Rr Dissapointment

[mbayley77 0]

Just back from having my car set up at the rolling road.

 

1.9 MI16 on weber 45's

 

Max power output = 126.6BHP

 

Best he could get out of it. reckons something is wrong - no sh!t, he reckons the cam timing could be out.

 

Well I have some cams on it which i was told were uprated but now I seriously doubt it. I have standard cams in a spare head in the garage so am gonna start off by replacing the cam belt and cams and see what happens. I am guessing that I should notice a definate improvement if the standard cams are better (ie I am guessing approx 30-40 BHP more than what i am getting so should be able to notice if it is different.

 

If not then what can anyone suggest. Oil pressure is good, temps are normal.

 

Any suggestions please.

[boombang 2]

Have you checked the engine timing at all?

 

Also worth a compression test

 

Only time I've heard of anything like this is a 2 litre turbo with the cambelt a few teeth out and another car with a bent valve.

 

126.6 at the wheels isn't bad really.

[mbayley77 0]

126.6 at the fly!!!! ahhhhhh

 

My thoughts were if the cam had jumped a tooth or if I set it up wrong from the beginning.

 

Think i will start again from scratch with cams that i know are for the engine for a start!

[boombang 2]

Also is it on ignition management?

 

If on dizzy adaptor did they have to retard to avoid low/midrange pinking which has reduced top end power?

 

Did they check exhaust gas to see if the engine is fuelling right?

[mbayley77 0]

Its on dizzy apater with no management what soever. He played with the timing and has it set for optimum.

 

It was constantly on the exhaust analyser, its high on hydrocarbons but other than that its fine.

 

On the standard cams how do you tell which is inlet and which exhaust as i think they are off the head!

Edited March 10, 2006 by mbayley77

[SweetBadger 91]

Its on dizzy apater with no management what soever. He played with the timing and has it set for optimum.

 

It was constantly on the exhaust analyser, its high on hydrocarbons but other than that its fine.

 

On the standard cams how do you tell which is inlet and which exhaust as i think they are off the head!

 

The inlet cam has a key way in the dizzy end to drive the MI rotor arm

[mbayley77 0]

I am going to halfords to get a compreession tester in the morning and then picking up the new cam belt in the afternoon so will swap the cams over in that time.

 

Fingers crossed or a box of matches and a gallon of fuel it is!

[Jonmurgie 2]

Damn, that's bad... hope it's an easy fix, usual is when theres a MASSIVE chunk of BHP missing. Good luck!

[huckleberry 0]

I am going to halfords to get a compreession tester in the morning and then picking up the new cam belt in the afternoon so will swap the cams over in that time.

 

Fingers crossed or a box of matches and a gallon of fuel it is!

 

Maybe you should check the timing of the current ones first in stead of just swapping. I can't imagine that the cams which are in can lose 40 bhp.

[Martin@PRD 0]

May sound a little harsh but sell the carbs, inlet mani etc and go full management, if your looking for good performance from carbs then a 3d ignition system will be required, but this will turn out to be more expensive than having full management set-up and mapped,

 

With management you will see the maximum gains available for your engine from the ignition and fuelling side, plus you will have the option to go throttle bodies at a later date

 

I struggled for months to see real performance from 45 carbs only to find out by have 3d ignition installed for £900 was the only answer (171bhp 150lb/ft)

[mbayley77 0]

Thanks for all the advice. I am gonna try and get some kind of answer as to my problem before I go stripping the carbs and other bits off the car.

So i know what I should be getting - what is a good reading if compresion on these engines? cheers

[Martin@PRD 0]

Yeah sorry, I would personally check

 

1. Cam timing

2. Lobes on cams

3. Compression test

4. Split join in down pipe

5. Chokes using

6. Stop screw adjust for full throttle

7. Whether full throttle is reached

8. Oh.....last one is there enough advance available on the dizzy adaptor?

 

I assume he removed the filters and balanced the carbs?

