Trakrat's 3.2 Engine Rebuild

[mepstein]

I would fix the crack on the fiberglass shroud and repaint. The stock shrouds fit better than the aftermarket ones.

[Trakrat]

Originally Posted by mepstein

I would fix the crack on the fiberglass shroud and repaint. The stock shrouds fit better than the aftermarket ones.

I'll probably just get the raw fiberglass. I don't really like the black.

[Trakrat]

ok.... so I loosened all the valve clearances off the rockers at all the cylinders.

I set the timing to TDC... buuuuuuttt... it seems that cylinder #2 is tighter than a -fill in the blank-.
I loosened the intake valve as far as possible, but the rocker just will not budge.

So my question is..... will this be an issue when pulling the camshaft out???

[Trakrat]

Originally Posted by Trakrat

ok.... so I loosened all the valve clearances off the rockers at all the cylinders.

I set the timing to TDC... buuuuuuttt... it seems that cylinder #2 is tighter than a -fill in the blank-.
I loosened the intake valve as far as possible, but the rocker just will not budge.

So my question is..... will this be an issue when pulling the camshaft out???

Just an update...Intake rocker on cylinder #2 is tight... backed off the valve clearance, but still not loose.

ALSO... exhaust rocker on cylinder #3 is tight... same thing.

I am going to attempt to pull the camshaft out this weekend and would really like someone's opinion on this.

thanks!

[Flat6pac]

You need all the rockers out of the way to pull the cam.
Remove all the rockers you can then get a 5 mil 3/8 drive to sit square to the allen
Tap it tight.
If the Allen bolt is stripped, I would heat the bosses and with them very warm drive the steel out of the aluminum
Bruce

[KTL]

I think the thing that's being missed here is that just backing off the rocker adjuster screws doesn't close all the valves when the engine is at TDC for cylinder #1. You need to rotate the crank to TDC for each cylinder and then remove the rocker arms for that cylinder. That's the deliberate/by-the-book way to do it. The other way is to just rotate the crank and watch whatever rockers you want to remove. You want to watch them by cylinder in pairs- intake and exhaust on the same cylinder. When the valves are closed at those rockers, stop there and remove those. Then rotate the crank again and watch for the next set of rockers to close that you want to remove.

[bpu699]

Originally Posted by Trakrat

Just an update...Intake rocker on cylinder #2 is tight... backed off the valve clearance, but still not loose.

ALSO... exhaust rocker on cylinder #3 is tight... same thing.

I am going to attempt to pull the camshaft out this weekend and would really like someone's opinion on this.

thanks!

soaking in wd40 worked for me...

Also, not sure if this applies but don't use an allen wrench. Get hardened allen sockets and use your socket wrench. I tried an allen wrench, total no go...

Low power impact gun may also help?

[Trakrat]

Originally Posted by KTL

I think the thing that's being missed here is that just backing off the rocker adjuster screws doesn't close all the valves when the engine is at TDC for cylinder #1. You need to rotate the crank to TDC for each cylinder and then remove the rocker arms for that cylinder. That's the deliberate/by-the-book way to do it.

Well... Wayne's book has you removing the entire head assembly as one piece.
Meaning, his book says to remove the camshaft and then remove the entire head assembly off and setting it aside.

[Trakrat]

Originally Posted by bpu699

Also, not sure if this applies but don't use an allen wrench. Get hardened allen sockets and use your socket wrench. I tried an allen wrench, total no go...

That's good to know. thanks!

[KTL]

I've always had no issue using an allen wrench/key. But I had to shorten the bent end of the key to fit in the tight locations. This would be for the nut side of the rocker shaft, not the bolt side.

I like leaving the heads on the engine when removing the cam housing. I think it's easier to free the heads from the housing when they're still on the cylinders because you can hit the housing with a mallet and pop it off the heads, thanks to them being held down by the head studs

Wayne's book ain't the only book. But it's definitely a good one!

[Trakrat]

Originally Posted by KTL

Wayne's book ain't the only book. But it's definitely a good one!

True... I've actually been using the Bentley since it's more specific for my model year.

I'm just excited and impatient to see the extent of the damage to my pistons. Sounds strange, I know.... but I looked into the spark plug openings and can see where the valves dug into the piston heads with that half moon shape indention.
It's difficult to see if this is something that will require new pistons or just refinishing.

