What cam is this? Suggestions for replacement?

[Peter Jones]

The heads off white due to blowing a head gasket at Phillip Island. I thought I'd investigate cams while it's all apart. Can anyone identify this cam for me?



Here's what I know

It's hydraulic. Two of the lifters seem stuck which I'd already guessed from the tappity noises when the car was cold, I'll replace the lot.

Engine is MK 2 1800 K-Jet engine no GX 095 597

I'd like to know if this is the standard cam and hear your suggestions on replacements based on continuing to run the K-Jet with extractors and 2.5" exhaust. Porting and valves might be done too.

Pete

[Golf Loon]

I dont think its a G Grind, they should have a G on it.

Probably standard cabrio cam.

Put either a G Grind, I have if you need, or pm demoIII as he has a tasty can for sale.

[Peter Jones]

I dont think its a G Grind, they should have a G on it.

Probably standard cabrio cam.

Put either a G Grind, I have if you need, or pm demoIII as he has a tasty can for sale.

I'll be in touch

I thought you'd know.

Pete

[Jarred]

Depends if you want driveability as much?

I know some Autotech cams can be had for about 120USD, these specs vary (of course) but something like a 270 sport, will be a nice strong cam, lumpier than a G grind, and work from about 3kRPM up to 7k+RPM. The bigger cams *may* require HD valve springs though. Should net about 10 Horse on a standard engine, so with some P&P + extractors and exhaust maybe higer comp ratio, you could be looking at comfortably 20 Horse I reckon.


Anyways. That's just my opinion. Tim (Golfworx) knows his cam's. PM him if he doesn't chime in here, I'd take his word over mine any day!

[Peter Jones]

A couple of more questions,

How big are the valves in the "Big Valve" 8v head?

What is the spec of the G Grind cam? 268 degrees?

Any links or websites I should read?

I'll drop the head off this week and see what the go is.

Pete

[deemoE36]

I dont think its a G Grind, they should have a G on it.

Probably standard cabrio cam.

Put either a G Grind, I have if you need, or pm demoIII as he has a tasty can for sale.

yeh thanks matt

i got a 270 deg cam, quiet lumpy and it really does give so much more from above 3K rpm all the way through to 7k rpm! i was surprised that it got there cus with my stock one, for what ever reason i couldnt even reach 6K rpm

[Oneofthegreats]

With head work & oversize valve's etc., it comes down to how much you want to spend.
Here's a mob in the states that port's a very nice 8V with some good flow number's. $800 US

http://scch-heads.com/viewhead2.php?id=17

Down side it's for a JH US spec 8V & that it really need's 10+:1 CR & a decent size cam to make full effect.

This place also does alot of nice mk1 part's to like a Spherical Shifter, Spehrical bearing ball joint Kit, Bump steer Elimination kit, Tubular Control Arms MKI & MKII etc.
Check out their part's section.

Also another place in the U.K. have have some very nice CNC head's with some even nicer result's.

http://www.cncheads.co.uk/vw_golf_8v.html

http://www.cncheads.co.uk/vw_golf_8v_bv.html

As far as I know the GX never came with a "G" grind cam as it was the low HP gti engine & as such came with a very low performance cam. It's also a hydraulic cam.

The RV (high output) engine had the hydraulic version G grind which wasn't as big as the solid version

The true G grind came in the DX solid cam GTI's like my 83 GTI & had a very nice lump to it & would start pulling strong after 3500rpm. Much more lumpier than a Autotech 270.

283° advertised
225° at 0.050"
0.423" lift

Just letting you know that your not alone with this engine code, my old beater engine, which I fitted to the GTI is a GX too!

GX engine cam - I don't have the advertised duration only these
duration @ 0.050" 210°/209°
Lift - .393"
Lobe center's - 110°

I fitted a Autotech 270 to my beater engine & made a nice difference. Also fitted Autotech's heavy duty valves spring's, Vernier Cam pulley & new OEM lifter's, which goes without saying.

Duration: 270° at 0.1mm check,
Lift: 0.449"
112° lobe center

Has alittle lump to the idle & has good manifold vacuum.

A word of warning though with big cam's & K-Jet. If it's too lumpy, the airflow reversion can upset the airflap causing very poor performance. I remember someone fitted a airflap off another vehicle (can't remember which one) which was thicker & heavier which eliminated the problem.

If I stick with the 8v hydraulic, I'd like to try a TT 276° with a Auto tran's & 3000rpm stall.

276° Advertised
234° @ 0.050"
.449" Lift
110° Lobe Center

Another note is that if you pick a cam with over .449" lift, you may have to clearance the lifter bore's. but if the head's apart, then this can be done quite easily.

