Home 
Home Search search Menu menu Not logged in - Login | Register
> Jensen Healey & Jensen GT Tech > Engine & Transmission > Cam tensioner - anyone got a solution?

 Moderated by: Greg Fletcher
New Topic Reply Printer Friendly
Cam tensioner - anyone got a solution?  Rate Topic 
AuthorPost
 Posted: 02-01-2020 09:23 am
  PM Quote Reply
1st Post
discogodfather
Member


Joined: 09-17-2007
Location: San Francisco, California USA
Posts: 139
Status: 
Offline
My cam pulley rubbed a little when it got loose one day years ago (against the crank pulley) and it's missing around 1/16" of an inch on the edge. No big deal, but I would love to replace it at some point. Could not find anything on ebay both in the US and Britain.

I know member qwerty had a solution a few years back and I contacted hi to see if that part was still available. I also found a UK supplier that reconditions them on an exchange basis, having them replated. Don't know if they would replace my damaged one though.

I found this UK supplier on UK ebay selling a kit that converts the newer tensioners that use the springs for any 907, 910, 912 engine. It basically converts it to an early manual tensioner. I looked at the pics and it seems slightly different than the OEM setup but very close, I emailed him to see if it might work for a JH. It converts to the newer integral bearing.

Does anyone have a pulley lying around? All I would need is the actual pulley, not the center cam piece.

Back To Top PM Quote Reply  

 Posted: 02-01-2020 02:44 pm
  PM Quote Reply
2nd Post
redracer
Member
 

Joined: 09-10-2012
Location: BROOKHAVEN, Georgia USA
Posts: 363
Status: 
Online
I have some of the earlier style around(the concave ones with replaceable bearings) as the later "flat" ones were expensive with the bearings part of the assembly.(I've retrofitted all the later engines that had these "flat" ones).
If you don't find whatever you're looking for, let me know.
bruce

Back To Top PM Quote Reply

 Posted: 02-08-2020 03:29 pm
  PM Quote Reply
3rd Post
discogodfather
Member


Joined: 09-17-2007
Location: San Francisco, California USA
Posts: 139
Status: 
Offline
I found a kit on ebay by Garry Kemp at Lotus Engine parts in the UK. I found the old thread in which Qwerty tried this kit out a few years back, but concluded it needed a spacer to make it work. Basically, this kit is designed for a newer Esprit 910 or 912 engine to get rid of the spring loaded tensioner and convert it to a manual adjuster like our JH 907 style tensioners, but with a newer Felnnor flat wheel style integrated bearing.

The unit is different than the JH design and has a longer shaft where it attaches to the engine. I contacted Garry and he said he would include a spacer ring to make it work. I rolled the dice and it works great, the spacer makes up the difference and puts the wheel in exactly the right alignment to the original. Note in my photos the front of my old pulley wheel is ground down from an incident where it slipped off the bearing and ground itself into the crank pulley and there is about 2-3mm missing from the edge. If you can imagine it with that extra metal, it's a 100% perfect alignment to the original pulley.

The Kit:



Differences in the design:



Wheel Alignment:



Installed:




Nicely machined and it looks to be hard chromed. Stainless hardware. I didn't use the stud but it's a nice stainless upgrade to the stock stud. With the spacer it seems to be a 100% bolt on to the JH. I really like the integral bearing and the single piece design with a nice robust 19mm adjuster size. Pricey at about $130 shipped to the USA but well worth the multiple upgrades from the early stock design. Garry had it to me within a week to, great shipping. The integral bearing is pretty standard Lotus part from what I understand and is available for $50 from multiple manufacturers.

Back To Top PM Quote Reply  

 Posted: 02-09-2020 01:55 am
  PM Quote Reply
4th Post
Esprit2
Member
 

Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 503
Status: 
Offline
discogodfather wrote:
I found a kit on ebay by Garry Kemp at Lotus Engine parts in the UK. I found the old thread in which Qwerty tried this kit out a few years back, but concluded it needed a spacer to make it work. (Snip)...The tensioners went through a series of evolutionary steps, as did some supporting parts... mainly the front main seal housing. The seal housings thickness changed in the area around the tensioner, and the tensioner changed with it to maintain the roller in the plane of the crank & cam sprockets. If you mix-n-match tensioner and seal housing parts, then tensioner roller alignment can be off.

Qwerty (Pieter) designed his tensioner to work on his engine, and it worked quite well. When some people tried using it on other model year J-H, they had problems with alignment that a spacer could fix. His tensioner wasn't wrong as designed, it was wrong as some owners applied it. Apples & Oranges.

Garry Kemp (Kemp Performance Engines in the UK) is a great source for Lotus parts, and the tensioner shown. But like Qwerty's tensioner, it works for the later Lotus front main seal housing application, and may not properly fit an early Mk 1 907.

They are not all the same, so you need to know what to buy.

