well i was setting the fueling up 2day on the 5 and it was spot on for 22psi took it out with justin then after a hour pop goes my head gasket. its a group a with uprated head bolts. so dont know why it went? justin said it could be because at one point it was peking 28psiso im wondering is there a better head gasket set out there on the market? dont really want to use a group a again. any idears and price to pay.?
you dont need a different hg you need to set the fueling (using an afr guage then rejet acordingly) that way you should never need more than an oe hg
Fueling @ the top end or quite possibly det at that boost.
& you do want the headgasket to go 1st, well it's a damn sight easier than replacing a liner or piston.
got a afr gage on the car fueling was spot on took 2hours to set up. also im hopring that a liner wont go as they are uprated steel lines. and cost me a bomb. is there any better head gaskets other than group a ?Originally Posted by 5teve L
Stick with the OE or the blue seal type. If something was to go you and I would prefer it to be the H/G. There is a 3 layer metal type MLS gasket fo the GTT matey, but by using that you will have no real weak point in your engine, the h/g is like a fuse that can blow ideally you need this weakish point as it saves alot more damage that could have occured
Last edited by James5; 02-01-2011 at 18:46.
What afr gauge are you using.i run 25 psi on stock internals with no masive problems
What timing, jets & fuel are you running ? a 6psi spike is a hell of alot as well at that pressure.
The jets 1.35 main with 1.2 AC and its running Tesco 99 ron petrol and it also has a 28mm ventria in the carb. Never had any problems apart from today. It has been on the car 18 months.
I am using a AEM gauge off Scoff.
I'd be a little surprised if it were running those jets & fueling for that boost TBH.
what makes you think that mate? i wouldnt lie. im 31years old not 18. its a full automedic race spec engine. built by ex ep motorsports employee justin. 15 plus years ex with 5gtts.
Me too. If it was stock sized ventria and 1.4 E2 it'll probably fuel ok ish. But those damn large ventria carbs are hard to fuel right and normally need very large main jets.
At your level of boost mate I'd say your into carb bowl emptying area of tune. Any idea of what your act's are? Was anyone listening for det?
yes i was mate it peeked at 28psi then we slowed down for some lights and pop smell of antifreeze then lumpy got back to garage and water all over the engine but no blow hoses.
I know every car is different but the spec I ran on my old GTT with milled forged pistons, 285 cam & a T25 was.
1.4 2nd stage, 2mm needle jet, .9 a/c, 1.2 main & I ran out of fuel at anything over 6.5k with 22 psi manifold, I tried a larger needle but it would bog down. ACT's were never above 40 deg & I had to retard the ign a little also. Afr's were 12-12.3 max as it hit 6k. I was using a standard venturi as well.
So your wanting to maintain a high boost of 22psi, do you know what caused the 28psi peak?? as that is a large spike
What's are you using to control max boost level???
What afr's were you seeing??
28psi that's a nice lump of boost.
What AFR's where you guys seeing as I know people have different opinions when it comes to them my engine man tells me to keep them in the mid to high 11's but others tune cars to low 12's. Or even mid 12's
At the frog of the pod last year I popped a h/g at only 20psi but two runs earlier I dropped a fan belt and cooked things a bit so put it down to that. Dropped any belts yourself?
no mate never dropped a belt hit about 5000rpm afrs were reading mid 11 late 12s.it took ages to set up right. it was bang on. imo.28psi that's a nice lump of boost.
What AFR's where you guys seeing as I know people have different opinions when it comes to them my engine man tells me to keep them in the mid to high 11's but others tune cars to low 12's. Or even mid 12's
At the frog of the pod last year I popped a h/g at only 20psi but two runs earlier I dropped a fan belt and cooked things a bit so put it down to that. Dropped any belts yourself?
11 to late 12s mate i think it could be the sping in the external waste gate as im running a t28 t3 roller bearing turbo. a lot of lag then at 3750 to 4000rpm bang a massive load of boost and a lot of toque steer hurts my wrist. maybe im just a wimp.
Are you saying AFR's are high 12's on full boost, not very clear ?11 to late 12s mate i think it could be the sping in the external waste gate as im running a t28 t3 roller bearing turbo. a lot of lag then at 3750 to 4000rpm bang a massive load of boost and a lot of toque steer hurts my wrist. maybe im just a wimp.
sorry mate yes reading 12 on full boost.
Its sounding like the spike at 28psi has killed the gasket mate, if it went up to there and you have set the carb to 22psi then that engine would have run lean enough to do some poss damage. At those sort of boost levels i'd want to keep it at very high 11's or very low 12's on the afr's.
Fitting stronger gaskets just hide the problems, you need to see why it went and fix the problem.
I'm thinking also carb could poss have emptied too if the only mods to the carb are a 1.35 main and different ac on a 28mm venturi
The important jets don't seem to be modded, i know Justin and no disrespect to him (knew him at Europarts) but its old school carb tuning that, pron to problems.
When you pull the gasket off have alook at the shape of the firerings, that can give idea of what has happened.
Madfive, it's not all about fueling though buddy. You need to listen for detonation. At that sort of boost your right at, or maybe a bit past what the standard compression ratio will deal with. You can have perfect AFR's but the engine will still detonate because there's too much compression or timing.
