Let build suggestions please.

[Nick J]

Hi all,

As the majority will know my engine had a fit with itself on route to billing this year so pretty soon its rebuild time. Whilst the car is in my ownership it will never run more than the phase two setup as I find that quick enough for me. So what Im after is sensible suggestions on what parts (specifics if you know them are welcome) to use when it goes back together..... pistons,headgasket,basic headwork worth it? and so forth are they worth uprating or keeping stock considering what power I will be running? Also things that can prolong/help the let's lifespan... A couple have mentioned the zlet oil pump and sbs pickup etc? Anything that springs to mind please feel free to comment. It will be built well with no shortcuts of anykind however as Ive said above I dont want huge power I just want to keep it practicle/reliable etc. If it helps For those who dont know the car It already has the sensible extras such as .... zlet headgasket, aet hybrid turbo, uprated actuator, Pace front mount ic, weber fuel reg, xe inlet cam, enlarged tophat, hard boost pipework etc. As said anything that springs to mind please comment as Id like to hear as many opinions as possible! My main aim is to be confident knowing it will last even when being used enthusiastically etc.

Thanks guys. :)

Nick.

[craig green]

I'd keep it mainly GM parts, with ARP's tbh. Zlet modded pump & pickup. trusted stuff. A good bottom end (std) is good for 300+ bhp anyway.

[Paul]

Speak to steveboyslim. He will talk you through what you need, and tell you no bullsh*t and sell you no sh*t.

ZLET oil pump doubled my oil pressure, i know you understand engines Nick, so ill say no more on that.

If i were in your shoes, just speak to Steve, hell tell you what you need to know.

Paul

[Graeme]

I met Steve last weekend and he is exactly as Paul describes, He really does know what he is talking about and If I was doing a full rebuild he would be where I was spending my money

[joff-turbo-nova]

Nick

I went down the same route with my nova - an up over standard but nothing too silly to keep it reliable.

Engine wise I went with a 0.5 mill overbore with JE low compression pistons - MIGWeb group buy rods rated to 500 bhp (IIRC) - similar to arrow ones - Z20LET oil pump and modded pickup pipe

Turbo was a Turbo Technics hybrid one - but beware my seals have gone after only 9000 miles.

Head was standard apart from SteveBoySlims ARP head set, a Z20LET headgasket and courtney reprofiled cams.

Pipework was enlarged to 50mm all round and a larger top hat was fitted.

With phase II chips that got me just below 300 bhp .

Would also recommend a external boost controller as the one in the ECU is a bit pants

Joff

[discoinferno]

it all comes down to how big is your budget,

for your build i would use mostly gm/ oe spec parts

most engines are worn by now so a rebore is needed to get a decent finish on the bores( however you may be lucky), 86.5mm or 87mm depending on how bad the bores are

i would use std 86.5mm -87mm mahle pistons for your application std rods, arp bolts, no need for uprated rods

z20let pickup and pump seem to be the way to go though i have no oil pressure troubles on a std gm pump with sbd steel gears (cost as much as a new zlet pump though ) how ever they do flow more

i'd use the standard gm head gasket, maybe some CS high torque cams, there is no need for head work imo, get injectors cleaned and tested as they wouldve done some serious miles by now or maybe up to saab reds and keep std fuel pressure reg if keeping yellows new pressure reg to around 3.5-4bar

for example in our vectra turbo we have done 12k miles on evo 3 chips on a standard engine(no arps) std let clutch, apart from intercooler some saab red injectors it made 279bhp 290ft lbs of torque hasnt given a minutes bother


best of luck fella:thumb:

you could how ever go for steel rods, and forged pistons under piston jets, imo this spec not required for your application and would be total overkill

[Nick J]

Thanks all for taking the time to respond....... anyone else feel free to add your opinions. :)

Nick.

[Shaun]

I agree with Disco tbh nick.

I rebuilt mine using all GM parts, including head gasket and oil pump(we rebuilt original)

Theres a local race engineering place near to me, he said for my spec. thats all i would need. just fit Arp bolts..

Mines running phase 3.5, xe inlet cam, forge actuator, custom inlet, 2.5inch boost pipes, large fmic, erm..

