Cam box stripped thread

Cliff R · Post by **Cliff R** » Thu Nov 15, 2012 7:26 pm

Just stripped one of the cam box cam shaft front seal bolt holes in the cam box on the L series

Bolt looks like an M6 x 1.00.
Anyone had any luck with Helicoils on this application or tapped out a larger hole or tapped out an imperial hole or some other method to repair

Matt · Post by **Matt** » Thu Nov 15, 2012 8:56 pm

Some pics would help. But you should be able to get away with it or change to a bigger size

stork955 · Post by **stork955** » Fri Nov 16, 2012 5:45 am

G'day, M6 x 1.0 mm helicoil is the best way.

Cheers,

Stork

Cliff R · Post by **Cliff R** » Fri Nov 16, 2012 2:54 pm

I forgot how expensive the Helicoils are.
$60 + bucks for the kit, had to buy it though.
Will only need the "refills" next time.

Silverbullet · Post by **Silverbullet** » Fri Nov 16, 2012 4:26 pm

Cliff R wrote:I forgot how expensive the Helicoils are.
$60 + bucks for the kit, had to buy it though.
Will only need the "refills" next time.

Amen to that, and don't get the kits "M6x1" tap mixed up with other taps, cos it ain't M6x1 that's for sure

Cliff R · Post by **Cliff R** » Fri Nov 16, 2012 8:04 pm

2 x M6 Helicoils inserted. The 2nd thread was stuffed too. Progress tonight as follows.
Cam shaft back into housing, front seal and cam keeper housing tightened to torque. Enough for tonight !
Need some rest at the moment as it has been a hell of a week at work. The "Minister" is out at a girls sewing night, kids in bed and I have been left with a very nice tea so a shower and some TV and off to bed for me.

Re normal taps compared to Helicoil taps. I found the following on a Helicoil website.

"To illustrate the difference between a standard tap and an STI (Screw Thread Insert tap)...

A standard tap used to create threads for a 1/2" NF fastener has a major diameter of .500" with a pitch of 20 threads per inch.

The corresponding STI tap for that particular insert has the same thread pitch of 20 threads per inch, but has a larger major diameter. (In this example, the STI tap major diameter measures .568".)"

Hope you all got that because I'm fragged if I have at the moment. What I take from this is a standard tape is differerent to a normal tap SO DONT BREAK IT.

YouTube · Post by **El_Freddo** » Fri Nov 16, 2012 8:45 pm

Bugger mate! I've been lucky with these bolts thus far.

How'd you go re-tapping on the threads with the engine in car?

Cheers

Bennie

Cliff R · Post by **Cliff R** » Sat Nov 17, 2012 8:10 am

Bennie
No problems with tapping as the issue is with the 2 bolts that hold the cam keeper and front cam seal in place.
I have the cam box out of the car and cleaned up, with the cam back in, the 2 treads sorted and I am waiting for the day to warm up a bit before having a go at putting the cam box and cam back onto the engine. I believe it will help to use some grease to hold the rockers in place so they dont fall off.
Will have a look at where the cam box attaches to the head to clean that up, the groove in the cam box is all clean, so I will prime the new lifters, insert them, put sealant onto the grooved side of the cam box, sit the rockers on, and attach the cam box.
Simple really isnt it...well in theory it is but I will see how I go shortly.

Cliff R · Post by **Cliff R** » Sat Nov 17, 2012 12:42 pm

What is the point of the circlip on each of the lifters.
Are they a stop for the lifter so it only goes into the head so far or what ?
Do they compress in and go into the lifter "tube" to hold the lifter ?

YouTube · Post by **El_Freddo** » Sun Nov 18, 2012 10:02 am

Cliff R wrote:Bennie
No problems with tapping as the issue is with the 2 bolts that hold the cam keeper and front cam seal in place.

Ah yeah, I thought you were talking about the 8 bolts that hold the cam box on the head - these are the buggers I've had a couple not quite tension up but are still holding!

Cliff R wrote:What is the point of the circlip on each of the lifters.
Are they a stop for the lifter so it only goes into the head so far or what ?
Do they compress in and go into the lifter "tube" to hold the lifter ?

They are as you said, there as a stopper. If you manage to compress one into the lifter tube then you're doing something very violent and very wrong!

Cheers

Bennie

Cliff R · Post by **Cliff R** » Sun Nov 18, 2012 11:02 am

"They are as you said, there as a stopper. If you manage to compress one into the lifter tube then you're doing something very violent and very wrong!

Bennie

Thought as much, realised the circlips dont compress enough into their groove to allow the lifters to go any further than the tube end.
All good.

z1000st · Post by **z1000st** » Sun Nov 18, 2012 11:47 am

Cliff R wrote:I forgot how expensive the Helicoils are.
$60 + bucks for the kit, had to buy it though.
Will only need the "refills" next time.

As an option check out Radum.com.au Thread repair kit [RDM-BM94-4060] 5 sizes for $36

Cliff R · Post by **Cliff R** » Sun Nov 18, 2012 11:50 am

z1000st
Thanks, interesting web site, will have a proper look when time permits.

AlpineRaven · Post by **AlpineRaven** » Fri Nov 30, 2012 10:31 am

if YOU have to stick with M6, you could drill a bigger hole to M10 in with locktite and redrill correct position and retap as M6. Ive done that a few times on machines where it has to be 6mm or specific size.
Cheers
AP

steptoe · Post by **steptoe** » Tue Dec 04, 2012 4:29 pm

done the M6 repair by helicoil meself, don't tink enough meat to do an oversize to M8

Cliff R · Post by **Cliff R** » Sat Dec 08, 2012 2:50 pm

Havent been on the forum for a while, too much going on at work.
All sorted with the el cheapo lifters from Repco going great with no noises and the M6 helicoils sweet.
Still leaking a bit of oil from the drivers side cam on the front seal but as long as this does not go on the belt I am not too concerned. Only a slight leak anyway.
Thanks for everyones help and comments.

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Cam box stripped thread

Cam box stripped thread

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