Vw 16v kr pistons issues

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dirty d
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Vw 16v kr pistons issues

Post by dirty d »

Hi guys, i have a issue that's been bothering me ever since i took my engine apart for a rebuild. At tdc, my pistons sit close to a 1cm below the surface of the block. Is this normal or has someone changed the crank? My Aal engine pistons sit flush with with the block at tdc. TIA Dario

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Re: Vw 16v kr pistons issues

Post by panic-mechanic »

Wrong crank or wrong rods. Measure the actual stroke and compare to what it should be. Can also be 2 l piston in a 1.8 block.
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Re: Vw 16v kr pistons issues

Post by dirty d »

Hi Stephan, how do you measure the stroke?
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Re: Vw 16v kr pistons issues

Post by Rudi46 »

dirty d wrote: Fri Jun 28, 2019 8:39 am Hi Stephan, how do you measure the stroke?
Measure the distance the top of the piston travels from the top to the bottom of the cylinder.
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Re: Vw 16v kr pistons issues

Post by dirty d »

Thanks, will do that. Do the 16v and 8v conrods differ because the piston that i see is a kr piston? Will the 8v piston fit on a 16v rod?

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Re: Vw 16v kr pistons issues

Post by panic-mechanic »

So KR and AAL will have the same conrod. To allow for the different crank stoke the piston will have a lower height from the gudgeon pin. so Hence me saying that if you have a 2l piston with the same conrod and 1.8 crank it will by definition turn the difference in stroke between the two lower in the bore.
so 92.8 mm of the 2l minus 86.4 of the 1.8 will give 6.4 mm that the piston sits low.
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Re: Vw 16v kr pistons issues

Post by dirty d »

Thanks for the info Stephan. What i can deduce is that i have the right pistons with conrods cause the kr pistons have the thick slit on the intake side and the Aal pistons have the half moons on the intake side. I think i need the correct crank, do you guys possibly have a kr crank for me?
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Re: Vw 16v kr pistons issues

Post by PapaJo »

KR 1800 crank is a forged crank and hens teeth. Other 1800 cranks are cast cranks. Any 1800 will work.
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Re: Vw 16v kr pistons issues

Post by dirty d »

PapaJo wrote:KR 1800 crank is a forged crank and hens teeth. Other 1800 cranks are cast cranks. Any 1800 will work.
Do you have one, anyone actually, i just need the car performing well?

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Re: Vw 16v kr pistons issues

Post by PapaJo »

Did you measure the stroke as suggested by panic?
Post some pictures of the current pistons and crank installed.
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Re: Vw 16v kr pistons issues

Post by dirty d »

Hi guys

From the bottom of the stroke till the top, I've measured 68mm.

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Re: Vw 16v kr pistons issues

Post by dirty d »

I'm currently pulling the engine.ImageImage

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Re: Vw 16v kr pistons issues

Post by PapaJo »

Wrong crank in motor as stated by panic before. Get a 1800 crank and install and you are good to go.
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Re: Vw 16v kr pistons issues

Post by dirty d »

I eventually bought a brand new goldwagen 1800 crank. The box was not a brazil box but a made in China branded box. I fitted it and it started. Then i started to hear a sound which was bearings chatter. I stripped the block again and the mains were fine but the big ends were chowed till the copper of the bearings. I have a schadek oil pump fitted and someone told me its the oil pump, but why are the mains fine and the big ends the problem?

Refitted the block with new mains and big ends but realised that the side play on the big ends is abit too much but I'm not sure if this is contributing to the crank running bearings.

I bought a second hand oem std crank and having that cut but I'm uncertain if i should cut this brand new crank also. I'm out of ideas and not sure which road to travel with this crank issue, should i cut both cranks or only cut the new crank?

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Re: Vw 16v kr pistons issues

Post by panic-mechanic »

basically none of you questions can be answered without seeing the parts and without being able to assemble the motor with a clearance check with plastigauge.
did ypu check for oil pressure by cranking it without starting etc.
it's imposible without knowing a great many things on where it went wrong.
Fom wrong parts to bad installation etc etc etc.
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Re: Vw 16v kr pistons issues

Post by Donavan »

best bet is take all the the parts to an engineering shop and have them check the clearances for you
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Re: Vw 16v kr pistons issues

Post by missioner »

Donavan wrote:best bet is take all the the parts to an engineering shop and have them check the clearances for you
This is your answer.

Also what you should have done in the beginning.

The engine shop would have been able to help you by the right parts from the start, including the bearings and any other parts required for a reliable motor.
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Re: Vw 16v kr pistons issues

Post by Dumisani5 »

Kr engine problem
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Re: Vw 16v kr pistons issues

Post by Dumisani5 »

Hi guys please help here,am having a 1.8 16v kr engine so i changed the 16v cylinder head and put 8v cylinder cubberater. But wen accelerate more is crunching.so don't know if is the pistons height.
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Re: Vw 16v kr pistons issues

Post by PapaJo »

Dumisani5 wrote: Thu Nov 09, 2023 11:39 pm Hi guys please help here,am having a 1.8 16v kr engine so i changed the 16v cylinder head and put 8v cylinder cubberater. But wen accelerate more is crunching.so don't know if is the pistons height.
Pistons are protruding above the block and is hitting the cylinder head. Compression height of 16v pistons is 33.4mm and 8v piston compression height is 32.7mm thus piston goes above deck and hitting cylinder head.

You are bound for some major engine damage!!!
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Re: Vw 16v kr pistons issues

Post by missioner »

PapaJo wrote:
Dumisani5 wrote: Thu Nov 09, 2023 11:39 pm Hi guys please help here,am having a 1.8 16v kr engine so i changed the 16v cylinder head and put 8v cylinder cubberater. But wen accelerate more is crunching.so don't know if is the pistons height.
Pistons are protruding above the block and is hitting the cylinder head. Compression height of 16v pistons is 33.4mm and 8v piston compression height is 32.7mm thus piston goes above deck and hitting cylinder head.

You are bound for some major engine damage!!!
16 uses flat top pistons and 8v are dished. His comp ratio is through the roof. Detonation is killing that engine fast.

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