Oh and my bores were fine, i just got them honed and got the crank checked/polished.

hope this is of some use
Shaun

[shrtwrec20]

Hi guys. Sorry to jump on your thread Nick but I'm interested in the same sort of info so I'm gonna subscribe :)
I've got stuck with the lump I bought off flea bay. Long story but I'm now going to rebuild it from scratch so I know I can Rely on it. Including getting the knackered turbo rebuilt or replaced with a hybrid? I'd like to hear some suggestions on that also :)

[Benn]

ZLET oil pump doubled my oil pressure,

Is that good tho? As tomuch will blow it down breathers and such...

[MK999]

Z20LET oil pump and modded pickup pipe

Turbo was a Turbo Technics hybrid one - but beware my seals have gone after only 9000 miles.

Well if what Paul says is correct and common and not just a random occurrence, it may well explain the above.

[Shaun]

indeed, funk that.

id rather stick to the original pump. just rebuild it with the kit.

[philip]

heres what ive built for a mates LET, most parts i get through steveboyslim, but i do all the headwork/building, shimming etc. its a pretty much bullit proof long motor and mates running about 400bhp with no problems at all. and if going for track days then the solid lifters are definately the way to go over hydraulics..if want head sorting or whatever just drop me a pm.

spec:

bottom end:

steel rods
omegas
1.9mm cometic
sbd main bolts
lightened fly
helix paddle

head:

ported head
stopck valved
new guides
2angle seats
double valve springs
steel caps
arrow solid lifters
xe cams
piper verniers

[craig green]

Is that good tho? As tomuch will blow it down breathers and such...

No benn.

[sr jack]

No benn.

what about gaskets, wont they leek because of high oil pressure( they always leek anyway lol)

[craig green]

Oil pressure is within the oil ways & bearing journals. Not in the sump or rocker cover cavities.

Oil pressure doesnt push dip-sticks out or blow gaskets, thats another issue altogether.

[krobinson]

My oil pump ring gear broke recently, thankfully causing no damage. But i'd recommend doing ZLET pump, or SBD ring gear.

Mine is back to a standard GM pump which should be fine, I was just unlucky that mine broke.

I'm running 10W 60 oil now which has helped give great oil pressure and the engine feels even smoother than before.

Nick, I'd stick with standard internals, you'll need +.5mm pistons now due to needing a rebore, and use ARP big end bolts to keep it all together.

[Paul]

Sorry I didnt make my point clearly.

The ZLET doubled my oil pressure at warm tickover, was 18psi with under piston oil jets on std CLET pump.

On the ZLET pump its now 35psi.

It has increased oil pressure through the rev range by approx 5-10psi.

Paul

[Alex J]

Sorry I didnt make my point clearly.

The ZLET doubled my oil pressure at warm tickover, was 18psi with under piston oil jets on std CLET pump.

On the ZLET pump its now 35psi.

It has increased oil pressure through the rev range by approx 5-10psi.

Pauland where did all the oil go on the track daylol lol

[MattBrown]

and where did all the oil go on the track daylol lol

What a nice friendlol

[discoinferno]

My oil pump ring gear broke recently, thankfully causing no damage. But i'd recommend doing ZLET pump, or SBD ring gear.

Mine is back to a standard GM pump which should be fine, I was just unlucky that mine broke.

I'm running 10W 60 oil now which has helped give great oil pressure and the engine feels even smoother than before.

Nick, I'd stick with standard internals, you'll need +.5mm pistons now due to needing a rebore, and use ARP big end bolts to keep it all together.

was yours a genuine gm pump that failed ?

[Paul]

and where did all the oil go on the track daylol lol

My oil catch tank (evian bottle) fell over?

Whats that got to do with anything?

[krobinson]

was yours a genuine gm pump that failed ?

Yes, it was the pump supplied on the VXpro engine.

[Alex J]

My oil catch tank (evian bottle) fell over?

Whats that got to do with anything?too much oil presure, there was more oil in the car, than the engine, when you pulled in the pits it looked like you had smoked 200 bensons at once with all the windows up, oil everywherelol lol

[steveboyslim]

indeed, funk that.

id rather stick to the original pump. just rebuild it with the kit.

The zlet oil pump is designed to be used on a turbo engine.
As Paul corrected his eailer post, hot oil pressure can be a bit low, with or without oil jets, the zlet pump puts the oil pressure back to a sensible level.
Rebuilding a genuine GM oil pump is the next best option, steer well clear of the pattern oil pumps.
The zlet oil pump has a higher flow rate which is also very important, if the oil pressure is found to be too high it can be adjusted.
Any turbo will not see much of an increase in oil pressure unless you restrict the oil return path.