Regards,
Tim Engel

Last edited on 02-10-2020 04:14 pm by Esprit2

Back To Top PM Quote Reply

 Posted: 02-09-2020 02:04 am
  PM Quote Reply
5th Post
discogodfather
Member


Joined: 09-17-2007
Location: San Francisco, California USA
Posts: 139
Status: 
Offline
Esprit2 wrote:
If you mix-n-match tensioner and seal housing parts, then tensioner roller alignment can be off.



I'll see if this setup works, it sits very nicely and seems to line up but I am going to be scrutinizing it in use. Truth be told my stock tensioner was always a problem, I think the pulley was sliding around on the bearings quite a bit. It had some minor alignment issues from time to time. I was always fiddling with it if I remember correctly. Going to be running the blue belt, hopefully that helps.

Is there a way to tell what year the engine is from it's serial number? I am not sure if this is the original engine in my 73.

Last edited on 02-09-2020 01:51 pm by discogodfather

Back To Top PM Quote Reply  

 Posted: 02-09-2020 09:15 pm
  PM Quote Reply
6th Post
NigelK
Member
 

Joined: 07-16-2014
Location:  
Posts: 200
Status: 
Offline
Yes, depending on what carbs were fitted and the year the engine serial number will start with an A (Dellorto carbs), B (Strombergs) or T (Strombergs, heavily smogged setup) followed by the last 2 digits of the year of manufacture (72, 73, 74 or 75) followed by the 2 digit month of manufacture (01 to 12), then a 4 or 5 digit number showing order off the production line. For example my UK GT originally had engine number A741210883. Hope this helps. Best wishes, Nigel

Back To Top PM Quote Reply

 Posted: 02-10-2020 12:43 am
  PM Quote Reply
7th Post
JensenMike
Member
 

Joined: 11-23-2019
Location:  
Posts: 4
Status: 
Offline
If you give me the engine number or the chassis number I can give you the information you need. I have a Jensen chassis data book.

Back To Top PM Quote Reply  

 Posted: 02-10-2020 03:46 am
  PM Quote Reply
8th Post
discogodfather
Member


Joined: 09-17-2007
Location: San Francisco, California USA
Posts: 139
Status: 
Offline
JensenMike wrote:
If you give me the engine number or the chassis number I can give you the information you need. I have a Jensen chassis data book.

Chassis code is 10777

Engine code reads B74 12 10 822

Back To Top PM Quote Reply

 Posted: 02-10-2020 08:01 am
  PM Quote Reply
9th Post
NigelK
Member
 

Joined: 07-16-2014
Location:  
Posts: 200
Status: 
Offline
So it’s a December 1974 Stromberg engine

Back To Top PM Quote Reply  

 Posted: 02-10-2020 11:30 am
  PM Quote Reply
10th Post
JensenMike
Member
 

Joined: 11-23-2019
Location:  
Posts: 4
Status: 
Offline
Chassis number 1110/10777 would have engine number B72110894. It was built 12/1/72 and would have been mustard body color. Engine B741210822 came from chassis number 1111/19835. It was built 2/7/75. That chassis was black with a tan interior. Have a good day.
Mike

Back To Top PM Quote Reply

 Posted: 02-10-2020 11:44 am
  PM Quote Reply
11th Post
discogodfather
Member


Joined: 09-17-2007
Location: San Francisco, California USA
Posts: 139
Status: 
Offline
JensenMike wrote:
Chassis number 1110/10777 would have engine number B72110894. It was built 12/1/72 and would have been mustard body color. Engine B741210822 came from chassis number 1111/19835. It was built 2/7/75. That chassis was black with a tan interior. Have a good day.
Mike


Thanks,

She has been modified a little. Going to do a project thread when I organize all the photos. Went for something new- a Gold Leaf Colin Chapman inspired Lotus version of a JH. A "what if" car.

She's coming along nicely! Coming soon.....

Back To Top PM Quote Reply  

 Posted: 02-10-2020 04:38 pm
  PM Quote Reply
12th Post
Esprit2
Member
 

Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 503
Status: 
Offline
The attached JPEG applies to LOTUS engines, and doesn't apply to the early J-H tensioners and parts. So why post it here? Just to illustrate that you're not dealing with ONE set of tensioner parts, and that not everything you see that is tensioner related will be an automatic, perfect fit on your 907. You need to buy the correct parts. Or in the case of Qwerty's tensioner, buy the ONE that he has, and then perhaps a spacer that will make it fit correctly on your engine.

FYI, any of the Lotus tensioner set-ups will fit on a J-H 907 'IF' taken as a complete set. But individual loose parts may not.

Regards,
Tim Engel

PS... The JPEG covers the Lotus eccentric tensioners. Then there was an evolutionary series of five spring-loaded, semi-automatic tensioners that are not covered.

Attachment: 9XX Timing Belt Tensioner - Parts Evolution - Seal Housing & Tensioner.jpg (Downloaded 43 times)

Last edited on 02-10-2020 04:40 pm by Esprit2

Back To Top PM Quote Reply

Current time is 08:43 pm  
> Jensen Healey & Jensen GT Tech > Engine & Transmission > Cam tensioner - anyone got a solution? Top




UltraBB 1.172 Copyright © 2007-2011 Data 1 Systems