Edited March 10, 2006 by Martin@PRD

[veloce200 3]

The std curve on the dizzy would be fine with std cams but certainly not right for higher lift/longer duration cams. I doubt though if it would lose that much power. It either got to be (assuming compression is good and cams are timed in)

1- airflow restriction on inlet

2- high backpressure on exhaust

3- ignition problem

[mbayley77 0]

I can confirm from the rolling road today that the following are ok.

 

chokes ok

stop through ok

full throttle reached

Advance reatrd is ok on the dizzy.

 

Tomorrow I wil confirm the rest. New cams are going in. And the compression is gonna be tested.

[PumaRacing 1]

Sounds rather like the 'cowboy engine builders' thread about Dave Walker some time ago. I'd look very carefully at the exhaust system first. I think you'd struggle to get cam timing so far out that you'd lose that much power without the valves hitting the pistons. However it's certainly something you want to check properly.

 

To be honest your RR operator ought to have been able to narrow the problem down fairly closely unless you specifically stopped him to save money. That's his job after all. A cylinder balance test would have identified bad rings, valves or injectors. A compression test wouldn't have taken long. If he just threw his hands in the air and said that's all I can do with it then I'm not greatly impressed. Lots of these people are fine when everything works ok and they only have to tinker with fueling and ignition but when a problem engine comes up they haven't a clue how to diagnose major faults.

[pug_ham 242 3 Cars]

Just back from having my car set up at the rolling road.

 

1.9 MI16 on weber 45's

 

Max power output = 126.6BHP

126.6 at the wheels isn't bad really.

Sorry but thats absolutely horrendous for an Mi16 on twin 45's at the fly, you must be at least 40bhp down even allowing for the dizzy adaptor. My 8v makes 14bhp more than that!!

 

Check everything suggested that you haven't already but it sounds worrying to me.

 

Graham.

[keith 0]

just to make you feel a little better, my HDi was RR'd at exactly 126.6BHP

 

[mbayley77 0]

just to make you feel a little better, my HDi was RR'd at exactly 126.6BHP

 

 

You havnt swapped my engine without me knowing have you?

 

Right then. new compression tester in hand im going to see if all is good! Or bad or whatever!

[mbayley77 0]

Compression test results not good. Whats the advice?

 

cylinder 1 : 130

cylinder 2 : 95

cylinder 3 : 150

cylinder 4 : 90

 

Something wrong with 2 and 4. most likely causes people please?

looks like the head is gonna have to come off anyways.

 

just re done the test and got the following,

 

1 : 130

2 : 110

3 : 150

4 : 90

Edited March 11, 2006 by mbayley77

[PumaRacing 1]

You are doing it with the throttle held open I take it?

[base-1 17]

All of those readings are s*it, assuming you are testing it right?

[mbayley77 0]

Yep thats what i thought.

The throttle is held open when doing the compression test yes.

 

Are you lot doubting my ability to do a compression test here or something?

[pug309twin40s 1]

Compression test results not good. Whats the advice?

 

cylinder 1 : 130

cylinder 2 : 95

cylinder 3 : 150

cylinder 4 : 90

 

Something wrong with 2 and 4. most likely causes people please?

looks like the head is gonna have to come off anyways.

 

just re done the test and got the following,

 

1 : 130

2 : 110

3 : 150

4 : 90

 

 

all those readings are pants. a good condition engine should have around 200psi.

 

 

are you doing the test correctly.

 

on a warm engine,

throttle fully open,

ignition and fuel system disabled,

 

 

when you done a normal test do it again with a drop of oil in each cyl and see if the readings are higher.

[mbayley77 0]

Yes thats the test done that way.

 

Oil dropped into the bores caused a rise of 5 - 10 PSI

[base-1 17]

Are you lot doubting my ability to do a compression test here or something?

Not specifically but it's always worth asking, very often when people are on an internet forum asking about poor compression test readings it's because they've done it wrong