[KTL]

I bought a set of pistons and cylinders from a low mileage '85 3.2 a few years ago. I wanted only the cylinders and figured I could re-sell the pistons. Once I got them cleaned up (removed the carbon off the piston crowns) I found smiley marks on the pistons. Point being is somebody zinged the engine a bit and then drove it awhile longer to cover up the marks with carbon. Even though the pistons had been apparently lightly tagged by the valves, the piston skirts didn't show any major problems because of it. I would have expected the skirt to show some significant side wear/scuffing due to the valve contact causing it to cock in the cylinder. Nope.

It was very easy to massage the smiles out of the piston top and blend it in. The amount of material you remove is a minimal amount and does not affect the balance. You'd be surprised how much material you can remove and it still doesn't amount to a major amount of weight. Reason I say this is because a few years ago I balanced some pistons by removing material under the crown. One piston was not from the original group of pistons and weighed quite a few grams more. I was surprised how much aluminum debris I created to get that piston lightened enough to be within range of the other 5 pistons.

I know the feeling of excitement. Been there. Although mine was a bit less feeling giddy and feeling more sick

Engine Bearing Failure- Disassemble Heads Too?

[Trakrat]

Got the timing chain covers off...
Is it recommended to replace the chain?

ALSO... some of the studs came out with the nuts... should I just treat these the same way I do my exhaust studs? *put them back in using double nuts? Or should I replace them as part of the rebuild????

[bpu699]

Originally Posted by KTL

I bought a set of pistons and cylinders from a low mileage '85 3.2 a few years ago. I wanted only the cylinders and figured I could re-sell the pistons. Once I got them cleaned up (removed the carbon off the piston crowns) I found smiley marks on the pistons. Point being is somebody zinged the engine a bit and then drove it awhile longer to cover up the marks with carbon. Even though the pistons had been apparently lightly tagged by the valves, the piston skirts didn't show any major problems because of it. I would have expected the skirt to show some significant side wear/scuffing due to the valve contact causing it to cock in the cylinder. Nope.

It was very easy to massage the smiles out of the piston top and blend it in. The amount of material you remove is a minimal amount and does not affect the balance. You'd be surprised how much material you can remove and it still doesn't amount to a major amount of weight. Reason I say this is because a few years ago I balanced some pistons by removing material under the crown. One piston was not from the original group of pistons and weighed quite a few grams more. I was surprised how much aluminum debris I created to get that piston lightened enough to be within range of the other 5 pistons.

I know the feeling of excitement. Been there. Although mine was a bit less feeling giddy and feeling more sick

Engine Bearing Failure- Disassemble Heads Too?

Ouch...

How many $7000 spec-Miata-equivilents did it take to fix that ?

Read your thread... amazed you were getting 80-100psi oil pressure at high rpm... I would kill for those oil pressures...

Bo

[bpu699]

Originally Posted by Trakrat

Got the timing chain covers off...
Is it recommended to replace the chain?

ALSO... some of the studs came out with the nuts... should I just treat these the same way I do my exhaust studs? *put them back in using double nuts? Or should I replace them as part of the rebuild????

If its anything like the main/rod bearings, the old chain is probably better quality than a new chain .

When you get to the bearings, before you install them, I would highly recommend you goto harbor freight and get their digital 1 inch .00001 accuracy micrometer. $25 or so.

You may find as I did, and based on tons of threads on here - many others have found too, that your old bearings are thicker/better than new ones (assuming no damage to them)...

Also, scour ebay, I bought an awesome $300 bore indicator, professional grade, for $60. The things works great, super reproducible results... The cheap bore indicators most guys buy only read to .0005... Which is not great from what I gather. A clearance of .002 and .0025-.003 is pretty broad...

Good luck

[KTL]

Yep just put the studs back in. The chain cover studs are non-critical studs that are under virtually no stress.

I don't think you necessarily need to replace the chains. Your tensioners show minimal extension and I don't see any significant wear marks on the side of the large camshaft sprocket on the right bank of cylinders (4-5-6). So your chains appear to be running nice and parallel. Plus it's good practice to replace chains and sprockets together, or else you just accelerate the wear on whatever's new- in this case the chain. You will want to replace the ramps since the plastic can get old and brittle.

