Terry Oxandale
Skinny Man
Unrequested, but perhaps in this situation (nature of the car), desirable?
Mclaren M8b replica (visual)
- Thread starter russell keach
- Start date
Unrequested, but perhaps in this situation (nature of the car), desirable?
With regard to retarding cam helping top end yes, but if the crank key-way, timing set, and camshaft manufacturer were all having a bad day it could be miles off.... don't try to tell me it doesn't happen!
Jac..you are correct, I did just line it up with the marks. I do not know how to dial in a cam and cant see how I could adjust it if its out as moving 1 tooth either way would be a massive variation. Now that I have given it a run to bed in the cam ( I hope) and know that the systems work I will be able to sort out these other matters as it seemed to `rev` ok. I am still trying to get in touch with Webber Specs before I run it again and have just bought a laser thermo gun so that I can be confident of the cooling. The main thing is my list of adjustments is getting smaller every day.
Cheers
Cheers
Jac, the questions just keep coming...many thanks for your help.
The cam is a Crower 50230 and yes reading the specs, it has 4 deg of advance ground in.
260 Dur intake and 266 Dur ex.
does this mean that my timing mark (TDC) would appear advanced via the strobe?
Even when i had it running at what I thought was its best, I was getting intermittent backfiring thru the carbs,
Can I still check the cam timing once assembled as a runner?
I have attached a scan of the cam build sheet.
Cheers
Russell
The cam is a Crower 50230 and yes reading the specs, it has 4 deg of advance ground in.
260 Dur intake and 266 Dur ex.
does this mean that my timing mark (TDC) would appear advanced via the strobe?
Even when i had it running at what I thought was its best, I was getting intermittent backfiring thru the carbs,
Can I still check the cam timing once assembled as a runner?
I have attached a scan of the cam build sheet.
Cheers
Russell
By at least performing that check Russell you can also verify that your timing mark pointer on the damper etc is accurate and then you will know that any ignition timing changes you make are correct. with regard to the cam timing if its within 2 or 3 degrees of the card you can then decide if its going to be a major factor and /or need correction.
Terry Oxandale
Skinny Man
Russ,
Was this a cam you chose for a specific reason? Just curious on the specs. Have you used it before in your previous project?
Was this a cam you chose for a specific reason? Just curious on the specs. Have you used it before in your previous project?
Thanks Jac, I will go thru all those points this weekend and reconfirm, I also have the correct carb jets now so will also throw then in before I run it. Any strip down will involve pulling the motor / trans out so keen to avoid that.
Terry
Cam was chosen on the excellent US / Kiwi dollar exchange, along with it being a mild to medium cam that could run safely on hyd cam followers...nothing special.
Cheers
Russell
Terry
Cam was chosen on the excellent US / Kiwi dollar exchange, along with it being a mild to medium cam that could run safely on hyd cam followers...nothing special.
Cheers
Russell
Jac
Success at last, went thru and double checked TDC and that is correct then measured 4deg and 7 deg marks on the front pully so there could be know confusion. Also checked that the rotor was in the correct position for TDC.
Fitted the new jets now 150 main (was 132) 60 idle (was 52)disconnected the vac advance and then hit the button......
What a difference, started easily with no back fire and was quickly able to flash the timing light and make a minor adjustment that at this stage looks like around 4 to 5deg btdc, it even idled! Armed with my trusty new $22.00 heat laser I was then able to watch and compare temps. As I have only balanced the carbs by eye so far, i have yet to make or borrow some form of air flow meter....it seems that one side is running a little hotter that the other, after a good 10 minutes of running I was still to see 60c plus running on the fan only for cooling.
temps are as follows
L hand side R hand side
head 45c head 53c
pipe in 27c pipe out 36c
radiator 27c radiator 36c
It was amazing how much difference the jet change made, I can only think that the reason for the exhaust temp difference (+80c) could be due to a slightly more open throttle on that side.
The good thing is that all appears to be fine and I can now get on with fine tuning it, its nice to see that it can hold its temp sitting on the trailer in the workshop and its sure nice to be able to run its temp down on the electric pump and fan...who knows
Success at last, went thru and double checked TDC and that is correct then measured 4deg and 7 deg marks on the front pully so there could be know confusion. Also checked that the rotor was in the correct position for TDC.
Fitted the new jets now 150 main (was 132) 60 idle (was 52)disconnected the vac advance and then hit the button......
What a difference, started easily with no back fire and was quickly able to flash the timing light and make a minor adjustment that at this stage looks like around 4 to 5deg btdc, it even idled! Armed with my trusty new $22.00 heat laser I was then able to watch and compare temps. As I have only balanced the carbs by eye so far, i have yet to make or borrow some form of air flow meter....it seems that one side is running a little hotter that the other, after a good 10 minutes of running I was still to see 60c plus running on the fan only for cooling.
temps are as follows
L hand side R hand side
head 45c head 53c
pipe in 27c pipe out 36c
radiator 27c radiator 36c
It was amazing how much difference the jet change made, I can only think that the reason for the exhaust temp difference (+80c) could be due to a slightly more open throttle on that side.
The good thing is that all appears to be fine and I can now get on with fine tuning it, its nice to see that it can hold its temp sitting on the trailer in the workshop and its sure nice to be able to run its temp down on the electric pump and fan...who knows
Hows the hearing Russell, a length of rubber or plastic tube from ear to venture will give an audible indication of flow to each barrel.. Assuming that you have been a good lad and kept the RPM up for cam run-in purposes you could check the total timing you have by marking the front pulley/damper for 25° thru 35°. Being only 3.500" bore I cannot imagine it needing any more than 30/32° total with vac disconnected at 2500/3000 RPM.
Jac,Thanks again.