Steve

[Benn]

Good info^

[steveboyslim]

Hi all,

As the majority will know my engine had a fit with itself on route to billing this year so pretty soon its rebuild time. Whilst the car is in my ownership it will never run more than the phase two setup as I find that quick enough for me. So what Im after is sensible suggestions on what parts (specifics if you know them are welcome) to use when it goes back together..... pistons,headgasket,basic headwork worth it? and so forth are they worth uprating or keeping stock considering what power I will be running? Also things that can prolong/help the let's lifespan... A couple have mentioned the zlet oil pump and sbs pickup etc? Anything that springs to mind please feel free to comment. It will be built well with no shortcuts of anykind however as Ive said above I dont want huge power I just want to keep it practicle/reliable etc. If it helps For those who dont know the car It already has the sensible extras such as .... zlet headgasket, aet hybrid turbo, uprated actuator, Pace front mount ic, weber fuel reg, xe inlet cam, enlarged tophat, hard boost pipework etc. As said anything that springs to mind please comment as Id like to hear as many opinions as possible! My main aim is to be confident knowing it will last even when being used hard etc.

Thanks guys. :)

Nick.

Final specification will depend on budget.
You also need to establish what cause the failure as it could causse your rebuilt engine to fail.
Not a fan of using the zlet gasket can cause corrosion and overheating problems, would rather use a standard Goetz or Cometic gasket.
If budget allows I would install some sort of aftermarket engine managment which will allow the correct amount of fuel and ignition.

Steve

[discoinferno]

My oil catch tank (evian bottle) fell over?

Whats that got to do with anything?

some body needs a baffled sump to stop surge :d:d:d

[Nick J]

Final specification will depend on budget.
You also need to establish what cause the failure as it could causse your rebuilt engine to fail.
Not a fan of using the zlet gasket can cause corrosion and overheating problems, would rather use a standard Goetz or Cometic gasket.
If budget allows I would install some sort of aftermarket engine managment which will allow the correct amount of fuel and ignition.

Steve

Thanks for the advice Steve...... Once the engines out and stripped/inspected we'll be able to determine exactly what caused the problem in the first place then can obviously consider the cause in with the rebuild spec etc. Im sure there may be one or two things Id like to run by you considering your experiance so when the time comes If you dont mind Ill drop you a pm.


Thanks everyone else for help/advice. :)

Nick.

[blue_peg_16v]

Thanks for the advice Steve...... Once the engines out and stripped/inspected we'll be able to determine exactly what caused the problem in the first place then can obviously consider the cause in with the rebuild spec etc. Im sure there may be one or two things Id like to run by you considering your experiance so when the time comes If you dont mind Ill drop you a pm.


Thanks everyone else for help/advice. :)

Nick.

nick id go with pritty much standard internels, no offence but your not ragging the ass off it every day and the rods are more than upto the power that your looking at, obviously oversived pistons due to the rebore, sbd steel head gasket, and oil pick up, zlet pump and arp rod bolts and head stud kit

when phil stripped mine down after it melted 2 pistons in the previous owners hands the problem was found to be that the head had been skimmed way beyond the usable limit so one scrap coscast head was replaced and all bolted to another let bottom end and other than the head gasket popping a few months ago its been awsome (i was running a cheap gasket as i was skint) and i run phase 3 on full boost most of the time and i do abuse it as thats what i built it for lol

[steveboyslim]

nick id go with pritty much standard internels, no offence but your not ragging the ass off it every day and the rods are more than upto the power that your looking at, obviously oversived pistons due to the rebore, sbd steel head gasket, and oil pick up, zlet pump and arp rod bolts and head stud kit

when phil stripped mine down after it melted 2 pistons in the previous owners hands the problem was found to be that the head had been skimmed way beyond the usable limit so one scrap coscast head was replaced and all bolted to another let bottom end and other than the head gasket popping a few months ago its been awsome (i was running a cheap gasket as i was skint) and i run phase 3 on full boost most of the time and i do abuse it as thats what i built it for lol

The rods are a bit of an unknown quantity as most engine have done 100k miles, no one will be able to give you any idea if or when they will fail.
SBD have cometic gasket, so do I except I have thicker options upto 2.0mm.
For the short motor other than which rods are used (also which brand) and if oil jets are installed there is not much difference between a high or low power short motor.

Steve