Bo,

I didn't add up what it cost to rebuild it. I just slowly gathered replacement parts. Some new, some used and reconditioned. Still isn't back together yet. Not much urgency on my part to go racing with nobody. I'd rather fart around with the street car in the garage, apparently.

I will agree that decent high resolution measuring tools are nice to have on hand to check your work. We're at a point now where we apparently can't trust much when it comes to bearings and they're critical to making the engine function properly.

Regarding the oil pressure, I don't know what to say about that. I was fortunate to have a mechanical oil pressure gauge in the dash so I could see what kind of oil pressure was coming from the top of the engine where the low oil pressure warning light gets its oil source. However, after the 1st rebuild, with a 964 oil pump, I had noticeably less pressure on the gauge. Just over 60 vs. the previous just over 80. I think that was attributed to the lack of a bypass spring spacer that the later 3.6 cases typically use. But never was able to do a test to confirm pressure w/out vs. with the spring spacer.

[bpu699]

Originally Posted by KTL

Yep just put the studs back in. The chain cover studs are non-critical studs that are under virtually no stress.

I don't think you necessarily need to replace the chains. Your tensioners show minimal extension and I don't see any significant wear marks on the side of the large camshaft sprocket on the right bank of cylinders (4-5-6). So your chains appear to be running nice and parallel. Plus it's good practice to replace chains and sprockets together, or else you just accelerate the wear on whatever's new- in this case the chain. You will want to replace the ramps since the plastic can get old and brittle.

Bo,

I didn't add up what it cost to rebuild it. I just slowly gathered replacement parts. Some new, some used and reconditioned. Still isn't back together yet. Not much urgency on my part to go racing with nobody. I'd rather fart around with the street car in the garage, apparently.

I will agree that decent high resolution measuring tools are nice to have on hand to check your work. We're at a point now where we apparently can't trust much when it comes to bearings and they're critical to making the engine function properly.

Regarding the oil pressure, I don't know what to say about that. I was fortunate to have a mechanical oil pressure gauge in the dash so I could see what kind of oil pressure was coming from the top of the engine where the low oil pressure warning light gets its oil source. However, after the 1st rebuild, with a 964 oil pump, I had noticeably less pressure on the gauge. Just over 60 vs. the previous just over 80. I think that was attributed to the lack of a bypass spring spacer that the later 3.6 cases typically use. But never was able to do a test to confirm pressure w/out vs. with the spring spacer.

4 bar or 60 is what I was seeing warm, perhaps a hair over. Tracked 10 times, main bearings looked new...I really wish I had just let those be... So seems like 4 bar is adequate...

Keep looking for some discrepancy internally that would allow some folks to have such higher pressures... Haven't found it yet. Bearing were in spec, though on the loose end...

Best I can figure, folks getting really high oil pressures must have bearing clearances much tighter than .0025...

Trakrat, if you intend to get new main and Rod bearings, and you intend to throw the old ones out, would you be willing to send them to be to measure? Happy to pay postage.

I am still surprised that new bearing are so much thinner than the old ones...

[bpu699]

Originally Posted by Trakrat

Just an fyi... I took off the shaft cover below the pulley... I think I see what you mean, it's not perfectly smooth between the creases of the two halves?
I'd take a pic, but it's really really REALLY dirty and grimy below the pulley and would have to clean it first.

Here is a pic, started a new thread...




IMS shaft won't spin...case misaligned? Input appreciated...

[KTL]

The grimy condition there is often thought to be the crankshaft seal but it's most often the main bearing insert o-ring. So just another FYI to add to the list of things to watch out for/recognize.

Bo,

Did you check your pressure with a different gauge? That old pressure sender can be a bit iffy as far as accuracy goes.

[faapgar]

Hi,maybe my wife made me the wrong batch of brownies this morning and I am FUBAR here on the beach in C.R.but the previous post said chain sprockets and wear looked good on the right side which is 4-6 cylinder.Right side chain sprocket is installed backwards and the small chain sprocket does not look so good to me.I would question everything from the previous build.I just finished a 3.0 Carerra engine for Nathambs in September that had the left side & right side reversed and it ate the aluminum intermediate shaft gear.Fred