When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Potentially a minor snag today - got both heads on and torqued, which was great. But started preparing to place the pushrods and tighten rockers and came to the conclusion that my old pushrods are just too nasty, and I’m a bit worried that regardless stock ones will now be too short and/or weak to work the new springs etc. According to the machine shop tension is now about 330 lbs when open, which exceeds the rating of the stock pushrod replacements I’m seeing (for example Melling MPR373 which say max 300 lbs). I think I’ll do the Sharpie marker test with one of the old stock ones just to see how close it is with regard to length. But it might take a few days to get new ones if I need something special. Am I over thinking this?
New pushrods are cheap, so I agree. But why would they be too short now? Should just be stock length for roller lifters as you didnt do anything drastic valvetrain/milling wise. But also, yeah do the sharpie test to be sure.
New pushrods are cheap, so I agree. But why would they be too short now? Should just be stock length for roller lifters as you didnt do anything drastic valvetrain/milling wise. But also, yeah do the sharpie test to be sure.
Probably only a small difference, just due to the resurfacing. But then I’m using what is probably a slightly thicker gasket.
Still need stronger pushrods in this case though, right?
Test result - a little hard to see but seems to be pretty close. Slightly lower than right in the middle (lash adjustment?) but stock length seems right.
Wellll… both heads are on, pushrods and rockers tightened and adjusted, was finally installing the intake manifold and stripped the threads of one of the intake bolts going into the head. The damn thing didn’t even take 20 ft lbs before giving way.
Is Heli-coil the way to go here?
Man, so frustrating. I hope none of the other threads strip.
Looks like the bolt may be too short, only some of the threads at the top look damaged.
Yup, this was part of the problem. I decided to buy new bolts and they are 1”, a couple of threads shorter. Bad idea. Going to reuse the originals and Heli-coil that one - hopefully that will take care of it. 🤞
Only thing I’m not clear on, is that since this isn’t a hole that has a bottom and instead just passes through to open space, will the coil still be ok given it has nothing to bottom out against?
Last edited by Incipheus; Jun 22, 2023 at 03:34 AM.
Yup, this was part of the problem. I decided to buy new bolts and they are 1”, a couple of threads shorter. Bad idea. Going to reuse the originals and Heli-coil that one - hopefully that will take care of it. 🤞
Only thing I’m not clear on, is that since this isn’t a hole that has a bottom and instead just passes through to open space, will the coil still be ok given it has nothing to bottom out against?
Try a longer bolt first (make sure to use liquid Teflon tape to prevent oil migration). If it dosent grab the threads, go to heli coil.. they do not need to bottom out. Red loctite it. But you need to break the tang off 1st. Obviously do this with intake off and don't loose the piece as it would not be good!
This is tempting. But I think I'm going to heli-coil it and use the longer bolts for as robust a solution as possible. By tonight I hope to be back in business.
For some reason the FSM says to torque bolts 1 and 4 an extra 10 pounds (45 instead of 35). Why? I can't see any obvious reason for this...
Over the last several days I've been finishing reassembling this engine, cleaning out the fuel system, and working through a series of smaller issues that slowed me down on this first start-up.
Water pump, exhaust manifolds, freshly-painted valve covers
Distributor placed! Plus EGR tube and left accessory brackets
Right accessory brackets and hoses, ready for fuel rail!
Full assembled! Minus a couple of vacuum lines
Yesterday evening, I thought it was time to fire it up. Filled it with water, topped off oil, and then at the last minute I realized that the oil pressure gauge was pegged high (with engine off). Troubleshooting led to a bad pressure sensor (wish I realized this before re-installing the old one). So, today another parts store run and couple of hours spent replacing the sensor, and finally I was ready for another try this afternoon.
I disabled spark and cranked until it showed oil pressure, then fired it up for real. It sputtered to life in a few seconds - she's alive! I checked timing and I actually had estimated it pretty close to correct - it was around 2 degrees over TDC, so I dialed that back to 6 degrees BTDC. It started rough but seems to be smoothing out a bit. I actually drove it under its own power out of the garage and on to the street, and later back in which was fabulous. I will post a video soon, and also some follow-up notes - there is still a lot of work to do!! But fortunately transmission, power steering, and brakes seem good which is a relief.
This is a major milestone for me - it is the first time I have dug this deep into engine work before, and I was having these scary images in my head of head gasket leaks, water ingress, oil pressure problems - you name it. I *think* I actually did an alright job on this! Looking forward to getting the rest of the kinks ironed out - and breaking it in properly!
First, there is an intermittent electrical problem that is causing ECM problems. I know when this happens because upon switching the key to the run position the primary cooling fan starts running and the "Sys" message flashes on the instrument panel LCD. I haven't checked today, but previously it was throwing a code 41 (faulty or incorrect MEM-CAL). When it's in this state the engine will only run a few seconds before sputtering out. But I notice if I move the wiring under the dash this can go away. When it's not an active problem the fan doesn't turn on when key is in run position, and no Sys message. Looks like I will be digging around looking for a short or loose connection. Not going to be fun because I'm not sure where it's occurring.
Second, after running the new engine for about 10-15 minutes it nicely warmed up, I could see when the thermostat did its job and temp held right in the middle of the gauge for a while. But eventually it started to get too hot so I shut it down. The primary fan never turned on.
Both of the above issues will stop me from taking this new engine on some drives for break-in - I don't want to get stranded with a dead ECM, and I most certainly do NOT want it to overheat.
There is a third important issue as well, also electrical: the "CTSY" fuse blew. Less of a priority but this might be challenging to trace down. Meanwhile I have no interior lighting, nor running lights (not sure why running light are affected though).
I have been using the FSM for my 1991 to work on this '90, and although the '90 is really really similar I have noticed a few small discrepancies that might be particularly important when it comes to electrical work, so I might need to get a 1990 FSM after all. This applies to vacuum line routing as well - in '91 they moved the vapor canister to the back of the car and that changed a lot of these vacuum lines. This '90 had a lot of broken/bad lines when I bought it that are proving pretty hard to reverse engineer. For now I've simply capped a few of these vacuum connections at the plenum.
Good Job! The engine sounds great and I could hear that cam. Has a nice throaty sound. Should be a strong runner once you get things sorted. You are well on your way to bringing this one back from the grave and I have a feeling you will get lots of smiles and miles cruising in it. Really glad to see the positive outcome here!
Based on where you started, with what you got, I think you've done a great job here man. The thing was D E D when you started, and now you've gotten through most of the serious work and mechanicals so that she's a runner. I agree the wire-sorting is a PITA, but man, look how far you've already come!
The damn thing didn’t even take 20 ft lbs before giving way.
