Winter Strip Down and Rebuild (Done and Dusted)

[Mikie711]

Managed to get a couple of jobs out of the way today before my better half dragged me off shopping . Finished making the brackets and fitting the last two wheel sensors, all tested and picking up the nuts on the back of my disc's. Also fitted the cowl for the oil cooler......



which looks like this, £60 from lotus for a lump of plastic...........ridiculous



And in place under the front crash structure.

[Mikie711]

I was sitting thinking last night when I realised that the Jenvey DHTB's don't have a vacuum take off for the fuel pressure regulator. Now they do sell an adapter that screw into the air bypass screw hole but what I was wondering was if this would make balancing the air flow through each of the bodies difficult if not impossible. I don't see any other way of getting a vacuum feed from each cylinder other than by doing away with the air bypass needle and fitting the adapters. I suppose I could just drill and tap the body behind the butterfly but it's not terribly thick material without a boss. Anybody any thoughts or experience of these things and how did you over come this problem ?



Picture speaks a thousand words.

[r10crw]

Dont know much about it mike, but with the VHPD I used a fixed fuel pressure and understood that using variable FPR fed from the Manifold was usually kept for boosted applications. I did this with inital charged honda but then had to tune for it accordingly. When balancing the throttle bodies I thought it was the same as twin carbs where you are measuring flow rate and adjusting these to balance, this is then done with a seperate tool. Like I said I dont actually know and ready to be enlightened, cheers Craig.

[tut]

Mike

Ricky has done lots of T/B installs so he should be able to advise.

tut

[Mikie711]

tut you were right, Ricky did know. The answer is you just don't use the vacuum take off on the fuel pressure regulator, just leave it open and set your fuel pressure to what you want. Also suggested that I change the coil pack for a citroen AX one which has got 4 plug leads on one col pack, easier to wire in than the double packs .

[Mikie711]

After discovering that I don't need to worry about a vacuum take off I decided to go ahead and rebuild the throttle bodies and newly acquired Bernard Scouce airbox backplate. The 330cc/min injectors looked clean enough so am not going to bother with the expense of having them cleaned professionally. Will find out if they are OK once I get it started, any problems with them will show up soon enough.
Pictures of the assembled DHTB's





The gold colour bracket is QED's and allows me to retain the original Elise throttle cable. Trumpets are 110mm, not sure if they are maybe a bit long for this airbox. Might end up getting Bernards 90mm which is the longest he sells. They do fit but are quite close to the wall IYSWIM.

[Mikie711]

The plastigauge I was waiting for arrived today, more like cut up chop sticks this stuff is so thick. So first job was to stick some in the piston cut outs............






little strips in each valve pocket, plan was to do all of them but after thinking about it unless the results were really close I decided to do 1 exhaust and 1 inlet at random.



Head on and torqued down, followers in number 1 exhaust and number 2 inlet.



Already set number 1 cylinder at TDC, dial gauge on the follower ready to turn the cam to give 3.05mm lift. Never felt any resistance when doing the exhaust which was encouraging, but when doing the inlet to 3.63mm on number 2 I did know it was pushing against the plastigauge.



This was proved to be true on removing the head, exhaust hadn't been touch so more than 70 thou, 1.75mm clearance. On the inlet it had touch the plastigauge but didn't compress it enough to get a true measurement, still over 70 thou 1.75mm, but only just.



You can see the marks in the pastigauge left by the inlet valves, still above 70 thou clearance which means no more machining .

All that remains now is to strip it all down and get it away for balancing. Hopefully that won't take to long and might start getting the engine finish built before I go back to work which would put me ahead of where I thought I would be around now.

[Kev]

Awesome stuff Mike, great read

Out of interest and not knowing much in depth on piston engines, how do you balance the engine? I read your sending it to Agra in Dundee, just wondered how its carried out.

[Mikie711]

The black art of engine balancing, I've no idea myself just know it's a must do when so much has been changed. The crank, rods, pistons, flywheel and clutch cover are going to AGRA hopefully this week> WIll speak to them when I'm down and find out what it is they do to it.

[Kev]

I can see the basics behind it, just wondered how they carry it out. Can imagine it's slightly different engine balancing than I'm used to, working on gas turbines. Saying that, these days the onboard computer tells you what part number of weight and what postion to put it when balancing the Fan Blades. It would interesting to see the set up balancing a piston engine.

Give me a shout when you want your late Xmas present

[woody]

I can see the basics behind it, just wondered how they carry it out. Can imagine it's slightly different engine balancing than I'm used to, working on gas turbines. Saying that, these days the onboard computer tells you what part number of weight and what postion to put it when balancing the Fan Blades. It would interesting to see the set up balancing a piston engine.

Give me a shout when you want your late Xmas present

Onboard computer, what engines is it you work on? On wing I take it? We usually get the F1 blades in pre balanced and plotted from vendors now, which makes it easy. I know a few people at work have used the balance machines when building piston engines in the past.

Mike, were you thinking of having the injectors ultrasonically cleaned?

[Mikie711]

Mike, were you thinking of having the injectors ultrasonically cleaned?

Yes I was, but think I will wait and see if they need it once I get it running. Not that big a job to whip them out if they are knackered.

[Kev]

I can see the basics behind it, just wondered how they carry it out. Can imagine it's slightly different engine balancing than I'm used to, working on gas turbines. Saying that, these days the onboard computer tells you what part number of weight and what postion to put it when balancing the Fan Blades. It would interesting to see the set up balancing a piston engine.

Give me a shout when you want your late Xmas present

Onboard computer, what engines is it you work on? On wing I take it? We usually get the F1 blades in pre balanced and plotted from vendors now, which makes it easy. I know a few people at work have used the balance machines when building piston engines in the past.

Mike, were you thinking of having the injectors ultrasonically cleaned?

Yeah on wing, the IAE V2500s on the Airbus A319/20/21. Theres not much you cant do on them through the CFDS (on board computer), great piece of kit. Unfortunately dont see them that often these days. 99.9% of the time I work on RR AE3007s on the Embraer 135/145s.

[woody]

I can see the basics behind it, just wondered how they carry it out. Can imagine it's slightly different engine balancing than I'm used to, working on gas turbines. Saying that, these days the onboard computer tells you what part number of weight and what postion to put it when balancing the Fan Blades. It would interesting to see the set up balancing a piston engine.

Give me a shout when you want your late Xmas present

Onboard computer, what engines is it you work on? On wing I take it? We usually get the F1 blades in pre balanced and plotted from vendors now, which makes it easy. I know a few people at work have used the balance machines when building piston engines in the past.

Mike, were you thinking of having the injectors ultrasonically cleaned?

Yeah on wing, the IAE V2500s on the Airbus A319/20/21. Theres not much you cant do on them through the CFDS (on board computer), great piece of kit. Unfortunately dont see them that often these days. 99.9% of the time I work on RR AE3007s on the Embraer 135/145s.

I think we handle a few V2500 AGB's as a third party vendor. We do a few CFM accessories, but the bulk are CF6 overhaul and we're gearing up to be the overhaul shop for the GEnx (787 & 747-800) when it launches. All off wing in the nice indoors, barring the odd mobile, of course.

[Mikie711]

Engine stripped and off down to Dundee this afternoon to drop off the parts for balancing. Should get it all back start of next week. New Eibach springs arrived today so will crack on and get the suspension and steering done while I am waiting. Some more wiring to do once some switches I ordered arrive and then screw it all back together.