Hey Guys,

Did the oil pan bolts change between the SA and FB?

I recently built an engine where the front cover came from an SA but the rest came from two S3 12a blocks and I noticed that all the bolts I put in the front cover part for the oil pan are too loose and are stripping themselves (possibly forking the holes in the front cover because it's aluminum)

Were coarser threaded bolts used on the SA for the oil pan vs. the FB?

Jon

 

not to my knowledge Jon..i thought they were the same..are you using the bolts with the unthreaded nipple on the end?

 

Jon, i have to get back to work (speeders or drunks to catch), but check here: http://foxed.ca/foxed/index.php?page=rx7manual under the parts manuals and see if they list different part numbers for the oil pan bolts SA to FB. keep us updated on what you find.

 

That's a good idea.

Yeah I was using the ones with the unthreaded bit at the end. They fit nice and snug and torque up to spec everywhere except the front cover where they just keep turning

Jon

 

Well the manuals list two different part numbers, but the weird thing is that they're very different from any of the other part numbers I've ever seen in the manual.

SA : 987960616
S3 : 987940612

At least I think it's "98..." it could be "99..." it's so blurry. At least I know they're different part numbers..

I guess I have to go digging through my bolt bucket now.

Jon

 

1979 & 1980 had different thread pitchies...Not only for the oil pan but also for the brake calipers the the, the calipers themself, all the hard line brake lines. Master brake clutch, the master clutch cylinder, clutch cylinder line "hard" & "rubber" line, clutch slave cylinder, and all the hard line brake lines in the front of the engine bay...

1981-1985 including the 13b gsl-se all had the same thread pitch for all the parts listed above...

 

Take a look on here. http://www.mazdamotorsports.com/pages/cats/rx7pubs.html I will be changing over to the higher res ones soon.

 

SWEET! New high-res fiche. Freakin' eh!

Never before has "RTFM" sounded so sweet.

Jon

 

interesting and scary all at the same time ..... i really need to find myself a 79 parts car and strip the entire thing for future use .

good luck with the bolts Jon

 

Oil pan bolt thread pitch and diameter is the SAME!!! Always has been 6mm x 1.00 x length. Anyone who tells you different is smoking something. Length may be different which depends on whether 'load spreaders' are present; they act like an oilpan brace; older models had them but were absent on the FB.

 

the first couple pages of the fische has an explaination of the part numbers including bolts.

i forget exactly, but the first 4 tell you what TYPE of bolt, middle two give you the size (6mm 8mm etc) and the last 3 give you the length.

 

Viper, don't you have several front covers to compare? I'm telling you the bolts are the same (other than length, with lock washer or without etc) from at least '71 to at least '95 (beyond these years I have no direct experience). Someone obviously hamfisted that particular front cover of yours; stripped out the threaded holes (easy to do if you're trying to do things 'fast' instead of 'right', and because it's aluminum) and drilled and/or tapped for a larger size. Pretty easy to do; my friend had to do this on his rotary baja when he broke a load spreader bolt due to length when there was no load spreader present. He wound up going to 8mm x 1.25 and a nice'n short rat's nest bolt.

Do this for me, if you would: get out a thread guage and tell me the thread pitch, the diameter and if possible whether it is imperial or metric. And yes please post some pictures because I really do appreciate not being wrong. Thanks.

 

I'll see what I can do. I don't have a thread gauge, but I've organized my bolt box and I'll figure out exactly which bolts did fit and which ones didn't, and post pictures beside my vernier caliper.

I never thought of the fact that someone might have tapped them out. That makes sense.

So if I understand you right, the small 10mm-head bolts with the bit of unthreaded section at the end go on the S2-S3 blocks with no washer-like-object, and the ones that look to be the same diameter but are longer and threaded all the way go in the SA blocks with a sort of cut-washer pressure spreader thing?

But they should be the same thread pitch and diameter, just longer and using a washer? So technically, the small bolts *should* be able to work if the holes were undamaged because with the same thread and diameter it doesn't matter which you use.

When I go back out to add the washers to the bolts that I found which fit but bottomed out 1mm from the surface of the pan, I'll measure and take pics. That'll have to be tomorrow though, it's too late at night for that now.

Jon

 

yep iv used viser versa no difference
if it keeps turning it may be stripped the front cover and housings are easey to strip iv done it couple times

 

Jon, we'll look forward to the update!

 

Jon: I have a spare 12A cover (SA) that I can send your way if ya need it. It is just collecting dust at the moment.

In my experience, the bolts are the same in terms of size/pitch. I've mixed/matched between the old SA engine and my SE engine without problem. I is likely that the front cover had been stripped at some point (you have to be gentle with those oil pan bolts).

 

Thanks Kent,

I've got two spare front covers since I took apart 3 12a engines. I cleaned up and painted the SA front cover because it was the cleanest/nicest one of the bunch. I figured there were no differences between them so I didn't think much of it. I'll have to clean and paint one of my other ones and swap it if these bolts don't work. I just don't like removing it and re-placing it because I used black RTV on both sides of the oil pan and front cover gaskets for extra adhesion. I know that at least on the front cover gasket you shouldn't need RTV if the surfaces are clean enough but I didn't want to chance oil leaks since I had to sand some of the old caked-on gasket off.

Jon