Valve lash (Compression Checks on a 7MGE W/ 56K Miles)

Hey.Friend

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Hey everyone,

I did some compression checks on the 7MGE for an issue I thought I might be experiencing with the valves. I actually got some measurements that are low but not outside of what the book outlines as the minimum (128PSI). However, the book does allow for a difference of 14 PSI between cylinders and I do have measurements outside of that. Readings are as follows:
Cylinders:
1-145psi
2-170psi
3-170psi
4-155psi
5-140psi
6-170psi
I poured a skosh of ATF in cylinders 1, 4 and 5 and the compression jumped up to 235, 235 and 265 on those cylinders respectively. Because of this it looks like those piston rings or cylinder bores are damaged or worn.
Here's my question. Seeing as none of the readings were below the 128psi minimum, is this more something that I need to keep an eye on as it may progressively become worse? I guess this is a noob question but i appreciate any insight. Thanks!

The pictures are of my initial readings in order 1-6. I included the spark plug that came out of 5 because I have never seen what looks like carbon burnt on in that spattered pattern before. Also all the plugs were a brown, white-ish color so it looks like it is running lean.
 

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Hey.Friend

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I might just let the compression thing go until I start having issues as the compression is still above the minimum required.

I opened up the valve covers today so I can check valve lash and shims. I think whoever did this last put the camshaft bearing caps in backwards though and my ocd can't let it stay like that.
 

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f00g00

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Looks like they also got the intake and exhaust sides swapped as well.
Did you check compression with the throttle body open?
Valves are a pain in the ass due to the shims. You have to change the shims to change the adjustment. I tried it before on my original 7MGE bought the tools to take them out and used their chart to determine which thickness to get and the gaps ended up being too close.
At that time the shims were still available, not sure now.
 
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Hey.Friend

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Valves are a pain in the ass due to the shims. You have to change the shims to change the adjustment. I tried it before on my original 7MGE bought the tools to take them out and used their chart to determine which thickness to get and the gaps ended up being too close.
At that time the shims were still available, not sure now.
I was going to look through the vendors list on here as well, but i wonder if anyone who has recently replace shims has a reliable source for them?
 

debrucer

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I was going to look through the vendors list on here as well, but i wonder if anyone who has recently replace shims has a reliable source for them?
I am in the process of doing that now and I got the price down to $6.06 per shim.

When I did my head the length of the valves wasn't adjusted to compensate for the work on the seats and valve faces. The result being that everything was too tight. The current plan calls for my engine being in the car this year, and I'm still mucking with trigger wheels and sensors, and valve lash.

Basically, I needed 24 shims. They list at $15 at the local dealer. He sells them to me for $12. DriftMotion sells them for $10.05.

Amazon sells them bags of five for one size for between $28. and $34. Not on Prime and take a week plus to arrive.

In the meantime, a local Facebook group has gotten at least two people to contribute to a collection that will be passed around in San Diego.

Yes they are available. For Toyota they come in 17 different sizes between 2.5 mm and 3.3 mm.

They are 25mm diameter for the 7M. They are 28mm diameter for the JZs... i.e., not compatible (Thanks you @andrew_mx83).

If buying on Amazon, you will find a broader range because Honda and something else also use 25mm.

I would suggest that you ask in a local Facebook group if there is a tray of these floating around "take one / return one" sort of thing. The guy at a local cylinder head shop had four in the range I needed... and of course, a cylinder head shop is going to do it the right way anyway. They don't need odd-ball sizes. A lot of time you can play a shuffle game and simply move shims from one location to another. That might work at least with an occasional purchase of one or two.

I have the two tools to do the job with the cam in place. I really do not use them. They are available on Amazon, btw.

There is a spreadsheet somewhere, probably on this site, that calculates the shim thickness you need based on your 1) gap while installed and 2) thickness of your existing shim. I do "1)", and take the cam off to do "2)" then do 3) replace with proper shim, and 4) torque cam.

Needless to say, I'm not done yet. Most of my shims have arrived. Short answer to your question: Yes. they are available :)
 
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debrucer

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Yeah here is the chart from the TSRM. View attachment 84814
That's good info. Thank you. I was talking about an excel spreadsheet that lets you enter the info and calculates the required shim.

No big deal, but it let's you play with values... something some find interesting ;) especially while playing the swap game.

Does anyone know where on this site to find this?

screen-print-of-spreadsheet.JPG

I don't know where to upload it here. PM me with request and email. The formula is nothing elaborate, it's just visually simple for me.
 
