Oil pressure

[cp2295]

Okay got a 4.0 i rebuilt 10k miles ago, it ticks pretty hard not been able to get it to go away so i kinda gave up on it. It has a 410 comp cam and dual valve springs. Replaced the lifters twice (it has melling in it now). Got the correct length pushrods and all. I was just curious, does 28 psi oil pressure at hot idle sound about right? Just put in a mechanical oil pressure gauge today and finally got some numbers lol


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[adsm08]

28 PSI at hot idle sounds great.

My 4.0 that I rebuilt myself only holds about 20 at idle once it gets warm.

 

[monstermazda]

Standard engine tech says for ever 1000rpms needs 10 psi of oil pressure at warm.

Are you priming then lifters before you torque rockers?

I would make should ever lifters mover freely I put engine builder lube on the lifters with I install them.

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[RonD]

Have you checked the fuel injectors, they can tick pretty loud, certainly can sound like valve train noise.

Use a longish vacuum hose as stethoscope and listen to each injector

No rocker adjustment on the 4.0l OHV and even 8psi oil pressure will keep enough oil in lifters and valve train to keep them quiet.
You could have a worn rocker, or valve stem
Next time valve covers are off check for loose pushrod by trying to turn pushrod with you fingers when valves are closed, you should be able to turn it, but should be hard to do, easy to turn would be worn parts.

You can get custom length pushrods to compensate for worn valve stem, rocker also needs to be replace if thats the case

 

[cp2295]

Ticking is loudest in the exhaust manifolds. Weird as that sounds.. Injectors are noisy but make a different noise. Ive gone through the valvetrain 1,000 times lol. New rockers, shafts, pushrods and lifters. New heads, which have new guides valves and seals.. Contact pattern is good on valve tips, had one set of rockers and valves go to shit in about 500 miles because i didnt line everything up correctly. Pushrods have correct preload and yes i always let lifters soak overnight and apply assembly lube.. Noise hasnt really changed in 10,000 miles just always kinda pisses me off lol.. Could it be from those dual valve springs putting too much force on the lifters, or possibly even making the valves smack the seats too hard sounds far fetched to me but i have ran out of ideas.


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[cp2295]

Would a high volume/flow oil pump be a bad idea? Ive heard good and bad things. But mostly that it can create too much pressure and blow seals out, followed by bearings..

I do wonder if its because of the cam having .500" lift idk though


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[cp2295]

28 PSI at hot idle sounds great.

My 4.0 that I rebuilt myself only holds about 20 at idle once it gets warm.

No problems with motor i take it then? Funny because before i rebuilt the motor it made a horrible rattle when it would cold start, and then when it was hot and above 3000 rpms. I hooked an oil pressure gauge to it and it only had 8 psi pressure at idle with even 15w40 in it! And the motor made no ticks other than the marbling noise these years make.

Also a side note, i did put 90-94 pistons in it to bump up the compression, could my valves be hitting the piston....? I doubt it because i pulled the heads when i changed the lifters out-twice- and there was no signs of contact.

Another side note, which should be of no surprise but if it sits for a few days and its real cold out, itll tick real hard until the lifters pump up.


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[RonD]

Well if it isn't valve train or injectors, what about exhaust leak

Cold and louder can be exhaust leak

Have you tried disabling 1 cylinder at a time while engine is idling?
Spark or injector stopped

That can tell you if it is an exhaust leak, or wrist pin or piston slap
Valve train noise wouldn't be effected by this so it would also confirm if it is valve train or at least a mechanical noise

 

[cp2295]

I have checked that noise does not change. So what you are saying is that most likely its valve train noise... So i hear it loudest in the exhaust and my exhaust lobes have a higher lift. The intake lift is .465" and the exhaust is .500" do i possibly need longer pushrods on the exhaust lifters maybe?

Does anyone know where i can find a pushrod length checking tool for our size pushrods!? The ones i got are 5.550" and the ones that are for sell on summit are all over 6" and theyre the only site i can find with pushrod length checking tools


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[adsm08]

No problems with motor i take it then? Funny because before i rebuilt the motor it made a horrible rattle when it would cold start, and then when it was hot and above 3000 rpms. I hooked an oil pressure gauge to it and it only had 8 psi pressure at idle with even 15w40 in it! And the motor made no ticks other than the marbling noise these years make.

Also a side note, i did put 90-94 pistons in it to bump up the compression, could my valves be hitting the piston....? I doubt it because i pulled the heads when i changed the lifters out-twice- and there was no signs of contact.

Another side note, which should be of no surprise but if it sits for a few days and its real cold out, itll tick real hard until the lifters pump up.


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If it runs you didn't hit valves.

 

[RonD]

If it runs you didn't hit valves.

Oh I don't know, lol.

I rebuilt a chevy 454 for/with a friend, he installed timing chain and cover one night when I wasn't there, I asked him if he lined up the marks(dots), he said, "I'm not an idiot, of course I did".

fast forward to starting up the engine, started fine but 'tick, tick, tick'
popped valve covers, install the oil clips and did rocker adjustment with engine running, could kill a cylinder by over or under tighting, but could not get ticks to go away.
Engine was running fine just frigging noisy, lol.
Did compression test and it was lower than I expected but not much, and equal across all cylinders

Started tear down, popped 1 head and sure enough marks on the pistons, same on other side.
Got timing cover off...................yup, he had used round manufactures stamp as cam gear timing mark, in fairness it did "look like" a dot, but not that much, lol.

Pistons were fine, did replace 4 valves on each side

But it DID run with valves hitting the pistons
Ran alot better and quieter when they didn't

This was years and years ago, before the snake cameras were available.
Now-a-days you could rent one of those cameras and pull out a spark plug to view top of the piston to see if that was happening, just to take it off the table once and for all