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Author Topic: JMR powered hillclimb & sprint MK2  (Read 274 times)

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Offline JMR

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JMR powered hillclimb & sprint MK2
« on: July 04, 2014, 12:25:13 am »
Some MK2 action for your pleasure...

Rising Hillclimb & Sprint man Jon Wool runs Mr Sticker along with father Chris and makes all my Logo's, cards, stickers etc, and started taking an interest in MK2 Golf's a couple of years ago, first with a 16v road car which he swapped in an ABF after killing the KR, then the current race car came up for grabs at a steal with a modded 8v on K-star, Koni's, Eibach bars etc. Jon stripped it to use in the road class in Hill's & Sprints after a couple of local fun day events saw the "go faster" bug tap him on the shoulder, first with a head and cam upgrade from what was originally fitted, followed by some bargain 45 Dellorto's...the bug was starting to nibble a bit harder by then, along with a 4.25 final drive and Quaife diff...actually "my" Quaife diff...about time I upgraded!

We squeezed 150hp from the old engine with poor squish, a std valve ported head and a Newman 280 road cam, which saw Jon start to harass some of the mid field cars in the class, along with some more chassis & brake work & a bit of a diet...the car not Jon. However, upon starting the car to put on the trailer for the last event of last year we had a call from Jon to "come and listen to this noise will ya and tell me if I can use it"!.....not with a knocking big end you cant no!

So over the winter Jon hunted down a std 1800 block with good bores & pistons and we set about a fresh bottom end. Jon wanted to get involved to not only lighten my load but just show an interest in what goes on to build a modified engine. I had the piston crowns machined to give a full diameter squish band and a reduced bowl to raise the C.R, along with tighter clearance once the block was machined down to suit. Jon set about cleaning everything to my standard & gave the block a fresh coat of paint. I fitted up the rods with ARP bolts and re rung the pistons and popped them into the freshly honed bores, leaving Jon to torque everything up and dress up the block ready for the head.

A part way through the build I had regular calls along the lines of "what if we..." from Jon, resulting in his "budget" engine getting some of our steel buckets, my favoured 318 degree hillclimb cam ground by Piper for me some and Isky valve springs. The head received it's third round of mods with some 40.5mm inlets as they fit on the std seats and the original 33mm exhausts.

We popped it on the engine dyno for a work out at AP Motorsport where Alvin and I squeezed 170hp at 7000 from it. The above spec head/cam/carb combo is capable of making well over 180hp in 1800 form at 500-1000 more rpm, but we've found the realistic ceiling of std piston rings. Due to the thicker nature of them over thin items in forged pistons they break the seal against the bore wall much over 7k due to flutter and create high crank case pressure which in turn forces oil out of the breather...at least Alvin's dyno wont go rusty!

I've seen this before and thought it was an isolated case but this is the 3rd time now on 1800's with std pistons...Nick Penfold's VAG trophy car above is showing signs of it after a couple of years hard use knocking on the door of 7-1/2k at times, though driving through 7000 isn't as hard on them as holding it over 7 on the dyno....the positive side of this is knowing the limits and making engines survive by using them as intended, though they appear to be withstanding the abuse so far on a 13:1 C.R and have given Jon a couple of 3rd's in class this year to date, his times now knocking on the door of some of my old times but 20hp less and over 100 kilo's more, so we're both more than happy with the performance.









Jon in action at Wiscombe hillclimb...

http://www.youtube.com/watch?v=Ye0hdtEyc04
« Last Edit: July 04, 2014, 12:28:36 am by JMR »

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Offline ces

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Re: JMR powered hillclimb & sprint MK2
« Reply #1 on: July 04, 2014, 03:40:33 pm »
interesting & nice  8)

Offline Tristan

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Re: JMR powered hillclimb & sprint MK2
« Reply #2 on: July 08, 2014, 11:34:57 pm »
Interesting idea on machining the pistons, does it make much difference? Do you need to deck the block after?

Offline JMR

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Re: JMR powered hillclimb & sprint MK2
« Reply #3 on: July 09, 2014, 02:02:49 am »
Thanks ces

Yes block needs decking Tris. If you go too overboard tho with the bowl reduction the ring land can break up due to a combination of weakened piston deck, higher cylinder pressures and the rings fluttering...I only reduced the bowl by 2cc to 8cc. The same trick will work on a 16v too.

Offline RobertsJulia

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Re: JMR powered hillclimb & sprint MK2
« Reply #4 on: December 17, 2018, 04:36:17 am »
's, cards, stickers etc, and started taking an interest in MK2 Golf's a couple of years ago, first with a 16v road car which he swapped in an ABF after killing the KR, then the current race car

Offline Henmeawna

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Re: JMR powered hillclimb & sprint MK2
« Reply #5 on: November 11, 2019, 10:18:25 am »
The feeling of me now is very glad to be with everyone here.

 

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