10.5:1 JE pistons
- DC40 cams from Dougherty.
- 2.2S spec cylinder heads
- twin plug ignition.

I had the engine in my car and had it running a few times (2 or 3) but never had a chance to rev the engine or put it under load (I was basically using the engine bay as a test stand). Because of the leaking crank shaft freeze plug I ended up having to tear the engine down so I can send the crank back to Ollie's for a new freeze plug. During the tear down I found other problems and, as frustrating as it is, the oil leak in the crank shaft may have prevented further issues.

When I pulled the the heads off there was evidence of all the valves coming in contact with the pistons. All 6 pistons have witness marks on all 12 valve pockets. One valve pocket has a small semi-circle groove where the edge of the valve hit it. It looks like (other than the valve that cut a groove) all the valves were just barely touching the pistons and not slamming into them.

During my rebuilding, I used clay to measure the piston to valve gaps and obviously did this process wrong since there is no clearance. Looking through notes and taking measurements as the engine came apart shows 1mm of deck height so that was set correctly.

I'm looking at what needs to happen next and I think, based on the valve to piston contact, I'm probably going to have to go through everything. I'm planning to have the heads (valves, seats etc.) checked to make sure they're ok. I'm also going to inspect the cams and rockers as well. With regard to the rods and pistons:

- Can I reuse the pistons? With the marks, I'm assuming I'd need the pockets machined a bit to clean them up at a minimum. I'm thinking part of this problem may have been due to the high lift of the cams and the valve pockets not being deep enough but I'm not sure.

- Could the rods (stock 2.2E rods) have been damaged or are they okay to reuse pending inspection of the bearings?

What else am I missing? I've never built a high performance engine and I've never had to deal with something like this so thoughts and recommendations to avoid this again would be appreciated.

[brighton911]

Sorry to hear of your troubles. Have you checked to see if any valves are bent from contact? If they are OK and all you have is witness marks on the pistons, they are probably fine. But to be sure, I would examine them closely with a 10X magnifier. The naked eye is no match for optical assistance. Take your time on the re-assembly and as you have been doing, ask lots of questions as you go.

[dannobee]

Was the cam timing correct? I'd start there.

And check P-to-V using a dial indicator and not clay. The smallest clearances will be somewhere around 10 deg BTDC and 10 deg ATDC.

Pistons should be fine. Valves will need to be removed and checked for damage.

[Jeff Alton]

^^^^^^^ this.....

[Stretch32]

Gents,

Thanks for the replies.

It’s possible the cam timing was off. We did use one of the Stomski digital cam timing tools but that doesn’t mean anything at this point. We’ll use it again on the rebuild and make sure everything is set up correctly.

With regard to my pistons and rods, besides inspecting the piston tops, where else could the damage be on the pistons? Should I have the pockets machined a bit to clean up the marks?

Also, what about the connecting rods and crank shaft? What damage should I be looking for here?

[stownsen914]

Damn, well it sucks to tear it down, but better to discover these issues now and before serious damaged happened.

For peace of mind, you may wish to recheck the cam timing before you fully disassemble. So you know if it was mis-timed, or you need to have the piston valve pockets cut. It'll save you time doing this upon reassembly.

[Neil Harvey]

Welcome to the "failure club". Some of us have been long time members. Remember you learn more from your mistakes than your successes.

Here is my advice. And in no particular order. Just do the checks.

Check the rod bearings. When contact is made you lose all clearance and the Valve, piston, rod bearing all become one solid shaft. The bearings can pancake. The shell will tell if it was damaged and the "length will increase. The length is the side to side dimension.

Straight check the rods. Probably will not have had any change, but check. Same for the SE diameter. You probably had less than 0.001" pin clearance so the bushing may have seen some solid contact. Again, check.

The pistons should be checked and the skirts checked. One valve, one side of the head would have touched first and may have pushed the shirt into the cylinder wall. Check both parts. As for machining the pockets, this has to be determined by the damage and the P/V check. There are some checks to perform before this can be decided.

