Engine rebuild gone wrong!
Thread Starter
Teching In
Joined: Mar 2024
Posts: 24
Likes: 4
Ok great tear it down again. Ugg. Ok i’m about to give up on this project. I turned wrenches and many other mechanical jobs all my life. But this was supposed to be a bucket list build.
If this was just a fresh in up rebuild stock maybe it would have been easier. But heads and block have been milled and cylinders bored. So now it’s requiring a ton of technical stuff i thought i could handle. Wish i had a friend or neighbor that could help. What a bummer!
Now I'm checking pushrod length and getting 8.75 * .050 = .4375 + 6.80 checker length 7.2375 + .060 ls7 preload .060 = 7.30 pushrods. I guess the new stock 7.4 pushrods are not going to work. I cant find correct 7.30 pushrods. Could i have done this wrong also.
I can see the intake is on the base circle.
I have never given up before.
I’m probably going to either have a shop finish building this, cant imagine what that will cost? or sell this and buy crate motor.
One bummed old guy! Thanks for the help everyone has given!
If this was just a fresh in up rebuild stock maybe it would have been easier. But heads and block have been milled and cylinders bored. So now it’s requiring a ton of technical stuff i thought i could handle. Wish i had a friend or neighbor that could help. What a bummer!
Now I'm checking pushrod length and getting 8.75 * .050 = .4375 + 6.80 checker length 7.2375 + .060 ls7 preload .060 = 7.30 pushrods. I guess the new stock 7.4 pushrods are not going to work. I cant find correct 7.30 pushrods. Could i have done this wrong also.
I can see the intake is on the base circle.
I have never given up before.
I’m probably going to either have a shop finish building this, cant imagine what that will cost? or sell this and buy crate motor.
One bummed old guy! Thanks for the help everyone has given!
Installed dot to dot.
Another newbie builder question came up.
I installed my stock rods with Mahle CB-1776A bearings that the machine shop supplied.
A friend asked me if i made sure i put the upper and lower bearings in the right place?
I didn't know there was a different bearing they all looked the same.
Do i need to take oil pan back off and check? I dont remember seeing anything like upper or lower or U or L on the bearings. Ugg
Another newbie builder question came up.
I installed my stock rods with Mahle CB-1776A bearings that the machine shop supplied.
A friend asked me if i made sure i put the upper and lower bearings in the right place?
I didn't know there was a different bearing they all looked the same.
Do i need to take oil pan back off and check? I dont remember seeing anything like upper or lower or U or L on the bearings. Ugg
In your case, yes because the upper is a .001 and the bottom is std. When half-shelling rod bearings like this to find a tedious clearance number, the standard size always goes in the cap, while the over/under goes in the beam side.
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I asked some other builders and was told it didn't matter that much as long as you put them all the same way throughout the engine.
Is it the same on the Mains do you put the standard on the block side or the cap side.
Same with half-shelling mains also, std bearing on the cap, and odd size goes in block. I don’t really have a science to explain here, other than it’s simply what the bearing manufactures tell you to do. I’ve never asked someone smarter than me as to the whys here…I believe I will phone a friend here…you have triggered my interest on the subject of placement.
Same with half-shelling mains also, std bearing on the cap, and odd size goes in block. I don’t really have a science to explain here, other than it’s simply what the bearing manufactures tell you to do. I’ve never asked someone smarter than me as to the whys here…I believe I will phone a friend here…you have triggered my interest on the subject of placement.
Thread Starter
Teching In
Joined: Mar 2024
Posts: 24
Likes: 4
Ok I finally finished the rebuild! Work schedule and 120 degree heat here in Vegas, Uggg! I oil primed the engine before startup and it fired up first try! Wow! My first build! Runs great kind of...
Recap
New pistons, rings, bearings etc. And DOD-AFM Delete kit - New stock GM Cam single bolt, ICT Billet Valley cover, Melling M365 oil pump suggested by Michigan MS and pickup tube o-ring, LS7 Lifters, Cam shaft plate, Replaced the oil pressure relief valve, (should I have plugged it instead?). Deleted DOD-AFM using Diablo sport I3 tuner. Engine runs great. Seems to have an idle surge. But problem I'm having is, the oil pressure drops real low when warmed up. 20-40psi cold then sitting at traffic light drops closer and closer toward 0. Never has hit 0 yet but maybe 5psi on the cluster gauge. Don't have a mechanical gauge.
When I did the rebuild I thought I researched oil pumps, but guess I didn't. Could it be the Melling M365 pump?
I used Lucas 30w oil breakin oil and AC Delco pf48 filter. Drove it maybe 50 miles so far drained oil and replaced again same oil but tried a STP Extended Life Oil Filter S10060XL. No change still low oil pressure when warmed up driving. Google search turns up tons of could be's! Oil pump, pickup tube ring, plug towers with revits, oil pressure sending unit, etc.
You guys have helped me so much! Got me out of the dumps when the going got ruff! I almost ditched the project!
Now I need help on this.
