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Discussion Starter #1 (Edited)
I've ad this issue since I bought it, I figured one of the things I was planning to fix would solve the problem but still no luck. Regardless if it's in gear or just revving in neutral it seems to top out at 4500 rpms, I had a tach on here for a bit to verify. Acceleration and everything feels normal just like my last 142 did.

So far I have changed out:
  • the su carbs out for a weber carb
  • fuel pump
  • plugs & wires
  • distributor cap
  • points
  • condensor

For your viewing pleasure: https://www.youtube.com/watch?v=bLmVfCGo0Z0&feature=youtu.be

Also I set the timing 10 degrees before tdc, the crank pully on this car looks like [10 0 10 20 30], I set the timing to the bold 10, is that correct? I ask bc my reference material was a b20 and the numbers were backwards.

The hard warm start issue is fixed and the car seems to run a bit better but still topping out at 4500 rpms, not a huge deal around town but impossible to get it on the highway when it stops at 50mph. Running out of ideas here, any help is appreciated.
 

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I've ad this issue since I bought it, I figured one of the things I was planning to fix would solve the problem but still no luck. Regardless if it's in gear or just revving in neutral it seems to top out at 4500 rpms, I had a tach on here for a bit to verify. Acceleration and everything feels normal just like my last 142 did.

So far I have changed out:
  • the su carbs out for a weber carb
  • fuel pump
  • plugs & wires
  • distributor cap
  • points
  • condensor

For your viewing pleasure: https://www.youtube.com/watch?v=bLmVfCGo0Z0&feature=youtu.be

Also I set the timing 10 degrees before tdc, the crank pully on this car looks like [10 0 10 20 30], I set the timing to the bold 10, is that correct? I ask bc my reference material was a b20 and the numbers were backwards.

The hard warm start issue is fixed and the car seems to run a bit better but still topping out at 4500 rpms, not a huge deal around town but impossible to get it on the highway when it stops at 50mph. Running out of ideas here, any help is appreciated.
The bold 10 should be 10 deg BTDC.

Do you have a timing light? If so, connect it up and check the timing advance as you increase the engine RPM. Depending on whether your engine is a B20A of B20 B, it should probably top out around 32 deg - 35 deg total advance by about 3000 - 3200 RPM. Check to see if the timing is steady at around 3000 RPM. If the timing marks are moving around a lot at 3000 RPM then you may have a distributor wear issue that is affecting higher RPM timing. If the timing hits 32-35 deg by about 3000-3200 RPM and the timing is steady your problem is likely not ignition timing related. The next logical place to look would be the Weber carb; but, I really know zip about the Weber.

Is this engine mostly original? If so, B18 andB20 engines are a bit notorious for cam and lifter wear. In severe cases the cam lobes can sort of disappear. If you haven't done so already, check the valve lash. Aside from visual inspection, the only way to check for cam and lifter wear is to measure the actual valve lift on every valve using a dial gauge. The design lift will vary with the cam installed in the engine; but, some where around 0.4 " would be a good starting guess. A severely worn cam will definitely lack high RPM go.
 

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Discussion Starter #3
Ok thanks, I do have a timing light and did check it was 10 degrees btdc at idle but didn't rev it up. I'll give that a try next, if not start inspecting the cam and valves. I don't think this is carb related since I had the exact same issue with the SU's, installed the Weber a few weeks ago.

The video doesn't really show it but it's as if I hit a governor at 4500 rpm's, just stops accelerating, the weber has a bit of a misfire at that point, the SU's didn't.
 

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C;

The first thing I though of also was Ign and Cent advance...you should check this again with the timing light while reving to see where it tops out...I wouldn't rev to 4500 without load too often, but momentarily to 3000 for this test is OK...

...but misfire also might be due to carb issue...I'm no expert on the Weber either, but if its similar to its DCOE cousin, which has multiple jets for different operating ranges, maybe its high range jet is clogged or otherwise inoperative...

Good Hunting!
 

