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6G Celicas Forums > 6th Generation Celica > Engine/Transmission/Maintenance
Langing
What bolts do you use to hang 1994 7AFE block on Harbor Freight engine stand?

I just tore down my 7AFE and want to hang its block from my Harbor Freight engine stand. Was told to use the four threaded holes used by the larger transmission bolts, so that is what I am trying to do, but the bolts need to be longer than the xmission bolts and I am having trouble understanding a couple of things.

1) My bolt heads are marked with two slashes which indicates (to me) they are Grade 3 SAE (obsolete) standard bolts. I measured one to be:

(L = 3.0', T = 20 tpi, D = 0.47")

BUT. . . since they have a diameter I measured to be 0.47", and I noticed that 15/32" diameter equals 0.46875" = 11.906 mm

AND. . . the guy at Fastenal showed me that it will easily screw into his 12 mm METRIC hole, suggesting that the bolt is METRIC?

FIRST QUESTION: Is this bolt SAE, as the Grade marks indicate, so did Toyota use SAE bolts in their 1994 7AFE engines, or is it a mismarked METRIC, or something else entirely? Does anyone know what bolt is specified by Toyota.

2) The bolt hole template at Fastenal has a variety of both SAE and METRIC threaded holes. There is no hole even close to the size of this bolt except for the 1/2" hole, and the 1/2" hole is far too big to be the correct size of this bolt. On the other hand, this bolt screws easily into the 12 mm hole of that template. I think it was slightly loose, but otherwise seemed to fit perfectly.

SECOND QUESTION: If I tried to use a 12 mm bolt with the same threads (very fine machine) as an equivalent to the bolt in question, and it happened to actually be SAE, would it not be 'slightly' different than the original bolt, and if so, would tighting the metric bolt into the SAE hole somehow screw up the threads?

3) The guy at Fastenal said to me that he did not have a bolt of even the same length as the 12 mm (SAE) bolt, the original one taken out of my engine (3.0"). The length of his bolts are all less than 3.0". Therefore, I surely cannot get one from them that is 3.5" (the length I actually need to make the engine stand work)

THIRD QUESTION: Where can I get a 3.5" bolt with 20 threads per inch (or 1.25 mm per thread) that is 0.47" in diameter?

The only thing left to say that has any possibility of relating to my problem is that several years ago I had the clutch replaced, which required separation of the engine and transmission. There is a possibility that during that operation the bolt was switched. I am saying this because their failure to replace two of three fasteners in the passenger side motor mount caused the motor to give way and drop almost 2 inches subsequent to the operation, and that is why I have never let another auto technician touch my Celica.

I am perplexed. . .
Bitter
I'm sure they're M12 diameter, double check the thread pitch then plug M12x*** into ebay and find some the right length somewhere or buy some threaded rod of the correct pitch and diameter and make your own bolts with double nuts to serve as the head.
slavie
This is a Toyota, absolutely all bolts are metric. The only exception are the bolts that tie down the seat belts - those are required by US law to be specific SAE thread, so they made this weird bolt with SAE threads and Metric head to comply without having to supply their factories and dealers with non-metric tools. Ask me how I know that. And don't ask me if I've ever had to drive without a seatbelt for 2 days.

Toyota uses it's own marking system on the bolts (or maybe it's some Jap/global standard that I don't know about), which is detailed in the factory service manual. They do NOT correspond to SAE markings. Here:
https://poetryoverland.wordpress.com/tag/toyota-bolts/

You can get the longer M12 bolts at Lowes - that's where I got mine from. They're expensive at a few bucks a piece, but what are you gonna do.
Smaay
actually they are M14 bolts. i think i got mine from lowes as well
Langing
Thanks all for taking time to read and reply. Much appreciate!

The link provided by slavie captures the reason I was so completely perplexed, as it gives Toyota's version of 'standard' bolts. The symbol on the head of the bolt I was looking at is in that diagram. It is the bolt with two slashes, one going up (radially) and one going down. Originally, when looking on-line for what the heck that symbol meant, I discovered that the SAE grading standard once used the same two radial slashes to mean Grade 3, but that source noted that the symbol was obsolete. At that time I was convinced that I had an SAE bolt that was obsolete. Yes, even though it was a Toyota engine and I knew Toyota used metric hardware. That conflict was bothering me, but in the way back of my mind.

It was when I carefully remeasured the bolt using both the SAE and metric thread gages that I finally realized that I had mistakenly thought it fit both SAE 20 threads per inch AND metric 1.25 mm per thread. In fact, it did NOT perfectly fit SAE 20 threads per inch. Though close, those two bolts are NOT IDENTICAL! Only then did I start to believe it was a metric bolt, making sense of it being a Toyota engine using metric bolts.

Once I believed it to be metric, I could find plenty of bolts that fit my need from my friend's 800 pound bin of (useless but expensive) metric hardware collected as he parted out high end motorcycles for his on-line business. So, I have a source of free bolts, thank you.

It seems that Toyota has its own 'standardized' world, despite all the work corporations put into creating the SAE and metric standards. The lesson I am taking away from this issue drives home the importance of that Toyota 'standard' bolt chart slavie pointed out. That chart is in my Toyota (Celica) Repair Manual. I just needed to know it was there and how important it was to my question.

BTW: bolt size is M12
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