The valves, as has been suggested, need to be checked for straightness. If the valves hit "straight" often you get away with it on minor contact. Check for any run out. Also check the guide clearance.

Now that these parts have been checked and appear to be good, call your cam supplier and ask for the cam lifts 20° BTDC every 5° to 20° ATDC at the cam timing you are using. They will know the LC's at the TDC lift you are using. This will be the maximum valve lifts for your cam, just before and after TDC.

If you are sure about the piston deck height and the CR number you want, refit one piston and cylinder to the engine. Zero out and find true TDC for that Piston. I assume by using the tooling you have said, it comes with some sort of digital readout for crank position. If not buy and fit a degree wheel. There is reason for this that will become apparent later.

Turn the Crankshaft clockwise until you are 20° BTDC. Fit one cylinder head with the valves loose. No springs. Let the valves drop (carefully) until they contact the pockets. You will quickly see if the pocket diameter is large engine for side clearance. Making sure the valves do not contact one another too. Simple rubber band will hold the valves against their seat.

With a dial indicator attached to the head have the pointer contact the Intake valve stem. Pull the valve until its in contact with the valve seat. Zero the dial. Now lower the valve until it touches the piston. This is the maximum possible travel with any Cam that the valve will travel at 20° BTDC. With the valve back against its seat, turn the crank to 15° BTDC. repeat the measurement. Keep a record of these drop numbers. Repeat until you get to 20° ATDC. Then do the same for the Exhaust valve.

With the lift numbers you get from your cam supplier, subtract them from what you measured at the same crank position. This will give you your P/V clearance. Why this way. Before the engine is assembled proper, you can see if the pockets are deep enough or another cam position has to be set, or the pistons need added pocket depth machined. Remember, if this is what is required, you will lose CR. Sometimes added piston deck height can solve a problem, but this will always lower the CR more than a pocket change.

Now knowing what your clearances will be and that you have checked all parts, reassemble with confidence. Double check before refitting the heads that your TDC is still zero'ed. You can perform the cam timing with lift at TDC on the Intake or with the LC from the cam supplier, by crank degrees ATDC, Intake full lift.

If you want to double check your work once completed, every turn on the rocker arm adjuster is 1.0mm. Set the cam timing with the lash required. The checks I suggest will show where the clearances are the tightest. Put the engine into this crank position and turn the adjuster screw in until it just touches the piston. Count the turns and it should be the same as what you measured before. This is what I understand is the most common way to check P/V for many, but in your case if the piston pockets are been questioned, the way I have explained will help decide before the engine is assembled.

One last thing, when you do the P/V check with the dial indicator, do the same for the lower spark plugs. Dead stop the piston or remove the valves and do the same checks looking into the chamber looking for clearance.

This may sound really long winded, but you will learn something and then in the reassembly, feel a lot more confident about the end result.

[Dpmulvan]

Where do you live? Maybe somebody could swing by and help you out.

[dannobee]

I'm with Neil on this one. First assemble one cylinder and head on each bank and measure "valve drop at TDC." With everything assembled, but with light valve springs or no springs, you need to accurately know how far the valve can drop before touching the piston at verified TDC (don't just blindly trust the timing mark). Call John up and ask if that is in the ballpark for your cam choice. Next you'll need to install a few other heads and the cam carrier and time the cams. Install one intake rocker to start, and rotate the crankshaft two complete revolutions (one cam revolution). Go slowly and stop if you feel any interference! Once you have establish that there is sufficient clearance to at least rotate the engine without hurting anything, check the P-to-V clearance at each crank degree from 20 deg BTDC to 20 deg ATDC. At each degree, push down on the valve and measure the clearance using the dial indicator. Now repeat the same process with one exhaust rocker installed.

Here's a page from one of my engine build sheets. I've used similar build sheets for all of my nascar engines over the years. This page references that point in engine assembly where valve drop, valve timing, and P-to-V clearance is measured on the final assembly. Clearances on mock up had already been established and measured. This particular engine is a high boost turbo engine that has GT2Evo cams, but the same checks apply to yours. Your cams are even bigger than these, but it should give you some insight on some checks that need to be performed. (Actual readings are in BOLD)

[Stretch32]

Gents,

Thanks again.

