TENSIONERS

[bones]

I know I have to replace my chain tensioners soon, however I was talking to someone at the Autojumble on Saturday and he said I should also change the chains as they would be stretched , this would involve replacing the sprockets too (which he didn't suggest, leading me to think he might not be such an 'experet') and then I would need to retime the engine with it in the chassis.
Whilst I appreciate the chains may well be past their new status at 151,000 miles this is the first time I've heard this spoken of outside of a complete or top end overhaul. My plan is just to replace the tensioners (and I may refit the original solid type as they have been so reliable but open to suggestions), the chain guides and possibly upgraded idler arms.
Thoughts appreciated on renewing the cam chains.

 

[bruceb]

Bones

I still have the solid tensioner in my car, I used to worry about changing them to the later carrera style but not any longer as several independents have advised me not too. They mostly suggest upgrading if and when the engine is rebuilt.

With regard the chains, as long as the tensioners are still tensioning I would assume that the chains are not worn or stretched so my preference would be to leave well alone.

The only thing worth checking is the style of tensioner you have. I believe from about 1980 there was a modification to the tensioner which prevented total loss of chain tension should the tensioner fail. The earlier tensioners can collapse completely hence losing all chian tension and causing more damage.

hope this help

Bruce
83 sc

 

[bones]

I've left well alone till now for the reasons you mention Bruce but at 150,000 miles my biggest nagging worry is the state of the chain guides and so if I'm changing those it makes sense to at least refit the early tensioners which is my inclination and also fit new idler arms 'while I'm in there'. I believe the 80 modification was an additional collar to prevent a piston/valve 'conversation' in the event off tensioner failure. My knowledge is that there are only two tensioners for N/A engines, early - solid and 3.2 Carrera type - oil damped. I'm going to pick Chris Turner and Francis Tuthill's brains shortly over this issue because it's getting confusing where once it was simple.

 

[Guest]

ORIGINAL: bones

I'm going to pick Chris Turner and Francis Tuthill's brains shortly over this issue because it's getting confusing where once it was simple.

Talking to Paul (Green) at Tuthills when I left my car there the other day about valve clearances and so on. He asked whether I wanted them done, I said Almeras did them about 5,000 miles ago and they still sound OK to me. Opened the engine lid so he could have a listen, he commented on how well it sounded and noticed that it didn't have the oil-fed tensioners fitted. He suggested that the downside of fitting them to the SC's was that they could often be noisy due to lower oil pressure on the early cars.

Three things have been top of my most wanted list for this car since day one: turbo tie rods, Carrera tensioners and full stainless early-type exhaust. Number one is now done, number three has to wait until I rob the bank, number two I'm not so sure about any more.

 

[bones]

Up until about two years ago Carrera chain tensioners were a must for me I'm having second thoughts, I'm planning on doing the job later in the year if anyone wants to join in, likely hood is I'll fit original style tensioners providing I can be assured of quality control and investigate more on the collar (doubtful), definitely chain guides and maybe new idler arms once I fully understand why I should fit them.

 

[bruceb]

Bones changing the tensioners to the later style along with the ramps sound like the best compromise to me. I would be sure to source the parts from porsche dealer tho.

I fitted the turbo tie rods sometime ago and I must say that there was no real difference in feel to the steering. Likewise with the SSI's and single outlet silencer did not make a big (like £1500 fitted ) difference to the cars performance. The system sounds great and the heater is brilliant but it is in my view a marginal performance gain. The best performance modification IMHO has been to lower, align, corner weight and fit new original Bilsetin Sports alround. It really transforms the drive.

Bruce Balchin
83sc

 

[vitesse]

At 150k miles any quality camshaft chain will be worn,it is after all transmitting approx 2% of the engine power at most times and suffers the inertial shocks of rapid engine acceleration/decceleration.
If also the tensioners are worn and their wear pads badly grooved,the chains will not run in a the designed controlled fashion.
The normal recommended wear limit is 2%,this is the limit of the case hardened circular components that make up the chain,ie the bearing pins and the bushes they articulate inside,also the rollers inside of which the bushes rotate as the chain goes round the sprockets.It is also the limit imposed by the sprocket teeth,so worn chain,worn tensioners can mean flapping chain running near the tips of the sprocket teeth,excacerbating sprocket wear,broken teeth,jumping teeth,chain failure.
However undamaged sprockets should last two sets of chains in normal road use cars.

 

[bones]

Whist I appreciate the cam chains ae past their prime I have no intention of changing them just yet, I intend to rebuild the original tensioners, fit new chain guides, inspect the idler arm shafts and fit the upgraded arms if necessary. I probably won't be fitting the collar.

 

[SJW BASIRE]

I see that Bruce has an 83 204 bhp car and that he did not rate the difference SSI's made to his car.Well if anyone is considering fitting them :all I can say is that they work wonders on a 180 or 188bhp low compression engine.It brings the torque peak down from 4200 revs to about 2500 revs and really closes up the gaps in the gear ratios.Add to that the fantastic engine note and I'd say it was the best thing I have done to my car.

 

[bones]

When fitted with a suitably tuned exhaust equal length headers whether by SSI or anyone else cannot fail but make a significant difference to the engine performance. If the headers are combined with an exhaust that is inappropriate the difference won't be as noticeable or be there at all, some exhausts with shiny finishes and unproven boasts of bhp gains actually rob the engine of performance, I have a Triad West Perforrmance exhaust on my 180bhp SC and the difference in response and the lower torque curve is very noticeable. I only chose this exhaust after a lot of investigation and dyno evidence.

In house muffler test, Caney Engineering, Ealing, England

Engine: 3.2 liters, 10.8:1 pistons, flycut for Solex (901) cam, 46 mm
Webers with 38mm venures, 1 5/8" Triad headers, flowed heads, Euro
(centifugal) distributor recurved, K&N air cleaners, MSO ignition, Amsoil
10-40 synthetic oil.

Baseline was determined by established maximum horsepower with 24" open
megaphones attached. This occurred @6100 rpm with a reading of 289.
Muffler tests were done at the same rpm with no changes except for final
exhaust.

Horsepower
----------
Open tapered megaphones 289 off meter
Triad dual outlet track unit 285 100 Db
Triad dual outlet 90 dB unit 283 88 Db
Leistritz (factory sport) 2 outlet 279 103 Db
Triad single outlet with crossover 279
Borla 277
Super trap (disced to 95 dB) 275
Flowmaster 273
Bischoff (factory stock) 272 84 Db
Bursch Steelpak(supplied with SSI systems) 270
Ansa (4 pipe) 269
Supersprint 267

Notes:
On the units where decibel readings were taken, they were
obtained by methods outlined in California DER Supplement 82, Part III,
17-18.76
The possibility exists that slight differences of comparatives could
occur with engines/headers of a different configuration or horsepower
band.

This is my Triad exhaust with early equal length headers (HEs) .

 

[engleflick]

Hi Bones,

I'm sure you've said before but...

Where did you get your rear box from, I can't find it listed anywhere in the UK also what sort of cost was it.

 

[bones]

Dan I bought it from the U.S they are not available here and are built to order, at the time they only made 2 in 2 out units but may have a one in two in one out now. The price including shipping and taxes came to £263.00 but somehow it slipped through customs without additional costs being added. I think Dave marked it as a low priced item. All units are mild steel and not polished but the welding is superb and the fit and finish excellent, (at least on my unit)
The website is www.triadwestperformance.com but I noticed that the site is down. You could try emailing Dave at
Newtriadwest@aol.com
Search Pelican for info from other Triad West users.