richardm6994

Hi everyone, I've just bought a alko caravan chassis off ebay for £100 and plan to convert it into a car transported trailer. with a bit of luck, all the box section will be "borrowed" from work and a couple of weekends with th angle grinder and welder should see it on the road! Anyone else done this?

I think I'm going for trumpets and socks. I had considered gauzes but have read a lot of bad things about them...i.e. disrupting the air flow, better off without them at all etc... I know the ideal solution is to run trumpets on their own, but I just don't feel comfortable doing that. I'll keep a look out as well for the socks being sucked in, however I don't think that's going to be a problem.

The 48's are choked to 36mm which is the same size as 45's are. They work fine

Cheers Nigel, Good point! the trumpets are 30mm long (full back lip) and the K&N filter are 54mm long and yes they are solid face, which would mean that the end of the trumpet would only be 24mm away from the end of the solid filter face.... I guess that rules out option 4 (trumpets in the K&N filters)! So i'm left with K&N on their own.......Trumpets with gauze......or trumpets with socks..... which will rob me of the least amount of power?

I don't really fancy running without filters..because my luck would be that a stone or sommate gets sucked in a buggers up the engine!

As my rolling road session is fast approaching, I've been thinking about my air filters on my twin 48's (weber). I'm currently using K&N filters on the front of the carbs, but the trumpets I have are too big (OD) to fit inside these filters. My choics are as follows; 1) leave the K&N filters as they are and run without trumpets. 2) ditch the K&N's....and fit the trumpets with wire gauze over the ends 3) ditch the K&N's.....and fit the trumpets with pipercorss sock filters over each trumpet (I have 4 left over from another engine) 4) the final thought I've had.........I can machine the tumpets so they fit within the K&N filters. This can be achieved by either turning down the OD of the trumpets....or machining 2 flats on the trumpets (12oclock and 6oclock positions) so that they do not clash with the fliters? What do you think would give the best result?

Im just hoping my maths is right and i dont end up with broken pistons in a few months time!!

Dan....change of plan.......I'm leaving well alone now and will let the boys at the RR have a play. I don't think I have a problem and have made a Mountain out of a mole-hill

I've had a good long chat this afternoon with the guys at the rolling-road place I'm going to on the 30th April. They got quite a lot of experience with Pinto's and are specialist in Megasquirts. With what they have told me, they sound like they know what they are talking about and have put my mind at ease somewhat..... When the car goes for the RR session, they will MAP the megajolt accordingly and make sure I dont get any pinking. Also, they seem to think that my "mathematical" compression ratio as detailed above (10.45 : 1) is probably a closure representation to my actual CR is, and that the compression test reading (220 psi) I'm getting doesn't give any real indication to the CR......it only shows that I'm getting a good piston and valve seals. They have told me that at cranking speed, two different engines both at 10.5 : 1 CR can give very different compression readings (they can range from 180-225 psi), however when these engines are both at running speed, their combusion pressures will be very similar to each other becasue their CR's are both at 10.5 (assuming same cam). So the long and short of it is that the mathematical CR is what I need to work to, and although it's close to the limit for cast pistons....I should be okay (he says very nervously). Thank you for your offer Mick, but I think I've just made the biggest mountain out of a mole-hill I'm going to leave it now and let the boys at the RR set things up and tell me if I've got any problems. And to everyone else......I realise that I have just gone around in one big circle back to what you was all saying at the start of this thread (and the other thread I hi-jacked). Sorry! I'm 30 this year so not many marbles left!!!

Dan.....I don't suppose you fancy popping over to mine (with your compression tester) sometime and having a look at my engine's compression. I'm starting to think my tester is knackered which is why my readings are so high (the maths suggest it shouldn't be that high)!

I know people are getting sick of me talking about compression ratios, but in a last ditched effort, I'm hoping someone can cast some light onto my concerns; My Engine; 2.1 pinto (93mm bore from memory and 94.5mm x 70tho thick cometic gasket). Pistons are approx 10tho above the deck height. Standard crank stroke of 76.95mm Combustion chambers were 48cc (std I think), but the head has been skimmed 15tho and I didn't measure them after skimming. For the sake of arguing, I'm going to assume they are 46cc (kind of worse case senario) Cam is Kent FR32 Okay, now for the maths (for ease assume 40tho is 1mm); 1) Because the piston is 10tho higher than the deck, it only travels 76.7 (0.25mm less) in the bore than standard. As such, Piston - Cyl displacement = 532.28cc 2) The 10tho that the piston is above deck high, it is in the 94.5mm bore of the gasket. Piston - gasket displacement = 1.75cc 3) The gasket is 70tho thick, therefore 60tho is left empty when the piston is at top stroke. Gasket remaining volume = 10.52cc 4) Assume combustion chamber are 46cc. Total volume = 590.55cc Total compressed volume = (10.52cc+46cc) 56.52cc Therefore CR = 10.45 : 1 suggesting that cast pistons will be okay. In practice, I'm getting around 220psi on compression test (it has always been this high). After talking to JEM engines (who supplied my bottom end and head), they have said that this pressure is too high as a safe figure is no higher than 210psi. I am also aware Burtons suggest no higher 190psi Jem engines are also advising me that if I am getting these readings, to make sure my ignition timing does not exceed 33degrees to prevent predet. I current run a nice 3d map on my megajolt, but it has figures around 38degrees in it (worrying). I'm really struggling what to think. Either leave it as it is and let the rolling road guys set it up (but make them aware of the compression readings), or take the head off and fit a 10tho ticker gasket (this is the last thing I want to do!!) ....other than that, I'm borrowing another compression tester tonight to double check the compression readings I've been getting against my £15 Draper tester. Is there anything you can see that I've overlooked...miss calculated etc...? Also if any nearby feels like popping in to have a look over the engine....it would be greatly appreciated and the kettle will be on....or beers in the fridge! In short.......I had hoped that after this winters hard work, I would have a sound engine which I could simply enjoy.......however all this CR talk (and my own compression readings) has got me in a spin! HELP!!!!!!!

