Thursday 28 April 2011

New Sprint engine (part 2)

Collected my two spare Sprint heads recently and took them to a friend’s workshop to get them cleaned a bit in preparation for flowing, polishing and rebuilding the best of the two. All in preparation for the rejuvenation of ‘t Kreng.



After cleaning, it was time to remove the valve gear from the second head. With the proper tools that wasn’t too difficult. The exhaust valves were removed rather quickly ...





Sadly though the valve spring compressor tool couldn’t be used on the inlet valves. So I had to revert to a slightly more robust approach, a correct size socket and a hammer! Worked pretty good and was even quicker than with the valve spring compressor!



With the valves removed it was time to inspect both heads. Overall they are both in fairly good condition, but it looks that both have been skimmed somewhere in the past. There are also some minor dents in the edge of a few chambers. These need to be filled in with some welding ...



Also one of the valve guides is damaged, which means all need to be renewed, but that gives me the chance to look for some slimmer lightweight valves ...



More can be gained by opening up and polishing the ports ...



And to finish, I at last got round to find someone who could machine some nice and shiny alloy spark plug tubes. First sample (to double check the measurements) looks really good, can’t wait to get them fitted to ‘t Kreng’s engine, as the (still original) spark plug tubes are starting to leak a little oil ...



Sunday 3 April 2011

Spring’s in the air

With the temperatures rising and the days becoming longer, it’s been time to start on the TR7’s again. With the DHC more or less finished it is time to start with some long postponed work on ‘t Kreng. Over the past months I have done a bit of reading on what to do with the rear suspension ones the coil overs are fitted. Original plan was to adapt two sets of upper linkages arm, fitting rose joints on the axle side and poly bushes on the body shell end. So I took two sets out of the spares stock and after removing the original bushes ...




I got the angle grinder out and cut of one end ...



As you can see they are fairly thick walled. Compared to this the weld looks a bit suspect to me, so that will get a bit of extra metal added for extra peace of mind.



At this stage it was time to decide whether to stick to the TR7’s original four link rear set up, or adapt it into a parallel four link plus a Panhard or Watts linkage. I have decided to go for the latter one as the roll centre for this set up lies much lower so should improve handling. But that also means I’ll have to fabricate the necessary box sections to change the upper pick up points on the body and brackets for the axle and lateral linkages. Or find one of the so called “Increased lateral location kit” (STN 0104) which ST manufactured for theTR7 rally program, in order to comply with homologation requirements. The third option, and probably the easiest, is to go shopping at some Ford escort specialists to source parts which can then be adapted to fit. To be continued.

As the weather was rather fine last weekend I thought it a good idea to take the DHC out of hibernation. My only worry when I drove to the shed was that something might be wrong (I hadn’t seen the car since October last year). But after the most basic of checks all looked OK and she fired up fairly quickly. For the rest I can be pretty short, it was a rather enjoyable afternoon. Actually so enjoyable that I forgot to stop so now and then to take some pictures.

Another thing on the to do list for last weekend was removing the starter motor from ‘t Kreng. Over the past few weeks this had developed a problem. With the engine cold it was rather reluctant to work properly. So time to get it out and put one of the second hand spares in. Should have been no more than an hour’s work. But one way or another the old starter motor refused to be taken from the car. But after an hour and a half’s struggle and lots of swearing it came out ...




Needless to say I wasn’t in a mood to put the spare one in, so I left that till yesterday. Again took much longer than it should, not helped by a knee injury which started to play up after less than 15 minutes and a fluorescent tube that fell from its aperture when I went in search of some wire to hold the steering column out of harm’s way. Got it all sorted in the end and in time to take the car for a spin to a neighbouring village to visit an old school engine builder. Was as if the engine felt I went for its replacement. It was rather reluctant to run properly, sometimes backfiring heavily both under load or with the throttle closed. First guess is that I drowned the engine whilst starting, which has been a problem a few times in the past. At least by the time I got home she behaved quite normal again. Will check all likely culprits in the next few weeks just to be sure.