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I Agree about it not being a Carb issue. Hopefully you still have the SU's

Is the Weber you installed the 2 barrel Downdraft ? The SU's will out perform that if serviced, and setup correctly.

ALSO, To my eye Engine Compartment looks Vintage Volvo, Vintage European for that matter with them.

The Timing issue seems the likely suspect, as 142 guys states you really do need to check the timing with a light as you bring the RPM up, and see that it maxes out at 32º-35º Have you had the Dist off recently? When you have the Dist off, Can you hear the mechanical centrifugal advance mechanism inside move when you spin the rotor quickly?

Scrub through this thread ...

https://forums.swedespeed.com/showthread.php?44152-Distributor-timing-advance
 

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Discussion Starter #6
Checked the timing today at around 3k rpms, or maybe a bit more and it was 30 btdc which seems ok. Going up higher to the point the car bogs it seemed like things were bouncing around a bit
but could just be the engine itself moving as it bogs down. I think I might change out the distributor anyway, it doesn't look like this one was oiled in a long time. Does anyone have a good source for these? I see a few with the vacuum line but mine doesn't have that.

Re: the Weber, this carb is garbage, I wish I had done more research. I pulled my SU's and rebuilt but didn't have a drill press for the throttle shaft bearings. Once I get that sorted Ill eventually re-install the SU's. Looks like there is just one jet on this carb and the mixture screw. I finally have the weber dialed in but I still get a small not really backfire but pop through the exhaust when I turn the car off. Leaning/richening the mixture doesn't seem to fix this. I am hoping it goes away with the new distributor.
 

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There are no new Bosch distributors available. Anything available from Ebay or like sources will be used and of equal age so likely suffering from the same problems. Cardonne offers a rebuild service through Rockauto for about $150 which requires that you send them your distributor to be rebuilt. I have no idea how good or bad they are.

Before starting a search for a new distributor I suggest a search of the yellow pages to see if you can find an automotive electrical repair specialist. They may be equipped to test your distributor and can confirm whether the bushings or the advance mechanism is worn. They may be able to rebuild your distributor for you. If you don't want to go the rebuild route the preferred option appears to be the 123 electronic distributors. They are not cheap; but, considering the cost of a Cardonne rebuild plus shipping costs in both directions, maybe not that much more expensive than rebuilding.

There was somebody that offered a rebuild service for SUs which included new bushes on the throttle shaft. I am an EFI guy so the name does not come to mind; but, some other forum member can probably point you in hte correct direction.
 

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There are 2 good sources for SU rebuild/repair, I have used both

In New York you have Joe Cuerto, He has a new Website and it's currently not fully functional, and his old website seem to be down already, but he's active on Facebook

https://www.facebook.com/joecurtoinc/ 718-762-7878 [email protected] NEW WEB SITE https://www.britishsuperior.com/

***

The Other option that I know of is in Canada, on Vancouver Island, call Island Automation, https://www.sucarburetors.com/

250-479-5482 or 250-479-5192, 2:00 PM - 8:00 PM Pacific time, or e-mail Rhys Kent at [email protected]


***

As your car is a '68 I guess you have a pair of HS6's (Unless somebody had changed them to later HIF6's) If it is just the Throttle shafts that you need to do there is probably a MG/Jaguar/Triumph shop locally that has experience. There always seems to be 2 MG/Jaguar/Triumph shops in every town.
 

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Forgot to add my 2 cents about the Distributor.

I have not used a 123Distributor but think that the concept is brilliant and being able to tune the curve to match the desired advance at any RPM is ideal. I agree with 142guy that spending 500 bucks on a distributor seems expensive, but considering that you get a newly machined unit with electronic points (with programmable advance curves) seems Like a BARGAIN.

I Currently have original BOSCH distributor in both my B20 powered cars and both have been disassembled and re-assembled to ensure that the bearings are decent and that the advance mechanisms are functioning properly, My 142 has a Petronix unit in place of the points and the 1800ES has a Crane so eliminating the points is a good start, as it elimanted the Lobe Wear Issue. But if you need to get your Distributor rebuilt and buy an electronic points module, just add the extra and get the 123.