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andrew_mx83

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You can download my valve clearance spreadsheet here:
Www.Technicoracing.com/valveclearances.xls

It will do all the calculations automatically for you.

Debrucer - if the valves were cut too far into the head, your shims should all be too thick. Any engine machinist or general engineering shop can surface grind them slightly thinner for you without having to buy new ones.
If you are able to calculate how much thinner they need to be ahead of time and they grind accurately, they should drop straight in with minor shuffling. Install them ground side down.

Oh and btw JZ shims are 28mm dia so will not fit the 7m head without considerable work. We share shims with couple other Toyotas, but not many. 4age is a good donor.
 

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Even more fun if you go with the under bucket style.
But you have to get your measurements spot on before buying.
Those suckers aint cheap.
 

debrucer

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You can download my valve clearance spreadsheet here:
Www.Technicoracing.com/valveclearances.xls

It will do all the calculations automatically for you.

Debrucer - if the valves were cut too far into the head, your shims should all be too thick. Any engine machinist or general engineering shop can surface grind them slightly thinner for you without having to buy new ones.
If you are able to calculate how much thinner they need to be ahead of time and they grind accurately, they should drop straight in with minor shuffling. Install them ground side down.

Oh and btw JZ shims are 28mm dia so will not fit the 7m head without considerable work. We share shims with couple other Toyotas, but not many. 4age is a good donor.
While I don't like being wrong, I'm sure glad to have learned this. Thank you. I have three friends with JZs who have, upon my insisting they are the same, are getting their surplus shims to me... to create a tray to pass around the group. I saw the 28mm diameter and though that was for the JZ buckets, and that the shims were still 25mm.

I bought two from the dealer, and 25, 5 each of 5 sizes, from Amazon, only after trying to get someone to machine them for me. Their first suggestion was bring the head in and let me fix the valves. I bit the bullet, bought the shims, and hope to get the job done within the next week. I'm not about to get that far back into my engine if I don't have to do so.

Thanks for the info. I will go back up and correct me original post.
 
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All is not great.
While switching the cam shaft caps (can't remember the right name for them) back to their correct spots and re-orientating them so the arrows were facing towards the radiator, I inspected the rubbing surfaces. Every one of them had damage that could be felt with the finger. I'm attaching the pictures below if you want to see that damage. The last cap, 2nd to last image, has the worst damage where it looks like someone tried to pry it out.
It took me forever but after 37 hours i was able to check the thickness of 2 shims. I plan on doing the rest this week.

I don't know what to do going forward with the damage.
Should I take my caps and cams to a machine shop and have them resurface the contact points?
Can you run the engine with this level of damage?
 

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debrucer

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All is not great.
While switching the cam shaft caps (can't remember the right name for them) back to their correct spots and re-orientating them so the arrows were facing towards the radiator, I inspected the rubbing surfaces. Every one of them had damage that could be felt with the finger. I'm attaching the pictures below if you want to see that damage. The last cap, 2nd to last image, has the worst damage where it looks like someone tried to pry it out.
It took me forever but after 37 hours i was able to check the thickness of 2 shims. I plan on doing the rest this week.

I don't know what to do going forward with the damage.
Should I take my caps and cams to a machine shop and have them resurface the contact points?
Can you run the engine with this level of damage?
Sucks man. I'm not a good one to ask, as I'd be asking myself. It certainly does not look good, and it definitely did not look good the way it was. There are no cam bearings. I think it's time for the head to come off and go to the machine shop. That's me, and it would pain me greatly to have to do that... again.

Yesterday I was torqueing mine down to 14 lbs., and there was a funny release that turned out to be the threads coming off the head and releasing all torque on the bolt. I have a helicoil coming from Amazon, and I'm praying an easy fix. I've fixed worse, but I don't see a self-done cure for you :(
 
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Hey.Friend

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Sucks man. I'm not a good one to ask, as I'd be asking myself. It certainly does not look good, and it definitely did not look good the way it was. There are no cam bearings. I think it's time for the head to come off and go to the machine shop. That's me, and it would pain me greatly to have to do that... again.