As far as valve sizes go.
Inlet 38mm or 40mm?, 8mm stem
Exhaust 33mm, 8mm stem

You can go
I 41mm, 7mm stem
E 34mm, 7mm stem

I 42mm, 7mm stem
E 35mm, 7mm stem

If you choose not to fit oversize valve's, a cheap mod to do is to back cut the valves, which can improve flow.

Porting, well that's in the eye of the beholder.
I reckon a nice clean up of the down turn's, throat's & around the guide's, fitting 7mm stem valve's,opening the port's upto the gasket's, & also skimming the head to bring the CR up alittle should be benificial.

Hope this info help's you out Pete.

[Peter Jones]

Thanks for the info, it's options I'm after, your feedback is great.

I think the approach I will take is that I will build another motor next year with all the trimmings, so for this build I'll just go one step further than it's at currently.

If the Hydraulic G Grind or Autotech cam is known to work OK with the K-Jet, I might head down that path for now.

For the headwork I've had an initial chat with my head guy and we'll see what he can come up with. I'll pass on your suggestions.

At this stage I don't want to go down the radical modification path too far, what I'll try and establish is a setup that has been seen working in the past.

I'll save the major engineering work for the project motor later on.

That said, I'll up the valves if I can and port to match.

I'll get the head and manifold tanked and media blasted, those K-Jet manifolds look like a bugger to clean out otherwise.

Keep the suggestions coming! If I get the head setup right I can always play with different cams later on.

Interesting point on the GX vs RV motors. Do you have any detail on what the mechanical differences were?

Pete

[Oneofthegreats]

Thanks for the info, it's options I'm after, your feedback is great.

Interesting point on the GX vs RV motors. Do you have any detail on what the mechanical differences were?

Pete

No problem's Pete. Glad to help out.

The major difference's were compression & cam's as advertised.

GX 8.5:1 85HP,
RV 10.0:1 112HP

When I measured my GX corrected, it was as follow's

Deck height - 1.00mm
Head gasket height - 1.65mm
Piston Crown Volume - 17.69cc
Deck Height + Gasket Volume - 13.6609cc
Cyl. Head Volume - 30.00cc

Compression Ratio
Piston Crown Volume - 17.69cc
Deck Height + Gasket Volume - +13.6609cc
Cyl. Head Volume - +30.00cc
Total Combustion Chamber Volume = 61.3509
Swept Volume - 445.398
= 506.7489
Total Combustion Chamber Volume - +61.3509
= 8.2598:1 Compression Ratio.

My setup's been tried & tested, although it hasn't been on a dyno for quite sometime, but from ET & MPH with only the spare removed, I've been told it's on par with a US Spec G60.
Roughly 100WHP.

Mine's a GX with the compresion raised to 9.4246:1 Corrected & balanced with the clutch/flywheel assembly.
- Autotech 270 Cam
- Autotech Heavy Duty Valve Springs
- Autotech Vernier Pulley - retarded 1-2°
- Autotech Intermediate Pulley
- Stage 1 Ported intake manifold from this bloke http://www.scientificrabbit.com/
- Match Ported Audi Throttle body
- Volvo 240 2.2L Fuel Distributor & Airflow sensor flap assembly, swiss cheesed airbox, K&N air filter & rocker cover breather blocked off. Now routed into a filtered Powerade Bottle! Yeh Yeh, I know, but it works!
- Late Model stock GTI distributor without vac. advance. Big Difference. (Can't remember ignition timing spec, approx stock 3° ATDC)
- HD 210mm clutch kit
- Very old Hurricane 4-2-1 Extractors
- 2" exhaust system, hotdog (can't remember the length) & straight through offset rear muffler with 2.5" tailpipe
- 4 spd Stock Diesel gearbox with a ABD short shift kit & weighted shifter rod.

[Peter Jones]

Wow, you keep some pretty detailed records there.

I forgot I'd have to account for the head gasket volume, my engine building experience has mainly been with the aircooled stuff .

That's very useful stuff to know. I think I've still got enough gear to cc everything at home, if not I can soon make it up again.

Sound like the head's going to be a bit thinner by the time I'm done.

I always run the highest octane fuel I can get so the compression should be fine. Cooling has never been an issue with this motor. (Until the hose burst.)

Sounds like the budget solution would be to increase the CR, grab Matt's G Grind and back cut the valves.

Next option Autotech 270, bigger valves and springs, porting.

Beyond that and I may as well start building a 16v 2.0L.

Any thoughts on the ramp angle of the G grind lobes and the need for heavier springs? I had this motor reving clean off the tacho and into the fuel gauge (7500+ ?) with no sign of valve bounce with the stock cam.

Pete

[Oneofthegreats]

When it comes to building engine's, I like to keep detailed record's of what get's done & what goes into them.

