924Board.org

Scorpio · Posted: Tue Oct 14, 2008 3:31 pm Post subject:

saw that one pete..yeap no head!

ok ran around brisbane the last few hours...turns out $660 + valve stem guide installation( $80) isnt as bad(comparitively) as i thought

includes

valve dismantling
sand blasting
alloy welding
3 angle valve job
caustic dipping
reassemble valves
head refacing

Should i get the new valve guides put in? the machinist said something about when i put in the turbo the engine will run hotter and i may need that slightly looser fit to prevent seizing

I need to order some thread to sew my arse back up....just been raped by the 924 wallet thieves

_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

Peter_in_AU · Joined: 29 Jul 2001 Posts: 2743 Location: Sydney, Australia

How much without the welding?

I have a spare head but it would probably need a lot of that stuff done.
_________________
1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)

Learn to love your multimeter and may the search be with you

leadfoot · Posted: Tue Oct 14, 2008 10:49 pm Post subject:

Scorpio, I would say you are getting ripped on this head rebuild.
If you can get a head from the states cheaper I would go with that option, surely there's someone on the board with a spare.

As for perfect tune... go to a engine dyno mate. I can help with the other stuff I mentioned and show you what I learned along the way.

Stu
_________________
1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

Scorpio · Posted: Wed Oct 15, 2008 1:47 am Post subject:

sorry just cut and pasted my response.. from bumble bees thread

as a matter of comparison i ran across town with my own head to a completely different head macine shop to get a second opinion on the head...
These guys were a performance engine machine shop...they looked at it and basically there was no way they could match $660. They said the alloy welding involved was too fiddly and time consuming for them to be able to match that price..

problems on mine
1) corrosion (loss of material)around one of the valve seats needing to be machined out
2) hairline crack on spark 2 and 3.."hot spots"
3) will need more material in some of the coolant chanel bits

Breaking down the price it seems semi reasonable
1) sand blasting $50
2) removal and reassembly of valve train = 50 each= 100
3) machine face = 120
4) machine out old stem guides and install new valve stem guides = 80
5) caustic bath = 70
6) pressure test = 60
7) re sleeve spark holes..?

3 angle valve job ??
so im guessing grinding out material and alloy welding trouble areas is about $200 which doesnt seem overly bad

The guy from the performance machine shop said welding was fiddly...charged at $80/hour and usually involved a few goes untill it was gotten right..ie grinding out crack...filling..tap and die spark holes..pressure testing..then doing it again if not happy with it

on a happy note Dan ive found somewhere that can match your o-rings.. $100 aus dollars! woot woot.. might also ask them about the head
theyre also chasing down mls gaskets but i wont hold my breath

... but after breaking it down and talking with the other guys turns out that the price isnt overly bad??? or am i missing something

the thing about another head is theres no guarantee it isnt exactly the same as mine...mine looked perfect at the start untill closer inspection! and in all honesty i could probably get away leaving the cracks..but i want to know i have a new engine

bumblebees had a little more corrosion and required the valve seat on two vaves removed and material ground down then filled as his crack ran from face about 1.5 cms into the head.. he also needed material added to water pump flange to ensure flat gasket seal..ie more corrosion. They also noted that his intake valves had more than the 3/1000 of an inch tolerance and recommended he source new ones..but i felt the wear and it seemed ok..
_________________
1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

leadfoot · Posted: Wed Oct 15, 2008 11:13 am Post subject:

A generous board member parted with a spare 931 head / manifold and cam for $100US for me.
Wear and tear on a heads pretty obvious.

I reckon your heads gone soft too, did the machine shop do a brinnel test across the cylinder face?
What werre the measurements?

I'd let Dan do a quick search at least, you never know, you might be able to pick up a 931 head and some 931 pistons at the same time.

Stu.
_________________
1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

I actually have a spare 931 head complete, needs cleaning badly, but the cam and lifters all looked pretty good, have not done a complete thorough inspection, but the deck did measure within tolerance. I also have a complete set of S1 931 pistons, first tolerance, in great shape.
_________________
erstwhile owner of just about every 924 variant ever made

Min · Posted: Wed Oct 15, 2008 1:32 pm Post subject:

just finished o-ringing the block on a 22re, only cost me 1 hour of my time. I must say I like that tool alot. heh.

Min
_________________
Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting.

Bumblebee77 · Joined: 09 May 2008 Posts: 372 Location: Brisbane

What sort of cost and time is involved in getting a head sent in from the states? Would a 931 head even be compatible with my 77 NA?
_________________
77 NA 924
Hopefully one day a little sleeper... although at this point i'll settle for the bloody thing to start...

StienbargerR · Joined: 28 Oct 2005 Posts: 1362 Location: Richmond, IN

Bumblebee- No, it is not compatible. It willl bolt on, but your compression will be crap. You can however Modify your block and other things to make a Dprod? I think? engine, which makes a good deal more power, but there is a long list of modifications one has to do in order to make the engine run properly.

Ryan

edit- see linky- http://www.924.org/models/924D933.htm
_________________
1978 924 NA
-250lb lowering springs, Euro Pistons

Bumblebee77 · Joined: 09 May 2008 Posts: 372 Location: Brisbane

Yeah, didn't think so. That just sounds like way too much effort. The more i think about it the more i'm thinking i don't have much of an option but to cop the expense of getting the head work done. A lot of people here seem to think its a rip off, but from what Scorpio's seen around town and based on the amount of work which seems to be involved in repairing my head.

Its a lot of money but i'm nearing the point where i just want to be able to drive my sodding car around again.
_________________
77 NA 924
Hopefully one day a little sleeper... although at this point i'll settle for the bloody thing to start...

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Bumble, I can't comment on the 931 head fitment on an NA from experience. It's been done with some success, but as Ryan notes, may not be as straightforward of a solution as you'd be after.

However, NA heads here in the US should be relatively cheap. To make things even better, I am coordinating an ocean freight shipment for four board members in the Brisbane area. I am pretty confident that there will be room in the shipment for an NA head. If you want to consider having a spare, now would be the time to get it. The guys are planning to share / split the freight costs, which right now are looking to be ~$530 total, which will be split somehow by the participants. I'm sure they'd welcome another participant.

Let me know soon if you want to pursue this. I can certainly reach out to some local guys here to see if we can scare up a decent condition head, even if it's just the bare head.
_________________
erstwhile owner of just about every 924 variant ever made

Bumblebee77 · Joined: 09 May 2008 Posts: 372 Location: Brisbane

The other guys involved are...? Scorpio, Charles, Peter? Is that right? Anyone else? What are those guys getting so far? I know Scorpio's getting wheels and maybe tyres?
_________________
77 NA 924
Hopefully one day a little sleeper... although at this point i'll settle for the bloody thing to start...

pocketscience · Posted: Wed Oct 15, 2008 8:02 pm Post subject:

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

So far, this is what is planned to be shipped over:
3 complete alu suspensions
1 set of 4-lug wheels
1 complete custom turbo

It may also include a G31+LSD gearbox, but that is still up in the air.

There may be some other odds and ends added in for good measure by the time this is all ready to go.
_________________
erstwhile owner of just about every 924 variant ever made

Peter_in_AU · Joined: 29 Jul 2001 Posts: 2743 Location: Sydney, Australia

We're doing our bit to help save the US economy

_________________
1979 924 (Gone to a better place)
1974 Lotus 7 S4 "Big Valve" Twin-cam (waiting)
1982 924 (As featured on Wikipedia)

Learn to love your multimeter and may the search be with you