As far as

Checked the timing today at around 3k rpms, or maybe a bit more and it was 30 btdc which seems ok. Going up higher to the point the car bogs it seemed like things were bouncing around a bit but could just be the engine itself moving as it bogs down.
It sounds like the bearings in the distributor are going, and above 3K rpm it gets into some gyroscopic speed wobble, I don't think the engine moving around would upset the timing.


If I get to the point where I need to rebuild or replace a Distributor I would get a 123, and I think that if your considering a Distributor replacement I would suggest that you move in that direction as well, especially if you also need to upgrade to Electronic Points anyway

https://www.123ignitionshop.com/gb/83-tune-volvo


EDIT

FYI this is the type of Crane Electronics Points unit that is in my 1800ES (all tough mine is a much older version) Looks like this would be usable in the Bosch distributors as used in our B20's

https://www.summitracing.com/parts/fst-700-0231
 

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I've ad this issue since I bought it,
Did you have this issue prior to the SU to Weber conversion? If so, I definitely would not be focusing on carburetion problems.

Have you checked your valve lash? If the valve lash is really out of spec you won't be able to address any carb issues. Also, a grossly out of spec valve lash could be an indication of cam lobe and lifter wear issues. Be aware that on older engines the rocker shoe develops a groove where it contacts the tip of the valve. To get an accurate lash measurement you need a feeler gauge with a fine V tip that can fit in that groove to measure the true rocker to valve clearance. The solution for worn rockers is to remove the rocker stand and take the rockers (or the complete stand) to a competent automotive machine shop (not always easy to find) and have them reprofile the rocker shoes. If you just take the rockers in the cost will probably somewhere around $50. It will be more if you have them R&R the rockers from a complete stand. Checking the valve lash costs 0 $. There is no point in spending money on a distributor test or a new 123 distributor if valve train wear has turned your C cam into the equivalent of a worn out A cam.

Also, have you done a compression check? If the rings are tired or the vales are not seating there may be other reasons why the engine runs out of power at higher RPMs.
 

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Discussion Starter #12
Did you have this issue prior to the SU to Weber conversion? If so, I definitely would not be focusing on carburetion problems.

Have you checked your valve lash? If the valve lash is really out of spec you won't be able to address any carb issues. Also, a grossly out of spec valve lash could be an indication of cam lobe and lifter wear issues. Be aware that on older engines the rocker shoe develops a groove where it contacts the tip of the valve. To get an accurate lash measurement you need a feeler gauge with a fine V tip that can fit in that groove to measure the true rocker to valve clearance. The solution for worn rockers is to remove the rocker stand and take the rockers (or the complete stand) to a competent automotive machine shop (not always easy to find) and have them reprofile the rocker shoes. If you just take the rockers in the cost will probably somewhere around $50. It will be more if you have them R&R the rockers from a complete stand. Checking the valve lash costs 0 $. There is no point in spending money on a distributor test or a new 123 distributor if valve train wear has turned your C cam into the equivalent of a worn out A cam.

Also, have you done a compression check? If the rings are tired or the vales are not seating there may be other reasons why the engine runs out of power at higher RPMs.
I was thinking about the compression test this morning actually. Also, am planning on inspecting the cam and valve clearances mentioned above before ordering anything. If this was just a $150 part I would probably change it out anyway since it looks as old as the car. But these are a bit spendy so time to be more thorough.

I agree re: carbs, just got a little side tracked. Some cold start issues with the weber but that's another discussion
 

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Discussion Starter #13
The 123 distributors are cool and probably worth the money since I can't seem to find the stock one anywhere really. The tunability would be nice just to get it running smoothly, not too concerned about the performance here seeing how its a 130hp engine haha.

Also, I do see a lot of distributors with the vacuum advance for ~150, is it a problem to use one of these on the 142?
 

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The 123 distributors are cool and probably worth the money since I can't seem to find the stock one anywhere really. The tunability would be nice just to get it running smoothly, not too concerned about the performance here seeing how its a 130hp engine haha.