Yesterday I was torqueing mine down to 14 lbs., and there was a funny release that turned out to be the threads coming off the head and releasing all torque on the bolt. I have a helicoil coming from Amazon, and I'm praying an easy fix. I've fixed worse, but I don't see a self-done cure for you :(
This all started because i was looking for the cause of the tapping i could hear under the valve cover. I think at this point i'm going to finish getting my measurements, put it all back together and just keep in mind that the head needs to go in for work, most likely this time next year. I'm staying positive because i'm 90% sure these head bolts are still at factory torque anyway lol. Also, this is TYPICAL of my experience with 7m's. I love these cars but these engines really have a special place in my heart and soul and they didn't get there because they treat me well.

Ohhh man you're in my thoughts. You're too strong haha.
 
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" i'm 90% sure these head bolts are still at factory torque anyway lol. "

@Hey.Friend Could not let this go... you are aware that this is an issue, right?
Yeah i am. I'm gonna have to replace the gasket and put in ARP bolts along with all the machining required. The TSRM wants 58ft-lbs but I saw posts on here saying it should be 75ft-lbs. I think on my last 7M we did 80. That was a long time ago though so i might not remember that correctly.
 
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debrucer

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Yeah i am. I'm gonna have to replace the gasket and put in ARP bolts along with all the machining required. The TSRM wants 58ft-lbs but I saw posts on here saying it should be 75ft-lbs. I think on my last 7M we did 80. That was a long time ago though so i might not remember that correctly.
I’d feel awful if you weren’t aware and nobody said nothing :) it’s like the #1 weakness.
 
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JustAnotherVictim

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All is not great.
While switching the cam shaft caps (can't remember the right name for them) back to their correct spots and re-orientating them so the arrows were facing towards the radiator, I inspected the rubbing surfaces. Every one of them had damage that could be felt with the finger. I'm attaching the pictures below if you want to see that damage. The last cap, 2nd to last image, has the worst damage where it looks like someone tried to pry it out.
It took me forever but after 37 hours i was able to check the thickness of 2 shims. I plan on doing the rest this week.

I don't know what to do going forward with the damage.
Should I take my caps and cams to a machine shop and have them resurface the contact points?
Can you run the engine with this level of damage?
Which cap is that?
Doesn't look like E1 or I1 so you should be able to get the nics smoothed out without really causing any issues.
I might be concerned if it was holding the cam seals though.
 

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Which cap is that?
Doesn't look like E1 or I1 so you should be able to get the nics smoothed out without really causing any issues.
I might be concerned if it was holding the cam seals though.
If i remember correctly it is I7 which was previously on the exhaust side. If that's the case I'll get in there with some fine sand paper and oil and gently try to make those burrs less aggressive.

Something I was hoping someone may be able to help me understand is the noise i am hearing. It is a ticking sound towards the rear of the engine that speeds up with the RPM of the motor. It can be heard particularly well inside of the car. I thought that if i was hearing a valve "ticking" that could be a sign of too much clearance between the cam lobe and the Shim. But as seen in the above numbers i do not have an insane difference in valve clearance amongst the valves. So now i'm wondering if the engine is starting to experience rod knock. I just didn't think that was the case sense the sound seemed to be coming from up top.
I guess i'm asking if with the numbers above for clearance could the sound still be the lobe smacking the shim?

Can i just attach a video file in here or does it have to go through Youtube?
 

debrucer

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If i remember correctly it is I7 which was previously on the exhaust side. If that's the case I'll get in there with some fine sand paper and oil and gently try to make those burrs less aggressive.

Something I was hoping someone may be able to help me understand is the noise i am hearing. It is a ticking sound towards the rear of the engine that speeds up with the RPM of the motor. It can be heard particularly well inside of the car. I thought that if i was hearing a valve "ticking" that could be a sign of too much clearance between the cam lobe and the Shim. But as seen in the above numbers i do not have an insane difference in valve clearance amongst the valves. So now i'm wondering if the engine is starting to experience rod knock. I just didn't think that was the case sense the sound seemed to be coming from up top.
I guess i'm asking if with the numbers above for clearance could the sound still be the lobe smacking the shim?

Can i just attach a video file in here or does it have to go through Youtube?
It looks like the maxium size of "media" that a user can add here is 2 meg. It's probably best to put on youtube and link to it from here.
 
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debrucer

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To be honest i didn't even think to do that. I will need to find a shop In the area that can do that for me.
My head was "banana shaped" when I took it to the shop the first time. It had been shaved after that wasn't discovered. I had it straightened, which took several hours in the oven, and whatever else they have to do to accomplish that... then it was machined again. I replaced the cams with two, new, OEM cams. When the old cams were laid on the newly straightened head, they were clearly bent. I don't know if it's always so obvious, but I would think an inspection, once you're looking for it, would tell you.

