xu5m engine rebuild

I now have my 205 back at the workshop thanks to some relaxation of Covid lockdown. Waiting on a new fuel pump though. I've gone through 3 pumps now, put it down to old fuel and standing but I did let the 2nd pump drain the tank into a container and then put 20 litres of fresh fuel in. I guess put the new pump in, drain the fuel again and put more fuel in and hope it works.
 
Pistons look OK, which end is the arrow pointing to?
I can't remember but I drew an arrow on the block will have check

Figures for distance H

Measured with cam fitted and torqued down. Different heads are stamped with different numbers which indicates std or oversize cam journals.
This confuses me even more! The 205 haynes manual says an xu8v head is 141mm but your picture and the 405 haynes manual says 158mm.

Does anyone know what cc the chamber should be? The engine builder I'm dealing with said we could go off that if I can find it but I havent seen it aywhere it the haynes manuals yet
 
I've got a Haynes 306 manual and it states the XU & XUD head thickness is 157.4-157.7mm.
 
141mm from where and to where? Although my pics are crappy, if you take a good look that measurement is, as stated, with the cam fitted. Its merely one method of measuring the head there may be other ways. I believe that method i gave you is from a Genuine Peugeot Build Manual.
 
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I can't remember but I drew an arrow on the block will have check


This confuses me even more! The 205 haynes manual says an xu8v head is 141mm but your picture and the 405 haynes manual says 158mm.

Does anyone know what cc the chamber should be? The engine builder I'm dealing with said we could go off that if I can find it but I havent seen it aywhere it the haynes manuals yet

if your engine builder cant cc the chamber id be shopping around.
 
at a guess its 35cc if its small/closed chamber head, but i wouldn't be building a engine based on my guess.
 
if your engine builder cant cc the chamber id be shopping around.
he can cc it but want's to know what it is standard so we have a base to go off. I would also like to know what it should be standard so I can learn more about all of this and this is the 141mm mentioned in the 205 manual
 

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I can't remember but I drew an arrow on the block will have check


This confuses me even more! The 205 haynes manual says an xu8v head is 141mm but your picture and the 405 haynes manual says 158mm.

Does anyone know what cc the chamber should be? The engine builder I'm dealing with said we could go off that if I can find it but I havent seen it aywhere it the haynes manuals yet
405 engine in Haynes is possibly the downdraft port SRi engine (D6A, D6D). This was fitted with flat top pistons in Euro spec, so disregard. The version we got here (DFV) had DFZ style pistons so only gave 8.3 to 1. This engine was also used in the BX 8V GTi.
 
I'm confused why you're considering double valve springs. An engine needs to be matched in its components and to the gearing, if it's going to be useful package. In your case, you're limiting RPM by camshaft choice, which in turn is limited by CR. The gearing has to match the RPM range of the engine. Your decision to run highway gearing and keep the CR modest, means it doesn't need a lot camshaft and thus probably not double valve springs. Until you have the camshaft and have measured the installed height of the standard valve springs, you really don't know where you're heading with springs. I would imagine though, that the standard springs will be fine when installed with enough seat pressure. It's only a question your engine builder can answer.

To answer your question though, the head will need to be machined around the spring/guide area, to accept the new spring bases supplied in that kit.

I'm considering them cause I don't know any better mate. I'm new to this and trying to figure things out. I'm wanting to make my engine have more power but be strong so thought they would help. When the car gets used for autox or when I was in aussie and did khana's the car usually saw the limiter fairly often so I thought a more aggressive cam and springs would help there too. I love revving it out and would love for it to have more up top.

CR is limited by the octane used right? or can that be solved with the right tuning and having the right parts?

Also gonna take your advice and look for a shorter ratio box to use. I know these options aren't what you said to use but will start off with my spare one and look for an mi16 box because that is what's available in North America.
 