Also, I do see a lot of distributors with the vacuum advance for ~150, is it a problem to use one of these on the 142?
Which engine do you have, A or B? Later engines, the 1970 E and I think maybe the B in 1971 got a vacuum retard function which is to be used with a ported vacuum source not a normal manifold vacuum source so its quite different.

On most B engines you can disconnect the and plug off the vacuum servo and the engine will run happily on the mechanical advance with perhaps a slight loss in fuel efficiency. So, theoretically and distributor with a vacuum servo could be fitted to a non servo equipped car. However, I am confused because you made earlier reference to SUs (plural) which made me think two which made me think B20B. The B20B would normally have a vacuum servo on the distributor, at least on the later cars. Do you have an engine with mixed parentage?

You should be able to install a later distributor with vacuum servo and delete the servo running on mechanical advance. However, the mechanical advance ranges are different for the B20 A, 20B and B20E/F (if you were to pick up a used one). Make sure you get one with a range that matches your engine - whatever it is. However, I would avoid buying a used distributor because it is likely to have wear issues unless it has been rebuilt.
 

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That Setup for the crankcase ventilation does NOT look correct

The Hose that is coming towards the camera from the T, Where does it go? Hopefully not the Brake Booster !

And the hose that goes Vertical, does it go to the Air Filter on the Weber? And is there a vent on your Oil Filler Cap ?

You may have some Vacuum issues going on there,

Not that that is causing your problem, but if this is setup incorrectly it doesn't help ... and your Power Brakes may not be getting much power

EDIT Perhaps post a picture including the entire Crankcase Ventilation arrangement, Including the Filler Cap, Where the Vertical Hose goes and where the Hose coming towards the Camera Goes (I see something on the Intake, and that should go directly to the Brake Booster)

EDIT 2: Check these diagrams from Ron's website, Either way will work fine, B-20 or B-18, but make sure that you have the Brake Booster connected to the Correct Port on the Intake, (With the correct orifice size) and the CrankCase Ventalation System connected to the correct port, or to the Air Filter Housing

https://www.sw-em.com/pcv_diagrams_and_notes.htm

https://www.sw-em.com/manifolding_notes.htm
 

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I'm not sure what you have going on there, (Once you post a picture it will be clearer)

but just saw this thread showing how to and how not to, and features the Weber Downdraft ...

https://forums.swedespeed.com/showthread.php?339953-B18-valve-breather-weber-placement

EDIT: Another EDIT addition , Sorry Guys

But I did just watch the Video you posted in your Original Post,


and can see that you have the Brake Booster Vacuum hose connected to the CrankCase ventilation system. This is incorrect. You should have a the Crankcase Ventilation System connected to it's own port on the Manifold, and this port (Nipple) should have a small Orifice. The Port for the Brake Booster should have a much larger Orifice (Basically just a Hollow Tube of a Nipple) as it dosen't have any FLOW, but just holds the static Vacuum pressure. There should then also be a one way Check Valve inline in the Brake Booster Vacuum hose.

The Oil Filler Cap vent to Air Filter looks correct
 

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Vintage Volvo's do seem to suffer from the creative efforts of previous owners.
 

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Discussion Starter #19
Oh man, I'll go grab a couple good shots of the engine bay. The brakes don't feel 100%, little hard, I was going to take a look at the booster but might just be a simple vacuum line issue. The vacuum line from the oil cap goes to a plastic fitting on the weber.

Once warmed up it seems to run pretty good til ~4500 rpms with the weber now but wants to stall when cold. I was going to start going through everything to look for vacuum leaks. Also, I converted the carb to a manual choke yesterday but didn't seem to do anything. Re-checked the mixture and timing, both seem correct.

As for the distributor, a local Volvo shop in town had a good condition distributor off a '74. I put a new condensor, cap, and points on it. Figure it was worth a try. If not I'll probably break down and buy the 123 dist.

I've noticed some creative things with the wiring too.
 
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