Recap
New pistons, rings, bearings etc. And DOD-AFM Delete kit - New stock GM Cam single bolt, ICT Billet Valley cover, Melling M365 oil pump suggested by Michigan MS and pickup tube o-ring, LS7 Lifters, Cam shaft plate, Replaced the oil pressure relief valve, (should I have plugged it instead?). Deleted DOD-AFM using Diablo sport I3 tuner. Engine runs great. Seems to have an idle surge. But problem I'm having is, the oil pressure drops real low when warmed up. 20-40psi cold then sitting at traffic light drops closer and closer toward 0. Never has hit 0 yet but maybe 5psi on the cluster gauge. Don't have a mechanical gauge.
When I did the rebuild I thought I researched oil pumps, but guess I didn't. Could it be the Melling M365 pump?
I used Lucas 30w oil breakin oil and AC Delco pf48 filter. Drove it maybe 50 miles so far drained oil and replaced again same oil but tried a STP Extended Life Oil Filter S10060XL. No change still low oil pressure when warmed up driving. Google search turns up tons of could be's! Oil pump, pickup tube ring, plug towers with revits, oil pressure sending unit, etc.
You guys have helped me so much! Got me out of the dumps when the going got ruff! I almost ditched the project!
Now I need help on this.
On The Tree
Joined: Jun 2022
Posts: 111
Likes: 35
From: Las Vegas, NV
I had similar low oil pressure when warm... see the link for what I found. My oil pressure would rise with RPMs but was probably around 10psi warm idle. After the cam bearing swap with 10-40w hot idle is ~30psi @ 220* oil temp. This is with johnson 2110r lifters which I've read several posts claiming ~ 5-10psi pressure drop
Low oil pressure for me was..
Low oil pressure for me was..
Thread Starter
Teching In
Joined: Mar 2024
Posts: 24
Likes: 4
Lucas break in 30w oil
I cant find where i wrote down clearances, but seams i remember .0019. I only remember they were in spec when i checked. Ive research so much now i dont remember what was mine or research. Ugg. I wrote them done and cant find it.
I did install a brand new crank and the machine shop that balanced the engine supplied the bearings.
Oh no, cam bearings!!!??? This would mean r&r engine tearing it down again correct? I dont think i can do it. Ugg.
I installed Dura-Bond CH25 bearings
Could i run a different wt oil?
plugging the oil pressure relief valve? How would this help my hot idle oil pressure? Trying to understand this is all!
Thank you guys for the help.
I cant find where i wrote down clearances, but seams i remember .0019. I only remember they were in spec when i checked. Ive research so much now i dont remember what was mine or research. Ugg. I wrote them done and cant find it.
I did install a brand new crank and the machine shop that balanced the engine supplied the bearings.
Oh no, cam bearings!!!??? This would mean r&r engine tearing it down again correct? I dont think i can do it. Ugg.
I installed Dura-Bond CH25 bearings
Could i run a different wt oil?
plugging the oil pressure relief valve? How would this help my hot idle oil pressure? Trying to understand this is all!
Thank you guys for the help.
Last edited by Billh1961; Aug 21, 2024 at 09:08 AM.
On The Tree
Joined: Jun 2022
Posts: 111
Likes: 35
From: Las Vegas, NV
Should use a mechanical gauge to verify oil pressure.
Some common reasons I have seen for low oil pressure (in order of difficulty)
- Oil and oil filter... try a WIX filter and 20/50w (or 15/50w oil)
- Valley cover O rings... did you use them or block off the oil passages in the towers?
- O ring for the oil pickup tube
- Oil pump pressure relief spring
- Cam retaining plate
- Cam bearings (or other bearing clearances)
Dura-Bond cam bearings was what the machine shop ended up using that solved my oil pressure problems. Not sure what exact part number though. He did tell me that one block he setup with cam bearings and verified with a cam he uses in his shop was picked up by the customer who used his own comp cam. When installed he wasn't able to rotate the cam very easily while the shop cam spun freely... swapped the cam bearings from dura-bond to cleveite and resolved the issue.
I think special attention is needed with cam/cam bearing choice to verify clearances and each journal may be a little different.
Only relating what my experience was and really can't provide any more insight on how to measure or verify cam bearing clearances. I would start with a mechanical oil pressure gauge and go from there.
Some common reasons I have seen for low oil pressure (in order of difficulty)
- Oil and oil filter... try a WIX filter and 20/50w (or 15/50w oil)
- Valley cover O rings... did you use them or block off the oil passages in the towers?
- O ring for the oil pickup tube
- Oil pump pressure relief spring
- Cam retaining plate
- Cam bearings (or other bearing clearances)
Dura-Bond cam bearings was what the machine shop ended up using that solved my oil pressure problems. Not sure what exact part number though. He did tell me that one block he setup with cam bearings and verified with a cam he uses in his shop was picked up by the customer who used his own comp cam. When installed he wasn't able to rotate the cam very easily while the shop cam spun freely... swapped the cam bearings from dura-bond to cleveite and resolved the issue.
I think special attention is needed with cam/cam bearing choice to verify clearances and each journal may be a little different.
Only relating what my experience was and really can't provide any more insight on how to measure or verify cam bearing clearances. I would start with a mechanical oil pressure gauge and go from there.
