What year did 11mm head bolts start?

[turbovanman²]

I am putting together an 87 TII engine, casting date is dec 86, fuel pump blockoff plate but the 11mm bolts are very tight? I thought 10mm was over in 85 or do I have a weird one off block?

[DodgeZ]

I think it was the end of 85 and all 86+

[Gaboon]

I think it was the end of 85 and all 86+

That's right as far as I'm aware.

[turbovanman²]

I think it was the end of 85 and all 86+

I must have the end of 10mm bolts, crap, need to retap them now, grrrrrr.

[Turbodave]

Simon, the block you've got should be 11mm, I've never seen any 87's with 10mm bolts. Personally I've never seen any 86 model year cars with 10mm bolts either, even ones with late 85 block castings. Make sure you've got the right bolts and that the threads are clean.

[turbovanman²]

Simon, the block you've got should be 11mm, I've never seen any 87's with 10mm bolts. Personally I've never seen any 86 model year cars with 10mm bolts either, even ones with late 85 block castings. Make sure you've got the right bolts and that the threads are clean.

Yes, there the right bolts, studs actually,

[Turbodave]

I would clean out the threads with a good bottoming tap and see how they go in.

[2.216VTurbo]

No such thing as TII with 10's

I know, it's Mopar so never say never I think your threads are just gunky.

Ha, Simon has GUNK in his TRUNK, er, underhood that is. SOmetimes you just gotta go with it

[sdac guy]

I don't think you can even get an 11 mm bolt or stud started in a 10 mm hole. Also, I do know that the ARP bolts & studs have a tiny bit more meat in the threads than the stock bolts. The advice on cleaning out the holes with a bottoming tap is good advice for all engine builds. It gives accurate torque application to every hole then.

Barry

[turbovanman²]

I don't think you can even get an 11 mm bolt or stud started in a 10 mm hole. Also, I do know that the ARP bolts & studs have a tiny bit more meat in the threads than the stock bolts. The advice on cleaning out the holes with a bottoming tap is good advice for all engine builds. It gives accurate torque application to every hole then.

Barry

If your using studs, that doesn't matter,

But anyhow, I guess every hole I tried was gummed up even though the machine shop was supposed to do all this. Cleaned them up and in they went. False alarm,

[DodgeZ]

If your using studs, that doesn't matter,

But anyhow, I guess every hole I tried was gummed up even though the machine shop was supposed to do all this. Cleaned them up and in they went. False alarm,

Sounds like it was an I d ten T error

[Turbo Joe]

the 10 mm swap was in mid 1985 for a fact. and yes never trust the machine shop to rechase all the threads. I always check everyone myself and find a couple that didn't get done...

[dodgeboy77]

Here's a slight thread hijack: I have an '85 that I'm going to change the head on. I got the Mopar Performance 11mm bolts for this job. If the engine has the 10mm bolts (I got an 11mm tap just in case) do I have to run a pilot drill down the 10mm holes? Since the thread pitch is the same I figured that may not be necessary. Can I just use the existing holes as pilot holes and start tapping?

The production date on my barely legible door sticker looks like 6/85 so I may get lucky. Thanks, Bill

[88_pacifica]

Only, and I mean only, if the tap is HIGH QUALITY and strong. If not and it breaks... you're fudged.....

[Turbodave]

When Mopar used to sell the tap it came with a drill bit.

[Turbo Joe]

The production date on my barely legible door sticker looks like 6/85 so I may get lucky. Thanks, Bill

its the date on the block you have to look at.. the closer to the mid and later on through 85 the better your chances for 11mm
this was the main reason I hated owning 85's.. when i popped a head gasket it was a gamble on the first try so I'd pull a head bolt out first and check it.
then I'd go get the right parts, although back then I bought the affordable fel-pro parts... on a sunday morning cause i beat on it sat nite...

[dodgeboy77]

Thanks, it sounds like the drill bit is a must. I've dealt with too many snapped taps in the past (actually, one is too many).

If I recall, the block casting date is somewhere in the vicinity of the turbo so I think I'll wait until I have good reason to be under there. Bill

[turbovanman²]

I would try without the drill first. 1mm isn't really that much so if you drill first, you could be rounding off the threads and thus weakening them.

[88_pacifica]

I would try without the drill first. 1mm isn't really that much so if you drill first, you could be rounding off the threads and thus weakening them.

I concur with the aforementioned statement.

[dodgeboy77]

Maybe some day I'll take a tap, drill bit and cordless drill to the local u-pull-it, find an older 2.2 with the head missing and experiment. Bill