1st and 2nd in an Mi16 are the same as the S3 205 GTi ratios but with a 4.43 FD instead of 3.6. From there they are a bit wider than the GTi ratios to give a good top speed without the need to go to a 6 speed. The Mi16 box is a massive improvement for an Si.
I've been driving mine around for the past two days, goes so much better than my auto and I'm sure the engines are pretty much the same. The ZF is a very good auto box but needs at least one more ratio. Standard Si manual would be in the middle of the two for performance.
 
1st and 2nd in an Mi16 are the same as the S3 205 GTi ratios but with a 4.43 FD instead of 3.6. From there they are a bit wider than the GTi ratios to give a good top speed without the need to go to a 6 speed. The Mi16 box is a massive improvement for an Si.
I've been driving mine around for the past two days, goes so much better than my auto and I'm sure the engines are pretty much the same. The ZF is a very good auto box but needs at least one more ratio. Standard Si manual would be in the middle of the two for performance.

That's good to hear then. we had an autox last week and the standard gearing really made me suffer. the first part was up a hill so the car struggled and 3rd gear on the faster parts didn't really feel like I was accelerating much. courses here a set up for bigger American cars (about 11 of the 50 cars we corvettes). here is a pic from it!
Has Victoria changed stages with isolation so you can get the car tuned or are you driving around near your home?
 

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We may be ahead in the coming months, I think people are getting a bit too confident, particularly in Qld. Look what happened in NZ. Meanwhile my area has been sitting on zero active cases for months now. Just waiting for the all the Covidiots to wake up to themselves, getting pretty stressful looking at the daily cases now that we are so close.
 
That's good to hear then. we had an autox last week and the standard gearing really made me suffer. the first part was up a hill so the car struggled and 3rd gear on the faster parts didn't really feel like I was accelerating much. courses here a set up for bigger American cars (about 11 of the 50 cars we corvettes). here is a pic from it!
Has Victoria changed stages with isolation so you can get the car tuned or are you driving around near your home?
Car repairs now allowed so I got an ABN and signed myself off (allowed) as a permitted employer. Will run the engine in when the fuel pump arrives, booked in for tuning on the 27th, but will need to get a better exhaust system first.
 
I'm considering them cause I don't know any better mate. I'm new to this and trying to figure things out. I'm wanting to make my engine have more power but be strong so thought they would help. When the car gets used for autox or when I was in aussie and did khana's the car usually saw the limiter fairly often so I thought a more aggressive cam and springs would help there too. I love revving it out and would love for it to have more up top.

CR is limited by the octane used right? or can that be solved with the right tuning and having the right parts?

Also gonna take your advice and look for a shorter ratio box to use. I know these options aren't what you said to use but will start off with my spare one and look for an mi16 box because that is what's available in North America.

forget fitting double valve springs unless your building a serious race engine you wont need them. The cost to do it would be better spent elsewhere, stronger springs also put more strain on valve train. If you are planning on running carbs just bump the compression up to around 10:1 and fit a cam to suit
Id recommend a euro spec d6b cam if you can find one or cat cams 4900365 that way you will retain some torque which is far more useful to you. You will be suprised with how well this combo works if you get it tuned right.
 
minor update. I dropped all my pistons off to machinist to get checked and he said some are .12mm off. they are warn at the bottom of the skirt. should I be looking for replacements?

He has started to get the valves all cleaned up and going to give it a skim in the next few days and get it ready for new parts.

Is it worth replacing the oil pump or will the standard one be fine to throw back in?
 
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0.12mm (0.0047”) is an enormous amount. It would have been rattling badly. He must have measured in the wrong spot.

The oil pump is the most reliable part of XU engines. They rarely need replacing.

He said it would have been bouncing around in there. around the rings is in spec. its the bottom of the skirts that he said are off

I'll get a picture of the worst one tomorrow
 
I have the pistons out of my engine available. You would need to change at least one of the rods though, destroyed by the run big end bearing. Callum did say that your engine was getting pretty tired Whoever installs the rods has to know what they doing, not to use too much heat.
 
Got the new fuel pump fitted today on my 1.6 project, going to do a few runs up and down the street first thing in the morning to bed in the rings then tuning on the 27th.
 
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