To be honest I'm not sure. My servo is connected as I don't have any problems with lock-ups etc.... I can't see why it would restrict anything though and I think you should be fine to leave it where it is......however someone who has done modification this is better placed to answer this than me

just an update.....after looking at the voltage regulator, my alternator is a bosch and not lucas. New regulator on it's way!

Rear discs are a bit pointless as you've probably read from other threads, and I do tend to agree with this in theory...but having 17" alloys as well, I do agree with you that drums look a bit rubbish!! From what you have described.....points 1 and 2 will make the biggest improvements, point 4 is purely asthetic reasons and point 3 is only required to balance points 1-2 & 4 together. Also, just make sure you get the right pads on the front as this can make all the difference!

Nice video! Looks like the weather stayed okay? I've got some mileage under my belt now on mine (without things dropping off or fluids escaping) so I will certainly be at the next track event!!

Simon.....great stuff...v.helpful Chris, that's very interesting about the PHd student. I understand that there are loads of variables to consider.....which I why I was going to ignore the variables and just collect data from everyone. By doing it this way, you are not looking for a mathematical formula, but simply a pattern......and then extrapolate from that. For example...lets say for instance that 10 people confirm they are running 10.7:1 ratio's....and there compression readings are between 195 - 210 psi. You can then take a good guess when measuring an "unknown" engine that if it's compression reading is between 195-210psi, it is also running around 10.7:1. Collate as much info as possible from as many engines as possible, and it will soon become apparent what PSI reading equate to what ratios. The you don't need a formula, because you can just average these these figures and plot them on a graph? The reason for doing this is 1) simple curiosity and 2) I come across no end of "tuned" pinto engines which people ask me work on...and half the time I do not believe the CR I'm being told.

Hi everyone, this may not work out how I hope, but you'll never know if you don't try.... Basically I'm trying to collect as much "real life" data as possible regards your engine's compression ratios. If you know the compression ratio of your engine (e.g 10.5:1)...and you know what that ratio gives you on a compression test (e.g in psi or bar) can you please reply with your engine's readings. Compression test readings need to be "warm engine" & wide open throttle. Hopefully with enough responses...a pattern between PSI compression test readings and compression ratio's will start to emerge? Then with this data, I hope to produce a rough scale to indicate what PSI readings equate to what compression ratio.... The more people who respond...the better chance this stands of working, and I think it may end up actually being useful to people in the future.

cheers simon, i hear your points.... i'm going to start a new thread and try and collect as much data from every as possible....then we shall see if there is a "rough" relationship that can be worked out.

Simon, you are spot on with the correct way to work out compression ratio......but what I'm thinking about is when the engine is built up.....and you are unsure what cc the combusion chambers are, how much material has been skimmed off the block and head etc....and all you have to go on is a compression test psi reading. I understand that there are a lot of factors to take into account, such as cam duration, volumetric efficeny etc....but surely there must be a basic relationship between compression ratio and compression test (psi). I know that my pinto is running 220 psi, but I don't know what that is on the ratio thingy.

If the people on here who know both there psi compression reading nd their compression ratio....would it be possible to plot these on a graph to give a rough scale? For example if 10.8=220psi and 10.6=180psi, then 10.7 u would expect somewher e in the region of 200psi?or is it not that easy?

Out of interest....how do you convert the psi reading into a "10.8-1" kind of reading?

if you want to reduce the compression.....go for a thicker head gasket (adjusa is 1mm thick and after that your looking at cometic gaskets)

hi, im running around 220psi on a 2.1 pinto without any problems (that I know of!!), but I wouldn't go any higher than that. The only difference is that I'm running a multi layer steel head gasket (cometic) which are designed to take high comp / pressure. If the felpro head gasket is up to taking that kind of pressure....then the next weakest point is the grooves on the pistons which the piston-rings sit in (basically they break...followed by the piston rings). I have taken a pinto to "breaking point" regarding compression ratio...which is 240-250psi

you have prob seen this because I posted it on your last thread....but I will post it again anyway. indicator wiring for a sierra which may help ( or may not as your switch is metro / saab)

this is the wiring diagram I used for indicators & hazards....based on ford sierra column. hth