Author Topic: ROUNDED PRESSURE SENSOR THREAD ON BLOCK  (Read 491 times)

Offline jcollyer

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ROUNDED PRESSURE SENSOR THREAD ON BLOCK
« on: August 10, 2017, 12:34:20 pm »
HI GUYS JUST GOT A G40 FEW MONTHS BACK BASICALLY I HAVE AN ISSUE AND NEED ADVICE ON WHAT TO DO.... BASICALLY I WAS FITTING A NEW PRESSURE SENSOR AND I HAVE MANAGED TO ROUND OF THE THREAD IN THE BLOCK WHAT DO YOU GUYS THINK IS THE BEST WAY TO SORT THIS AND ALSO WOULD I NEED TO STRIP ENGINE AS ALIMUNIUM BITS MAY HAVE GONE IN BLOCK WHILST ROUNDING BOLT DO YOU THINK I COULD GET AWAY DRAINING OIL AND FLUSHING SYSTEM PLEASE IF ANYONE IS A GOOD MECHANIC OR HAS EXPERIENCE PLEASE PM ME IF YOU THINK YOU KNOW WHAT I SHOULD DO I WOULD REALLY APPRECIATE IT MY LOVLEY G40 IS OFF ROAD BECAUSE OF ME BEING AN AMATEUR SOMEONE PLEASE HELP ME GET MY POCKET ROCKET SORTED

Offline randombadger69

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Re: ROUNDED PRESSURE SENSOR THREAD ON BLOCK
« Reply #1 on: August 10, 2017, 11:06:02 pm »
So you're replacing an oil pressure sensor in the cylinder head?

When you say you've rounded off the thread in the block, do you mean the thread has stripped out as you've removed the sensor?

If so; ideally a helicoil would need to be fitted. This involves cutting a larger thread (casting permitting) and winding a threaded insert with the correct internal pitch into the now oversized thread. To do this job you would really want to do it on the bench and be sure all swarf is cleaned out of the head.

Either remove head and have a go yourself if you're a confident engineer or take to a machine shop to have the job done. Other option is the change the cylinder head itself. The polo GT shares the same cylinder head casting (although the exhaust valves differ on a G40 and the camshaft is G40 specific, the internals can be swapped however). The part number is on the exhaust side of the head iirc and ends in a G.
« Last Edit: August 10, 2017, 11:09:58 pm by randombadger69 »

Offline ereeiz

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Re: ROUNDED PRESSURE SENSOR THREAD ON BLOCK
« Reply #2 on: August 11, 2017, 11:34:07 am »
I thought all the petrol Polo heads were the same. Just what I've read over time though, never looked it up myself. The only differences are G40's have sodium coated valves and each engine would have its own cam. Everything is the same size though I thought?

Here's a link to a parts catalogue in case you want to look into it; http://www.oemepc.com/vw/part_single/catalog/vw/markt/RDW/modell/PO/year/1991/drive_standart/120/hg_ug/103/subcategory/3010/part_id/3685734/lang/e#sec_1

Offline jcollyer

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Re: ROUNDED PRESSURE SENSOR THREAD ON BLOCK
« Reply #3 on: August 11, 2017, 03:33:18 pm »
cheers guys so the best thing to do is get cylinder head out and get helicoil kit.....do you guys know where i could get replacement cylinder head bolts ?

Offline PeteG40

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Re: ROUNDED PRESSURE SENSOR THREAD ON BLOCK
« Reply #4 on: August 12, 2017, 11:18:58 am »
Take head off.  But if it's off I'd recommend getting o it skimmed and refurbed it'll funds allow.  The machine shop can fit a helicoil etc too.

Most people use stock cl head bolts.

For proper G40  spec ones try BGA.

Pete

Offline randombadger69

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Re: ROUNDED PRESSURE SENSOR THREAD ON BLOCK
« Reply #5 on: August 12, 2017, 03:47:21 pm »
@Ereeiz the 3F and PY share the same head. That parts catalogue lists the number as 030103351E
The ports are dimensionally different to the other heads on spi models. I did measure them myself years ago. Not sure whether the info ever got saved on cp. Someone did measure them and shared their findings although can't remember who.

Offline ereeiz

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Re: ROUNDED PRESSURE SENSOR THREAD ON BLOCK
« Reply #6 on: August 18, 2017, 10:50:28 am »
@Ereeiz the 3F and PY share the same head. That parts catalogue lists the number as 030103351E
The ports are dimensionally different to the other heads on spi models. I did measure them myself years ago. Not sure whether the info ever got saved on cp. Someone did measure them and shared their findings although can't remember who.

Interesting to know. Thanks! I'll try and remember to look into it next time I'm playing about with car stuff, reckon my mate has a couple of non G40/GT heads lying about. Would be interesting to see.