One last question..I have balanced the carbs and all are on the same settings and sucking the same on an air flow meter. Still the left bank runs hotter on the heads by about 10 deg, but the exhaust is significantly hotter for the left bank 145 deg v 80 deg. The left bank is also running very black / sooty which kinda points to being rich. Before I start tearing carbs to bits, could the float levels be to high on the left bank?
It all starts easy and idles comfortably now so most other issues have been solved.
Your thoughts.
Cheers
Russell
One last question..I have balanced the carbs and all are on the same settings and sucking the same on an air flow meter. Still the left bank runs hotter on the heads by about 10 deg, but the exhaust is significantly hotter for the left bank 145 deg v 80 deg. The left bank is also running very black / sooty which kinda points to being rich. Before I start tearing carbs to bits, could the float levels be to high on the left bank?
It all starts easy and idles comfortably now so most other issues have been solved.
Your thoughts.
Cheers
Russell
Russell, I wonder if your getting a coolant flow rate differential from left bank to right bank due to the front cover design for the water pump, without the impellor to evenly distribute the coolant you might find your single inlet/lower hose needs to be repositioned. On raw feed cooling systems for jet boats we found it better to feed into a 'Y' or 'T' junction and feed each bank of cyls equally from that rather than using the front cover design to decide on who gets first bite! Looking at pics of Rover front covers they vary a lot, the attached pic of a later serpentine reverse rotation cover looks to be no-good for your setup.
By all means check the float levels, if jets / chokes etc are all the same and your getting similar flow rates in each carb barrel its about the only fuel thing left.
By all means check the float levels, if jets / chokes etc are all the same and your getting similar flow rates in each carb barrel its about the only fuel thing left.
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Russel i have been having exactly the same problems with the 5000, exhaust hotter on the right than left, also much louder on right than left, problem was solved when i re balanced the throttle bodies with a good quality balancer and the closer i got the two banks in sync, the closer both the temps and sound equalized till i had them almost identical again. and that was how it came off the dyno, to say i wasnt impressed would be an understatement.
so what i.m saying is recheck your balance across the banks, as i'm almost certain thats where your problem lies.
kaspa
so what i.m saying is recheck your balance across the banks, as i'm almost certain thats where your problem lies.
kaspa
John
Yes considering that the 4 carbs were installed in no particular order, it`s a bit of a `fluke` that I could have selected 2 carbs as a pair of faults. I am using a good quality meter to check so will do it again. The black exhaust gas from the same bank is pointing to something?
Cheers
Yes considering that the 4 carbs were installed in no particular order, it`s a bit of a `fluke` that I could have selected 2 carbs as a pair of faults. I am using a good quality meter to check so will do it again. The black exhaust gas from the same bank is pointing to something?
Cheers
Problem solved...checked that both sets of rockers are rockin..checked all cylinder temps and found that 4 and 6 were cold, checked both plugs were sound, checked my checks.....and swapped the leads on plugs 4 and 6....problem solved.
It seems that no matter how careful and meticulous you are in numbering etc, it still pays to check everything. Best little tool I bought was the lazer thermo gun as it identified the problem the moment I checked each cyl extractor pipe. Now it runs sweet as.
Thanks for the help, its been a learning curve no having done much motor work before, this was the first full engine build.
Cheers
It seems that no matter how careful and meticulous you are in numbering etc, it still pays to check everything. Best little tool I bought was the lazer thermo gun as it identified the problem the moment I checked each cyl extractor pipe. Now it runs sweet as.
Thanks for the help, its been a learning curve no having done much motor work before, this was the first full engine build.
Cheers
More action...
Axles at last, now fitted and all seems ok with no binding. Been using the last few days catching up on all the little small bits of finishing, so that I can actually put it on its wheels and test drive it. Looking forward to that once I have set up the alignment etc. Any comments on toe and camber angles front and rear?
Cheers
Axles at last, now fitted and all seems ok with no binding. Been using the last few days catching up on all the little small bits of finishing, so that I can actually put it on its wheels and test drive it. Looking forward to that once I have set up the alignment etc. Any comments on toe and camber angles front and rear?
Cheers
Attachments
Stage Two...the smelly part!
I down loaded a fie from a slot car forum early in 2000 because it had a segmented cross section drawing of an M8B ...I thought it might be handy one day, little did I realize what the future held.
So, spent Thursday cutting out the profiles and yesterday mounted them onto rails to set up the correct spacing. When you bend a flexible stick over them you can see the shape start to emerge. I have now down loaded a bunch of car pics and will fine tune my radius corners. Then it will be a case of layering thin custom wood over the forms and working the shape from there. I have convinced myself that this will be real easy....if it dosn`t work then maybe I could throw an out board on it and make a boat.
Watch this space.
Russell
I down loaded a fie from a slot car forum early in 2000 because it had a segmented cross section drawing of an M8B ...I thought it might be handy one day, little did I realize what the future held.
So, spent Thursday cutting out the profiles and yesterday mounted them onto rails to set up the correct spacing. When you bend a flexible stick over them you can see the shape start to emerge. I have now down loaded a bunch of car pics and will fine tune my radius corners. Then it will be a case of layering thin custom wood over the forms and working the shape from there. I have convinced myself that this will be real easy....if it dosn`t work then maybe I could throw an out board on it and make a boat.
Watch this space.
Russell
Attachments
Terry Oxandale
Skinny Man
Me too!
Bit more progress, starting to see the shape emerge now once panels are in place. I have trial fitted sides and top so can check dimensions against the build v plans. Thinking long and hard about the cutouts in the rear panel...may do then as a separate function after molding as they could cause difficulty in removing the body from the mold.
So far this is all been quite bulk stuff so the hard rewarding work will come when I start the sanding.
Cheers
So far this is all been quite bulk stuff so the hard rewarding work will come when I start the sanding.
Cheers