If you're unsure of compression ratio then you should measure the head height when you fetch it off. (73.5mm is standard). Shorter than that and on stock pistons you'll have raised compression and that definately isn't good. But if it's an EP related engine I guess you probably have some low compression pistons. In which case the compression ratio might still be too high if the head is short, so you still need to be carefull. If in doubt, pull a few degrees out of the timing and at least keep an eye on spark plugs for signs of detonation. Better yet, borrow a knock box and monitor it properly.
well find out why the gasket went it was all because there was a air lock in the water pipe going to the water pump. so while driveing on full boost not enough water going round and pop the head gasket.on a good point all the pistons rings and liners are all spot on.
so clean all the head up ang fit new gasket service and set up then back on road. happy days.
thats good news then fella at least its not a major problem, i see its all beem set up now as well bet it flies
You got pic of the head gasket mate? Did it go out of shape anywhere on the firerings?well find out why the gasket went it was all because there was a air lock in the water pipe going to the water pump. so while driveing on full boost not enough water going round and pop the head gasket.
not got a pic mate as im back in leicester and the cars up in stoke. just spit mark thats all thank god. also justin says there no out of shap around the firerings.
I wouldn't worry too much about that, more likely the air lock apeared once you'd pressurised the whole lot when you blew the gasket. It'll have been related to the tune I think. Like mark says, if it's gone egg shaped, it detonatedwell find out why the gasket went it was all because there was a air lock in the water pipe going to the water pump. so while driveing on full boost not enough water going round and pop the head gasket.
yes it was doing really great until the gasket went.what made me and justin mad was it was booked in at psi tuning tomorrow to get a power reading. and thats now gone out of the window.
How you mean spit marks mate?not got a pic mate as im back in leicester and the cars up in stoke. just spit mark thats all thank god. also justin says there no out of shap around the firerings.
from what justin says it sounds like its split the ring around the gasket .
If it split means it was being forced outwards, sounds like detting may have been occuring mate for gasket to do that.
out of interest what can cause the boost to spike by that much ?
cool cheers mark im going to lower the boost to 20psi. got the carb spec for you if it helps 1.4 main 1.25ac 1.15 sec stage with 28mm venturi just wanting to know if that would be ok for 20 to 22psi mate.?
I'm sure that the main is to large and the second stage too small
:edit: ohh and the venturi would be better standard
im unsure at the moment mate. but were thinking it could be the spring in the wastegate. think it mite be to weak. its only a 14lb spring.
what about if i put a 1.3 main back in. would that fuel better?
:edit: ohh and the venturi would be better standard
No one can say without seeing your afr's and what your car is doing through the rev range and at WOT.
Large Venturi carbs tend to need larger main jets to compensate for the bigger venturi
i see james that what i think. thats why i fitted the 1.4 main to compensate the bigger venturi. but the people on here are telling me its to big.
Your best bet is to go back to a standard 25mm venturi and then re-jet it from there. For 20psi i'd be looking at sticking with a standard 1.2 main jet, larger 2nd stage (poss 1.3-1.4), 1-0.9mm ac and 2mm needle valvecool cheers mark im going to lower the boost to 20psi. got the carb spec for you if it helps 1.4 main 1.25ac 1.15 sec stage with 28mm venturi just wanting to know if that would be ok for 20 to 22psi mate.?
As James says though you need to check AFR's while doing it as every car is different so your car may need slightly different spec to that but that one is a rough guide
thanks mate i wish i kept the car standard now. its been doing my head in.think im going to leave it for a cuple of weeks. ive got till march 19th to get it ready for bluntys rolling road day. time for a beer me thinks.
Know what you mean mate but once done they are worth it.thanks mate i wish i kept the car standard now. its been doing my head in.
I'll be at that rolling road, if you get it done can watch it on the rollers and see what it looks like.
Take ur time with it mate get it bang on and am sure it will be sorted for.marchthanks mate i wish i kept the car standard now. its been doing my head in.
Out of interest are you using a suitable size External wastegate it might not be the wastegate spring itself?? what size are you using and I take it your screamer pipe is going to atmosphere and not back into the system?
Your not using a bleed valve aswell as the external wastegate are you, to long a vacum line will aslo creat small spikes due to delay.
Last edited by James5; 04-01-2011 at 15:09.
yo.you proberbly have most things coverd but..........are you using an uprated fuel pump??? I would above 15psi
yo.you proberbly have most things coverd but..........are you using an uprated fuel pump??? I would above 15psi
Ohh eugines popped up again.... EUG for the win
hi mate yes its got a uprated fuel pump on it. also aem water injection kit. its running t28 t3 roller bearing turbo steel liners low com pistons.ie its been very reliable 3 months ago had it rolling roaded and it pulled 233bhp at 26psi with no problems at all.yo.you proberbly have most things coverd but..........are you using an uprated fuel pump??? I would above 15psi
sounds so sweet........hi mate yes its got a uprated fuel pump on it. also aem water injection kit. its running t28 t3 roller bearing turbo steel liners iow com pistons.ie its been very reliable 3 months ago had it rolling roaded and it pulled 233bhp at 26psi with no problems at all.
I wish i had a road 5 again ...........
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