Aragorn Posted September 24, 2013 Share Posted September 24, 2013 So as per my other recent thread, i've helped a mate change the head gasket on his 300tdi 90 after it had been blowing for a while, then laid up for 6 months.We ended up using a different cylinder head due to the original one having a stuck injector, and got it all installed and changed the timing belt. I didnt have the crank locking pin, so i set the timing by using the pointer on the crank pulley, which lined up before we removed the timing belt and didnt move until after it was refitted.We've got it all back together, and hes finally done the last few bits it needed and got it back on the road. It seems to drive fine, no smoke or odd noises, but both of us feel its a bit slow.We're not entirely sure if it IS slow, hes spent the last 6 months driving round in an Audi A6 TDI, and my daily is an A4 1.8T, both significantly quicker than a stock 300tdi 90, so we're not sure if its just feeling slow relative to what we've been driving otherwise, or if it IS actually slower than it should be due to something being not quite right...Potentially the timing is very slightly out, due to not having the locking pin, but we're not sure if this could have a significant effect on performance or just smoke etc.Any thoughts?We're thinking we might just need to tweak the pump up a little to close up the difference in performance between the Audi and the 90, but obviously doing that to mask some other issue isnt a great idea... Quote Link to comment Share on other sites More sharing options...
duncmc Posted September 24, 2013 Share Posted September 24, 2013 I always found my 300tdi 90 to be fairly slow, even when it was nearly new. I got it when it had about 20,000 miles on it and it was 1 year old. By today's standards, especially modern diesel cars, there are very slow. I thought the same with my 3.9 Classic when I got one again, but then realised it is just that everything else has got so much faster. In the end, I fitted an Allisport Intercooler and tweaked the fuel pump on the 90. It was then a lot quicker, but I still don't think that it would have been as quick as your Audis. The 300tdi as stock was 111.3 BHP and 195 ft/lb of torque. The 90 weighs about 1800kg and is as aerodynamic as a brick. The 2.0Tdi A6 has 175BHP and 280 Ft/lb's of torque, and its kerb weight is 1575kg. It does 0-60 in 8.7 secs, and that is the smaller engine! Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted September 24, 2013 Share Posted September 24, 2013 Whats it like for starting, normally a good place to spot timing issues. Quote Link to comment Share on other sites More sharing options...
Aragorn Posted September 24, 2013 Author Share Posted September 24, 2013 His A6 is one of the earlier ones with 130hp, so not quite as huge a difference to the 90 as the newer 2.0-170 models. Hes texted saying its now missfiring at high rpm/load, so looking into fuelling issues now. Hes going to change the filter and check for any obvious contamination. Quote Link to comment Share on other sites More sharing options...
Aragorn Posted September 24, 2013 Author Share Posted September 24, 2013 Whats it like for starting, normally a good place to spot timing issues. Starts pretty much on the button, just a puff of smoke immediately after starting. I thaught the idle felt a little low, but that may be a historic issue. It just felt a lot happier if you very slightly leant on the throttle pedal and raised the rpm slightly. If you revved it up then shut the throttle and let it drop to idle it felt as though it wanted to stall. No tacho to check the actual speed though. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted September 24, 2013 Share Posted September 24, 2013 Thet don't have to be slow - I'd suggest giving it an "Italian tune-up": drive it for 50 miles or so using foot-to-the-floor-all-the-time and only-change-gear-when-you-hit-valve-bounce attitude. After you've blown the last decade's cumulative carbon/coke contamination out of the cylinders and exhaust, do an oil-change. It always worries me when I'm a passenger in a Defender and the driver's got the change-up-early taxi-driver mentality: hobbling along at 35MPH in 5th - apart from the shock-loading on the transmission that's guaranteed to coke the engine and - because you're loading it hard when the oil-pressure's low - this spells slow but inevitable death to the main/big-end bearings. Change-down early and often; let your engine rev!! Quote Link to comment Share on other sites More sharing options...
Aragorn Posted September 24, 2013 Author Share Posted September 24, 2013 Yeh RPM's are good. I'd already given it a bit of a thrashing round the farm after i put it back together and its had an oil change after that to flush any junk out. Hes going to do another one in a few hundred miles. It wasnt taxed when i'd put it together, hence not taking it out on the road. Hes started driving it yesterday as the A6 needs a CV joint, and hence discovered these issues! Quote Link to comment Share on other sites More sharing options...
Disco-Ron Posted September 24, 2013 Share Posted September 24, 2013 If its been laid up i would suggest it might have a weak lifter pump, hence not getting enough fuel, esp if mis firing at higher rpm..... my 300 has been tweaked, and i keep meaning to get round to checking the pump timing, as mine appears to 'pink' slightly on high throttle settings........ or maybe i'm just paranoid......... i've had my 90 up to three figures on a private track! Quote Link to comment Share on other sites More sharing options...
Texpis Posted September 24, 2013 Share Posted September 24, 2013 I'm not sure how you have removed the belt without a pin of some sort, the pump when in the correct position is like on the top of a spring loaded cam. ( hard to explain) but would not stay in the same position when the belt is removed. The correct way is align the crank timing point and the pin should slip in the pump hole keeping it in position, change the belt and everything will be fine. The correct pin is not necessary a drill will do I think its 6mm. I will be very surprised if the timing is not out by a fair chunk could have gone either way. Mick Quote Link to comment Share on other sites More sharing options...
Yostumpy Posted October 8, 2013 Share Posted October 8, 2013 Check the fuel lift pump. If it is a delphi one, there is a small screw on the top, undo this and remove the top, and inside is a gauze filter. bet its blocked with crud. Carefully prize it out, and clean in white spirit or deisel.. Also the fuel filter could be due for a replacement. Quote Link to comment Share on other sites More sharing options...
Aragorn Posted October 9, 2013 Author Share Posted October 9, 2013 Sorry i never updated this. He'd taken it for a long run, and it got worse and worse until it would barely run. Managed to limp it home, and blew out the fuel lines with an airline and fitted a new filter and that cured it. Once sorted it went back to how it was immediately after putting it together. IE driving normally but feeling a bit flat. Hes since taken it out with the horsebox on the back and reports that it tows like it always has, so we've decided that its not infact down on power, its just much slower than his A6 and he'd forgotten the difference Quote Link to comment Share on other sites More sharing options...
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