I'm in Virginia Beach / Norfolk, VA area and I've got some help from a friend that's pretty knowledgeable but we're in unfamiliar territory to some degree since the engine isn't a cookie cutter T/E/S. I built a 2.2T motor for my old car several years ago using completely stock components so I didn't spend a ton of time measuring everything as I probably should have. If there are any recommended engine builders familiar with high performance / custom engines in or near the area who might be able to help us during the top end reassembly I'd be interested to talk to them.

I'll continue to pull the engine down and have all the parts inspected to make sure they're still serviceable. I'm planning to call JE today to see what they recommend on the pistons and I'll closely inspect everything (bearings, rods and such as suggested) as it comes apart. Hopefully there's no damage to the camshafts or rockers....

I failed to recheck cam timing prior to pulling the head units off so I'll have to check everything when it goes back together. Since I wasn't sure if I would be buying new parts, I wasn't sure measurements with the old parts would be applicable (assuming they don't get reused).

I'm sending the heads to a local head shop and they'll be able to check all the components to make sure everything is still good and undamaged.

Right now I need to see what's serviceable and what (if anything) needs to be replaced or repaired. I'm sending the crank back to Ollie's to get the leaking freeze plug repaired and I'll ask if they can inspect the crank while it's there.

[Dpmulvan]

Virginia Beach home of free daily air shows. Check out Kurt’s series on YouTube might help you out.
The guy deserves some more views for all the work that went into his videos.

[Stretch32]

I’m fond of jet noise myself….

I’ll take a look at the videos and see if there are any others that might help.

Neil, where do I find the specs for the width of the rod bearings to know whether they’ve been smashed?

I’m considering tossing the rods in the box and sending them to Ollie’s along with the crank.

Again thanks for the detailed description on taking measurements and putting everything back together. I need to find the dial indicator holders for checking these measurements (assuming someone sells something more custom than the usual holders).

[Neil Harvey]

Originally Posted by Stretch32

I’m fond of jet noise myself….

I’ll take a look at the videos and see if there are any others that might help.

Neil, where do I find the specs for the width of the rod bearings to know whether they’ve been smashed?

I’m considering tossing the rods in the box and sending them to Ollie’s along with the crank.

Again thanks for the detailed description on taking measurements and putting everything back together. I need to find the dial indicator holders for checking these measurements (assuming someone sells something more custom than the usual holders).

Sorry did not see this.

Although they will be different, measure the shell at the parting line and compare at the middle. Probably best to measure not at the tang side.

[PeteKz]

Obviously, if you have everything apart, check it. But I seriously doubt you did any damage to the crank, rods, or pistons. Remember, in a running engine, those parts see TONS of force from combustion. More likely the rockers got bent or cracked, so inspect and compare those too.

When you are reassembling it, do a test assembly of at least one bank with the cam timing set and valve clearance set. As Neil recommended, slowly crank the engine through the top 40 degrees or so of rotation. stop every few degrees ad measure the clearance from the valve to the piston, either by using a dial indicator or the "count the turns of the valve adjuster" method. You should have .060' (1.5mm) or more of clearance at all points in the rotation. I settled for .050" on my engine, but it's a 3.2, so I won't rev it beyond 6200 RPM.

Extra credit: advance the cam 5 degrees or so and measure again. Then retard the cam 5 degrees and measure again. Of course, record all these numbers for future reference. You may discover that you cannot advance or retard the cam without running into interference issues.

