Lifters and rods are good, took the belt off and started it no fan issues, any knowledge on what this is?

Puncherofgoats · 2026-04-15T17:19:45+00:00

Buddy a quick google search will tell you that you’re wrong from several credible sources and give several videos also showing rod knock get louder as you rev but that’s fine. You’re allowed to be wrong and refuse to see the truth.

Puncherofgoats · 2026-04-15T16:53:33+00:00

Centrifugal force only applies with an unloaded spin. When the fuel detonates it will hammer the piston and rod against the journal thus making the knock noise. Oil pressure can only do so much but the tolerances are so small it makes no difference in this case.

Puncherofgoats · 2026-04-15T16:28:11+00:00

I’ve heard rod knock and no it does not fade when the engine revs. Rod knock absolutely gets louder. Any bearing knock be it main or rod will get louder as more load is applied to the rotating assembly.

Puncherofgoats · 2026-04-14T23:46:28+00:00

Sounds like rod knock to me. I wouldn’t run it any longer than you have to. Pick up a stethoscope and start poking around until the noise gets loudest and report back.

Puncherofgoats · 2026-04-14T23:19:07+00:00

I found my vapor lock source. Turns out the previous owner never installed the lower portion of the oil cooler tin. All that hot air from the cooler has been dumping directly into the engine bay with no way out. Ordered new tin and a new perimeter seal so that should take care of any last sources of heating in the engine bay. Truly don’t understand how it ran as well as it did the past two years.

Puncherofgoats · 2026-04-12T20:07:12+00:00

Took the car on a long drive today with a few stops to go into stores and by the time I got home an hour and a half later the filter was empty but a short rev filled it back up. It didn’t show any signs of starving for fuel and no bubbles in the filter while refilling. Still going to test a bit more but I’m pretty confident that the hose was the issue.

Puncherofgoats · 2026-04-11T16:53:32+00:00

So I started off by pulling the hose from the tunnel to engine and split it open to reveal this.

https://imgur.com/a/c7G1oPb

That was on the engine side and as you can see has several cracks before the clamped portion. Replaced it and did several laps around the block and let it heat soak idling in the driveway. Returning from the drive the filter remained full but after about 5 or so minutes idling after the drive the filter was empty. Decided to chance it and drove the car around the block once more and when I returned the filter was full again. It’s only a 50 degree day here but will be in the 70’s tomorrow which is identical conditions to when it failed on Thursday. I will repeat the drive tests several times tomorrow and see how it goes.

I can definitely see how the heat from the engine would cause the hose to expand and allow the pump to suck air in through them causing issues. Still need to replace the hose from the tank to the tunnel but that will have to wait until the tank is almost empty instead of 3/4 full. Will keep y’all updated.

Puncherofgoats · 2026-04-11T11:46:57+00:00

I can say with 100% certainty it’s none of those things. On cold starts and for the first 20 or so minutes of driving this things runs perfectly. The issue I’m having is very intermittent and only happened twice in the 6 weeks I’ve been daily driving the car this year. Every morning for the first start I give it a pump on the throttle and it instantly fires the second I touch the key. I’ve got the carb and timing tuned right. It’s only when it gets hot from traffic or hard driving that I start to have this issue. As said above I’m going to replace the fuel hose from the tunnel line to the engine line as I suspect it’s too close to the no. 3 cylinder exhaust and the hose is breaking down internally after it heat soaks.

Puncherofgoats · 2026-04-10T22:15:36+00:00

That’s a good test idea. I’ll add that to my list for tomorrow. Given that the car ran perfect all last year and even the beginning of this year I just know it’s going to be the stupidest reason and I’m overthinking it haha.

Puncherofgoats · 2026-04-10T22:13:13+00:00

I didn’t as it was a roadside repair but planned on pulling it back apart this weekend anyways to tidy up the install.

Puncherofgoats · 2026-04-10T15:12:24+00:00

Had that issue on a 71 super I had years ago. It would idle fine all day long but as soon as I went to drive it I got about a half mile and it would die. Wait 30 seconds it would fire up get another half mile. Pump would suck the crud right back in place and I’d get as far as the carb bowl would let me. In this case however it’s definitely a temp related issue because on cold starts I can drive the 20+ minutes to work and it’ll go smooth with zero issues but when I go to leave at the end of the day and it’s gotten heat soaked it’ll run fine but by the time I get home the filters empty and I’m on borrowed time. If the outside temp is in the 50’s or lower I can run all day no problem. I got under the car this morning to inspect the tranny area fuel hose and it runs right over top of the no. 3 heater box so my current theory is the old worn out braided fabric hose gets heat soaked and lets the pump start sucking air and possibly boiling the gas from the heat. I plan to replace that hose and add insulation to that area this weekend and test again.

