Hezath

Yeah totally Tony. Thanks for the input. FWIW, my intention was to get this thing running right but that seemed like a bit of a lost cause with the oil consumption I was experiencing. I actually pulled it apart to change other stuff (alter carb position, die grind some aggressive surfaces in the piping to stop fuel pooling, fit a wall covering 80% of the CSA in the log manifold, etc.) It was only ONCE I had the thing apart that I wanted to be thorough and do a compression test, and the discussed results came in.

Well tonight the motor came out and I pulled #3 (a known good one) and #6 out. #6 has a scratch up the bore... no damaged ring lands, no cracked rings. The only other thing I'm seeing is that it looks like the rings haven't bedded in properly on #6 but I'm no expert on this stuff. Needless to say, I didn't expect this. I also am not seeing the merit in investing in forged pistons if nothing has been damaged. Not entirely sure what the best next move is. I guess I'll clean the shit up and take it to an engine builder/machinist on Monday.

Hey Fletch! If I anticipated this issue and general complexity of getting this stuff to work, I probably wouldn't have done anything to the motor apart from twin carbs. If I had better performance & reliability, I might have blown up the box, but not yet. seattlejeseter, whilst ~140psi may be ultimately acceptable, having that huge difference between the pots - and the motor's oil retention issues - tells me that something is very wrong. I don't know how much/little power the motor was making, it has 'Grose' high flow needle/seats, and the fuel pressure was consistent even coming onto full boost - the wideband was telling me the right things but there may be more to it. I am going to pay someone to tune it when it's back together. JelmerPatrol I spoke with PPM and they were reasonably helpful. Price is no more extreme than anywhere else.

Thanks for the feedback so far. Cool, were they custom or somehow 'off-the-shelf'? Motor is coming out and apart tonight. Just don't want to have the car apart for long so trying to be prepared. I'm from Aus, I've never dealt with that company. I should be in touch? Yep it's a H230 Cedric. This certainly is not in elevated RPM ranges - no more than 6000rpm really, and 10psi on 98 octane fuel, carbureted with no water/meth injection (at this stage). I will assess the damage shortly.

Hi all, I don't make it on here enough and probably should have consulted this great knowledge-base more thoroughly when I was building my setup. My car had an L26 originally, I sourced an L28E and rebuilt it. It's an N42 block and N42 head also I think? The bores were corroded so I sourced some .030" (I believe) oversized hypereutectic pistons, Hastings chrome rings, and the motor was mostly standard apart from some cooling system alterations, standard camshaft & RPM range, etc. After driving it part time for a year, I pulled it off the road and set up a Draw-Thru Turbo system (I sourced a used kit that I modified to suit my engine bay) and when I got that running, I struggled to get the tune and boost-retard function working well, I babied it around a little and tried to get it better but ultimately I had big oil consumption issues (blowing out the tail pipe on boost). I investigated further with a compression test: 1 - 185psi 2 - 185psi 3 - 185psi 4 - 185psi 5 - 170psi 6 - 145psi The leakage is into the crank-case not out the ports. I believe my compression was 8.7:1 or close, and the turbo system runs up to 10psi and I have certainly been able to run it at 10psi with no detectable detonation - but in various states of tune (different timing/fuel mixture) who knows what it experienced momentarily. I am pulling this motor out tomorrow night to assess the damage. My hunch is that forged pistons would be a suitable upgrade, but I am not sure how necessary they are. I feel compelled to frame this right too, I don't really have an appetite for more than 200 and a bit horsepower - whatever I can run with the standard fuel pump and two HS6 SU's. Just to clarify this car is a noise-maker, not something that will be doing motorsport or ever see sustained boost. The only pistons that I have found available are custom so far ('Ross' seem the most cost-effective but still a very pricey upgrade), but perhaps someone on here has alternative suggestions? I'd rather avoid the price and lead time of custom pistons if possible. Then again, my bores may be in good condition and if so, I don't necessarily want to machine the block. For those interested, this is the vehicle powered by the L-series in discussion: Look forward to hearing your feedback.

haha that four barrels arrangement wouldn't really get me out of trouble. If I was just wanting to 'make something work that's easy' I'd go an EFI manifold with a single TB - I've already got the pipe that goes from the compressor outlet to the throttlebody lol! The thing is I don't think it really looks period in a H230.

Yeah I could just go an open plenum with a throttlebody at the front but the twin TBs would just be so much 'nicer' I think, particularly while it's still N/A I found a nice cheap pair of Z32 throttles that had already been bored out (almost 60mm) but I think they're just too damn big for the manifold. Shame

Thanks for the input guys, with the LPG system that I'm planning on using, I won't need any ECU stuff at all haha. In Australia, we don't really have any GM trucks or econoboxes (the only GM stuff is Holden Commodores or european things like Astras), but I guess I can start to scout out some wreckers with measurements and see what works off simply whatever I find. Are the 280ZXT TB's hard to find? They are not the same TB as the L28E I take it? Do you know if the bolt pattern matches or anything like that? I've had it suggested by someone else just then that Z32 300ZX TB's may be a good thing, and keep it in the family too. Anyone heard of people using them? Not sure what size or bolt pattern they have.

Hi guys, I've picked up an N42 L28 that came with a british SU setup. I actually want to put the SUs aside and set up some simple throttlebodies in their place - to run LPG. I'll fabricate up a plenum etc and eventually I'd like to turbo the car through that setup so I need throttlebodies that can deal with a bit of boost. Don't need a TPS or anything, preferably something nice and simple and not too expensive or hard to find a pair of (it could be off a carb'd or injected car with no problem at all), but obviously something very old where the throttleshafts have become loose isn't really suitable either. Really like to hear people's ideas, don't mind if it's an OEM thing I could get from a car at a wrecker, new aftermarket part which is reasonably priced etc. Any advice is appreciated