Edit: after thinking this through, you probably can't do what I said I did with the cups and shims in place :(
 

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Just an update for the thread.
I took the car into the dealership today just for them to listen and see if the tapping is on the top or bottom end as I may not be hearing it right. Long story short they said they think my exhaust manifold is cracked. I have to buy the stands and jack but I’ll be taking it off to look for any evidence that it’s cracked, but that would explain the noise as the sound of the valves opening and closing might be escaping through the manifold.
 
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debrucer

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Just an update for the thread.
I took the car into the dealership today just for them to listen and see if the tapping is on the top or bottom end as I may not be hearing it right. Long story short they said they think my exhaust manifold is cracked. I have to buy the stands and jack but I’ll be taking it off to look for any evidence that it’s cracked, but that would explain the noise as the sound of the valves opening and closing might be escaping through the manifold.
That sounds positive. I hope it resolves the issue. Be careful when you buy your stands. Do not buy the Harbor Freight brand. They've had two recalls, and as far as I'm concerned they did not address the issue. I purchased 4 Torin "Big Red" stands (on Amazon) that in addition to the standard locking mechanism, have a pin that slides through... making the stand impossible to collapse. It could still fail if used improperly, but it won't fail like the HF stands did/do. Good luck!
 
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I have felt a little skeptical about the exhaust manifold having a crack. So i started the car up today and started feeling around for warm exhaust. As i made my way to the end of the manifold i felt warm air and found a huge exhaust leak coming from the EGR Cooler. The gasket on the exhaust manifold side is blown out. I'm going to attempt fixing it with a 10mm socket end wrench.
 
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debrucer

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I have felt a little skeptical about the exhaust manifold having a crack. So i started the car up today and started feeling around for warm exhaust. As i made my way to the end of the manifold i felt warm air and found a huge exhaust leak coming from the EGR Cooler. The gasket on the exhaust manifold side is blown out. I'm going to attempt fixing it with a 10mm socket end wrench.
It’s a tough one in the car. Good luck.
 
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That EGR plate is a bear. I would look into disconnecting the tranny mount and tilting the engine up.

Those bearings look like every other 7M cam bearing I have seen. There is a layer of babbit-like soft metal on the bearings. Your finger nail will dent it to test. Plastigauge the clearance and lap the caps to bring clearance back to spec. The rears are last to be lubricated on startup and wear the most. Valve spring pressure causes the caps to wear vertically (egg shaped). The horizontal clearance should still be good.
 

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That EGR plate is a bear. I would look into disconnecting the tranny mount and tilting the engine up.

Those bearings look like every other 7M cam bearing I have seen. There is a layer of babbit-like soft metal on the bearings. Your finger nail will dent it to test. Plastigauge the clearance and lap the caps to bring clearance back to spec. The rears are last to be lubricated on startup and wear the most. Valve spring pressure causes the caps to wear vertically (egg shaped). The horizontal clearance should still be good.
Wow, thank you for the info! You just took a lot of weight off my shoulders. I felt pretty bad about the bearing caps being so rough.

I saw the tranny drop is one method and the other would be to remove the valve covers and come at it from the top. As that’s the “least invasive” i’ll try that method first. I work in a small garage and it’s been Very cold here so this work is being postponed until I feel like freezing my hands off. I’ll also need to buy a jack and jack stands and that’s held up progress as well.

This thread has really gone off the rails from the original topic so I’ll be making a build thread soon. I appreciate all the help so far from this community!
 
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3p141592654

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Yes, to start you need the valve covers off for sure. If you get too frustrated then look at pivoting the engine. But plan ahead. Assume you may need to get under there to release the transmission mount.
 
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No reason to pull valve covers or trans use a 1/4 inch flex head ratchet with the shortest 10mm socket you have. I used a gear wrench brand and through a 12" pipe on the end when needed to crack some stubborn ones loose. If you have a collection of 10mm sockets consider grinding one down a little. Between this, and couple different length 10mm wrenches maybe even one that ratchets its not bad
 
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No reason to pull valve covers or trans use a 1/4 inch flex head ratchet with the shortest 10mm socket you have. I used a gear wrench brand and through a 12" pipe on the end when needed to crack some stubborn ones loose. If you have a collection of 10mm sockets consider grinding one down a little. Between this, and couple different length 10mm wrenches maybe even one that ratchets its not bad
I ended up getting a low profile pass through socket set and that did the trick