Mk1 16v Project

**Preen59** · 22-04-2008, 06:07 PM

Originally Posted by Jarred

Yeah I get that. In theory only though. So expect alot of questions if I ever decide to rebuild an engine!

What happens, though, when the bores have too much clearance - do you need bigger rings to suit??

Yeah a ring will have a certain size it is made for, generally you get a ring that is a little big for your bore and file the end on one side to give the clearance you want. You quite simply push it in the bore (make sure its square) and measure the gap with a feeler, if it needs more, take it out and hit it with a flat smooth file to take off a couple of thou and re check.

When i was talking about the bore, i meant that you will end up with too much piston to bore clearance.

**Preen59** · 22-04-2008, 06:49 PM

Got my Genuine VW motorsport windage tray today, along with my scirocco handbrake cables, new rack boots and new clutch cable end.

Got stuck into the oil pickup this arvo. I was mocking up the windage tray on the block and fitted the oil filter in when Dad came over to have a look, i wasn't thinking much of it, but he said "cut the bottom off that pickup, its too restrictive, thats the last thing you need". And he's right, they are.

I cut about 8mm off the bottom with a hacksaw and filed it down and i've ended up with almost double the surface area, which is, you know, good n stuff.

Heres some pics of the windage tray and pump.

Whats it leaning up against? Come on Golfworx....

Here it is assembled

And here's the pickup with the offcut.

See how much more surface area the is..

**Oneofthegreats** · 22-04-2008, 07:22 PM

Whooooo Hell Yehhhhh!!!

Very nice Blower with alcohol injector's.

Steering wheel for a dragster attendant,

A couple of old school wooden handles for a parachute, brake or fuel shut off.

If your at Nat's, we'll have to catch up for a chat. Would like to know more about this Hemi!

Where about's did you get your windage tray from?

I'm currently waiting on mine to arrive form the US. Cost me all of $38 US, as I brought a large shipment of part's.

I like the oil pickup mod. May do this to mine when I fit the tray!

Excellent explanation with the bearing's & ring's too!

Another thing with setting up ring gap, is what the engine is used for. A turbo engine should run a higher gap & from what I've learn't, a straight NOS race engine run's the largest gap (0.0070" - 0.0073 for every inch of bore), with a blown race engine right behind it (0.0060" - 0.0063").

Different manufacturer's also run different gap's to. Most company's run a larger top ring gap than a second.
JE on the other hand run a larger second ring gap to stop ring flutter on high rpm.

Another suggestion for race motor's is to gas port the piston crown's, which mean's you can use low tension ring's. This allow's the engine to spin up faster, as there's less drag/resistance. A engine's worst enemy for making power.

**Preen59** · 22-04-2008, 08:09 PM

Originally Posted by golfworx

Whooooo Hell Yehhhhh!!!

Very nice Blower with alcohol injector's.

Steering wheel for a dragster attendant,

A couple of old school wooden handles for a parachute, brake or fuel shut off.

If your at Nat's, we'll have to catch up for a chat. Would like to know more about this Hemi!

Where about's did you get your windage tray from?

I'm currently waiting on mine to arrive form the US. Cost me all of $38 US, as I brought a large shipment of part's.

I like the oil pickup mod. May do this to mine when I fit the tray!

Excellent explanation with the bearing's & ring's too!

Another thing with setting up ring gap, is what the engine is used for. A turbo engine should run a higher gap & from what I've learn't, a straight NOS race engine run's the largest gap (0.0070" - 0.0073 for every inch of bore), with a blown race engine right behind it (0.0060" - 0.0063").

Different manufacturer's also run different gap's to. Most company's run a larger top ring gap than a second.
JE on the other hand run a larger second ring gap to stop ring flutter on high rpm.

Another suggestion for race motor's is to gas port the piston crown's, which mean's you can use low tension ring's. This allow's the engine to spin up faster, as there's less drag/resistance. A engine's worst enemy for making power.

The handles are actually off the wheel but we have a matching brake lever.

Yeah i'll be at the nats, even if i have to lose a finger... No wait i take that back..

The barrel valve is set up for, and injector is jetted for nitro. We'll be able to run anywhere from 85 to 100 percent. OOo-right.

Here's something you'll find interesting.. The piston-to-bore clearance we'll be running on the hemi will be 12-14 thou, 4.050" bore.

I got the windage tray for US40.00 from Mk1 Autohaus on ebay. I've been buying a lot of stuff from him.

Yeah i think the oil pick up mod i did is a really good idea.

Also, i forgot to mention before.. My engine had suffered oil starvation at some stage. No. 1 cyl had grabbed in the bore on 4 points pretty bad, and 2 journals had picked up. Fortunately the pump is ok.

Yeah the ring gap application comment you made is spot on. The more combustion heat is produced the more the rings will expand. Power can't be confused with heat though, a methanol engine will produce more power than a petrol engine, but with less heat transfer due to the lower combustion temperature and the comparatively twice as rich charge.

And obviously at the other end of the scale you have the good old crown burner, NOS itself. Massive combustion temperature insisting on more ring gap.

Thanks for the info too.

**Oneofthegreats** · 22-04-2008, 08:33 PM

No prob's.

Love talking engine's. Would love to get into a position one day to build/machine full time with them.

Nitro!!! Even better. At 95+% it will be a time bomb

I'm suprised that's it's only a 4" bore too. Thought it would be bigger, then realized it's a 392! Same as bore size as a stock 308 Holden & 350 Chev. Except 0.050" up.
Must have a long rod/stroke ratio being a Hemi. Great for torque!

Must be the only new engine setup with piston slap! Ha ha.

Ben at Mk1 autohaus is the same bloke I've been speaking to. Really easy to deal with, very helpful & can highly recommend him. Just brought $450+ of part's for myself.

**Preen59** · 22-04-2008, 08:47 PM

Yeah its 4" standard. We have to go over to clean it up. Big stroke yeah. I think the 426 is same stroke bigger bore. Same with the Donnovan 417 (The first purpose built all aluminium hemi).

I think i've spent about $500 with Ben over the last few months, he's a champ and really good to deal with.

**Jarred** · 22-04-2008, 11:34 PM

wow. my head hurts.

sure is a lot of info going around here, and I'm glad for it.

I'm sure I'll absorb some of it.

hahahaha

and I want to see some vids of that Hemi once it's done! Sounds like it is defiantly going to be full hat!

**Preen59** · 23-04-2008, 06:31 PM

Originally Posted by Jarred

wow. my head hurts.

sure is a lot of info going around here, and I'm glad for it.

I'm sure I'll absorb some of it.

hahahaha

and I want to see some vids of that Hemi once it's done! Sounds like it is defiantly going to be full hat!

Don't worry if you don't understand everything. I'm still not that clued up. You just pick things up as you go.

Oh and an update on that race engineer job.. Looks like i'm the man.

Oscar Fiorinotto (used to be craig lowdes' engineer etc etc) is going to ring me tonight when he is free to discuss a few things and i'll probably be flying to Adelaide in the next couple of weeks to spend some time with him at his workshop learning some stuff before Sandown in 5 weeks. Very happy.