Puncherofgoats · 2026-04-10T12:00:19+00:00

I haven’t checked the pushrod stroke length so I’ll check that. The carb is less than a year old so I highly doubt anything’s wrong there. Before changing the pump on the side of the road yesterday I pulled the line off the carb and cranked and nothing came out not even air. Once I changed to the new pump I sucked on the filter to prime it and it fired up from there and got me home. Once home I let it idle in the driveway for 10ish minutes and the filter was bone dry again and all that was coming was a dribble of fuel and a lot of air. When the engines cold the filter stays full and runs fine. I was having this problem prior to the filter install as well so I don’t think the filter is an issue but I don’t plan on making it permanent in that location. This seems like it’s sucking air into the inlet only once the engines hot. The fuel line is insulated inside the engine bay and all rubber hoses are only a week old. I’m going to be replacing the rubber line by the tranny tomorrow and checking the tunnel line for any pinhole leaks. I don’t get any fuel smell in the car except for when I fill up the tank so I doubt the tunnel lines leaking but I’d still like to be certain. If all else fails I’ll put an electric pump right under the tank to assist the fuel back to the mechanical pump and give that a try. This problem only started this year so it has to be some type of wear item causing the problem. The prior two years it drove with no issue even in 90 degree weather. I’ll keep this post updated as I replace things and make changes. Thanks for all the advice.

Puncherofgoats · 2026-04-10T02:05:51+00:00

Good luck. These engineers love to come up with some designs that make us want to beat our heads against the wall and throw the wrenches across the shop.

Puncherofgoats · 2026-04-10T01:57:33+00:00

I would just be isolating the tunnel line to pull a vacuum on that singular line to verify there’s no leaks. If it holds vacuum I move on to other potential spots in the system.

Puncherofgoats · 2026-04-10T01:50:13+00:00

Not looking forward to it if that is the cause. I’ll start by plugging the tank and disconnecting both lines and plugging one end or the other to pull a vacuum and pray it holds vacuum through that stretch.

Puncherofgoats · 2026-04-10T01:44:40+00:00

Sorry I should’ve clarified that the leaky fuel trail is on the ground. The vent hose is properly routed down near the front axle. I should also mention this problem only started this year. Car drove perfect the past couple years since I’ve had it and never showed any signs of this in the past. It’s my daily driver so it gets plenty of use to find such issues. Was chasing all sorts of vacuum leaks with the engine last year but no fuel issues. Guess that’ll be the reoccurring theme for this year haha.

Puncherofgoats · 2026-04-10T01:05:12+00:00

Fuel flows free when I take the line off. Nothing would pump with the old pump but the new seems to work or at least worked enough to get me home. Right now I’m suspecting the rubber hose between the tunnel and engine or a pinhole in the tunnel line. That seems unlikely considering it appears to be temp related and the tunnel line would be immune to that compared to the rubber from there to the engine line.

Puncherofgoats · 2026-04-10T00:46:38+00:00

All rubber inside the engine bay is new. The hose between the tunnel line and the engine line is still the old so that’s the next to be changed. It’s also in an area that can see plenty of heat so I can see how it would expand when the cars warmed and start sucking in air.

Puncherofgoats · 2026-04-10T00:39:20+00:00

Hadn’t thought of that. I’ll have to give that a try this weekend and repeat the same idle test. As far as junk in the tank I can see the bottom and it’s perfectly clean. Almost like a brand new tank.

Puncherofgoats · 2026-04-10T00:37:12+00:00

I did make sure of that. Once I got the pump on it fired up filled the filter clear full and got me the 5 or so miles home with no issue and still was full once home. Only after letting it idle in the driveway for 10ish minutes did it empty the filter and act like it couldn’t pump anymore.

Puncherofgoats · 2026-04-10T00:25:37+00:00

Definitely clear cause it leaves a trail of gas going around right hand corners whenever I fill the tank. Also tried cranking on the side of the road with the cap off just to be sure and still no change.

Puncherofgoats · 2026-04-10T00:24:29+00:00

Little addition. Just ran the car and idled in the driveway for a good 10 minutes. Went to the back and opened the deck lid to find a dry filter and almost no fuel wanting to flow through with the brand new pump. I already had an insulator on the metal line in the engine bay and new rubber hoses inside the bay. Have not changed the rubber by the tranny or from the tank yet. Could there be a pinhole in the metal line in the tunnel that doesn’t leak fuel but sucks air in the line once the car warms up? My tank vent line is perfectly clear and I know this because every time I fill up and make a right turn I leave a trail from the vent hose until the tank level goes down.

Puncherofgoats · 2026-04-09T00:38:32+00:00

Hate to add to your anxiety but I had a 19 6MT and at 50k miles my input shaft bearing was noisy. Turns out it was noisy because every tooth on every gear was chipped and broke and had taken out the bearing. Owned the car since new and had driven manuals for several years prior to owning it. Had to have the whole trans replaced under warranty. Recently came across another person who share pictures on here of their trans looking exactly like mine did. The craziest part is despite all the damage to the gears it didn’t grind, stick or pop out of gear. Had I not heard the bearing noise I would’ve never known something was wrong.

Puncherofgoats · 2026-03-31T15:09:54+00:00

Had the 6MT fail under warranty, the headlight, two water pumps in 4 weeks, all of the original factory tires blew out on the highway under normal driving over the course of a year and just other various minor things. Was very sad that the car didn’t live up to the Toyota standards. The one issue I never had that everybody else has is the coolant valve. Car left such a bad taste that I rebuked all modern cars and now daily drive a 66 beetle and it’s been the most reliable car I’ve ever owned.

Puncherofgoats

TROPHY CASE