heres the newest encounter.

i'm ready to install the heat exchangers, but the heads i have do not have exhaust studs. no problem right? i measure my 1.7... roughly 2" long 8mm x 1.25. i get 8 studs and am all set to install. nope too big. check the hole it's a 10mm x 1.5. o.k. thats all good maybe 2.0 got a bit more h.d. then i look at the h.e. (1.7/1.8 s/s) and check the fit into the flanges. barely fit and might work but only if the alignment is exact to to heads (no room for out of align stud variance).

the heads are a vary well done set from LN i bought from jake so i'm sure nothing hoki was done. if in fact 2.o heads had the same size studs as 1.7/1.8 then i expect the theads were stripped and retapped to a larger 10mm.

i'm thinking to tap and heli coil to the 8mm size... what doeth ye all say?

mike

They are all the same size (stock). Those have obviously been drilled and tapped larger. I'd have to research it, but I think a 10x1.5 hole is already too big for a 8x1.25 helicoil. Although IIRC, the timesert 8x1.25mm insert requires a slightly larger hole than a helicoil does. I'd have to check all of that though.

according to the local flaps, the heli coil for the 8 x 1.25 calls for a 21/64 drill bit. i checked the butt of the 21/64 bit into the hole and it wont fit. i think i can drill it and tap to heli coil it. i have (8) 8mm heli coils in my misc heli collecton. i just have to dig up the right drill/tap. i'm just a little surprised this detail was left undone on these heads.

Heli-coils will fail. They can't stand the stresses of the exhaust. 8mm/9mm and 8mm/10mm step studs are available or Timeserts, no helicoils. Do some research, find out exactly which threads are in the heads and find the right thing to screw into the holes. The first rule of 914 repair- do no harm.

You will have to use the step studs. 10mm for the head & 8mm for the HX.
I had Len do my heads, complete with new studs installed. IIRC, the 2.0 had slightly longer studs than the 1.7, not sure why, and the step stud is probably only in one length. Check with Jake to order the correct ones. Be sure it is a 10mm threaded hole first. I believe the first oversize is 9mm, and it is not easy finding 9mm hardware to test fit, however a 10mm will not go in.

what are timeserts? where are they avalible?



step studs sound like the way to go. i havent tried to hard yet, but it would be great if i could find them locally to cut time delays of sending for them. i swear this type IV has attempted to suck punch with hidden at any given time.

yes i ran a 10 x 1.5 in the threads

Fastest is to order from Jake. They are not a common item, so a local source is not too likely except a bug specialty shop.

http://www.914world.com/bbs2/index.php?showtopic=81400
http://www.914world.com/bbs2/index.php?showtopic=79727
http://www.914world.com/bbs2/index.php?showtopic=76983

o.k. good stuff. soo... i guess this time sert is another form of helicoil? i've seen a few say the've used heli coils sucessfully, and an other recomend not to use. why from what i got the time sert requires a kit to tap/seat. what i'm wondering is, does this lock the stud in and why is it better than heli coil. is it an reasonable option to tap and install the stepped stud (10 x 8mm) w/o the addition of either h.c. or time sert on the exhaust?

The timeserts are solid rather than a spring, and they're harder so they're more resistant to damage. There's a lot of information here-
http://www.timesert.com/
If the holes are already threaded for 9mm or 10mm step studs then that's what I'd use. If not I'd use a timesert.

did the heads come from len or charles? len does the heads and charles does the nickie cyls.

k

I understand you want to get this done but, if the heads already are drilled and tapped for 10mm step studs , why would you even consider timecerts? Adding a couple of extra steps is never good. It is just that much that can be screwed up. Timecerts are no sure thing if you are installing them under the car. I know I ruined a head once. If you ruin the heads think about how long that will take to fix. Do it right the first time.

Jakes store gets things out fast if they have them in stock. Be patient, it will pay off in the end.

Dave

i bought them from jake, built by len. they were for a project he decided not to use them. they are beautifully done but this rockerstud and now oversize holes with no studs is really setting me back.



dave, i in no hurry to get this done as i've already way overshoot or goal (going on 6 mo.'s due to every delay imaginable) i've never dealt with the oversize studs, are the stepped stucs drilled for 10mm x 1.5? if so, then i just have to purchase and install the studs, i just haven't been able to get info on aircooled forum about if i can substatute the h.d. stepped rocker studs that another member recommended. the engine is on the stand so its easy enough.

Talk directly to Len, his handle here is HAM Inc, and he can tell you everything you need to know about heads.

Helicoils and Timeserts use the same tap. The Cap'n

One of the reasons I shy away from 30 year old head castings is because of exhaust stud issues. The heads you have were my personal heads, they had flawless threads in the heads for the larger diameter studs.



First off, you should never seta time line for an engine build. Remove the clock from the shop and don't let time dictate ANYTHING! As soon as it dies, you have beaten yourself.

This is as simple as buying the correct studs from my store and installing them, they are not cheap, but they are also 4140 chromoly and you'll never break them.

What you need to do is verify if they are 9mm or 10mm, post a pic and I'll tell you.

great thats what i need to know so i can get the studs ordered. i'll confirm the thread size and get the spark plugs & studs ordered.



initially i had what i thought was a reasonable time set (hoping to have it drivable for kenny's last senior h.s. days). never letting the clock dictate the build or short cutting as is evedent here. i've been in and built alot of other motors in my day, but never this deep in a type IV... interesting to say the least. not to mention it's a different world from a chair



i 'll recheck to confirm size and get them ordered as soon as i can



i have no studs to take pictures of, i will run a bolt to confirm

Thats exactly what I state time and time again. I don't give a damn how much "other" experience anyone has, it is all thrown away when working on this engine.

People that believe that "All engines are the same and the the TIV is no different" usually have horrible experiences because they use their bad habits on the TIV and it won't tolerate them. At all.

hope thats not directed at mwa...