[Stretch32]

A quick update:

I called Dougherty today and got specs for the DC-40. What was provided is listed below:

Intake-
TDC: 4.5mm
15* ATDC: 6.1mm

Exhaust-
15* BTDC: 5.23mm
TDC: 3.05mm

The measurements I got doing the valve drops with a dial indicator were:

Intake-
15* BTDC: 9.10mm
TDC: 8.02mm
15* ATDC: 9.44mm

Exhaust-
15* BTDC: 6.85mm
TDC: 6.65mm
15* ATDC: 7.33mm

The critical measurements for this cam are BTDC for exhaust valves and ATDC for intake valves. With the numbers provided by Dougherty and the measurements I took, I'm showing valve to piston clearance as:

Intake: 3.34mm

Exhaust: 1.62mm (a bit tight)

Does this sound right? If so, why in the would I have had piston to valve contact?

We're pretty sure TDC was found correctly and we used a Stomski digital cam timing tool so I'm not sure where we went wrong or where the issue might be.

Stretch

[dannobee]

My experience with JE's is that the valve pockets are plenty big for nearly any cam you could put in there, but here we are with theoretically plenty of measured valve clearance.

If the cam timing was off, EITHER the intake valves would be bent OR the exhaust valves would be bent. As you advance the cams, exhaust P-to-V clearance increases AND intake P-to-V clearance decreases. Conversely, if you retard the cams, intake P-to-V clearance increases while exhaust P-to-V decreases.

Would you happen to have pics of the pistons showing the witness marks? And is there carbon deposits (or dust or discoloration since it hasn't been ran very long) on the witness marks, or are they fresh and shiny?

[Stretch32]

The witness marks were covered in soot due to the overly rich mixture and the witness marks weren’t readily visible until we wiped the spot off. The marks indicate both the intake and exhaust valves were hitting the piston tops.

I sent pictures to JE and they said the marks did not concern them and that the pistons were okay to reuse. They felt the marks were light in their experience of this sort of event.

Pictures attached of the lightest and heaviest contact marks respectively.

[Neil Harvey]

Originally Posted by Stretch32

A quick update:

I called Dougherty today and got specs for the DC-40. What was provided is listed below:

Intake-
TDC: 4.5mm
15* ATDC: 6.1mm

Exhaust-
15* BTDC: 5.23mm
TDC: 3.05mm

The measurements I got doing the valve drops with a dial indicator were:

Intake-
15* BTDC: 9.10mm
TDC: 8.02mm
15* ATDC: 9.44mm

Exhaust-
15* BTDC: 6.85mm
TDC: 6.65mm
15* ATDC: 7.33mm

The critical measurements for this cam are BTDC for exhaust valves and ATDC for intake valves. With the numbers provided by Dougherty and the measurements I took, I'm showing valve to piston clearance as:

Intake: 3.34mm

Exhaust: 1.62mm (a bit tight)

Does this sound right? If so, why in the would I have had piston to valve contact?

We're pretty sure TDC was found correctly and we used a Stomski digital cam timing tool so I'm not sure where we went wrong or where the issue might be.

Stretch

The lifts at the crank positions will change by Cam position, (timing). are the numbers you show from the cam company at the same timing positions you used?

When you start to re assembly, do the TDC check with the pistons in place and no heads. Then you can be sure you have true TDC. Bounce the TDC either side of it by 20° and find true TDC.

I suggest you use a degree wheel. Does the apparatus you are using give lift and crank degrees? Forgive me, I do not know this timing tool. If you ask the cam company for the Intake centerline number, you can check the Intake cam timing by lift (overlap) and by the degree (full lift) ATDC.

[Stretch32]

Neil,

TDC of the piston we used was found with the cylinder head off and confirmed to be at actual TDC. From there, we used the Stomski tool which, once zeroed with #1 at TDC, measures crank rotation digitally in degrees (to the nearest tenth) like a degree wheel.

The measurement numbers provided above were given to me by the camshaft maker at those points. I measured everything at the points provided and my numbers from the drop test are also posted.

At this point, I’m rapidly exceeding my level knowledge and I’m not sure how to proceed.

[stownsen914]

There's only so much you can discern from a picture, but those pistons have pretty tall domes. Do you have the detailed specs on the pistons? If you haven't already, it may be worth confirming that they are compatible with your application, given the issues you are seeing.