The engine was rebuilt in 98, so it was a far while ago now. Has clocked up over 370+k with only a headgasket failure.

I wouldn't suggest skimming the head super thin to raise the CR, as this can cause mixture & ignition problem's.

I ended up fitting new piston's which had a smaller volume & higher deck height.

I should have posted this up before to save confusion
Here's all the dismantled & assemble spec's


GX Engine

Bore - 81mm
Stroke - 86.4mm
Swept Volume Per Cylinder – 445.398cc
Engine Capacity - 1781.582cc

As Dismantled/As Assembled

DeckDeck height -

1.00mm/0.60mm

Head gasket height -

1.65mm/1.65mm

Piston Crown Volume -

17.69cc/11.27cc

Deck Height + Gasket Volume -

13.6609cc/11.5989cc

Cyl. Head Volume -

30.00cc/ 30.00cc

Compression Ratio

Piston Crown Volume -

17.69cc/11.27cc

Deck Height + Gasket Volume -

+13.6609cc/+11.5989cc

Cyl. Head Volume -

+30.00cc/+30.00cc

Total Combustion Chamber Volume

=61.3509/=52.8689

Swept Volume -

445.398/445.398

=506.7489/=498.2669

Total Combustion Chamber Volume -

+61.3509/+52.8689

Compression Ratio

= 8.2598:1/9.4246:1

Cam Specs – Stock GX

In Opens 15°BTDC
In Closes 55°ABDC
Ex Opens 55°BBDC
Ex Closes 15°ATDC

Duration In + Ex 250°
Lift @ Lobe .360”

As you can see, a Autotech 270 is a much bigger cam.

If you just going to fit a Hydraulic G Grind, I wouldn't bother about HD valve spring's, just lifter's. But on the other hand, if the engine has had a hard time for most of it's life, new spring's wouldn't be such a bad idea.

Just out of interest sake, the Autotech 270 is $129.95US. They should post to OZ.

[Peter Jones]

Ok, that makes sense, thanks for taking the time to write it all up.

For now I don't really want to tear the whole motor down, so I don't think I'll be replacing pistons until I tackle the project motor.

If I do the pistons and rings I'd have to bore it and while I'm there I'd have to do the big ends, and if I did those I'd have to do the mains etc etc.

First rule of any project. Define scope.

I'm in the defining scope phase at the moment and trying to get a feel for what can be done beyond just sticking the head back on.

Hard to say what sort of life this motor has had. The previous owners were a couple of kids that neglected it. I don't think they could have driven it to hard because the fuel pump was stuffed when I got it and the throttle cable was so badly adjusted that the secondary wasn't pulling in. I think the owner before them must have fitted the 5 speed and K-Jet motor.

All the kids did to it was cut AND oxy the front springs

I'll see what my head guy has to say. it might be possible to get that CR up by other means, he's pretty handy at designing and shaping combustion chambers. Just depends how generous he's feeling. I don't know if he's still got the pantograph, that thing always amused me. He had all the VW combustion chamber reference models to go with it once upon a time.

I'll go and check out autotech tonight, I've already spent too much time on the net at work today.

Pete

[Jarred]

Pete, If you are planning on doing a project engine, it might be wise not to use up all your favours with you head fella. He could come in very handy for some full on work on perhaps a 2L 16V, which I'm my opinion is probably worth it as a next step.

8V are good for street and general use, but you can get so much more power out of a 16V, it's almost not funny.

having said that, my scope on this project would (just briefly): get the head back on with a bit of work (stage 1 kinda stuff; "mild street" perhaps) and get some more laps under your belt. Learn how to drive/race first, then by the time you are really confident, and at the absolute limit with the 1.8 8V you'll be able to pop in a worked 16V and progress from there.

That's just what I'd do, just my 2 cents. It's not really worth sinking a whole lot of coin in an engine you are planning on replacing in the near future.

[Peter Jones]

There's plenty of favours left in that bucket, I needn't worry on that score.

I've spent many weekends down at the shop repairing or re-wiring his phones, internet, alarm, mills, lathes lights etc. I just finished the phone cabling in his new house after Christmas. Basically we never charge each other for labour, just out of pocket material expenses. I can go down there and use any of the machines myself if he's busy or I can do some of the grunt work for him while he works on my stuff. These days we don't get to catch up too often because I work in town now and it's hard to get to the shop when he's open. To get the head to him I'll have to pop around to his place one night this week because he's not opening up on Saturdays any more.

Agree with you on the conservative approach for the moment, there's bigger things to come.

Pete

[Peter Jones]

Good range of cams here.

http://www.bahnbrenner.com/vw_audi/categories/176/8V_Hyd_Camshafts

Makes me want to build a crazy 8v.

Pete